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OBJECTIVE Toad venom(Venenum Bufonis)isalways used for analgesia in China from ancient to modern times,but the effective component of it remains unclear.METHODS In the present study,we investigated the anti-nociceptive effect and the underlying mechanism ofbufalin,an active ingredient fromtoad venom by animal behavior,patch clamp and calcium imaging.RESULTS Bufalin could significantly relieve formalin-induced spontaneous flinching and licking response as well as carrageenan-induced mechanical and thermal hyperalgesia.Using the whole-cel patch-clamp recording,bufalincaused remarkable suppressive effect on the peak currents of Na+channels in dorsal root ganglion neuroblastoma ND7-23 cel line in a U-shaped dependent manner.In addition,bufalinprompted the voltage-dependent activationand caused a negative shift of the fast-state inactivation of Na+channels.However,bufalin produced insignificant effect not onlyon voltage-dependent Kv4.2,Kv4.3 and BK channels,but also on the capsaicin induced Ca2+influx.CONCLUSION The present results indicate bufalin is capable of producing remarkable anti-nociceptive effects whichis probably ascribed to its specific modulation of voltage-gated Na+channels.
OBJECTIVE Toad venom (Venenum Bufonis) isalways used for analgesia in China from ancient to modern times, but the effective component of it remains unclear. METHODS In the present study, we investigated the anti-nociceptive effect and the underlying mechanism of bufalin, an active ingredient from toad venom by animal behavior, patch clamp and calcium imaging. RESULTS Bufalin could be relieve formalin-induced spontaneous flinching and licking response as well as carrageenan-induced mechanical and thermal hyperalgesia. Using the whole-cel patch-clamp recording, bufalincaused remarkable suppressive effect on the peak currents of Na + channels in dorsal root ganglion neuroblastoma ND7-23 cel line in a U-shaped dependent manner. In addition, bufalinprompted the voltage-dependent activation and caused a negative shift of the fast-state inactivation of Na + channels. However, bufalin produced insignificant effect not onlyon voltage-dependent Kv4.2, Kv4.3 and BK channels, but also on the capsaicin induced Ca2 + influx.CONCLUSION The present results indicate that bufalin is capable of producing remarkable anti-nociceptive effects whichis probablycribed to its specific modulation of voltage-gated Na + channels.