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Dizdar (Segrell), Nil
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Publications (10 of 35) Show all publications
Nord, M., Kullman, A., Hannestad, U. & Dizdar Segrell, N. (2017). Is Levodopa Pharmacokinetics in Patients with Parkinson’s Disease Depending on Gastric Emptying?. Advances in Parkinsons Disease, 06(01)
Open this publication in new window or tab >>Is Levodopa Pharmacokinetics in Patients with Parkinson’s Disease Depending on Gastric Emptying?
2017 (English)In: Advances in Parkinsons Disease, ISSN 2169-9712, Vol. 06, no 01Article in journal (Refereed) Published
Abstract [en]

Levodopa uptake from the gastrointestinal tract in patients with Parkinson’s disease (PD) can be affected by delayed gastric emptying (GE). This might lead to fluctuating levodopa levels resulting in increased motor fluctuations. Continuous dopaminergic stimulation (CDS) improves motor fluctuations and could be a result of smoothening in levodopa uptake. In this study we wanted to study the levodopa pharmacokinetics peripherally in PD patients with motor fluctuations and investigate the relation between levodopa uptake and GE and the effect of CDS. PD patients with wearing off (group 1) and on-off syndrome (group 2) were included. Breath tests were performed to evaluate the half time (T1/2) of GE. Concomitantly 1 tablet of Madopark® was given and the levodopa concentrations in blood and subcutaneous (SC) tissue were analyzed for both groups. Group 2 was then given a 10-d continuous intravenous levodopa treatment and the tests were repeated. Higher levels of levodopa in group 1 compared to group 2 in blood (p = 0.014) were seen. The GE was delayed in both group 1 (p < 0.001) and group 2 (p < 0.05) compared to a reference group with healthy volunteers with T1/2 median values 105 and 78 min vs. 72 min. There was no difference in GE between the two PD groups (p = 0.220) or in group 2 before and after infusion period (p = 0.861). CDS resulted in lower levodopa levels in blood (p < 0.001) and SC tissue (p < 0.01). In conclusion, PD patients in early complication phase have a more favourable levodopa uptake than patients later in disease. We found delayed GE in PD patients with motor fluctuations but no obvious relation between GE and levodopa uptake or GE and PD stage. The effect of CDS indicates no effect of CDS on the mechanisms of GE but on the mechanisms of levodopa uptake.

Place, publisher, year, edition, pages
Scientific Research Publishing, 2017
National Category
Neurology Gastroenterology and Hepatology Anesthesiology and Intensive Care Surgery Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:liu:diva-136685 (URN)10.4236/apd.2017.61001 (DOI)
Available from: 2017-04-20 Created: 2017-04-20 Last updated: 2018-01-12
Nord, M., Zsigmond, P., Kullman, A. & Dizdar Segrell, N. (2017). Levodopa Pharmacokinetics in Brain after Both Oral and Intravenous Levodopa in One Patient with Advanced Parkinson’s Disease. Advances in Parkinsons Disease, 6(2), 52-66
Open this publication in new window or tab >>Levodopa Pharmacokinetics in Brain after Both Oral and Intravenous Levodopa in One Patient with Advanced Parkinson’s Disease
2017 (English)In: Advances in Parkinsons Disease, ISSN 2169-9712, Vol. 6, no 2, p. 52-66Article in journal (Refereed) Published
Abstract [en]

Objective: One patient received oral levodopa during a study aiming for better understanding of the basal ganglia and of the mechanisms of deep brain stimulation of the subthalamic nucleus (STN DBS) with and without intravenous (IV) levodopa infusion in patients with Parkinson’s disease (PD). The results from oral and IV levodopa treatment are presented.

Methods: Five patients with advanced PD were included in the original study. During planned STN DBS surgery microdialysis probes were implanted in the right putamen and in the right and left globus pallidus interna (Gpi). During the study, microdialysis was performed continuously and STN DBS, with and without IV levodopa infusion, was performed according to a specific protocol. After DBS surgery, but before STN DBS was started, one patient received oral levodopa/ benserazide and entacapone tablets out of protocol due to distressing parkinsonism.

Results: The levodopa levels increased prompt in the central nervous system after the first PD medication intakes but declined after the last. Immediately the levodopa seemed to be metabolized to dopamine (DA) since the levels of DA correlated well with levodopa concentrations. Left STN DBS seemed to further increase DA levels in left Gpi while right STN DBS seemed to increase DA levels in the right putamen and right Gpi. There was no obvious effect on levodopa levels.

