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目的兔心房和肺静脉上的非选择性阳离子通道与TRPC3非常相似,本实验通过对兔肺静脉肌袖心肌细胞(PVC)和心房肌细胞(LAC)动作电位及TRPC3类通道电流特性的研究,进一步探讨TRPC3类通道在早后除极(EAD)中的作用及起源于肺静脉的阵发性房颤的电生理机制。方法采用全细胞膜片钳技术分别记录PVC和LAC的动作电位及非特异性阳离子流,同时加用胰岛素,观察胰岛素对动作电位及电流的影响。结果 PVC动作电位时程较LAC的明显延长,并可以诱发第二平台反应,加用胰岛素后PVC和LAC动作电位时程均明显缩短。通过加用GdCl3,我们在PVC和LAC上可记录到非选择性阳离子流,且PVC的电流密度较LAC的小;而如果我们加用胰岛素,PVC和LAC的电流密度均增加,且PVC的电流密度较LAC增加的少。结论 PVC较LAC的动作电位时程(APD)明显延长,表明其具有产生EAD的明显倾向,进而可能导致快速性心律失常的发生,胰岛素可明显的缩短动作电位时程。PVC的电流密度较LAC的明显减小,PVC和LAC存在的复极离子流的差异构成了两者动作电位差异的基础;胰岛素可使电流密度增加,可初步判定PVC和LAC上存在的TRPC3类通道为TRPC3。
The rabbit atrial and pulmonary venous non-selective cation channels and TRPC3 is very similar in this experiment through the rabbit pulmonary vein ventricular cardiomyocytes (PVC) and atrial myocytes (LAC) action potential and TRPC3 channel current characteristics of further study The role of TRPC3-like channels in early depolarization (EAD) and the electrophysiological mechanisms of paroxysmal atrial fibrillation originating in the pulmonary veins. Methods Whole-cell patch-clamp technique was used to record the action potentials and nonspecific cation currents of PVC and LAC respectively. At the same time, insulin was added to observe the effects of insulin on action potentials and currents. Results The duration of action potential of PVC was significantly longer than that of LAC and could induce the response of the second platform. The duration of PVC and LAC action potentials were significantly shortened when insulin was added. By adding GdCl3, we can record non-selective cation flow on PVC and LAC, and the current density of PVC is smaller than that of LAC; but if we add insulin, the current density of PVC and LAC increases, and the current of PVC The density is less increased than LAC. Conclusions Compared with LAC, PVC significantly prolongs the action potential duration (APD), indicating that it has a clear tendency to produce EAD, which may lead to the occurrence of tachyarrhythmia. Insulin may shorten the course of action potential. PVC current density significantly reduced compared with LAC, PVC and LAC exist complex ion current differences constitute the basis of the difference between the two action potentials; insulin can increase the current density can be initially determined PVC and LAC exist TRPC3 The channel is TRPC3.