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  • 1.
    Amandusson, Asa
    et al.
    Uppsala University, Sweden .
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Estrogenic influences in pain processing2013In: Frontiers in neuroendocrinology (Print), ISSN 0091-3022, E-ISSN 1095-6808, Vol. 34, no 4, p. 329-349Article, review/survey (Refereed)
    Abstract [en]

    Gonadal hormones not only play a pivotal role in reproductive behavior and sexual differentiation, they also contribute to thermoregulation, feeding, memory, neuronal survival, and the perception of somatosensory stimuli. Numerous studies on both animals and human subjects have also demonstrated the potential effects of gonadal hormones, such as estrogens, on pain transmission. These effects most likely involve multiple neuroanatomical circuits as well as diverse neurochemical systems and they therefore need to be evaluated specifically to determine the localization and intrinsic characteristics of the neurons engaged. The aim of this review is to summarize the morphological as well as biochemical evidence in support for gonadal hormone modulation of nociceptive processing, with particular focus on estrogens and spinal cord mechanisms.

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  • 2.
    Amandusson, Åsa
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Estrogen receptor-α expression in nociceptive-responsive neurons in the medullary dorsal horn of the female rat2010In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 14, no 3, p. 245-248Article in journal (Refereed)
    Abstract [en]

    Estrogens exert a substantial influence on the transmission of nociceptive stimuli and the susceptibility to pain disorders as made evident by studies in both animals and human subjects. The estrogen receptor (ER) seems to be of crucial importance to the cellular mechanisms underlying such an influence. However, it has not been clarified whether nociceptive neurons activated by pain express ERs. In this study, a noxious injection of formalin was given into the lower lip of female rats, thereby activating nociceptive neurons in the trigeminal subnucleus caudalis as demonstrated by immunohistochemical labeling of Fos. Using a dual-label immunohistochemistry protocol ERα-containing cells were visualized in the same sections. In the superficial layers of the medullary dorsal horn, 12 % of ERα-labeled cells, mainly located in lamina II, also expressed noxious-induced Fos. These findings show that nociceptive-responsive neurons in the medullary dorsal horn express ERα, thus providing a possible morphological basis for the hypothesis that estrogens directly regulate pain transmission at this level.

  • 3.
    Amandusson, Åsa
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Östrogenreceptorer kan reglera känsligheten för smärta. Möjlig förklaring till vissa kroniska smärttillstånd.2001In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 98, p. 1774-1778Article in journal (Other academic)
  • 4.
    Amandusson, Åsa
    et al.
    Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    Hallbeck, Martin
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Pathology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pathology and Clinical Genetics.
    Hermanson, Ola
    Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Estrogen-induced alterations of spinal cord enkephalin gene expression1999In: Pain, ISSN 0304-3959, E-ISSN 1872-6623, Vol. 83, no 2, p. 243-248Article in journal (Refereed)
    Abstract [en]

    Enkephalin-synthesizing neurons in the super®cial laminae of the spinal and trigeminal dorsal horn are critical components of the endogenous pain-modulatory system. We have previously demonstrated that these neurons display intracellular estrogen receptors, suggesting that estrogen can potentially influence their enkephalin expression. By using Northern blot, we now show that a bolus injection of estrogen results in a rapid increase in spinal cord enkephalin mRNA levels in ovariectomized female rats. Thus, 4 h after estrogen administration the enkephalin mRNA-expression in the lumbar spinal cord was on average 68% higher (P , 0:05) than in control animals injected with vehicle only. A small increase in the amount of enkephalin mRNA was also seen after 8 h (P , 0:05), whereas no difference between estrogen-injected and control animals was found after 24 h or at time periods shorter than 4 h. Taken together with the previous anatomical data, the present findings imply that estrogen has an acute effect on spinal opioid levels in areas involved in the transmission of nociceptive information.

  • 5.
    Amandusson, Åsa
    et al.
    Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    Hermanson, Ola
    Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    Colocalization of oestrogen receptor immunoreactivity and preproenkephalin mRNA expression to neurons in the superficial laminae of the spinal and medullary dorsal horn of rats1996In: European Journal of Neuroscience, ISSN 0953-816X, E-ISSN 1460-9568, Vol. 8, no 11, p. 2440-2445Article in journal (Refereed)
    Abstract [en]

    A double-labelling procedure combining immunohistochemical staining with in situ hybridization using a radiolabelled cRNA probe was employed to demonstrate oestrogen receptor-like immunoreactivity and preproenkephalin-A mRNA in the medullary and spinal dorsal horn of female rats. Both markers labelled large numbers of neurons in the substantia gelatinosa and its trigeminal homologue. Many of these neurons were double-labelled, displaying both oestrogen receptor-like-immunoreactivity and preproenkephalin-A mRNA; cell counts showed that 40-60% of the of the oestrogen receptor-like-immunoreactive cells in the superficial laminae also were labelled for preproenkephalin-A mRNA, and that 60-70% of the preproenkephalin-A mRNA-labelled neurons in the same laminae displayed oestrogen receptor-like immunoreactivity. Previous studies have shown that oestrogen receptors can bind to the promoter region of the preproenkephalin-A gene, and studies on the hypothalamus have demonstrated that oestrogen regulates enkephalin expression in select neuronal populations. The present results demonstrate that enkephalinergic neurons in the superficial dorsal horn contain oestrogen receptors and suggest that oestrogen may play an important role in the modulation of sensory and nociceptive processing in the lower medulla and spinal cord.

  • 6.
    Amandusson, Åsa
    et al.
    Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    Hermanson, Ola
    Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    Estrogen receptor-like immunoreactivity in the medullary and spinal dorsal horn of the female rat1995In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 196, no 1-2, p. 25-28Article in journal (Refereed)
    Abstract [en]

    Using an immunohistochemical technique, we demonstrate that large numbers of neurons in the laminar spinal trigeminal nucleus and spinal gray matter of the female rat express estrogen receptors (ER). Densely packed ER-immunoreactive neurons were present in lamina II, but labeled neurons were also present in lamina I, the neck of the dorsal horn, and in lamina X. Labeling was present throughout the length of the spinal cord, with the exception of segments caudal to S1, which were unlabeled. The distribution of ER-containing neurons to areas that are involved in processing of primary afferent nociceptive information suggests that the pain modulatory effects of estrogen may be exerted at the spinal level.

  • 7. Beggs, J
    et al.
    Jordan, S
    Ericson, Ann-Charlott
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Craig, AD
    Synaptology of trigemino- and spinothalamic lamina I terminations in the posterior ventral medial nucleus of the macaque2003In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 459, no 4, p. 334-354Article in journal (Refereed)
    Abstract [en]

    We used the electron microscope to examine lamina I trigemino- and spinothalamic (TSTT) terminations in the posterior part of the ventral medial nucleus (VMpo) of the macaque thalamus. Lamina I terminations were identified by anterograde labeling with biotinylated dextran, and 109 boutons on 38 terminal fibers were closely studied in series of ultrathin sections. Five unlabeled terminal boutons of similar appearance were also examined in detail. Three-dimensional, volume-rendered computer models were reconstructed from complete series of serial sections for 29 boutons on 10 labeled terminal fibers and one unlabeled terminal fiber. In addition, postembedding immunogold staining for GABA was obtained in alternate sections through 23 boutons. Lamina I TSTT terminations in VMpo generally have several large boutons (mean length = 2.16 ╡m, mean width = 1.29 ╡m) that are densely packed with vesicles and make asymmetric synaptic contacts on low-order dendrites of VMpo neurons (mean diameter 1.45 ╡m). They are closely associated with GABAergic presynaptic dendrites (PSDs), and nearly all form classic triadic arrangements (28 of 29 reconstructed boutons). Consecutive boutons on individual terminal fibers make multiple contacts with a single postsynaptic dendrite and can show evidence of progressive complexity. Dendritic appendages that enwrap and invaginate the terminal bouton constitute additional anatomic evidence for secure, high-fidelity synaptic transfer. These observations provide direct ultrastructural evidence supporting the hypothesis that VMpo is a lamina I TSTT thalamocortical relay nucleus in primates that subserves pain, temperature, itch, and other sensations related to the physiological condition of the body.