Conclusions: The results indicate that PD patients still have capacity to metabolize levodopa to DA despite advanced disease with on-off symptoms and probably pronounced nigral degeneration. STN DBS seems to increase DA levels with a more pronounced effect on ipsilateral structures in striatum.

Place, publisher, year, edition, pages
Scientific Research Publishing Inc, 2017
Keywords
Parkinson’s Disease, Levodopa, Dopamine, Brain, Microdialysis, Deep Brain Stimulation
National Category
Neurology Cardiac and Cardiovascular Systems Gastroenterology and Hepatology Anesthesiology and Intensive Care Other Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-139251 (URN)10.4236/apd.2017.62006 (DOI)
Available from: 2017-07-07 Created: 2017-07-07 Last updated: 2018-01-12Bibliographically approved
Pihlstrom, L., Rengmark, A., Anne Bjornara, K., Dizdar (Dizdar Segrell), N., Fardell, C., Forsgren, L., . . . Toft, M. (2015). Fine mapping and resequencing of the PARK16 locus in Parkinsons disease. Journal of Human Genetics, 60(7), 357-362
Open this publication in new window or tab >>Fine mapping and resequencing of the PARK16 locus in Parkinsons disease
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2015 (English)In: Journal of Human Genetics, ISSN 1434-5161, E-ISSN 1435-232X, Vol. 60, no 7, p. 357-362Article in journal (Refereed) Published
Abstract [en]

The PARK16 locus, spanning five genes on chromosome 1, was among the first genetic regions to show genome-wide association in Parkinsons disease (PD). Subsequent investigations have found variability in PARK16 top-hits and association patterns across populations, and the implicated genes and mechanisms are currently unclear. In the present study, we aimed to explore the contribution of PARK16 variability to PD risk in a Scandinavian population. We genotyped 17 single-nucleotide polymorphisms in a case-control sample set of 2570 individuals from Norway and Sweden to fine map the locus. Targeted resequencing of the full coding regions of SLC45A3, NUCKS1, RAB7L1, SLC41A1 and PM20D1 was performed in DNA pools from a subset of 387 patient samples. We find evidence for an association with PD for rs1775143 as well as a haplotype located around the 5 region of RAB7L1, implicating variants which are not in high linkage disequilibrium with the strongest signal from a recent large meta-analysis in Caucasians. We also provide suggestive support for epistasis between RAB7L1 and LRRK2 as previously hypothesized by others. Comparing our results with previous work, allelic heterogeneity at PARK16 appears likely, and further studies are warranted to disentangle the complex patterns of association and pinpoint the functionally relevant variants.

Place, publisher, year, edition, pages
Nature Publishing Group: Open Access Hybrid Model Option A, 2015
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-120747 (URN)10.1038/jhg.2015.34 (DOI)000358606400003 ()25855069 (PubMedID)
Note

Funding Agencies|Health Region South-East, Norway; Research Council of Norway; Norwegian Parkinson Association Research Fund; Swedish Medical Research Council; Swedish Parkinson Foundation; King Gustaf Vs and Queen Victorias Freemason foundation; Swedish Brain Power; Southeastern Regional Health Authorities; "Functional Genomics" program of the Research Council of Norway; "Infrastructure" program of the Research Council of Norway; Swedish Parkinsons Disease Association; Rebergs Legacy

Available from: 2015-08-24 Created: 2015-08-24 Last updated: 2018-01-12
Georgiopoulos, C., Davidsson, A., Engström, M., Larsson, E.-M., Zachrisson, H. & Dizdar (Dizdar Segrell), N. (2015). The diagnostic value of dopamine transporter imaging and olfactory testing in patients with parkinsonian syndromes. Journal of Neurology, 262(9), 2154-2163
Open this publication in new window or tab >>The diagnostic value of dopamine transporter imaging and olfactory testing in patients with parkinsonian syndromes
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2015 (English)In: Journal of Neurology, ISSN 0340-5354, E-ISSN 1432-1459, Vol. 262, no 9, p. 2154-2163Article in journal (Refereed) Published
Abstract [en]

