Interactions of neurotoxins with the action potential NA + ionophore.
Interactions of neurotoxins with the action potential NA + ionophore.
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神经毒素与动作电位 NA 离子载体的相互作用。
DOI：
10.1002/jss.400050312
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发表时间：
1976
期刊：
影响因子：
--
通讯作者：
R. Ray
中科院分区：
文献类型：
--
作者：
W. Catterall;R. Ray
四个神经毒素激活动作电位Na+离子载体的电兴奋性神经母细胞瘤细胞与两个不同的网站，一个特定的生物碱藜芦碱，batrachotoxin，乌头碱，和第二个特定的蝎子毒素。在这两类位点结合的毒素之间观察到正异嗜性协同性。河豚毒素是动作电位Na+电流的特异性抑制剂，以非竞争性方式抑制这些毒素的激活（KI=4-8 nM）。这些结果表明，存在三个功能上可分离的组件的动作电位Na+离子载体：两个监管组件结合激活神经毒素和变构相互作用，在控制的第三个离子转运组件，结合河豚毒素的活性。蝎毒素结合的解离常数增加10倍，通过去极化的细胞与K+，这表明蝎毒素结合位点位于电压敏感的调节成分的离子载体。
Four neurotoxins that activate the action potential Na+ionophore of electrically excitable neuroblastoma cells interact with two distinct classes of sites, one specific for the alkaloids veratridine, batrachotoxin, and aconitine, and the second specific for scorpion toxin. Positive heterotropic cooperativity is observed between toxins bound at these two classes of sites. Tetrodotoxin, a specific inhibitor of the action potential Na+ current, inhibits activation by each of these toxins in a noncompetitive manner (KI=4-8 nM). These results suggest the existence of three functionally separable components of the action potential Na+ionophore: two regulatory components which bind activating neurotoxins and interact allosterically in controlling the activity of a third ion-transport component, which binds tetrodotoxin. The dissociation constant for scorpion toxin binding is increased 10-fold by depolarization of the cells with K+, suggesting that the scorpion toxin binding site is located on a voltage-sensitive regulatory component of the ionophore.