Abstract: Objective: To investigate the effects of Caulis Sinomenii (traditional Chinese medicine) on electrophysiological character of sciatic nerve trunk of toad.Methods: Forty toads were randomly divided into four groups:Ringer's solution (as a control group) and three experimental groups were treated with 0.20, 0.10, 0.05 g/ml Caulis Sinomenii decoction, each group was soaked for 15 and 30 min respectively. The conduction velocity, amplitude and threshold intensity of the sciatic nerves from each group were measured by RM6240C Physiological signals recording system.Results: Compared with the control group, the conduction velocity in high dose group was significantly decreased(P<0.01), the amplitude of the action potential in medium and high dose groups were lower(P<0.01); but the threshold intensity of the nerve trunk action potential in high dose group was increased significantly compared with that in control group (P<0.01).Conclusion: The Caulis Sinomenii decoction can reduce the excitability sciatic nerve stem of toad and block the conduction of the action potential, which may play important roles in inhibiting of sciatica.

Key words: Caulis Sinomenii, sciatic nerve, action potential, Bufo gargarizans