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cGMP对原代培养猪冠状动脉平滑肌细胞钙激活钾通遭的作用

柴强, 曾晓荣

山东省医学科学院生理室；沪州医学院电生理室

摘要

3′，5′-环一磷酸鸟苷（cGMP）具有激活血管平滑肌细胞膜上钙激活钾通道（KCa通道）的作用，从而引起血管平滑肌细胞的舒张。但cGMP激活KCa通道的机制存在争论。本工作应用膜片箝技术以原代培养猪冠状动脉平滑肌细胞为对象研究了cGMP影响KCa通道的机制。实验结果显示：（1）在cell－attached膜片方式下，当浴液内游离Ca2+浓度为10－7mol／L，膜电位为＋70mV时，不同浓度的cGMP的膜透过类似物8－bromo-cGMP（0．25mmol／L，0．50mmol／L，1．00mmol／L）对此类通道有明显的激活作用；（2）在inside-out膜片方式下，1．00mmol／L的8－bromo－cGMP对通道却无激活作用。说明cGMP对KCa通道的激活作用并非是直接的，而是需要经过一系列的胞内过程才能实现。

关键词： 3′; 5′－环一磷酸鸟苷; 血管平滑肌; 膜片箝技术; 钙激活钾通道

MA Yong-Jie

2College of Information Engineering, Taishan Medical University, Taian 271016, China

Abstract

Guanosine 3′,5′-cyclic monophosphate(cGMP)is capable of relaxing vascular smooth muscle through activaing calcium-activated potassium channels(KCa channel)in the vascular smooth muscle cell membrane.But regarding the mechanism it is still under debate.In the present work the mechanism of the effect of cGMP on KCa channel in primary cultured porcine coronary artery smooth muscle cells using patch clamp technique was investigated.Exprimental results showed that(1)different concentrations of 8-bromo cGMP(0.25 mmol/L,0.50 mmol/L,1.00 mmol/L),serving as a membrane permeable anologue,could activate KCa channels,and(2)1.00 mmol/L 8-bromo-cGMP could not activate such kind of channels in inside-out patch under the same condition.These results suggested that the activaing effect of cGMP on KCa channls was indirect,being mediated by some intracellular process.

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引用本文：

柴强, 曾晓荣. cGMP对原代培养猪冠状动脉平滑肌细胞钙激活钾通遭的作用[J]. 生理学报 1998; 50 (1): .

MA Yong-Jie. . Acta Physiol Sin 1998; 50 (1): (in Chinese with English abstract).