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血小板活化因子对豚鼠心室肌细胞动作电位和钾通道的影响

杜以梅, 唐明, 刘长金, 柯琴梅, 骆红艳, 胡新武

华中科技大学同济医学院生理系. 湖北, 武汉 430030；华中科技大学同济医学院附属协和医院. 湖北, 武汉 430022

摘要

应用全细胞膜片钳技术研究了血小板活化因子(Platelet activatingfactor,PAF)对豚鼠心室肌细胞动作电位和钾电流的影响.结果发现,当电极内液ATP浓度为5 mmol/L(模拟正常条件)时,1 μmol/LPAF使APD_(90)由对照的225.8±23.3 ms延长至352.8±29.8ms(n=5,P＜0.05);使I_(K)尾电流在指令电压+30 mV由对照的173.5±16.7 pA降至152.1±11.5 pA(P＜0.05,n=4);使I_(kl)在指令电压为-120 mV时由对照组的-6.1±1.3 nA降至-5.6±1.1 nA(P＜0.05,n=5);但PAF在生理膜电位范围(-90mV～+20mV)对I_(K1)没有影响.当电极内液ATP浓度为0mmol/L时,I_(KATP)开放(模拟缺血条件),1 μmol/LPAF却显著缩短APD_(90),由对照的153±24.6 ms缩短至88.2±19.4 ms(n=5,P＜0.01).而用1 μmol/L格列本脲[I_(KATP)的特异阻断剂)预处理后,恢复了PAF可显著延长动作电位时程的作用.结果提示,PAF可能扩大缺血心肌和正常心肌细胞动作电位时程的不均一性,是缺血/再灌注性心律失常发生的重要原因。

关键词： 血小板活化因子; 心肌细胞; 动作电位; 钾通道; 膜片钳技术

Effects of platelet activating factor on action potentials and potassium channels in guinea-pig ventricular myocytes

Du Yimei, Tang Ming, Liu Changjin, Ke Qinmei, Luo Hongyan, Hu Xinwu

Department of Physiology, Tongji Medical College of Huazhong University of Science and Technology. Wuhan 430030, China；Department of Geriatrics, the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. Wuhan 430022, China

Abstract

This study was designed to investigate the effects of platelet activating factor (PAF) on the action potential and potassium currents in guinea-pig ventricular myocytes. Whole cell patch clamp techniques were used. With 5 mmol/LATP in the pipette electrode (mimic normal condition), 1 #mu#mol/LPAF increased APD_(90) from 225.8±23.3 to 352.8±29.8 ms (n=5, P＜0.05), decreased I_(K1) and I_(K) tail currents from -6.1±1.3 to -5.6±1.1 nA (n=5, P＜0.05) at -120 mV and from 173.5±16.7 to 152.1±11.5 pA (P＜0.05, n=4) at +30 mV,respectively. But PAF had no effect on I_(K1) at potentials within the normal range of membrane potentials (between -90 mV and +20 mV).restore prolongation of APD induced by PAF. In conclusion, in guinea-pig ventricular myocytes, with 5 mmol/L ATP in the pipette PAF hence a decrease in APD. It is suggested that PAF may amplify the heterogeneity between ischemic and normal cardiac myocytes during ischemia/reperfusion, which may play a vital role in the pathogenesis of the arrhythmias induced by ischemia/reperfusion.

Key words: Platelet activating factor;Cardiac myocyte;Action potential;Potassium channels;Patch clamp technique

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引用本文：

杜以梅, 唐明, 刘长金, 柯琴梅, 骆红艳, 胡新武. 血小板活化因子对豚鼠心室肌细胞动作电位和钾通道的影响[J]. 生理学报 2004; 56 (3): .

Du Yimei, Tang Ming, Liu Changjin, Ke Qinmei, Luo Hongyan, Hu Xinwu. Effects of platelet activating factor on action potentials and potassium channels in guinea-pig ventricular myocytes. Acta Physiol Sin 2004; 56 (3): (in Chinese with English abstract).