孕酮对兔窦房结细胞电活动的影响

目的：通过观察孕酮（P）对离体家兔窦房结细胞动作电位的影响，来探讨孕酮对窦房结细胞电活动的影响及其作用机制。方法：采用微电极技术，引导窦房结细胞动作电位，观察不同浓度孕酮对窦房结细胞动作电位各参数的影响。结果：（1）孕酮使兔窦房结细胞动作电位时程（APD20、APD50、APD90、APD）、总复极时间（RPT）显著延长。孕酮对窦房结细胞动作电位各参数的影响呈时间、浓度依赖性。（2）孕酮使兔窦房结细胞动作电位幅度（APA）减小，零期最大降极速率（Vmax)减慢，使窦房结细胞0期除极时间（DPT）延长。结论：较高浓度的孕酮对离体家兔窦房结细胞的K^ 通道有一定程度的阻断作用，对其Ca^2 通道可能也有阻断作用。

Electophysiological Effects of Progesterone on rabbit Sino-Atrial Node Pacemaker Cells

Objective: To study the effects of progesterone (P) on action potential of isolated rabbit sino atrial node cells. Methods: With intracellular microelectrode technique to investigate the changes of action potential (AP) at 10,20,40,60,80,100 and 120 minutes after administration with different doses of progesterone. Results: P induced prolongation of AP durations (APD 20 , APD 50 , APD 90 , and APD) and the total repolarization time(RPT) significantly in concentration dependent and time dependent manners. P also significantly decreased action potential amplitude(APA) and the maximal velocity rate of depolarization of phase 0(Vmax) in concentration and time dependent manners. Conclusion: All the results suggest that P inhibits the K++ channels and may also inhibit the Ca ++ channels of rabbit sino atrial cells.