The aim of the study was to compare the efficacy of olfactory testing and presynaptic dopamine imaging in diagnosing Parkinsons disease (PD) and atypical parkinsonian syndromes (APS); to evaluate if the combination of these two diagnostic tools can improve their diagnostic value. A prospective investigation of 24 PD patients, 16 APS patients and 15 patients with non-parkinsonian syndromes was performed during an 18-month period. Single photon emission computed tomography with the presynaptic radioligand I-123-FP-CIT (DaTSCAN (R)) and olfactory testing with the Brief 12-item Smell Identification Test (B-SIT) were performed in all patients. DaTSCAN was analysed semi-quantitatively, by calculating two different striatal uptake ratios, and visually according to a predefined ranking scale. B-SIT score was significantly lower for PD patients, but not significantly different between APS and non-parkinsonism. The visual assessment of DaTSCAN had higher sensitivity, specificity and diagnostic accuracy compared to olfactory testing. Most PD patients (75 %) had visually predominant dopamine depletion in putamen, while most APS patients (56 %) had visually severe dopamine depletion both in putamen and in caudate nucleus. The combination of DaTSCAN and B-SIT led to a higher rate of correctly classified patients. Olfactory testing can distinguish PD from non-parkinsonism, but not PD from APS or APS from non-parkinsonism. DaTSCAN is more efficient than olfactory testing and can be valuable in differentiating PD from APS. However, combining olfactory testing and DaTSCAN imaging has a higher predictive value than these two methods separately.

Place, publisher, year, edition, pages
Springer Berlin/Heidelberg, 2015
Keywords
Parkinsons disease; Atypical parkinsonism; Parkinsonian syndromes; Olfaction; I-123-FP-CIT SPECT
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-122669 (URN)10.1007/s00415-015-7830-4 (DOI)000363035400018 ()26122543 (PubMedID)
Note

Funding Agencies|Ostergotland County Council (ALF); Swedish Parkinsons Foundation

Available from: 2015-11-16 Created: 2015-11-13 Last updated: 2019-03-05Bibliographically approved
Lill, C. M., Rengmark, A., Pihlstrom, L., Fogh, I., Shatunov, A., Sleiman, P. M., . . . Bertram, L. (2015). The role of TREM2 R47H as a risk factor for Alzheimers disease, frontotemporal lobar degeneration, amyotrophic lateral sclerosis, and Parkinsons disease. Alzheimer's & Dementia, 11(12), 1407-1416
Open this publication in new window or tab >>The role of TREM2 R47H as a risk factor for Alzheimers disease, frontotemporal lobar degeneration, amyotrophic lateral sclerosis, and Parkinsons disease
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2015 (English)In: Alzheimer's & Dementia, ISSN 1552-5260, E-ISSN 1552-5279, Vol. 11, no 12, p. 1407-1416Article in journal (Refereed) Published
Abstract [en]

A rare variant in TREM2 (p.R47H, rs75932628) was recently reported to increase the risk of Alzheimers disease (AD) and, subsequently, other neurodegenerative diseases, i.e. frontotemporal lobar degeneration (FTLD), amyotrophic lateral sclerosis (ALS), and Parkinsons disease (PD). Here we comprehensively assessed TREM2 rs75932628 for association with these diseases in a total of 19,940 previously untyped subjects of European descent. These data were combined with those from 28 published data sets by meta-analysis. Furthermore, we tested whether rs75932628 shows association with amyloid beta (Ab42) and total-tau protein levels in the cerebrospinal fluid (CSF) of 828 individuals with AD or mild cognitive impairment. Our data show that rs75932628 is highly significantly associated with the risk of AD across 24,086 AD cases and 148,993 controls of European descent (odds ratio or OR = 2.71, P = 4.67 x 10(-25)). No consistent evidence for association was found between this marker and the risk of FTLD (OR = 2.24, P = .0113 across 2673 cases/9283 controls), PD (OR 5 1.36, P = .0767 across 8311 cases/79,938 controls) and ALS (OR 5 1.41, P = .198 across 5544 cases/7072 controls). Furthermore, carriers of the rs75932628 risk allele showed significantly increased levels of CSF-total-tau (P = .0110) but not Ab42 suggesting that TREM2s role in AD may involve tau dysfunction. (C) 2015 The Alzheimers Association. Published by Elsevier Inc. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE INC, 2015
Keywords
Neurodegenerative disease; Alzheimer disease; Frontotemporal lobar degeneration; Amyotrophic lateral sclerosis; Parkinson disease; TREM2; R47H; rs75932628; Rare variant; Genetic association; GWAS; Imputation; Meta-analysis
National Category
Basic Medicine
Identifiers
urn:nbn:se:liu:diva-123758 (URN)10.1016/j.jalz.2014.12.009 (DOI)000366721600002 ()25936935 (PubMedID)
Note

