小龙虾巨大轴突中相对离子通透性的pH依赖性。
The pH dependency of relative ion permeabilities in the crayfish giant axon.
作者信息
Strickholm A, Wallin B G, Shrager P
出版信息
Biophys J. 1969 Jul;9(7):873-83. doi: 10.1016/S0006-3495(69)86424-6.
The dependence of the membrane potential on potassium, chloride, and sodium ions, was determined at the pH's of 6.0, 7.5, and 9.0 for the resting and depolarized crayfish ventral nerve cord giant axon. In normal saline (external potassium = 5.4 mM), the dependence of the membrane potential on the external potassium ions decreased with lowered pH while that for chloride increased. In contrast, in the potassium depolarized axon (external potassium = 25 mM), the dependence of the membrane potential on external potassium was minimum around pH 7.5 and increased in either more acidic or basic pH. In addition, the dependence of the membrane potential on external chloride in the depolarized axon was maximum at pH 7.5 and decreased in either more acidic or basic pH. The sodium dependency of the membrane potential was small and relatively unaffected by pH or depolarization. The data are interpreted as indicating a reversible surface membrane protein-phospholipid conformation change which occurs in the transition from the resting to the depolarized axon.
在pH值为6.0、7.5和9.0的条件下，测定了静息和去极化的小龙虾腹神经索巨轴突膜电位对钾离子、氯离子和钠离子的依赖性。在正常生理盐水中（细胞外钾离子浓度=5.4 mM），膜电位对细胞外钾离子的依赖性随pH值降低而降低，而对氯离子的依赖性则增加。相反，在钾离子去极化的轴突中（细胞外钾离子浓度=25 mM），膜电位对细胞外钾离子的依赖性在pH值7.5左右最小，在更酸性或碱性的pH值下增加。此外，去极化轴突中膜电位对细胞外氯离子的依赖性在pH值7.5时最大，在更酸性或碱性的pH值下降低。膜电位对钠离子的依赖性较小，相对不受pH值或去极化的影响。这些数据被解释为表明在从静息轴突到去极化轴突的转变过程中发生了可逆的表面膜蛋白-磷脂构象变化。
Zotero 插件