| The effects of Progesterone(P) on isolated rabbit sino atrial node pacemaker cells were studied with intracellular microelectrode technique to investigate the changes of action potential(AP) at iON 20N 40~. 60~ 80N 100 and 120 minutes after administration with different doses of P. Results: P induced prolongations of AP durations (APD20,APD50,APD90 and APD) and the total repolarization time (phase 3 of AP) 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. All the results suggested that P inhibits the K+ channels maybe also the Ca2+ channels of rabbit sino atrial cells. |
PDF Full Text Request