兔肺静脉肌袖心肌细胞动作电位的特性

目的研究兔肺静脉肌袖心肌细胞(PVC)动作电位的特性,并与左房心肌细胞(LAC)进行比较。方法采用全细胞膜片钳技术,进行电流钳制。用800 pA×8 m s的刺激脉冲连续刺激5次,刺激间隔为1 s。引出并记录动作电位。结果PVC动作电位的幅度与LAC的无显著性差异,但前者具有较长的平台期,因而,动作电位时程(APD)较LAC的明显延长,并可以诱发出延迟后除极(DAD)。另外,PVC与LAC的动作电位均具有刺激次数依赖性,但前者更加明显。在APD延长的基础上,PVC可诱发出第二平台反应,表明其具有产生EAD的明显倾向。结论触发活动可能在肺静脉肌袖致心律失常机制中起重要作用。

Characteristics of action potential in rabbit pulmonary vein cadiomyocytes

Objective To investigate the characteristics of action potential in rabbit pulmonary vein cadiomyocytes(PVC),and to compare them with those in left atrial cadiomyocytes(LAC).Methods The whole-cell patch clamp with current clamp was used.Results PVC had similar action potential altitude(APA)with LAC,but had greater action potential duration(APD)and greater plateau phase than LAC.In addition,delayed afterdepolarization(DAD)could be induced in PVC,but could not in LAC.There was stimulating times-dependence of prolongation of APD in both PVC and LAC,but that in the former was more significant than in the latter.On the basis of prolonged APD in PVC,the second plateau response could be induced very easily,showing there was a strong tendency of EAD genesis in PVC.Conclusion The trigger activity might play an important role in the arrhythmogenis in pulmonary vein muscle sleeves.