孕酮对兔窦房结细胞电活动的影响

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

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 (APD2 0 、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 ,零期最大除极速率 (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 Ca2

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.