Immunohistochemical localization of 5-HT2A receptors in peripheral sensory axons in rat glabrous skin.
Serotonin (5-hydroxytryptamine, 5-HT) is a well known inflammatory mediator and algesic substance. It has been hypothesized that 5-HT can have a direct action on peripheral sensory axons, but there has been no anatomical demonstration of 5-HT receptors on peripheral primary afferent processes. The present study shows that 32% of unmyelinated axons at the dermal-epidermal junction are immunohistochemically stained with antibodies directed against the 5-HT2A receptor providing anatomical evidence that 5-HT can have a direct effect on sensory fibers in the skin. Furthermore, encapsulated nerve endings in Pacinian corpuscles also contain reaction product following immunostaining for 5-HT2A receptors, indicating that large myelinated axons can be activated by endogenous serotonin. These data suggest that peripherally acting 5-HT2A antagonists may be effective in reducing pain of peripheral origin.
Carlton
S M
SM
Department of Anatomy and Neuroscience, Marine Biomedical Institute, University of Texas Medical Branch, Galveston 77555-1069, USA.
Coggeshall
R E
RE
D000818:Animals; D001369:Axons / Q000737:chemistry* / Q000648:ultrastructure; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D009411:Nerve Endings / Q000737:chemistry / Q000648:ultrastructure; D009475:Neurons, Afferent / Q000737:chemistry / Q000648:ultrastructure; D010525:Peripheral Nerves / Q000737:chemistry* / Q000166:cytology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin / Q000032:analysis*; D012867:Skin / Q000294:innervation* / Q000648:ultrastructure
D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin