Melittin selectively activates capsaicin-sensitive primary afferent fibers.
Whole bee venom (WBV)-induced pain model has been reported to be very useful for the study of pain. However, the major constituent responsible for the production of pain by WBV is not apparent. Intraplantar injection of WBV and melittin dramatically reduced mechanical threshold, and increased flinchings and paw thickness. In behavioral experiments, capsaicin pretreatment almost completely prevented WBV- and melittin-induced reduction of mechanical threshold and flinchings. Intraplantar injection of melittin increased discharge rate of dorsal horn neurons only with C fiber input from peripheral receptive field, which was completely blocked by topical application of capsaicin to sciatic nerve. These results suggest that both melittin and WBV induce nociceptive responses by selective activation of capsaicin-sensitive afferent fibers.
Shin
Hong Kee
HK
Department of Physiology, College of Medicine, Hanyang University, 17 Haengdang-Dong, Seongdong-Gu, Seoul 133-791, Korea. shinhg@hanyang.ac.kr
Kim
Jin Hyuk
JH
D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D008555:Melitten / Q000494:pharmacology*; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology; D010147:Pain Measurement / Q000187:drug effects* / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley
D008555:Melitten; D002211:Capsaicin