Activation of capsaicin receptors on the sciatic nerve induces FOS expression in the spinal dorsal horn of adult rats.
By using immunohistochemical staining for FOS protein in the spinal cord, the role of capsaicin receptors on the sciatic nerve was investigated. After topical application of capsaicin (1%) to the sciatic nerve, FOS-like immunoreactive (FOS-LI) neurons were observed, chiefly in the superficial laminae of the lumbar dorsal horn. Topical application of capsazepine (5%) or lidocaine (2%) to the sciatic nerve for 15 min before the application of capsaicin reduced the number of FOS-LI neurons in the superficial dorsal horn (by 83.2 +/- 1.7 and 32.4 +/- 1.2%, respectively). One week after pretreatment of the sciatic nerve with colchicine, the number of FOS-LI neurons induced by capsaicin was greatly decreased (by 74.6 +/- 1.7%). Given that FOS protein expression after peripheral noxious stimulation is found in a location similar to that in the present study, our results indicate that the capsaicin receptor on the sciatic nerve is involved in the transmission of noxious information.
Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, People's Republic of China.
Yu-Peng
YP
Feng
Kun
K
Yang
Yun-Qing
YQ
Li
D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001370:Axonal Transport; D002211:Capsaicin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003078:Colchicine / Q000494:pharmacology / Q000633:toxicity; D004705:Endocytosis; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D016762:Genes, fos; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D009498:Neurotoxins / Q000494:pharmacology / Q000633:toxicity; D020671:Posterior Horn Cells / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011955:Receptors, Drug / Q000187:drug effects* / Q000502:physiology; D012584:Sciatic Nerve / Q000187:drug effects*
D000779:Anesthetics, Local; D009419:Nerve Tissue Proteins; D009498:Neurotoxins; D016760:Proto-Oncogene Proteins c-fos; D011955:Receptors, Drug; D008012:Lidocaine; C071423:capsazepine; D002211:Capsaicin; D003078:Colchicine