  • 8.
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Acta Gyllenbergiana IV.Psyche, soma and pain.Editors Eija Kalso, Ann-Mari Estlander and Matti Klockars.2003In: Skriv in din egen text för ej reg. tidskrift etc.,2003, 2003, p. 59-72Conference paper (Refereed)
  • 9.
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Sex hormones and pain: A new role for brain aromatase?2000In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 423, no 4, p. 549-551Article in journal (Refereed)
    Abstract [en]

    [No abstract available]

  • 10.
    Blomqvist, Anders
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Craig, A D (Bud)
    Is neuropathic pain caused by the activation of nociceptive-specific neurons due to anatomic sprouting in the dorsal horn?2000In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 428, no 1Article in journal (Refereed)
    Abstract [en]

    [No abstract available]

  • 11.
    Blomqvist, Anders
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences.
    Neural Mechanisms of Inflammation-Induced Fever2018In: The Neuroscientist, ISSN 1073-8584, E-ISSN 1089-4098, Vol. 24, no 4, p. 381-399Article, review/survey (Refereed)
    Abstract [en]

    Fever is a common symptom of infectious and inflammatory disease. It is well-established that prostaglandin E-2 is the final mediator of fever, which by binding to its EP3 receptor subtype in the preoptic hypothalamus initiates thermogenesis. Here, we review the different hypotheses on how the presence of peripherally released pyrogenic substances can be signaled to the brain to elicit fever. We conclude that there is unequivocal evidence for a humoral signaling pathway by which proinflammatory cytokines, through their binding to receptors on brain endothelial cells, evoke fever by eliciting prostaglandin E-2 synthesis in these cells. The evidence for a role for other signaling routes for fever, such as signaling via circumventricular organs and peripheral nerves, as well as transfer into the brain of peripherally synthesized prostaglandin E-2 are yet far from conclusive. We also review the efferent limb of the pyrogenic pathways. We conclude that it is well established that prostaglandin E-2 binding in the preoptic hypothalamus produces fever by disinhibition of presympathetic neurons in the brain stem, but there is yet little understanding of the mechanisms by which factors such as nutritional status and ambient temperature shape the response to the peripheral immune challenge.

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  • 12.
    Blomqvist, Anders
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Zhang, En-Tan
    Craig, A D (Bud)
    Cytoarchitectonic and immunohistochemical characterization of a specific pain and temperature relay, the posterior portion of the ventral medial nucleus, in the human thalamus2000In: Brain, ISSN 0006-8950, E-ISSN 1460-2156, Vol. 123, no 3, p. 601-619Article in journal (Refereed)
    Abstract [en]

    Previous studies in the macaque monkey have identified a thalamic nucleus, the posterior portion of the ventral medial nucleus (VMpo), as a dedicated lamina I spinothalamocortical relay for pain and temperature sensation. The dense plexus of calbindin-immunoreactive fibres that characterizes VMpo in primates enables its homologue to be identified in the human thalamus by immunohistochemical labelling for calbindin. We have now analysed in detail the cytoarchitectonic characteristics of VMpo and its relationship with immunoreactivity for calbindin, substance P and calcitonin gene-related peptide (CGRP) in the human thalamus. The area in the posterolateral thalamus in which dense calbindin-immunoreactive fibre terminations are present coincides nearly completely with a distinct region that contains small to medium-sized cells with round or oval shapes that are aggregated in clusters separated by cell sparse areas. This region, which we identify as VMpo, is located posteromedial to the ventral posterior lateral (VPL) and ventral posterior medial (VPM) nuclei, ventral to the anterior pulvinar and centre median nuclei, lateral to the limitans and parafascicular nuclei and dorsal to the medial geniculate nucleus. Calbindin-immunoreactive fibres enter VMpo from the spinal lemniscus and form large patches of dense terminal-like staining over clusters of VMpo neurons. A few of these clusters also display terminal-like substance P labelling. Small bursts of CGRP staining are intercalated between the calbindin-labelled clusters, but there is little or no overlap between these two markers. CGRP inmunoreactivity is also present over small, non-clustered neurons in the calbindin-negative area that separates VMpo from the VPL and VPM nuclei, which we denote as the posterior nucleus (Po). These observations provide a concise description of VMpo in the human thalamus. Further, they suggest that the lamina I spinothalamic tract fibres (represented by calbindin and probably also substance P immunoreactivity) and vagal-solitary-parabrachial afferents (represented by CGRP immunoreactivity) form closely related, but separate, termination fields that can be considered to represent different aspects of enteroceptive information regarding the physiological status of the tissues and organs of the body. The location of VMpo and the adjacent Po fits with clinical descriptions of the thalamic area from which pain, temperature and visceral sensations can be evoked by microstimulation, and where nociceptive and thermoreceptive neurons have been recorded in humans. It also corresponds to the area in which infarcts cause analgesia and thermoanaesthesia and can lead to the paradoxical development of central pain.

  • 13. Craig, AD
    et al.
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Is there a specific lamina I spinothalamocortical pathway for pain and temperature sensations in primates?2002In: Journal of Pain, ISSN 1526-5900, E-ISSN 1528-8447, Vol. 3, no 2Article in journal (Refereed)
    Abstract [en]

    [No abstract available]

  • 14. Craig, AD
    et al.
    Zhang, ET
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    A distinct thermoreceptive subregion of lamina I in nucleus caudalis of the owl monkey.1999In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 404, p. 221-234Article in journal (Refereed)
  • 15. Craig, AD
    et al.
    Zhang, ET
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Association of spinothalamic lamina I neurons and their ascending axons with calbindin-immunoreactivity in monkey and human2002In: Pain, ISSN 0304-3959, E-ISSN 1872-6623, Vol. 97, no 1-2, p. 105-115Article in journal (Refereed)
    Abstract [en]

    The calbindin-immunoreactivity of spinothalamic (STT) lamina I neurons and their ascending axons was examined in two experiments. In the first experiment, lamina I STT neurons in macaque monkeys were double-labeled for calbindin and for retrogradely transported WGA*HRP following large (n=2) or small (n=1) injections that included the posterior thalamus. Most, but not all (78%) of the contralateral retrogradely labeled lamina I STT cells were positive for calbindin. Calbindin-immunoreactivity was not selectively associated with any particular anatomical type of lamina I STT cell, 82% of the fusiform cells, 78% of the pyramidal cells and 67% of the multipolar cells were double-labeled. In the second experiment, oblique transverse sections from upper cervical spinal segments of three macaque monkeys, one squirrel monkey and five humans were stained for calbindin-immunoreactivity. In each case, a distinct bundle of fibers was densely stained in the middle of the lateral funiculus. This matches the location of anterogradely labeled ascending lamina I axons observed in prior work in cats and monkeys, and it matches the location of the classically described 'lateral spinothalamic tract' in humans. This bundle had variable shape across cases, an observation that might have clinical significance. These findings support the view that lamina I STT neurons are involved in spinal cordotomies that reduce pain, temperature and itch sensations. ⌐ 2002 International Association for the study of Pain. Published by Elsevier Science B.V. All rights reserved.

  • 16.
    Ek, Monica
    et al.
    Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden.
    Engblom, David
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Saha, Sipra
    Department of Medical Biochemistry and Biophysics, The Karolinska Institute, Stockholm, Sweden.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Jakobsson, Per-Johan
    Department of Medical Biochemistry and Biophysics, The Karolinska Institute, Stockholm, Sweden.
    Ericsson-Dahlstrand, Anders
    Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden.
    Inflammatory response: pathway across the blood–brain barrier2001In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 410, p. 430-431Article in journal (Refereed)
    Abstract [en]

    No abstract available.

  • 17.
    Elander, Louise
    et al.
    Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Linköping University, Faculty of Health Sciences.
    Engström, Linda
    Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Linköping University, Faculty of Health Sciences.
    Hallbeck, Martin
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pathology and Clinical Genetics.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Linköping University, Faculty of Health Sciences.
    IL-1β and LPS induce anorexia by distinct mechanisms differentially dependent on microsomal prostaglandin E synthase-12007In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology, ISSN 0363-6119, E-ISSN 1522-1490, Vol. 292, no 1, p. R258-R267Article in journal (Refereed)
    Abstract [en]

    Recent work demonstrated that the febrile response to peripheral immune stimulation with proinflammatory cytokine IL-1β or bacterial wall lipopolysaccharide (LPS) is mediated by induced synthesis of prostaglandin E2 by the terminal enzyme microsomal prostaglandin E synthase-1 (mPGES-1). The present study examined whether a similar mechanism might also mediate the anorexia induced by these inflammatory agents. Transgenic mice with a deletion of the Ptges gene, which encodes mPGES-1, and wild-type controls were injected intraperitoneally with IL-1β, LPS, or saline. Mice were free fed, and food intake was continuously monitored with an automated system for 12 h. Body weight was recorded every 24 h for 4 days. The IL-1β induced anorexia in wild-type but not knock-out mice, and so it was almost completely dependent on mPGES-1. In contrast, LPS induced anorexia of the same magnitude in both phenotypes, and hence it was independent of mPGES-1. However, when the mice were prestarved for 22 h, LPS induced anorexia and concomitant body weight loss in the knock-out animals that was attenuated compared with the wildtype controls. These data suggest that IL-1β and LPS induce anorexia by distinct immune-to-brain signaling pathways and that the anorexia induced by LPS is mediated by a mechanism different from the fever induced by LPS. However, nutritional state and/or motivational factors also seem to influence the pathways for immune signaling to the brain. Furthermore, both IL-1β and LPS caused reduced meal size but not meal frequency, suggesting that both agents exerted an anhedonic effect during these experimental conditions. Copyright © 2007 the American Physiological Society.

