渗透压梯度对皱襞盘鲍透析神经元外向钾电流的影响。

The effect of osmotic gradients on the outward potassium current in dialyzed neurons of Helix pomatia.

Suleymanian M A, Ayrapetyan S N, Arakelyan V B, Ayrapetyan V Y

Department of Biophysics, Academy of Sciences of Armenia, Yerevan.

Cell Mol Neurobiol. 1993 Apr;13(2):183-90. doi: 10.1007/BF00735374.

Abstract

The effect of outward and inward water flows through the membrane on outward potassium currents of dialyzed Helix pomatia neurons was studied. 2. An outward water flow increased the peak and sustained outward potassium currents and accelerated the kinetics of their activation. An inward water flow had quite opposite effects--it decreased the peak and sustained potassium currents and delayed the kinetics of their activation. 3. The analysis of the effect of water flow on the conductance of potassium channels showed that an outward water flow increased both the potassium conductance at a given potential (gk) and the maximum potassium conductance (gkmax). An inward water flow again had the opposite effect--it decreased the potassium conductance at given potential and the maximum potassium conductance. 4. Neither an outward nor an inward water flow significantly affected the fraction of open potassium channels at a given potential [n infinity(V)]. 5. These data suggest that in dialyzed neurons the changes of outward potassium current during water flow through the membrane are due mainly to the changes in single-channel conductance and the time constant of current activation.

摘要

研究了水通过膜的外流和内流对透析的罗马蜗牛神经元外向钾电流的影响。2. 水的外流增加了外向钾电流的峰值和持续外向钾电流，并加速了其激活动力学。水的内流则有相反的作用——它降低了峰值和持续钾电流，并延迟了其激活动力学。3. 对水流对钾通道电导影响的分析表明，水的外流增加了给定电位下的钾电导（gk）和最大钾电导（gkmax）。水的内流再次产生相反的效果——它降低了给定电位下的钾电导和最大钾电导。4. 无论是水的外流还是内流，在给定电位下对开放钾通道的比例[n∞(V)]都没有显著影响。5. 这些数据表明，在透析的神经元中，水流过膜时外向钾电流的变化主要是由于单通道电导和电流激活时间常数的变化。