中华眼镜蛇神经毒素的活性研究

目的：研究中华眼镜蛇神经毒素（ NT）的镇痛活性和对离体蛙腹直肌N2-AChR的拮抗作用。方法采用三种模型（电刺激-嘶叫法，热板法，醋酸扭体法）观察NT的镇痛活性，并观察NT对ACh所致蛙离体腹直肌收缩的影响。结果 NT能提高电刺激-嘶叫法，热板法的痛阈，抑制醋酸引起的扭体次数。NT镇痛具有剂量-效应关系，给药后2 h起效，5 h达峰。NT能使ACh引起的蛙腹直肌收缩的量效曲线平行右移。结论 NT对三种致痛模型均有确切的镇痛活性，NT对N2-AChR的拮抗作用为竞争性拮抗。

Experimental observation on the analgesic effect of NT on frog rectus abdominis N2 -receptor

Objective To study the analgesic effect and the drug-receptor interactions with frog rectus abdominis N2-receptor of the neurotoxin from Naja atra venom（ NT）. Methods Three model of pain（ tail electric stimulation-vocali-zation test ,the hot-plate test ,and writhing responses in mice）were used. The effects of NT on acetylcholine-induced i-solated frog rectus abdoninis were observed. Results NT could dose-dependently raise the pain threshold in hot-plate test in mice and inhibit the writhing reaction induce by acetic acid in mice . The analgesic effect of NT effect at 2 h and peaked at 5 h. NT produced a concentration-dependent parallel shift to the right of dose-response curve of acetylcholine applied exogenously with no change in the maximal asymptotic response. Conclusion NT had a better analgesic effect on the pain due to hot- plate ,acetic acid and electric stimulation. NT was determined as the competitive antagonists of N2 -AChR.