  • 18.
    Elander, Louise
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Engström, Linda
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Ruud, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Mackerlova, Ludmila
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Jakobsson, Per-Johan
    Karolinska Institute.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Nilsberth, Camilla
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Inducible Prostaglandin E-2 Synthesis Interacts in a Temporally Supplementary Sequence with Constitutive Prostaglandin-Synthesizing Enzymes in Creating the Hypothalamic-Pituitary-Adrenal Axis Response to Immune Challenge2009In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 29, no 5, p. 1404-1413Article in journal (Refereed)
    Abstract [en]

    Inflammation-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis has been suggested to depend on prostaglandins, but the prostaglandin species and the prostaglandin-synthesizing enzymes that are responsible have not been fully identified. Here, we examined HPA axis activation in mice after genetic deletion or pharmacological inhibition of prostaglandin E-2-synthesizing enzymes, including cyclooxygenase-1 (Cox-1), Cox-2, and microsomal prostaglandin E synthase-1 (mPGES-1). After immune challenge by intraperitoneal injection of lipopolysaccharide, the rapid stress hormone responses were intact after Cox-2 inhibition and unaffected by mPGES-1 deletion, whereas unselective Cox inhibition blunted these responses, implying the involvement of Cox-1. However, mPGES-1-deficient mice showed attenuated transcriptional activation of corticotropin-releasing hormone (CRH) that was followed by attenuated plasma concentrations of adrenocorticotropic hormone and corticosterone. Cox-2 inhibition similarly blunted the delayed corticosterone response and further attenuated corticosterone release in mPGES-1 knock-out mice. The expression of the c-fos gene, an index of synaptic activation, was maintained in the paraventricular hypothalamic nucleus and its brainstem afferents both after unselective and Cox-2 selective inhibition as well as in Cox-1, Cox-2, and mPGES-1 knock-out mice. These findings point to a mechanism by which ( 1) neuronal afferent signaling via brainstem autonomic relay nuclei and downstream Cox-1-dependent prostaglandin release and ( 2) humoral, CRH transcription-dependent signaling through induced Cox-2 and mPGES-1 elicited PGE(2) synthesis, shown to occur in brain vascular cells, play distinct, but temporally supplementary roles for the stress hormone response to inflammation.

  • 19.
    Elander, Louise
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Hallbeck, Martin
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Pathology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pathology and Clinical Genetics.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Prostaglandin E2 receptors in IL-1β induced anorexiaManuscript (preprint) (Other academic)
    Abstract [en]

    Anorexia in response to immune challenge by Interleukin-1β (IL-1β) has been shown to be dependent on Prostaglandin E2 (PGE2) produced by the inducible enzyme microsomal prostaglandin E synthase-1 (mPGES-1). However, it is not known which of the four known PGE2 receptors EP1-4, encoded by the genes Ptger 1-4, that mediates the PGE2-induced anorexia. Here we examined food intake in mice deficient in EP1, EP2 and EP3, respectively, during normal conditions and following treatment with IL-1β. Neither of the gene deletions affected baseline food intake, and all the three genotypes displayed anorexia following IL-1β injection, similar to wild type mice. Previous work has demonstrated that the EP3 receptor is critical for the generation of fever, and that EP1 and EP3 receptors mediate inflammationinduced activation of the hypothalamic-pituitary-adrenal (HPA) axis. The present data, showing intact anorexigenic responses in EP1 and EP3 deficient mice, as well as in mice with deletion of the EP2 receptor, hence suggest that PGE2-elicited acute phase responses are mediated by distinct set or sets of PGE2-receptors.

  • 20.
    Elander, Louise
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Ruud, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Korotkova, Marina
    Department of Medicine, Rheumatology Unit, Karolinska University Hospital and Karolinska Institute, S-171 76 Stockholm, Sweden.
    Jakobsson, Per-Johan
    Department of Medicine, Rheumatology Unit, Karolinska University Hospital and Karolinska Institute, S-171 76 Stockholm, Sweden.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Cyclooxygenase-1 mediates the immediate corticosterone response to peripheral immune challenge induced by lipopolysaccharide2010In: Neuroscience letters, ISSN 1872-7972, Vol. 470, no 1, p. 10-2Article in journal (Refereed)
    Abstract [en]

    Immune-induced activation of the hypothalamus-pituitary-adrenal axis is mediated by cyclooxygenase derived prostaglandins. Here we examined the role of cyclooxygenase-1 in this response, by using genetically modified mice as well as pharmacological inhibition. We found that mice with a deletion of the gene encoding cyclooxygenase-1, in contrast to wild type mice, did not show increased plasma corticosterone at 1h after immune challenge by peripheral injection of bacterial wall lipopolysaccharide, whereas the corticosterone levels were similarly elevated in both genotypes at 6h post-injection. Pretreatment of mice with the selective cyclooxygenase-1 inhibitor SC-560, given orally, likewise inhibited the rapid corticosterone response. These findings, taken together with our recent demonstration that the delayed stress hormone response to immune challenge is dependent on cyclooxygenase-2, show that the two cyclooxygenase isoforms play distinct, but temporally supplementary roles for the stress hormone response to inflammation.

  • 21.
    Engblom, David
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Ek, Monica
    Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden.
    Andersson, Ingela
    Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden.
    Saha, Sipra
    Center for Structural Biochemistry, The Karolinska Institute, Huddinge, Sweden.
    Dahlström, Marie
    Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden.
    Jakobsson, Per-Johan
    Department of Biochemistry and Biophysics, The Karolinska Institute, Stockholm, Sweden.
    Ericsson-Dahlstrand, Anders
    5 AstraZeneca R&D - Södertälje, Molecular Sciences, Novum, Huddinge, Sweden.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Induction of microsomal prostaglandin E synthase in the rat brain endothelium and parenchyma in adjuvant-induced arthritis2002In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 452, no 3, p. 205-214Article in journal (Refereed)
    Abstract [en]

    Although central nervous symptoms such as hyperalgesia, fatigue, malaise, and anorexia constitute major problems in the treatment of patients suffering from chronic inflammatory disease, little has been known about the signaling mechanisms by which the brain is activated during such conditions. Here, in an animal model of rheumatoid arthritis, we show that microsomal prostaglandin E-synthase, the inducible terminal isomerase in the prostaglandin E2-synthesizing pathway, is expressed in endothelial cells along the blood-brain barrier and in the parenchyma of the paraventricular hypothalamic nucleus. The endothelial cells but not the paraventricular hypothalamic cells displayed a concomitant induction of cyclooxygenase-2 and expressed interleukin-1 type 1 receptors, which indicates that the induction is due to peripherally released cytokines. In contrast to cyclooxygenase-2, microsomal prostaglandin E synthase had very sparse constitutive expression, suggesting that it could be a target for developing drugs that will carry fewer side effects than the presently available cyclooxygenase inhibitors. These findings, thus, suggest that immune-to-brain communication during chronic inflammatory conditions involves prostaglandin E2-synthesis both along the blood-brain barrier and in the parenchyma of the hypothalamic paraventricular nucleus and point to novel avenues for the treatment of the brain-elicited disease symptoms during these conditions.

  • 22.
    Engblom, David
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Ek, Monica
    Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden.
    Ericsson-Dahlstrand, Anders
    Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Activation of prostanoid EP3 and EP4 receptor mRNA-expressing neurons in the rat parabrachial nucleus by intravenous injection of bacterial wall lipopolysaccharide2001In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 440, no 4, p. 378-386Article in journal (Refereed)
    Abstract [en]

    Systemic inflammation activates central autonomic circuits, such as neurons in the pontine parabrachial nucleus. This activation may be the result of afferent signaling through the vagus nerve, but it may also depend on central prostaglandin-mediated mechanisms. Recently, we have shown that neurons in the parts of the parabrachial nucleus that are activated by immune challenge express prostaglandin receptors of the EP3 and EP4 subtypes, but it remains to be determined if the prostaglandin receptor-expressing neurons are identical to those that respond to immune stimuli. In the present study, bacterial wall lipopolysaccharide was injected intravenously in adult male rats and the expression of c-fos mRNA and of EP3 and EP4 receptor mRNA was examined with complementary RNA probes labeled with digoxigenin and radioisotopes, respectively. Large numbers of neurons in the external lateral parabrachial subnucleus, a major target of vagal-solitary tract efferents, expressed c-fos mRNA. Quantitative analysis showed that about 60% (range 40%–79%) of these neurons also expressed EP3 receptor mRNA. Conversely, slightly more than 50% (range 48%–63%) of the EP3 receptor-expressing neurons in the same subnucleus coexpressed c-fos mRNA. In contrast, few EP4 receptor-expressing neurons were c-fos positive, with the exception of a small population located in the superior lateral and dorsal lateral subnuclei. These findings show that immune challenge activates central autonomic neurons that could be the target of centrally produced prostaglandin E2, suggesting that synaptic signaling and paracrine mechanisms may interact on these neurons. J. Comp. Neurol. 440:378–386, 2001. © 2001 Wiley-Liss, Inc.

