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Kv4.2通道电流与大鼠海马神经元瞬间外向钾电流特性的比较

金宏伟, 张炜, 屈林涛, 王晓良

医科院中国协和医科大学药物研究所.北京 100050

摘要

转染的Kv4.2通道电流和海马神经元上I_(A)均具有明显的A型电流特征。海马神经元I_(A)的半数最大激活电位和斜率因子分别为-10.0±3.3mV和13.9±2.6mV;半数最大失活电位和斜率因子分别为-93.0±11.4mV和-9.0±1.5mV;失活后再激活恢复时间常数(#tau#)为27.9±14.1ms。Kv4.2的半数最大激活电位和斜率因子分别为-9.7±4.1mV和15.8±5.7mV;半数最大失活电位和斜率因子分别为-59.4±12.2mV和8.0±3.1mV;Kv4.2的灭活后再激活的恢复时间常数#tau#为172.8±10.0ms。结果提示:Kv4.2通道电流可能是海马神经元上的I_(A)电流的主要成分,但不是唯一成分。

关键词： 转染; 钾通道; Kv4.2; 海马; 神经元; 膜片钳

Electrophysiological correspondence between Kv4.2 current and transient outward potassium current in the cultured rat hippocampal neuron

Jin Hongwei, Zhang Wei, Qu Lintao, Wang Xiaoliang

Institute of Materia Medica,Chinese Academy of Medical Science & Peking Union Medical College.Beijing 100050

Abstract

The results showed that I_(A) in cultured rat hippocampal neurons and Kv4.2 expressed in HEK293 cells both displayed "A"-type current properties. The activation curves of I_(A) and Kv4.2 were better fitted by simple Boltzmann function with V_(1/2)-10.0±3.3mV, k 13.9±2.6 mV for I_(A) and V_(1/2)-9.7±4.1 mV, k 15.8±5.7 mV for Kv4.2, respectively. The steady-state inactivation curves of I_(A) had a midopoint of -93.0±11.4mV and a slope of 9.0±1.5 mV. The voltage-dependence of inactivation for Kv4.2 exhibited midpoint and slope values of -59.4±12.2mV and 8.0±3.1 mV, respectively. The time constants (#tau#) of recovery from inactivation of I_(A) and Kv4.2 were 27.9±14.1 ms and 172.8±14.1 ms and 172.8±10.0 ms, respectively. These results suggest that Kv4.2 is probably a major isoform contributing to I_(A) in hippocampus neurons.

Key words: Transfection;Potassium channels;Kv4.2;Hippocampus neuron;Patch;Clamp techniques

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引用本文：

金宏伟, 张炜, 屈林涛, 王晓良. Kv4.2通道电流与大鼠海马神经元瞬间外向钾电流特性的比较[J]. 生理学报 2003; 55 (6): .

Jin Hongwei, Zhang Wei, Qu Lintao, Wang Xiaoliang. Electrophysiological correspondence between Kv4.2 current and transient outward potassium current in the cultured rat hippocampal neuron. Acta Physiol Sin 2003; 55 (6): (in Chinese with English abstract).