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非洲窄头眼镜蛇有四类:黑色窄头眼镜蛇(Dendr-oaspis polylepis),西部绿色窄头眼镜蛇(D.viridis),东部绿色窄头眼镜蛇(D.angusticepis)和Jameson’s窄头眼镜蛇(D.jamesoni)。东部绿色窄头眼镜蛇毒的毒性比其他3种约低10倍,仅含很少量的突触后神经毒。它对离体神经肌肉的作用为:高浓度直接损伤肌肉,较低浓度阻滞ACh 受体,更低浓度加强间接刺激神经产生的肌肉收缩反应。有效成份是一种多肽dendro-toxin(Ⅰ)。(Ⅰ)约20nM 浓度即能增加肌肉对刺激神经的收缩反应,但对接头后受体的敏感性、乙酰胆碱酯酶活性或肌肉收缩性均无影响。(Ⅰ)增加终板电位的平均量子含量,但不影响自发ACh 释放的结果,证实(Ⅰ)是加强ACh 的释放。(Ⅰ)比3,4-二氨基吡啶起效慢,但有效浓度比后者低100～1000倍,与神经末梢结合快,
There are four types of African narrow-necked cobra: Dendr-oaspis polylepis, D. viridis, D.angusticepis, and Jameson’s D.jamesoni, . Eastern green narrow-neck cobra poison toxicity than the other three about 10 times lower, containing only a small amount of postsynaptic nerve poison. Its effect on isolated neuromuscular muscle is: high concentration directly injures the muscle, lower concentration blocks ACh receptors, and lower concentration strengthens the muscles that indirectly stimulate nerve contraction. The active ingredient is a polypeptide dendro-toxin (Ⅰ). (I) at a concentration of about 20 nM can increase muscle contractile response to stimulating nerves, but have no effect on receptor sensitivity after receptor, acetylcholinesterase activity or muscle contractility. (I) increases the average quantum content of the endplate potential but does not affect the spontaneous release of ACh, confirming that (I) enhances the release of ACh. (Ⅰ) than 3,4-diaminopyridine slow onset, but the effective concentration 100-100 times lower than the latter, and nerve endings fast,