乙醇对两种突触膜Ca2+转运系统的不同作用。

Differential effects of ethanol on two synaptic membrane Ca2+ transport systems.

作者信息

Michaelis M L, Kitos T E, Tehan T

出版信息

Alcohol. 1985 Jan-Feb;2(1):129-32. doi: 10.1016/0741-8329(85)90029-1.

Abstract

The Na+-Ca2+ exchange activity in synaptic plasma membranes is inhibited by very low concentrations of ethanol (less than 25 mM). The high affinity Mg2+- and ATP-dependent Ca2+ transport in highly purified synaptic membranes is much less sensitive to inhibition by ethanol, with no statistically significant inhibition observed until an ethanol concentration of nearly 800 mM was used. Manipulations of the lipid environment designed to increase membrane fluidity enhanced the activity of the Na+-Ca2+ exchange system but inhibited the ATP-dependent Ca2+ pump. The differential responses of the two synaptic plasma membrane Ca2+ transporting systems to such modifications of membrane structure suggest that these two ion transport processes differ in the extent to which their activity is dependent on the lipid microenvironment in which they reside. Thus, the effects of ethanol on the Na+-Ca2+ antiporter may represent a fairly selective inhibitory process.

摘要

极低浓度的乙醇（低于25 mM）可抑制突触质膜中的Na⁺-Ca²⁺交换活性。在高度纯化的突触膜中，高亲和力的Mg²⁺和ATP依赖的Ca²⁺转运对乙醇抑制的敏感性要低得多，直到使用近800 mM的乙醇浓度时才观察到统计学上显著的抑制作用。旨在增加膜流动性的脂质环境操作增强了Na⁺-Ca²⁺交换系统的活性，但抑制了ATP依赖的Ca²⁺泵。这两种突触质膜Ca²⁺转运系统对膜结构此类修饰的不同反应表明，这两种离子转运过程在其活性依赖于它们所处脂质微环境的程度上存在差异。因此，乙醇对Na⁺-Ca²⁺反向转运体的作用可能代表了一个相当具有选择性的抑制过程。