  • 23.
    Engblom, David
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Ek, Monica
    Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden.
    Ericsson-Dahlstrand, Anders
    AstraZeneca R and D–Södertälje, RA CNS and Pain Control, Department of Molecular Sciences, Novum, Huddinge, Sweden.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    EP3 and EP4 receptor mRNA expression in peptidergic cell groups of the rat parabrachial nucleus2004In: Neuroscience, ISSN 0306-4522, E-ISSN 1873-7544, Vol. 126, no 4, p. 989-999Article in journal (Refereed)
    Abstract [en]

    This study examines the distribution of prostaglandin E2 receptors of subtype EP3 and EP4 among brain stem parabrachial neurons that were characterized with respect to their neuropeptide expression. By using a dual-labeling in situ hybridization method, we show that preprodynorphin mRNA expressing neurons in the dorsal and central lateral subnuclei express EP3 receptor mRNA. Such receptors are also expressed in preproenkephalin, calcitonin gene related peptide and preprotachykinin mRNA positive neurons in the external lateral subnucleus, whereas preprodynorphin mRNA expressing neurons in this subnucleus are EP receptor negative. In addition, EP3 receptor expression is seen among some enkephalinergic neurons in the Kölliker-Fuse nucleus. Neurons in the central part of the cholecystokininergic population in the regions of the superior lateral subnucleus express EP4 receptor mRNA, whereas those located more peripherally express EP3 receptors. Taken together with previous findings showing that discrete peptidergic cell groups mediate nociceptive and/or visceral afferent information to distinct brain stem and forebrain regions, the present results suggest that the processing of this information in the parabrachial nucleus is influenced by prostaglandin E2. Recent work has shown that prostaglandin E2 is released into the brain following peripheral immune challenge; hence, the parabrachial nucleus may be a region where humoral signaling of peripheral inflammatory events may interact with neuronal signaling elicited by the same peripheral processes.

  • 24.
    Engblom, David
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Ek, Monica
    Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden.
    Hallbeck, Martin
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Ericsson-Dahlstrand, Anders
    Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Distribution of prostaglandin EP3 and EP4 receptor mRNA in the rat parabrachial nucleus2000In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 281, no 2-3, p. 163-166Article in journal (Refereed)
    Abstract [en]

    By using in situ hybridization, the distribution of mRNA for the PGE2 receptors EP3 and EP4 was examined in the rat parabrachial nucleus (PB), a major brain stem relay for autonomic and nociceptive processing. EP3 receptor mRNA was present in most subnuclei, with the densest labeling in the external lateral, dorsal lateral, superior lateral, central lateral and Kölliker–Fuse nuclei. EP4 receptor mRNA expressing cells had a more restricted distribution, largely being confined to the superior lateral and adjacent parts of the dorsal and central lateral nuclei in a pattern complementary to that for EP3 receptor mRNA. These findings suggest that EP3 and EP4 receptors in PB have distinct functional roles that include nociceptive processing, blood pressure regulation and feeding behavior.

  • 25.
    Engblom, David
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Ek, Monica
    Saha, Sipra
    Ericsson-Dahlstrand, Anders
    Jakobsson, Per-Johan
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Prostaglandins as inflammatory messengers across the blood-brain barrier2002In: Journal of Molecular Medicine, ISSN 0946-2716, E-ISSN 1432-1440, Vol. 80, no 1Article in journal (Refereed)
    Abstract [en]

    Upon immune challenge the brain launches a wide range of responses, such as fever, anorexia, and hyperalgesia that serve to maintain homeostasis. While these responses are adaptive during acute infections, they may be destructive during chronic inflammatory conditions. Research performed during the last decade has given us insight into how the brain monitors the presence of a peripheral inflammation and the mechanisms underlying the brain-mediated acute-phase reactions. Here we give a brief review on this subject, with focus on the role of prostaglandin E2 produced in cells associated with the blood-brain barrier in immune-to-brain signaling. The recent advances in this field have not only elucidated the mechanisms behind the anti-pyretic and anti-hyperalgesic effects of cyclooxygenase inhibitors, but have also identified novel and more-selective potential drug targets.

  • 26.
    Engblom, David
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Saha, Sipra
    Center for Structural Biochemistry, Karolinska Institute, Huddinge, Sweden.
    Engström, Linda
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Westman, Marie
    Department of Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden..
    Audoly, Laurent
    Inflammation Unit, Pfizer Global Research and Development, Groton Laboratories, Groton, Connecticut, USA..
    Jakobsson, Per-Johan
    Department of Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden..
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Microsomal prostaglandin E synthase-1 is the central switch during immune-induced pyresis2003In: Nature Neuroscience, ISSN 1097-6256, E-ISSN 1546-1726, Vol. 6, no 11, p. 1137-1138Article in journal (Refereed)
    Abstract [en]

    We studied the febrile response in mice deficient in microsomal prostaglandin E synthase-1 (mPGES-1), an inducible terminal isomerase expressed in cytokine-sensitive brain endothelial cells. These animals showed no fever and no central prostaglandin (PG) E2 synthesis after peripheral injection of bacterial-wall lipopolysaccharide, but their pyretic capacity in response to centrally administered PGE2 was intact. Our findings identify mPGES-1 as the central switch during immune-induced pyresis and as a target for the treatment of fever and other PGE2-dependent acute phase reactions elicited by the brain.

  • 27.
    Engström, Linda
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Björk, Daniel
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Eskilsson, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Vasilache, Ana-Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Elander, Louise
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Acetaminophen reduces lipopolysaccharide-induced fever by inhibiting cyclooxygenase-22013In: Neuropharmacology, ISSN 0028-3908, E-ISSN 1873-7064, Vol. 71, p. 124-129Article in journal (Refereed)
    Abstract [en]

    Acetaminophen is one of the world's most commonly used drugs to treat fever and pain, yet its mechanism of action has remained unclear. Here we tested the hypothesis that acetaminophen blocks fever through inhibition of cyclooxygenase-2 (Cox-2), by monitoring lipopolysaccharide induced fever in mice with genetic manipulations of enzymes in the prostaglandin cascade. We exploited the fact that lowered levels of a specific enzyme make the system more sensitive to any further inhibition of the same enzyme. Mice were immune challenged by an intraperitoneal injection of bacterial wall lipopolysaccharide and their body temperature recorded by telemetry. We found that mice heterozygous for Cox-2, but not for microsomal prostaglandin E synthase-1 (mPGES-1), displayed attenuated fever, indicating a rate limiting role of Cox-2. We then titrated a dose of acetaminophen that did not inhibit the lipopolysaccharide-induced fever in wild-type mice. However, when the same dose of acetaminophen was given to Cox-2 heterozygous mice, the febrile response to lipopolysaccharide was strongly attenuated, resulting in an almost normalized temperature curve, whereas no difference was seen between wild-type and heterozygous mPGES-1 mice. Furthermore, the fever to intracerebrally injected prostaglandin E2 was unaffected by acetaminophen treatment. These findings reveal that acetaminophen, similar to aspirin and other non-steroidal anti-inflammatory drugs, is antipyretic by inhibiting cyclooxygenase-2, and not by inhibiting mPGES-1 or signaling cascades downstream of prostaglandin E2.

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  • 28.
    Engström, Linda
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Systemic immune challenge induces preproenkephalin gene transcription in distinct autonomic structures of the rat brain2003In: Journal of Comparative Neurology, ISSN 0021-9967, Vol. 462, no 4, p. 450-461Article in journal (Refereed)
    Abstract [en]

    The involvement of enkephalins in the immune response was investigated in rats injected intravenously with interleukin-1 (2 g/kg). In situ hybridization with a riboprobe complementary to intron A of the preproenkephalin (ppENK) gene showed distinct transcriptional activation within several brain regions known to be activated by immune stimuli, including the nucleus of the solitary tract, the area postrema, the paraventricular hypothalamic nucleus, and the oval nucleus of the bed nucleus of the stria terminalis, and dual labeling confirmed that a large proportion of the intron expressing neurons co-expressed c-fos mRNA. Rats injected with saline (controls) showed little or no heteronuclear transcript in these structures. The induced signal was strongest after 1 hour but was present in some structures 30 minutes after interleukin-1 injection. At 3 hours, transcriptional activity returned to basal levels. High basal expression of the heteronuclear transcript that appeared unchanged by the immune stimulus was seen in regions not primarily involved in the immune response, such as the striatum, the olfactory tubercle, and the islands of Calleja and in the immune activated central nucleus of the amygdala. The heteronuclear transcript colocalized with ppENK mRNA, demonstrating that it occurred in enkephalinergic neurons and was not the result of alternative transcription from the ppENK gene in other cells. These results demonstrated that enkephalin transcription is induced in central autonomic neurons during immune challenge, suggesting that enkephalins are involved in the centrally orchestrated response to such stimuli.

