A topographical and physiological exploration of C-tactile afferents and their response to menthol and histamineShow others and affiliations
2022 (English)In: Journal of Neurophysiology, ISSN 0022-3077, E-ISSN 1522-1598, Vol. 127, no 2, p. 463-473Article in journal (Refereed) Published
Abstract [en]
Unmyelinated tactile (C-tactile or CT) afferents are abundant in arm hairy skin and have been suggested to signal features of soda) affective touch. Here, we recorded from unmyelinated low-threshold mechanosensitive afferents in the peroneal and radial nerves. The most distal receptive fields were located on the proximal phalanx of the third finger for the superficial branch of the radial nerve and near the lateral malleolus for the peroneal nerve. We found that the physiological properties with regard to conduction velocity and mechanical threshold, as well as their tuning to brush velocity, were similar in CT units across the antebrachial (n = 27), radial (n = 8), and peroneal (n = 4) nerves. Moreover, we found that although CT afferents are readily found during microneurography of the arm nerves, they appear to be much more sparse in the lower leg compared with C-nociceptors. We continued to explore CT afferents with regard to their chemical sensitivity and found that they could not be activated by topical application to their receptive field of either the cooling agent menthol or the pruritogen histamine. In light of previous studies showing the combined effects that temperature and mechanical stimuli have on these neurons, these findings add to the growing body of research suggesting that CT afferents constitute a unique class of sensory afferents with highly specialized mechanisms for transducing gentle touch. NEW & NOTEWORHY Unmyelinated tactile (CT) afferents are abundant in arm hairy skin and are thought to signal features of social affective touch. We show that CTs are also present but are relatively sparse in the lower leg compared with C-nociceptors. CTs display similar physiological properties across the arm and leg nerves. Furthermore, CT afferents do not respond to the cooling agent menthol or the pruritogen histamine, and their mechanical response properties are not altered by these chemicals.
Place, publisher, year, edition, pages
AMER PHYSIOLOGICAL SOC , 2022. Vol. 127, no 2, p. 463-473
Keywords [en]
affective touch; CT afferent; histamine; menthol; peroneal nerve
National Category
Neurosciences
Identifiers
URN: urn:nbn:se:liu:diva-183058DOI: 10.1152/jn.00310.2021ISI: 000751665900008PubMedID: 35020516OAI: oai:DiVA.org:liu-183058DiVA, id: diva2:1639847
Note
Funding Agencies|Ake Wiberg Foundation; Swedish Research CouncilSwedish Research CouncilEuropean Commission [2017-01717]; VaEurostra GoEurotaland RegionRegion Auvergne-Rhone-AlpesRegion Bourgogne-Franche-ComteRegion Hauts-de-FranceRegion Nouvelle-Aquitaine [ALFGBG-725751]
2022-02-222022-02-222022-02-22