Endothelium-derived Relaxing Factor Activates Calcium-activated Potassium Channels of Resistance Vessel Smooth Muscle Cells  

作　　者：汤云贵 郑永芳 

机构地区：[1]Department of Physiology, Institute of Basic Medical Sciences, CAMS, Faculty of Basic Medicine, PUMC, Beijing 100005, PRC

出　　处：《Science China Chemistry》1993年第4期439-450,共12页中国科学（化学英文版）

基　　金：Project supported by the National Natural Science Foundation of China.

摘　　要：Direct observation was made by using the patch-clamp technique with a specially designed microperfusion system to investigate the effect of acetylcholine (Ach 10^(-6) mol/L) elicited endothelium-derived relaxing factor (EDRF) on the calcium-activated potassium channel (IK(Ca))in the smooth muscle cells of mesenteric resistance vessels in Wistar rats. Activation of IK(Ca) was firstly observed by inducing the elicited EDRF or sodium nitroprusside (SNP 10^(-8) mol/L) under various clamping voltages in cell-attached configuration. While the pipette solution contained KCl 126 mmol/L and the bath solution contained KCl 5.9 mmol/L, two types of conductances of calcium-activated potassium current being 76.4±2.3 pS(mean±S.E. n = 7) and 160.3±7.5 pS (mean±S.E. n= 7) were recorded during the EDRF activation, one type of conductance being 100.5±2.8 pS (mean±S.E. n = 6) was activated by nitric oxide (NO) which is an effective component from SNP. Differences in kinetic characteristics of these channels between EDRF and NO activation were found, particularly the probability of the channel being open in EDRF activation was obviously greater than that in NO stimulation. It has been shown that the potassium channel mechanisms involved in the EDRF and NO actions might be different.Direct observation was made by using the patch-clamp technique with a specially designed microperfusion system to investigate the effect of acetylcholine (Ach 10^-6 mol/L) elicited endothelium-derived relaxing factor （EDRF） on the calcium-activated potassium channel （IK（Ca））in the smooth muscle cells of mesenteric resistance vessels in Wistar rats. Activation of IK（Ca） was firstly observed by inducing the elicited EDRF or sodium nitroprusside (SNP 10^-8 mol/L) under various clamping voltages in cell-attached configuration. While the pipette solution contained KCl 126 mmol/L and the bath solution contained KCl 5.9 mmol/L, two types of conductances of calcium-activated potassium current being 76.4±2.3 pS（mean±S.E. n = 7） and 160.3±7.5 pS （mean±S.E. n= 7） were recorded during the EDRF activation, one type of conductance being 100.5±2.8 pS （mean±S.E. n = 6） was activated by nitric oxide （NO） which is an effective component from SNP. Differences in kinetic characteristics of these channels

关 键 词：endothelium-derived relaxing factor (EDRF) calcium-activated potassium channel (IK(Ca)) mesenterie RESISTANCE VESSEL smooth muscle PATCH-CLAMP technique open MICROPERFUSION system. 

分 类 号：O6[理学—化学]