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目的:研究雌二醇(Estradiol,Est)对心室肌细胞动作电位(AP)、内向整流钾通道电流(I_(K1))及延迟整流钾通道电流(I_K)的影响。方法:全细胞膜片箝技术。结果:EST 10μmol·L~(-1)使豚鼠心室肌细胞AP时程明显缩短,APD_(50)由给药前(474±71)ms缩短至(330±75)ms(P<0.05),Est 100μmol·L~(-1)使APD_(50)缩短至(229±67)ms(P<0.01),使APD_(90)由(587±60)ms缩短至(418±79)ms(P<0.05)。Est浓度依赖性地抑制I_K尾电流(I_K·tail),10μmol·L~(-1)浓度下,I_K·tail减少53％(P<0.05),100μmol·L~(-1)浓度下,I_K·tail减少80％(P<0.05)。10μmol·L~(-1)以上浓度Est明显抑制I_(K1),在-100mV刺激电压下,内向电流最大抑制为49％(P<0.01);在-40mV刺激电压下,外向电流最大抑制为72％(P<0.01)。同时,Est使I_(K1)翻转电位向负电位方向移位(由-70mV变为-76mV)。结论:Est对豚鼠心室肌细胞I_(K1)和I_K通道具有明显的抑制作用。
Objective: To investigate the effects of estradiol (Est) on the action potential (AP), inward rectifier potassium channel current (I_ (K1)) and delayed rectifier potassium channel current (I_K) in ventricular myocytes. Methods: Whole cell patch clamp technique. Results: The AP time course of APD 50 was shortened to 330 ± 75 ms (330 ± 75 ms) before administration of EST (10 μmol·L -1) in guinea pig ventricular myocytes, Est (100 μmol·L -1) shortened APD 50 to 229 ± 67 ms and decreased APD 90 from 587 ± 60 ms to 418 ± 79 ms P <0.05). Est inhibited the I_K tail current (I_K · tail) in a concentration-dependent manner, and the I_K · tail decreased by 53% (P <0.05) at the concentration of 10μmol·L -1. In the concentration of 100μmol·L -1, I_K Tail reduced by 80% (P <0.05). The concentration of Est above 10μmol·L -1 significantly inhibited I_ (K1), and the maximum inward current inhibition was 49% at -100mV stimulation voltage (P <0.01). The maximum outward current inhibition was 72% (P <0.01). At the same time, Est shifts the I_ (K1) flip potential to the negative potential (from -70 mV to -76 mV). Conclusion: Est has a significant inhibitory effect on I_ (K1) and I_K channels of guinea pig ventricular myocytes.