Funding Agencies|German Ministry for Education and Research (BMBF) [16SV5538, 01UW0808]; Cure Alzheimers Fund; Michael J. Fox Foundation; Innovation Fund of the Max Planck Society [M.FE.A.BILD0002]; Katharina-Hardt-Stiftung, Bad Homburg, Germany; AXA Research Fund; Fondation Universite Pierre et Marie Curie; Fondation pour la Recherche sur Alzheimer, Paris, France; MND Association UK; Research Council of Norway; South-Eastern Norway Regional Health Authority; NIEHS of the National Institutes of Health [R01ES013717]; European Union [QLK4-CT-1999-01133]; program "Investissements davenir" [ANR-10-IAIHU-06]

Available from: 2016-01-11 Created: 2016-01-11 Last updated: 2018-01-12
Davidsson, A., Georgiopoulos, C., Dizdar Segrell, N., Granerus, G. & Zachrisson, H. (2014). Comparison between visual assessment of dopaminergic degeneration pattern and semi-quantitative ratio calculations in patients with Parkinson's disease and Atypical Parkinsonian snydromes using DaTSCAN SPECT. In: : . Paper presented at Annaul Congress of the European Assocation of Nuclerar Medicine, Gothenburg, Sweden, October 18-22, 2014 (pp. P921). European Assocation of Nuclerar Medicine
Open this publication in new window or tab >>Comparison between visual assessment of dopaminergic degeneration pattern and semi-quantitative ratio calculations in patients with Parkinson's disease and Atypical Parkinsonian snydromes using DaTSCAN SPECT
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2014 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

Background: Parkinson's disease (PD) is a degenerative disorder characterized by the progressive degeneration of dopamine-containing cells in substantia nigra, and it is the second most common neurodegenerative disorder worldwide. It can be difficult to differentiate between idiopathic PD and Atypical Parkinsonian syndromes (APS). In a high percentage of APS patients, the right diagnosis is not established even during late stages of the disease. Currently there is no specific test to verify PD, especially in the early stages of the disease.

The aim was to verify if 123I-FP-CIT, DaTSCAN ® can differentiate early stages of Parkinson's disease as well as patients with Atypical Parkinsonian syndromes from manifest Parkinson's disease.

Materials and methods: 121 consecutive patients were investigated with 123I-FP-CIT SPECT, during a four year period. All patients were diagnosed according to the established consensus criteria for diagnosis of Parkinson's disease (PD), (n=53), Atypical Parkinsonian syndromes (APS) (n=18). Remaining patients were grouped early PD (before onset the of L-dopa medication), (n=20), and non-PD syndromes (n=30). SPECT images were analysed visually according to a predefined ranking scale of dopaminergic degeneration, distinguishing a posterior-anterior degeneration pattern (egg shape) to a more global and severe degeneration pattern (burst striatum). Striatum ratios were quantitatively analysed with the 3D software, EXINI.

Results: In the group of APS patients the burst striatum pattern was most frequent and found in 61% (11/18 patients). In PD patients the egg shape pattern was dominating, especially in early PD where it was present in 95% (19/20 patients). The sensitivity of burst striatum degeneration pattern was 61% (95%-CI 36-83%), specificity 90% (95%-CI 81-96%). The sensitivity of egg shape pattern was 74% (95%-CI 62-84%), specificity 90% (95%-CI 47-90%). The uptake ratios were reduced in both PD and APS patients and closely related to the image pattern. The lowest putamen/caudate ratio was found in early PD.