  • 29.
    Engström, Linda
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Örtegren (Kugelberg), Unn
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Mackerlova, Ludmila
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Paues, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Preproenkephalin mRNA expression in rat parabrachial neurons: relation to cells activated by systemic immune challenge2001In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 316, no 3, p. 165-168Article in journal (Refereed)
    Abstract [en]

    By using a dual-labeling immunohistochemical/in situ hybridization technique we examined if enkephalin-expressing neurons in the pontine parabrachial nucleus, a major brain stem relay for ascending visceral and homeostatic information, were activated by systemic immune challenge. While rats subjected to intravenous injection of bacterial wall lipopolysaccharide expressed dense labeling for the immediate-early gene product FOS in parts of the parabrachial nucleus that also demonstrated dense preproenkephalin expression, only a small proportion of the enkephalin-positive neurons were FOS-positive. These data indicate that enkephalins, although implicated in a variety of autonomic responses, are not primarily involved in the transmission of immune-related information from the parabrachial nucleus to its different forebrain and brain stem targets.

  • 30.
    Engström, Linda
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cellbiology. Linköping University, Faculty of Health Sciences.
    Mackerlova, Ludmila
    Linköping University, Department of Clinical and Experimental Medicine, Cellbiology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cellbiology. Linköping University, Faculty of Health Sciences.
    Lipopolysaccharide induces preproenkephalin transcription in hypophysiotropic neurons of the rat paraventricular hypothalamic nucleus suggesting a neuroendocrine role for enkephalins during immune stress2006In: Neuroscience, ISSN 0306-4522, Vol. 142, no 3, p. 781-788Article in journal (Refereed)
    Abstract [en]

    Opioids have impact on stress responses and possess immune modulatory functions. We have previously shown that immune stress elevates the levels of preproenkephalin transcript in a variety of autonomic structures in the rat brain, including the paraventricular hypothalamic nucleus. By using in situ hybridization with an intronic probe recognizing the preproenkephalin heteronuclear RNA combined with retrograde tract tracing, we examined the efferent target of the enkephalinergic neurons in the paraventricular hypothalamic nucleus that display induced transcriptional activity during immune challenge. Rats were first given i.p. injections of the tracer substance Fluoro-Gold, which following this route of administration is taken up only by nerve terminals residing outside the blood–brain barrier, and were then given an i.v. injection of lipopolysaccharide. Neuronal cell bodies retrogradely labeled with Fluoro-Gold were detected by immunohistochemistry, and—using a dual-labeling approach—the same cells were then examined for their expression of preproenkephalin heteronuclear RNA. We found that over 90% of the neurons that expressed preproenkephalin heteronuclear RNA also contained Fluoro-Gold. In addition, approximately 40% of the neurons expressing preproenkephalin heteronuclear RNA co-expressed mRNA for corticotropin-releasing hormone, the main adrenocorticotropic hormone secretagogue. These data show that the paraventricular hypothalamic neurons that display induced preproenkephalin transcription following immune challenge are almost exclusively hypophysiotropic neurons, indicating a role for enkephalin in the hypothalamic control of hormone release during infectious and inflammatory conditions.

  • 31.
    Engström, Linda
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Rosén, Khadijah
    Angel, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Developmental Biology-IKE . Linköping University, Faculty of Health Sciences.
    Fyrberg, Anna
    Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Linköping University, Faculty of Health Sciences.
    Mackerlova, Ludmila
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Konsman, Jan Pieter
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Systemic immune challenge activates an intrinsically regulated local inflammatory circuit in the adrenal gland2008In: Endocrinology, ISSN 0013-7227, E-ISSN 1945-7170, Vol. 149, no 4, p. 1436-1450Article in journal (Refereed)
    Abstract [en]

    There is evidence from in vitro studies that inflammatory messengers influence the release of stress hormone via direct effects on the adrenal gland; however, the mechanisms underlying these effects in the intact organism are unknown. Here we demonstrate that systemic inflammation in rats elicited by iv injection of lipopolysaccharide results in dynamic changes in the adrenal immune cell population, implying a rapid depletion of dendritic cells in the inner cortical layer and the recruitment of immature cells to the outer layers. These changes are accompanied by an induced production of IL-1β and IL-1 receptor type 1 as well as cyclooxygenase-2 and microsomal prostaglandin E synthase-1 in these cells, implying local cytokine-mediated prostaglandin E2 production in the adrenals, which also displayed prostaglandin E2 receptors of subtypes 1 and 3 in the cortex and medulla. The IL-1β expression was also induced by systemically administrated IL-1β and was in both cases attenuated by IL-1 receptor antagonist, consistent with an autocrine signaling loop. IL-1β similarly induced expression of cyclooxygenase-2, but the cyclooxygenase-2 expression was, in contrast, further enhanced by IL-1 receptor antagonist. These data demonstrate a mechanism by which systemic inflammatory agents activate an intrinsically regulated local signaling circuit that may influence the adrenals’ response to immune stress and may help explain the dissociation between plasma levels of ACTH and corticosteroids during chronic immune perturbations.

  • 32.
    Engström, Linda
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Ruud, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Eskilsson, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Larsson, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Mackerlova, Ludmila
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Kugelberg, Unn
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Qian, Hong
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Hematology. Linköping University, Faculty of Health Sciences.
    Vasilache, Ana Maria
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Larsson, Peter
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Sigvardsson, Mikael
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Hematology. Linköping University, Faculty of Health Sciences.
    Jönsson, Jan-Ingvar
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Hematology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Lipopolysaccharide-Induced Fever Depends on Prostaglandin E2 Production Specifically in Brain Endothelial Cells2012In: Endocrinology, ISSN 0013-7227, E-ISSN 1945-7170, Vol. 153, no 10, p. 4849-4861Article in journal (Refereed)
    Abstract [en]

    Immune-induced prostaglandin E2 (PGE2) synthesis is critical for fever and other centrally elicited disease symptoms. The production of PGE2 depends on cyclooxygenase-2 and microsomal prostaglandin E synthase-1 (mPGES-1), but the identity of the cells involved has been a matter of controversy. We generated mice expressing mPGES-1 either in cells of hematopoietic or nonhematopoietic origin. Mice lacking mPGES-1 in hematopoietic cells displayed an intact febrile response to lipopolysaccharide, associated with elevated levels of PGE2 in the cerebrospinal fluid. In contrast, mice that expressed mPGES-1 only in hematopoietic cells, although displaying elevated PGE2 levels in plasma but not in the cerebrospinal fluid, showed no febrile response to lipopolysaccharide, thus pointing to the critical role of brain-derived PGE2 for fever. Immunohistochemical stainings showed that induced cyclooxygenase-2 expression in the brain exclusively occurred in endothelial cells, and quantitative PCR analysis on brain cells isolated by flow cytometry demonstrated that mPGES-1 is induced in endothelial cells and not in vascular wall macrophages. Similar analysis on liver cells showed induced expression in macrophages and not in endothelial cells, pointing at the distinct role for brain endothelial cells in PGE2 synthesis. These results identify the brain endothelial cells as the PGE2-producing cells critical for immune-induced fever.

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  • 33.
    Eskilsson, Anna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Mirrasekhian, Elahe
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Dufour, Sylvie
    Institute Curie, France.
    Schwaninger, Markus
    Medical University of Lubeck, Germany.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Immune-Induced Fever Is Mediated by IL-6 Receptors on Brain Endothelial Cells Coupled to STAT3-Dependent Induction of Brain Endothelial Prostaglandin Synthesis2014In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 34, no 48, p. 15957-15961Article in journal (Refereed)
    Abstract [en]

    The cytokine IL-6, which is released upon peripheral immune challenge, is critical for the febrile response, but the mechanism by which IL-6 is pyrogenic has remained obscure. Herewegenerated mice with deletion of themembranebound IL-6 receptor alpha (IL-6R alpha) onneural cells, on peripheral nerves, on fine sensory afferent fibers, and on brain endothelial cells, respectively, and examined its role for the febrile response to peripherally injected lipopolysaccharide. We show that IL-6R alpha on neural cells, peripheral nerves, and fine sensory afferents are dispensable for the lipopolysaccharide-induced fever, whereas IL-6R alpha in the brain endothelium plays an important role. Hence deletion of IL-6R alpha on brain endothelial cells strongly attenuated the febrile response, and also led to reduced induction of the prostaglandin synthesizing enzyme Cox-2 in the hypothalamus, the temperature-regulating center in the brain, as well as reduced expression of SOCS3, suggesting involvement of the STAT signaling pathway. Furthermore, deletion of STAT3 in the brain endothelium also resulted in attenuated fever. These data show that IL-6, when endogenously released during systemic inflammation, is pyrogenic by binding to IL-6R alpha on brain endothelial cells to induce prostaglandin synthesis in these cells, probably in concerted action with other peripherally released cytokines.

