虎纹捕鸟蛛（Selenocosimia　huwena）粗毒对蟾蜍神经肌肉接头传递的影响

Efeects of the Venom of the Spider (Selenocosmia huwena) On the Toad Neuromuscular Junction

１０－５～１０－４ｇ／ｍｌ虎纹捕鸟蛛粗毒对蟾蜍坐骨神经肌肉标本有阻遏作用，１×１０－４ｇ／ｍｌ粗毒发生阻断的时间为３８ｍｉｎ，但不改变神经干动作电位，不影响肌肉对直接刺激的反应。阻断后肌肉对间接强直刺激仍可发生强直收缩；粗毒对蟾蜍坐骨神经肌肉标本的阻断作用表现为：初期４～５０秒的收缩增强继而转向抑制；粗毒可对抗箭毒的阻断作用；蟾蜍在体坐骨神经肌肉标本可被粗毒阻断，但阻断后可以恢复；粗毒不改变蛙腹直肌对Ａｃｈ的敏感性，粗毒中含有拟胆碱成份。箭毒可以阻止粗毒对蛙腹直肌的拟胆碱效应；该粗毒对蟾蜍坐骨神经肌肉标本的阻遏作用发生在神经肌肉接头，粗毒中含有拟胆碱组份，此组份可能通过后膜去极化阻断神经肌肉接头。

The Huwena spider crude venom (10-5～10-4g/ml) can block the isolated toad sciatic nerve-gastrocnemius preparation. It takes 38min.to block the preparation at the venom concentration of 1.0×10-4g/ml, but the venom don't change the compound action potential of sciatic nerve and don't change the muscular contraction with direct stimulus,When the preparation blocked. tetanic contraction can occur with indirect tetanus stimulus;The effect of the venom on the isolated toad sciatic nerve-gastrocnemius preparation show that the tension of muscular contraction increase at early time from 4 to 50 sec. and then become into blocking; The crude venom can inhibite the effect of d-tubocurarinum;The effect of the venom on the toad sciatic nerve-gastrocnemius in vivo show that the neuromuscular contraction can be blocked but can Festores late;The crude venom don't change the frog rectus abdominis sensitivity to Ach.There are some cholinomimetic components in the crude venom.The d-tubocurarinum can inhibite the effect of the crude venom which is cholinomimetic on frog rectus abdominis. That bloking the isolated toad sciatic nervegastrocnemius is due to the crude venom which inhibite the synapitic transmission, The crude venom include cholinomimetic component, which maybe inhibite the synaptic transmission through postsynaptic depolarization.