金环蛇毒的分离及组分Ⅸ的初步研究

从金环蛇毒中分离到一个神经毒—组分Ⅸ。该组分阻断小鸡颈二腹肌神经肌肉接头传递;阻断标本对乙酰胆碱的反应,标本对直接电刺激以及对高浓度钾离子的反应性仍然存在;组分Ⅸ使蛙缝匠肌终板电位,微终板电位振幅逐渐减小,最后完全消失;但不影响微终板电位的发放频率,也不影响肌纤维的静息膜电位。实验表明组分Ⅸ是作用于突触后膜的神经毒。

Chromatography of Bungarus fasciatus venom and preliminary studies of its neurotoxin--fraction IX

A neurotoxin, Fraction Ⅸ, was separated from the venom of Bungarus fasciatus by CM-Sephadex C 50 chromatography. The fraction blocked both the neuromuscular transmission of chicken biventer cervicis muscle and the response of the preparation to acetylcholine with a long latent period (134±49 rain). Whereas, the responsibilities of the muscle to direct stimulation or high concentration of potassium chloride were not affected; not many contractures were found in the preparation. In frog sartorius muscle, fraction Ⅸ inhibited the amplitudes of endplate potentials (EPPs) and miniature endplate potentials (mEPPs). Neither the frequencies of miniature endplate potential nor the resting membrane potential of the muscle were changed by fraction Ⅸ. According to the experiments, it was suggested that fraction Ⅸ is a postsynaptic neurotoxin.