Conclusion: In this study we found that in more than half of the patients it was possible to differentiate between PD and APS by visual interpretation only. Similar results were obtained using semi-quantitative uptake ratios, but combining visual assessment with uptake ratios did not add to the discriminating power of DATSCAN ® SPECT in this material

References: Kahraman D, Eggers C, Schicha H, Timmermann L, Schmidt M. Visual assessment of dopaminergic degeneration pattern in 123I-FP-CIT SPECT differentiates patients with atypical parkinsonian syndromes and idiopathic Parkinson's disease. J Neurol. 2012;259:251-60

Place, publisher, year, edition, pages
European Assocation of Nuclerar Medicine, 2014
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-113418 (URN)
Conference
Annaul Congress of the European Assocation of Nuclerar Medicine, Gothenburg, Sweden, October 18-22, 2014
Available from: 2015-01-19 Created: 2015-01-19 Last updated: 2018-01-12Bibliographically approved
Davidsson, A., Georgiopoulos, C., Dizdar (Dizdar Segrell), N., Granerus, G. & Zachrisson, H. (2014). Comparison between visual assessment of dopaminergic degeneration pattern and semi-quantitative ratio calculations in patients with Parkinsons disease and Atypical Parkinsonian syndromes using DaTSCAN (R) SPECT. Paper presented at The Japanese Society of Nuclear Medicine 2014. Annals of Nuclear Medicine, 28(9), 851-859
Open this publication in new window or tab >>Comparison between visual assessment of dopaminergic degeneration pattern and semi-quantitative ratio calculations in patients with Parkinsons disease and Atypical Parkinsonian syndromes using DaTSCAN (R) SPECT
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2014 (English)In: Annals of Nuclear Medicine, ISSN 0914-7187, E-ISSN 1864-6433, Vol. 28, no 9, p. 851-859Article in journal (Refereed) Published
Abstract [en]

Objective To verify if I-123-FP-CIT, DaTSCAN (R) can differentiate early stages of Parkinsons disease (PD) as well as patients with Atypical Parkinsonian syndromes (APS) from manifest Parkinsons disease. Methods 128 consecutive patients were investigated with I-123-FP-CIT SPECT during a 4-year period. All patients were diagnosed according to the established consensus criteria for diagnosis of PD (n = 53) and APS (n = 19). Remaining patients were grouped early PD (before onset of L-DOPA medication), (n = 20), vascular PD (n = 6), and non-PD syndromes (n = 30) and SWEDD (n = 1). SPECT images were analyzed visually according to a predefined ranking scale of dopaminergic nerve cell degeneration, distinguishing a posterior-anterior degeneration pattern (egg shape) from a more global and severe degeneration pattern (burst striatum). Striatum uptake ratios were quantitatively analyzed with the 3D software, EXINI. Results In the group of APS patients, the burst striatum pattern was most frequent and found in 61 % (11/18 patients). In PD patients, the egg shape pattern was dominating, especially in early PD where it was present in 95 % (19/20 patients). The positive predictive value for the egg shape pattern to diagnose PD was 92 % in this material (APS and all PD patients) and the specificity 90 % for the burst striatum pattern to exclude APS. The uptake ratios were reduced in both PD and APS patients and closely related to the image ranking. Conclusion In this study, we found that in more than half of the patients it was possible to differentiate between PD and APS by visual interpretation only. Similar results were obtained using semi-quantitative uptake ratios. Combining visual assessment with uptake ratios did not add to the discriminating power of DaTSCAN (R) SPECT in this material.

Place, publisher, year, edition, pages
Springer Verlag (Germany), 2014
Keywords
I-123-FP-CIT SPECT; Parkinsons disease (PD); Early stage of PD; Atypical Parkinsonian syndromes; Semi-quantitative evaluation; Visual pattern assessment
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-113060 (URN)10.1007/s12149-014-0878-x (DOI)000345400100003 ()24997753 (PubMedID)
Conference
The Japanese Society of Nuclear Medicine 2014
Available from: 2015-01-09 Created: 2015-01-08 Last updated: 2018-01-12
Zsigmond, P., Nord, M., Kullman, A., Diczfalusy, E., Wårdell, K. & Dizdar (Dizdar Segrell), N. (2014). Neurotransmitter levels in basal ganglia during levodopa and deep brain stimulation treatment in Parkinson’s disease. Neurology and Clinical Neuroscience, 2(5), 149-155
Open this publication in new window or tab >>Neurotransmitter levels in basal ganglia during levodopa and deep brain stimulation treatment in Parkinson’s disease
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2014 (English)In: Neurology and Clinical Neuroscience, ISSN 2049-4173, Vol. 2, no 5, p. 149-155Article in journal (Refereed) Published
Abstract [en]

