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四周模拟失重大鼠后身动脉平滑肌细胞钾电流的改变

付兆君, 程宏伟, 张立藩, 马进

第四军医大学航空航天生理学教研室.陕西,西安 710032

摘要

采用全细胞膜片钳方法观察4周尾部悬吊大鼠(SUS)隐动脉及肠系膜前动脉第2-6级动脉分支血管平滑肌细胞(VSMCs)钾电流密度的变化。结果表明:SUS大鼠后身动脉VSMCs的静息电位(RP)较对照大鼠(CON)后身动脉VSMCs的RP更负。SUS组隐动脉和肠系膜小动脉VSMCs的全细胞钾电流密度较CON组显著增加。其中,SUS组的隐动脉和肠系膜小动脉VSMCs的大电导钙激活钾离子通道(BK_(Ca))和电压激活钾离子通道(K_(V))电流密度较CON组的BK_(Ca)和K_(V)电流密度均显著增加。以上结果提示,VSMCs的超极化及进一步引起的通过电压依赖性钙离子通道的钙内流减少可能是模拟失重引起后身动脉反应性降低的电生理机制之一。

关键词： 模拟失重; 膜片钳; 钾离子通道; 血管平滑肌

Changes in potassium currents of vascular smooth muscle cells isolated from hindquarter arteries of rats after 4 weeks simulated weightlessness

Fu Zhaojun, Cheng Hongwei, Zhang Lifan, Ma Jin

Department of Aerospace Physiology,Fourth Military Medical University.Xi^an 710032,Shaanxi

Abstract

The changes in potassium currents of vascular smooth muscle cells (VSMCs) isolated from saphenous arteries and the 2nd-6th order branches of the mesenteric arteries of 4-week tail-suspended rats (SUS) were examined using whole cell patch clamp technique. The resting potential (RP) of the VSMCs from SUS group was more negative compared with that of the control group (CON). The whole cell potassium current densities of VSMCs isolated from the saphenous arteries and small mesenteric arteries in SUS gruop were significantly larger thanthose of the CON group. The BK_(Ca) and K_(V) current densities of VSMCs from saphenous arteries and small mesenteric arteries from SUS group were also significantly larger than those from the CON group. It is speculated that the hyperpolarization of VSMCs and decreased calcium influx through voltage-dependent calcium channels might be one of the electrophysiological mechanisms involved in the depressed vasoreactivity of hindquarter arteries induced by simulated weightlessness.

Key words: Weightlessness simulation;Patch-clamp techniques;Potassium channels;Vascular smooth muscle

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引用本文：

付兆君, 程宏伟, 张立藩, 马进. 四周模拟失重大鼠后身动脉平滑肌细胞钾电流的改变[J]. 生理学报 2002; 54 (6): .

Fu Zhaojun, Cheng Hongwei, Zhang Lifan, Ma Jin. Changes in potassium currents of vascular smooth muscle cells isolated from hindquarter arteries of rats after 4 weeks simulated weightlessness. Acta Physiol Sin 2002; 54 (6): (in Chinese with English abstract).