Expression of capsaicin receptor (VR1) by myelinated primary afferent neurons in rats.
The expression of capsaicin (VR1) receptor by A-fiber primary afferent neurons has been investigated by double immunohistochemical staining with VR1 and 200 kD neurofilament (NF200; an A-fiber marker) antibodies, and by VR1 immunohistochemical staining in combination with cholera toxin B subunit (CTB; also an A-fiber marker) retrograde tracing. Approximately 30% of the VR1-positive dorsal root ganglion (DRG) neurons were NF200-positive. Intra-sciatic nerve injection of CTB labeled over 30% of the VR1-positive neurons in the L5 DRG. Size frequency distribution analysis revealed that these VR1 and NF200, or VR1 and CTB, double-labeled neurons were predominantly small and medium sized. These results suggest that capsaicin receptors are likely to be expressed by Adelta-fiber neurons as well as C-fiber neurons.
Ma
Qing-Ping
QP
Department of Pharmacology, Merck Sharp & Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, UK. qingping_ma@merck.com
D000818:Animals; D048429:Cell Size / Q000502:physiology; D002772:Cholera Toxin / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism*; D009413:Nerve Fibers, Myelinated / Q000378:metabolism* / Q000648:ultrastructure; D016900:Neurofilament Proteins / Q000378:metabolism; D009475:Neurons, Afferent / Q000166:cytology / Q000378:metabolism*; D009619:Nociceptors / Q000378:metabolism* / Q000648:ultrastructure; D010146:Pain / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011955:Receptors, Drug / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D014966:Xanthenes
D005456:Fluorescent Dyes; D016900:Neurofilament Proteins; D011955:Receptors, Drug; D014966:Xanthenes; C051774:neurofilament protein H; C034657:Texas red; D002772:Cholera Toxin; D016650:Fluorescein-5-isothiocyanate