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  • 34.
    Eskilsson, Anna
    et al.
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Biomedical and Clinical Sciences, Division of Neurobiology.
    Shionoya, Kiseko
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Biomedical and Clinical Sciences, Division of Neurobiology.
    Blomqvist, Anders
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Biomedical and Clinical Sciences, Division of Neurobiology.
    Prostaglandin production in brain endothelial cells during the initiation of fever2023In: Communicative & Integrative Biology, ISSN 1942-0889, E-ISSN 1942-0889, Vol. 16, no 1, article id 2166237Article in journal (Refereed)
    Abstract [en]

    The initiation of fever has been a matter of controversy. Based on observations of little or no induction of prostaglandin synthesizing enzymes in the brain during the first phase of fever it was suggested that fever is initiated by prostaglandin released into the circulation from cells in the liver and lungs. Here we show in the mouse that prostaglandin synthesis is rapidly induced in the brain after immune challenge. These data are consistent with our recent findings in functional experiments that prostaglandin production in brain endothelial cells is both necessary and sufficient for the generation of all phases of fever.

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  • 35.
    Eskilsson, Anna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Tachikawa, M.
    Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan, Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of of Toyama, Toyama, Japan; Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan .
    Hosoya, K.-I.
    Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of of Toyama, Toyama, Japan.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Distribution of microsomal prostaglandin E synthase-1 in the mouse brain2014In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 522, no 14, p. 3229-3244Article in journal (Refereed)
    Abstract [en]

    Previous studies in rats have demonstrated that microsomal prostaglandin E synthase-1 (mPGES-1) is induced in brain vascular cells that also express inducible cyclooxygenase-2, suggesting that such cells are the source of the increased PGE2 levels that are seen in the brain following peripheral immune stimulation, and that are associated with sickness responses such as fever, anorexia, and stress hormone release. However, while most of what is known about the functional role of mPGES-1 for these centrally evoked symptoms is based on studies on genetically modified mice, the cellular localization of mPGES-1 in the mouse brain has not been thoroughly determined. Here, using a newly developed antibody that specifically recognizes mouse mPGES-1 and dual-labeling for cell-specific markers, we report that mPGES-1 is constitutively expressed in the mouse brain, being present not only in brain endothelial cells, but also in several other cell types and structures, such as capillary-associated pericytes, astroglial cells, leptomeninges, and the choroid plexus. Regional differences were seen with particularly prominent labeling in autonomic relay structures such as the area postrema, the subfornical organ, the paraventricular hypothalamic nucleus, the arcuate nucleus, and the preoptic area. Following immune stimulation, mPGES-1 in brain endothelial cells, but not in other mPGES-1-positive cells, was coexpressed with cyclooxygenase-2, whereas there was no coexpression between mPGES-1 and cyclooxygenase-1. These data imply a widespread synthesis of PGE2 or other mPGES-1-dependent products in the mouse brain that may be related to inflammation-induced sickness symptom as well as other functions, such as blood flow regulation.

  • 36.
    Fritz, Michael
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Klawonn, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Nilsson, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Kumar Singh, Anand
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Zajdel, Joanna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Wilhelms, Daniel
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Emergency Medicine.
    Lazarus, Michael
    University of Tsukuba, Japan.
    Löfberg, Andreas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Jaarola, Maarit
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Örtegren Kugelberg, Unn
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Billiar, Timothy R.
    University of Pittsburgh, PA USA.
    Hackam, David J.
    Johns Hopkins University, MD USA.
    Sodhi, Chhinder P.
    Johns Hopkins University, MD USA.
    Breyer, Matthew D.
    Lilly Research Labs, IN USA.
    Jakobsson, Johan
    Lund University, Sweden; Lund University, Sweden.
    Schwaninger, Markus
    University of Lubeck, Germany.
    Schuetz, Gunther
    German Cancer Research Centre, Germany.
    Rodriguez Parkitna, Jan
    Polish Academic Science, Poland.
    Saper, Clifford B.
    Beth Israel Deaconess Medical Centre, MA 02215 USA; Harvard University, MA USA.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Prostaglandin-dependent modulation of dopaminergic neurotransmission elicits inflammation-induced aversion in mice2016In: Journal of Clinical Investigation, ISSN 0021-9738, E-ISSN 1558-8238, Vol. 126, no 2, p. 695-705Article in journal (Refereed)
    Abstract [en]

    Systemic inflammation causes malaise and general feelings of discomfort. This fundamental aspect of the sickness response reduces the quality of life for people suffering from chronic inflammatory diseases and is a nuisance during mild infections like common colds or the flu. To investigate how inflammation is perceived as unpleasant and causes negative affect, we used a behavioral test in which mice avoid an environment that they have learned to associate with inflammation-induced discomfort. Using a combination of cell-type-specific gene deletions, pharmacology, and chemogenetics, we found that systemic inflammation triggered aversion through MyD88-dependent activation of the brain endothelium followed by COX1-mediated cerebral prostaglandin E-2 (PGE(2)) synthesis. Further, we showed that inflammation-induced PGE(2) targeted EP1 receptors on striatal dopamine D1 receptor-expressing neurons and that this signaling sequence induced aversion through GABA-mediated inhibition of dopaminergic cells. Finally, we demonstrated that inflammation-induced aversion was not an indirect consequence of fever or anorexia but that it constituted an independent inflammatory symptom triggered by a unique molecular mechanism. Collectively, these findings demonstrate that PGE(2)-mediated modulation of the dopaminergic motivational circuitry is a key mechanism underlying the negative affect induced by inflammation.

  • 37.
    Hallbeck, Martin
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Effect of Stimulation of the Paraventricular Hypothalamic Nucleus on Noxious-Evoked Fos-immunoreactlvity In the Rat lumbar Spinal CordManuscript (preprint) (Other academic)
    Abstract [en]

    The paraventricular nucleus of the hypothalamus (PVH) provides a prominent descending projection to the superficial dorsal horn, and contains a number of neuropeptides that are know to influence nociceptive processing. In the present study, we injected formalin subcutaneously into the hind paws of unanesthetized rats and studied the noxious-evoked Fos protein expression in the dorsal horn following simultaneous unilateral injection of the glutamate receptor agonist kainic acid into the PVH. Although some cases displayed less Fos-inununoreactivity in the lumbar spinal cord on the side ipsilateral to the PVH activation than on the contralateral side, others displayed no side differences, and one case showed more labeling in the ipsilateral dorsal horn than on the contralateral side, Because different parts of the PVH were activated in the different experiments, the present observations suggest that the different peptide expressing populations of spinal cordprojecting neurons in PVH may have different, and perhaps opposing functions in the spinal dorsal horn.

  • 38.
    Hallbeck, Martin
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Spinal cord-projecting vasopressinergic neurons in the rat paraventricular hypothalamus1999In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 411, no 2, p. 201-211Article in journal (Refereed)
    Abstract [en]

    The paraventricular hypothalamic nucleus (PVH) is a key structure for the maintenance of homeostasis. Homeostatic regulation includes modulation of signaling in the spinal cord. This may be exerted by neurons in the PVH with spinal projections. However, the PVH is not a homogeneous structure, but consists of anatomically and functionally distinct subdivisions. In this study, we have analyzed the distribution of spinal cord-projecting PVH neurons that express vasopressin, an important neuropeptide in autonomic regulation. Vasopressinergic neurons were identified with a radiolabeled riboprobe complementary to vasopressin mRNA combined with immunohistochemical labeling of retrogradely transported cholera toxin subunit b in spinally projecting neurons. More than 40% of the spinally projecting neurons in the PVH of naive Sprague-Dawley rats were found to express vasopressin mRNA. The lateral parvocellular subdivision and the ventral part of the medial parvocellular subdivision contained the densest distribution of spinal cord-projecting vasopressin mRNA-expressing neurons. The magnocellular subdivisions displayed large numbers of vasopressin mRNA-expressing neurons, but very few of those projected to the spinal cord. The dorsal parvocellular subdivision contained a large number of spinally projecting neurons, but very few of those expressed vasopressin mRNA. These findings show that the PVH gives rise to a major vasopressinergic projection to the spinal cord and that the spinal cord-projecting vasopressinergic neurons are parceled into anatomically distinct cell groups. This provides an anatomical basis for a selective activation of functionally different groups in the PVH as part of a behaviorally adaptive response, including modulation of autonomic activity and pain processing at the spinal level.