Background The mechanism by which deep brain stimulation of the nucleus subthalamicus improves Parkinson’s disease symptoms remains unclear. In a previous perioperative study, we showed that there might be alterations of neurotransmitter levels in the globus pallidum interna during deep brain stimulation of the nucleus subthalamicus. Aim In this study, we examined whether deep brain stimulation of the nucleus subthalamicus and levodopa infusion interact and affect the levels of neurotransmitters. Methods Five patients with advanced Parkinson’s disease took part in the study. During subthalamic nucleus surgery, microdialysis catheters were inserted bilaterally in the globus pallidum interna and unilaterally in the right putamen. A study protocol was set up and was followed for 3 days. Levodopa infusion with and without concomitant bilateral deep brain stimulation of the nucleus subthalamicus was also carried out. Results The putaminal dopamine levels increased during deep brain stimulation of the nucleus subthalamicus. In addition, an increase of gamma amino buturic acid concentrations in the globus pallidum interna during deep brain stimulation of the nucleus subthalamicus and during levodopa infusion was found. Conclusions These findings provide evidence that the subthalamic nucleus has a direct action on the substantia nigra pars compacta, and that deep brain stimulation of the nucleus subthalamicus might indirectly release putaminal dopamine. There is also evidence that deep brain stimulation of the nucleus subthalamicus interferes with levodopa therapy resulting in higher levels of levodopa in the brain, explaining why it is possible to decrease levodopa medication after deep brain stimulation surgery.

Place, publisher, year, edition, pages
John Wiley & Sons, 2014
Keywords
deep brain stimulation, levodopa, microdialysis, neurotransmitters, Parkinson
National Category
Medical Bioscience Medical Biotechnology Basic Medicine
Identifiers
urn:nbn:se:liu:diva-113590 (URN)10.1111/ncn3.109 (DOI)
Available from: 2015-01-23 Created: 2015-01-23 Last updated: 2019-02-11Bibliographically approved
Dizdar (Dizdar Segrell), N., Zsigmond, P., Kullman, A. & Nezirevic, D. (2013). Letter: Untitled [Letter to the editor]. Journal of Neuroscience Methods, 212(2), 363-363
Open this publication in new window or tab >>Letter: Untitled
2013 (English)In: Journal of Neuroscience Methods, ISSN 0165-0270, E-ISSN 1872-678X, Vol. 212, no 2, p. 363-363Article in journal, Letter (Refereed) Published
Abstract [en]

n/a

Place, publisher, year, edition, pages
Elsevier, 2013
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-90766 (URN)10.1016/j.jneumeth.2013.01.005 (DOI)000315974200025 ()
Available from: 2013-04-05 Created: 2013-04-05 Last updated: 2018-01-12
Zsigmond, P., Nord, M., Kullman, A., Diczfalusy, E., Wårdell, K. & Dizdar (Segrell), N. (2013). Neurotransmitter levels in basal ganglia during L-dopa and Deep Brain Stimulation treatment in Parkinson’s Disease.
Open this publication in new window or tab >>Neurotransmitter levels in basal ganglia during L-dopa and Deep Brain Stimulation treatment in Parkinson’s Disease
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2013 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Background: Bilateral deep brain stimulation of the nucleus subthalamicus (STN DBS) is a wellestablishedtreatment in patients with advanced Parkinson’s disease (PD). The mechanism bywhich STN DBS improves the PD symptoms remains unclear. In a previous perioperativestudy we have shown that there might be alterations of neurotransmitter levels in the Globuspallidum interna (GPi) during STN DBS. In this study we wanted to examine if STN DBSand L-dopa infusion interact and affect the levels of neurotransmitters.

Methods: Five patients with advanced PD took part in the study. During STN surgery microdialysis catheters were inserted bilaterally in the GPi and unilaterally in the right putamen. A study protocol was set up and was followed for three days including STN DBS left side, right side and bilateral. L-dopa infusion with and without concomitant bilateral STN DBS was also performed.

Results: The putaminal dopamine levels increase during STN DBS. In addition an increase of GABA concentrations in the GPi during STN DBS and during L-dopa infusion was found.

Conclusions: These findings can provide evidence that the STN has a direct action on the substantia nigra pars compacta (SNc) and that STN DBS may indirectly release putaminal dopamine. There is also evidence that STN DBS interferes with L-dopa therapy resulting in higher levels of Ldopa in the brain explaining why its possible to decrease L-dopa medication after DBS surgery.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-91293 (URN)
Available from: 2013-04-19 Created: 2013-04-19 Last updated: 2017-06-19Bibliographically approved
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