effects of buthus eupeus venom on neuromuscular transmission on striated muscle in vitro

in this study, effects of buthus eupeus venom on chick biventer cervices nerve-muscle preparation were investigated by twitch tension method. the venom, at 1.3 ?g/ml, increased contractile responses in indirect stimulations. these effects were milder in direct muscle stimulations. it also caused significant enhancement in postjunctional sensitivity as assessed by responses to exogenous acetylcholine, carbacole and potassium chloride. these results indicate that b. eupeus venom can cause irreversible facilitation of neuromuscular transmission by affecting postjunctional excitability in both nicotinic receptors and ion channels of the muscle cells membrane.