  • 39.
    Hallbeck, Martin
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Hermanson, Ola
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Preprovasopressin mRNA is not present in dorsal root ganglia of the rat1996In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 209, no 10, p. 125-128Article in journal (Refereed)
    Abstract [en]

    Immunohistochemical studies on colchic ine-treated rats have suggested that more than half of the neurons in dorsal root ganglia (DRG) contain vasopressin. Thus, vasopressin would be the most commonly found peptide in DRG neurons. In the present study we have reexamined the presence of vasopressin in DRG neurons, using a sensitive in situ hybridization method employing long riboprobes that will detect very small amounts of mRNA. The C3, C6, T2, T12, L2 and L5 DRG were studied. None of these ganglia contained any preprovasopressin mRNA. Yet, dense labeling for preprovasopressin mRNA was seen on simultaneously processed hypothalamic sections and a heavy preprotachykinin mRNA expression was seen in adjacent DRG sections. These findings demonstrate that vasopressin is not produced in DRG in normal rats.

  • 40.
    Hallbeck, Martin
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Hermansson, Ola
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Distribution of preprovasopressin mRNA in the rat central nervous system1999In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 411, no 2, p. 181-200Article in journal (Refereed)
    Abstract [en]

    Vasopressin released in the central nervous system has been shown to be involved both in homeostatic mechanisms (e.g., water balance, thermoregulation, cardiovascular regulation, metabolism, and antinociception) and in higher brain functions (e.g., social recognition and communication, and learning and memory). Many nuclear groups have been proposed to synthesize vasopressin, but available data are conflicting. We have used a sensitive in situ hybridization technique to identify the distribution of the neurons that may be the origin of the vasopressin in the central nervous system of the male Sprague-Dawley rat. Vasopressin mRNA-expressing neurons were most abundant in the hypothalamus (e.g., the paraventricular, supraoptic, and suprachiasmatic nuclei) but were also seen in the medial amygdaloid nucleus, the bed nucleus of stria terminalis, and the nucleus of the horizontal diagonal band. Previously unreported vasopressinergic neurons were seen in the entorhinal and piriform cortices, the ventral lateral portion of the parabrachial nucleus, the pedunculopontine nucleus, and the rostral part of the ventral periaqueductal gray matter and the adjacent portion of the mesencephalic reticular nucleus. Vasopressin mRNA expression suggestive of neuronal labeling was seen in the pyramidal layer of the CA1–3 fields and the dentate gyrus of the hippocampus. In addition, vasopressin mRNA expression, probably representing axonal mRNA, was detected over the hypothalamopituitary tract. No or insignificant preprovasopressin mRNA expression was present in the cerebellum, locus coeruleus, subcoeruleus, or the spinal cord. These findings provide novel information on the distribution of vasopressin neurons that are important for our understanding of how vasopressin acts in the brain.

  • 41.
    Hallbeck, Martin
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Larhammar, Dan
    Department of Neuroscience, Unit of Pharmacology, Uppsala University, Sweden.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Neuropeptide expression in rat paraventricular hypothalamic neurons that project to the spinal cord2001In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 433, no 2, p. 222-238Article in journal (Refereed)
    Abstract [en]

    The paraventricular hypothalamic nucleus (PVH) exerts many of its regulatory functions through projections to spinal cord neurons that control autonomic and sensory functions. By using in situ hybridization histochemistry in combination with retrograde tract tracing, we analyzed the peptide expression among neurons in the rat PVH that send axons to the spinal cord. Projection neurons were labeled by immunohistochemical detection of retrogradely transported cholera toxin subunit B, and radiolabeled long riboprobes were used to identify neurons containing dynorphin, enkephalin, or oxytocin mRNA. Of the spinally projecting neurons in the PVH, approximately 40% expressed dynorphin mRNA, 40% expressed oxytocin mRNA, and 20% expressed enkephalin mRNA. Taken together with our previous findings on the distribution of vasopressin-expressing neurons in the PVH (Hallbeck and Blomqvist [1999] J. Comp. Neurol. 411:201–211), the results demonstrated that the different PVH subdivisions display distinct peptide expression patterns among the spinal cord–projecting neurons. Thus, the lateral parvocellular subdivision contained large numbers of spinal cord–projecting neurons that express any of the four investigated peptides, whereas the ventral part of the medial parvocellular subdivision displayed a strong preponderance for dynorphin- and vasopressin-expressing cells. The dorsal parvocellular subdivision almost exclusively contained dynorphin- and oxytocin-expressing spinal cord–projecting neurons. This parcellation of the peptide-expressing neurons suggested a functional diversity among the spinal cord–projecting subdivisions of the PVH that provide an anatomic basis for its various and distinct influences on autonomic and sensory processing at the spinal level.

  • 42.
    Hamlin, Lina
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Medicine and Health Sciences.
    Mackerlova, Ludmila
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Medicine and Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Medicine and Health Sciences.
    Ericson, Ann-Charlott
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Medicine and Health Sciences.
    AMPA-selective glutamate receptor subunits and their relation to glutamate-and GABA-like immunoreactive terminals in the nucleus submedius of the rat1996In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 217, no 2-3, p. 149-52Article in journal (Refereed)
    Abstract [en]

    Glutamate plays an important role in supraspinal nociceptive systems. Thus, glutamate is present in the nucleus submedius of the medial thalamus, a major relay for nociceptive information. In this study, immunoreactivity for the four subunits (GluR1-4) of alpha-amino-3-hydroxy-5-methyl-4-isoxasoleproprionate (AMPA) receptors was examined by a preembedding immunohistochemical method in order to evaluate the presence of this glutamate receptor subtype in the nucleus submedius. Combining the preembedding method with a postembedding immunogold technique, we found that AMPA receptor-like immunoreactivity was present postsynaptically to glutamatergic terminals but not to terminals containing gamma-aminobutyric acid (GABA). These findings suggest a role for AMPA receptors in excitatory synaptic transmission in the nucleus submedius of the rat thalamus.

  • 43.
    Hamzic, Namik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Nilsberth, Camilla
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Immune-Induced Expression of Lipocalin-2 in Brain Endothelial Cells: Relationship with Interleukin-6, Cyclooxygenase-2 and the Febrile Response2013In: Journal of neuroendocrinology (Print), ISSN 0953-8194, E-ISSN 1365-2826, Vol. 25, no 3, p. 271-280Article in journal (Refereed)
    Abstract [en]

    Interleukin (IL)-6 is critical for the febrile response to peripheral immune challenge. However, the mechanism by which IL-6 enables fever is still unknown. To characterise the IL-6-dependent fever generating pathway, we used microarray analysis to identify differentially expressed genes in the brain of lipopolysaccharide (LPS)-treated IL-6 wild-type and knockout mice. Mice lacking IL-6 displayed a two-fold lower expression of the lipocalin-2 gene (lcn2), and this difference was confirmed by real-time reverse transcriptase-polymerase chain reaction. Conversely, the induction of lipocalin-2 protein was observed in brain vascular cells following i.p. administration of recombinant IL-6, suggesting a direct relationship between IL-6 and lipocalin-2. Immunohistochemical analysis also revealed that LPS-induced lipocalin-2 is expressed by brain endothelial cells and is partly co-localised with cyclooxygenase-2 (Cox-2), the rate-limiting enzyme for the production of inflammatory induced prostaglandin E2 (PGE2), which is the key mediator of fever. The direct role of lipocalin-2 in fever was examined in LPS-challenged lipocalin-2 knockout mice. In both male and female mice, normal fever responses were observed at near-thermoneutral conditions (2930 degrees C) but when recorded at normal room temperature (1920 degrees C), the body temperature of lipocalin-2 knockout female mice displayed an attenuated fever response compared to their wild-type littermates. This difference was reflected in significantly attenuated mRNA expression of Cox-2 in the brain of lipocalin-2 knockout female mice, but not of male mice, following challenge with peripheral LPS. Our findings suggest that IL-6 influences the expression of lipocalin-2, which in turn may be involved in the control of the formation of Cox-2, and hence central PGE2-production. We have thus identified lipocalin-2 as a new factor in the pathway of inflammatory IL-6 signalling. However, the effect of lipocalin-2 on fever is small, being sex-dependent and ambient temperature-specific, and thus lipocalin-2 cannot be considered as a major mediator of the IL-6-dependent fever generating pathway.

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  • 44.
    Hamzic, Namik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Tang, Yanjuan
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Eskilsson, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Kugelberg, Unn
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Ruud, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Jönsson, Jan-Ingvar
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Pathology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Nilsberth, Camilla
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Interleukin-6 produced by non-hematopoietic cells mediates the lipopolysaccharide-induced febrile responseManuscript (preprint) (Other academic)
    Abstract [en]

    Interleukin-6 (IL-6) is critical for the lipopolysaccharide (LPS)-induced febrile response. However, the exact source(s) of IL-6 involved in regulating the LPS-elicited fever is still to be identified. One known source of IL-6 is hematopoietic cells, such as monocytes. To clarify the contribution of hematopoietically derived IL-6 to fever, we created chimeric mice expressing IL-6 either in cells of hematopoietic or, conversely, in cells of non-hematopoietic origin. This was performed by extinguishing hematopoetic cells in wild-type (WT) or IL-6 knockout (IL-6 KO) mice by whole-body irradiation and transplanting them with new stem cells. Mice lacking IL-6 in hematopoietic cells displayed normal fever to LPS and were found to have similar levels of IL-6 in the cerebrospinal fluid (CSF) and in plasma as well as similar expression of the IL-6 gene in the brain as WT mice. In contrast, IL-6 KO mice, with intact IL-6 production in cells of hematopoietic origin, only showed a minor elevation of the body temperature after peripheral LPS injection. While they displayed significantly elevated levels of IL-6 both in plasma and CSF compared with control mice, the increase was modest compared with that seen in LPS injected mice on WT background, the latter being approximately 20 times larger in magnitude. These results suggest that IL-6 of nonhematopoietic origin is the main source of IL-6 in LPS-induced fever, and that IL-6 produced by hematopoietic cells only plays a minor role.

