机械牵张对缺血乳头肌动作电位的影响  

Effects of mechanical stretch on action potential of ischemic isolated papillary muscles of guinea pig hearts

作　　者：王志强[1] 程龙献[1] 廖玉华[1] 王嘉陵[2] 张俊红[2] 周利龙[1] 纪科伟[3] 

机构地区：[1]华中科技大学同济医学院心血管病研究所华中科技大学同济医学院附属协和医院心内科,武汉430022 [2]华中科技大学同济医学院药理系 [3]华中科技大学同济医学院附属协和医院骨外科

出　　处：《临床心血管病杂志》2004年第2期104-106,共3页Journal of Clinical Cardiology

基　　金：国家自然科学基金项目 (No :30 2 70 5 5 9)

摘　　要：目的 :研究机械牵张对模拟缺血状态下体外豚鼠乳头肌动作电位 (AP)的影响。方法 :建立模拟缺血条件下体外豚鼠乳头肌机械牵张模型 ,2 4只豚鼠随机分为正常对照组、单纯缺血组和缺血加链霉素组 ,每组 8只。利用细胞内标准玻璃微电极技术 ,记录并观察一定牵张力 ( 2 0 0mg强度 )作用下体外豚鼠乳头肌细胞AP各参数 [AP 0相最大升速率 (Vmax)、AP幅值 (APA)、AP复极达 2 0 %的时程 (APD2 0 )、AP复极达 5 0 %的时程(APD50 )和AP复极达 90 %的时程 (APD90 ) ]的变化。结果 :正常对照组牵张前后AP各参数无明显变化 (均P >0 .0 5 ) ;与正常对照组相比 ,单纯缺血组和缺血加链霉素组在牵张前上述参数均显著降低 (均P <0 .0 1) ;单纯缺血组 ,牵张使AP的Vmax和APA显著下降 ,APD2 0 、APD50 和APD90 明显缩短 (均P <0 .0 1) ;在缺血加链霉素组 ,牵张前后AP的上述指标无显著变化 (均P >0 .0 5 )。结论 :机械牵张易导致缺血心肌电生理参数变化 ,即缺血心肌对牵张反应的敏感性增加 ;Objective:To investigate the effects of stretch under simulated ischemic conditions on action potential of isolated papillary muscles of guinea pig hearts. Methods:The stretch models were made in simulated ischemic isolated papillary muscles of guinea pig hearts, and they were divided randomly into three groups: the normal control group, the pure ischemia group and the ischemia & streptomycin group. The intracellular standard glass microelectrode technique was used, and effects of stretch(intensity:200 mg) on action potential(Vmax、APA、APD 20 、APD 50 and APD 90 ) were observed in ischemic papillary muscles of guinea pig hearts.Results:No significant parameter changes of action potential were found in control group when stretching was applied. Compared with those in control group, parameters of action potential were all distinctly decreased in ischemic group in the absence and presence of streptomycin. In pure ischemia group, stretching greatly reduced Vmax and APA, and greatly shortened APD 20 、APD 50 and APD 90 . In ischemia & streptomycin group, no significant changes were found in all above mentioned parameters.Conclusion:The stretch of ischemic papillary muscles of guinea pig hearts may more easily cause changes of their action potential than the stretch of the normal, that is, ischemic myocardium may respond more sensitively to the same stretch than normal myocardium. What's more, streptomycin (a blocker of stretch activated ionic channels) can effectively inhibit the effects of electric physiologic changes caused by mechanical stretch.

关 键 词：缺血心肌 牵张激活性离子通道 动作电位 链霉素 

分 类 号：R541.4[医药卫生—心血管疾病]