Capsaicin: actions on C fibre afferents that may be involved in itch.
Capsaicin selectively excites C-polymodal nociceptors in mammalian skin. In the rat, the only species so far studied in detail, a long-term desensitization of a subpopulation of C-polymodal nociceptors occurs after the initial excitation. After nerve treatment, permanent loss of some C-polymodal nociceptors is found in the rat. It is argued that capsaicin must act primarily on C fibres involved in signalling about pain and not itch, although there may be overlap between the C afferents involved in these two nociceptive sensations. The possibility is raised that C mechanoreceptors, with their good histamine sensitivity, are also involved in itch.
Lynn
B
B
Department of Physiology, University College London, England, UK.
D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D009412:Nerve Fibers / Q000187:drug effects*; D009475:Neurons, Afferent / Q000187:drug effects; D011537:Pruritus / Q000503:physiopathology*; D051381:Rats; D012867:Skin / Q000294:innervation*
D002211:Capsaicin