  • 45.
    Hamzik, Namik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Tang, Yan-juan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Eskilsson, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Örtegren Kugelberg, Unn
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Ruud, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Jönsson, Jan-Ingvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Nilsberth, Camilla
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Interleukin-6 primarily produced by non-hematopoietic cells mediates the lipopolysaccharide-induced febrile response2013In: Brain, behavior, and immunity, ISSN 0889-1591, E-ISSN 1090-2139, Vol. 33, p. 123-130Article in journal (Refereed)
    Abstract [en]

    Interleukin-6 (IL-6) is critical for the lipopolysaccharide (LPS)-induced febrile response. However, the exact source(s) of IL-6 involved in regulating the LPS-elicited fever is still to be identified. One known source of IL-6 is hematopoietic cells, such as monocytes. To clarify the contribution of hematopoietically derived IL-6 to fever, we created chimeric mice expressing IL-6 selectively either in cells of hematopoietic or, conversely, in cells of non-hematopoietic origin. This was performed by extinguishing hematopoietic cells in wild-type (WT) or IL-6 knockout (IL-6 KO) mice by whole-body irradiation and transplanting them with new stem cells. Mice on a WT background but lacking IL-6 in hematopoietic cells displayed normal fever to LPS and were found to have similar levels of IL-6 protein in the cerebrospinal fluid (CSF) and in plasma and of IL-6 mRNA in the brain as WT mice. In contrast, mice on an IL-6 KO background, but with intact IL-6 production in cells of hematopoietic origin, only showed a minor elevation of the body temperature after peripheral LPS injection. While they displayed significantly elevated levels of IL-6 both in plasma and CSF compared with control mice, the increase was modest compared with that seen in LPS injected mice on a WT background, the latter being approximately 20 times larger in magnitude. These results suggest that IL-6 of non-hematopoietic origin is the main source of IL-6 in LPS-induced fever, and that IL-6 produced by hematopoietic cells only plays a minor role.

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  • 46.
    Ihnatko, Robert
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Post, Claes
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Proteomic profiling of the hypothalamus in a mouse model of cancer-induced anorexia-cachexia2013In: British Journal of Cancer, ISSN 0007-0920, E-ISSN 1532-1827, Vol. 109, no 7, p. 1867-1875Article in journal (Refereed)
    Abstract [en]

    Background:

    Anorexia-cachexia is a common and severe cancer-related complication but the underlying mechanisms are largely unknown. Here, using a mouse model for tumour-induced anorexia-cachexia, we screened for proteins that are differentially expressed in the hypothalamus, the brain’s metabolic control centre.

    Methods:

    The hypothalamus of tumour-bearing mice with implanted methylcholanthrene-induced sarcoma (MCG 101) displaying anorexia and their sham-implanted pair-fed or free-fed littermates was examined using two-dimensional electrophoresis (2-DE)-based comparative proteomics. Differentially expressed proteins were identified by liquid chromatography-tandem mass spectrometry.

    Results:

    The 2-DE data showed an increased expression of dynamin 1, hexokinase, pyruvate carboxylase, oxoglutarate dehydrogenase, and N-ethylmaleimide-sensitive factor in tumour-bearing mice, whereas heat-shock 70 kDa cognate protein, selenium-binding protein 1, and guanine nucleotide-binding protein Gα0 were downregulated. The expression of several of the identified proteins was similarly altered also in the caloric-restricted pair-fed mice, suggesting an involvement of these proteins in brain metabolic adaptation to restricted nutrient availability. However, the expression of dynamin 1, which is required for receptor internalisation, and of hexokinase, and pyruvate carboxylase were specifically changed in tumour-bearing mice with anorexia.

    Conclusion:

    The identified differentially expressed proteins may be new candidate molecules involved in the pathophysiology of tumour-induced anorexia-cachexia.

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  • 47. Jakobsson, Per-Johan
    et al.
    Engblom, David
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Ericsson-Dahlstrand, Anders
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Microsomal prostaglandin E synthase: A key enzyme in PGE2 biosynthesis and inflammation2002In: Current Medicinal Chemistry - Anti-Inflammatory & Anti-Allergy Agents, ISSN 1568-0142, E-ISSN 1875-6131, Vol. 1, p. 167-175Article in journal (Refereed)
  • 48.
    Kastrup, Ylva
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Hallbeck, Martin
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Amandusson, Åsa
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Hirata, S
    Hermansson, O
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology.
    Progesterone receptor expression in the brainstem of the female rat.1999In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 275, p. 85-88Article in journal (Refereed)
  • 49.
    Kastrup, Ylva
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Le Grevès, M
    Nyberg, F
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Distribution of growth hormone receptor mRNA in the brain stem and spinal cord of the rat2005In: Neuroscience, ISSN 0306-4522, E-ISSN 1873-7544, Vol. 130, no 2, p. 419-425Article in journal (Refereed)
    Abstract [en]

    By using in situ hybridization histochemistry the distribution of growth hormone (GH) receptor mRNA was examined in the rat brain stem and spinal cord. Dense labeling was seen in the arcuate nucleus of the hypothalamus, as reported previously, but also in several other areas, including the locus coeruleus, the area postrema, and the commissural part of the nucleus of the solitary tract. Other labeled structures included the superior lateral parabrachial nucleus, the facial, hypoglossal and trigeminal motor nuclei, the nucleus incertus, the dorsal tegmental nucleus, the dorsal raphe nucleus, the nucleus of the trapezoid body, and the superficial layers of the dorsal horn of the spinal cord. These findings provide support for a direct action of GH on brain regions involved in various aspects of homeostatic control. Thus, the distribution of GH receptor mRNA to visceral sensory and motor structures is consonant with a role of GH in the regulation of food intake and energy homeostasis. Its presence in the superficial dorsal horn of the spinal cord indicates a role for GH in the initial processing of fine afferent input, and may help explain the beneficial effects of GH replacement in certain unclear pain conditions. © 2004 IBRO. Published by Elsevier Ltd. All rights reserved.

  • 50.
    Klawonn, Anna
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences.
    Fritz, Michael
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences.
    Nilsson, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Bonaventura, Jordi
    NIDA, MD USA.
    Shionoya, Kiseko
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences.
    Mirrasekhian, Elahe
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences.
    Karlsson, Urban
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences.
    Jaarola, Maarit
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences.
    Granseth, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences.
    Michaelides, Michael
    NIDA, MD USA; Johns Hopkins Sch Med, MD USA.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences.
    Motivational valence is determined by striatal melanocortin 4 receptors2018In: Journal of Clinical Investigation, ISSN 0021-9738, E-ISSN 1558-8238, Vol. 128, no 7, p. 3160-3170Article in journal (Refereed)
    Abstract [en]

    It is critical for survival to assign positive or negative valence to salient stimuli in a correct manner. Accordingly, harmful stimuli and internal states characterized by perturbed homeostasis are accompanied by discomfort, unease, and aversion. Aversive signaling causes extensive suffering during chronic diseases, including inflammatory conditions, cancer, and depression. Here, we investigated the role of melanocortin 4 receptors (MC4Rs) in aversive processing using genetically modified mice and a behavioral test in which mice avoid an environment that they have learned to associate with aversive stimuli. In normal mice, robust aversions were induced by systemic inflammation, nausea, pain, and. opioid receptorinduced dysphoria. In sharp contrast, mice lacking MC4Rs displayed preference or indifference toward the aversive stimuli. The unusual flip from aversion to reward in mice lacking MC4Rs was dopamine dependent and associated with a change from decreased to increased activity of the dopamine system. The responses to aversive stimuli were normalized when MC4Rs were reexpressed on dopamine D1 receptor-expressing cells or in the striatum of mice otherwise lacking MC4Rs. Furthermore, activation of arcuate nucleus proopiomelanocortin neurons projecting to the ventral striatum increased the activity of striatal neurons in an MC4R-dependent manner and elicited aversion. Our findings demonstrate that melanocortin signaling through striatal MC4Rs is critical for assigning negative motivational valence to harmful stimuli.

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