软体动物神经元钠钾渗透率比的温度依赖性

Temperature dependence of the sodium-potassium permeability ratio of a molluscan neurone.

作者信息

Gorman A L, Marmor M F

出版信息

J Physiol. 1970 Nov;210(4):919-31. doi: 10.1113/jphysiol.1970.sp009249.

DOI:10.1113/jphysiol.1970.sp009249

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1395632/

Abstract

The temperature dependence of the membrane potential of a molluscan giant neurone was examined under conditions which block the electrogenic activity of the Na-K exchange pump.2. When the Na pump was blocked by ouabain or the removal of external K, the membrane potential depolarized as temperature was increased.3. This depolarization was prevented by the replacement of external Na with impermeant cations, but was greater when Na was replaced with Li.4. All observed effects of ouabain were attributable to inhibition of the Na pump. The depolarization in response to ouabain at warmer temperatures was completely reversible, and the rate of both onset and reversibility of the ouabain effect was dependent upon temperature.5. Using a modified form of the constant field equation, the internal K concentration and the Na-K permeability ratio, P(Na)/P(K), were calculated from the experimental data.6. P(Na)/P(K) was found to increase from 0.028 at 4 degrees C to 0.068 at 18 degrees C. It is suggested that this increase is due primarily to a change in P(Na).

摘要

在阻断钠钾交换泵电活动的条件下，研究了软体动物巨型神经元膜电位的温度依赖性。
当钠泵被哇巴因阻断或去除细胞外钾时，膜电位随着温度升高而 depolarized。
用非渗透性阳离子替代细胞外钠可防止这种 depolarization，但用锂替代钠时这种情况更明显。
观察到的所有哇巴因效应均归因于钠泵的抑制。在较高温度下对哇巴因的 depolarization 是完全可逆的，哇巴因效应的起始和可逆速率均取决于温度。
使用常数场方程的修正形式，根据实验数据计算了细胞内钾浓度和钠钾渗透率比P(Na)/P(K)。
发现P(Na)/P(K)从4℃时的0.028增加到18℃时的0.068。有人认为这种增加主要是由于P(Na)的变化。