醛固酮对心室肌细胞动作电位及L型钙通道的影响

Effects of aldosterone on L-tpye calcium channel and action potential of cardiocytes.

目的研究醛固酮对心室肌细胞动作电位及L型Ca2+通道的影响,探讨其致心律失常的机制。方法分离Wister大鼠心室肌细胞,随机分为对照组和Ald组,采用全细胞膜片钳记录方法记录动作电位时程(APD)、L型钙电流(ICa-L)。结果 Ald组APD较对照组显著延长(P<0.05)。Ald组ICa-L电流密度峰值较对照组显著增大[-(9.73±0.90)pA/pF vs-(7.07±0.83)pA/pF,P<0.01]。Ald组与对照组比较,I-V曲线显著下移。结论醛固酮可能通过增加L型Ca2+通道的电流密度,延长心肌细胞APD,参与醛固酮的致心律失常作用。

Objective To investigate the effect of aldosterone on L-tpye calcium channel and action potential of cardiocytes. Methods Single ventrieular myocytes were isolated by enzymatic dissociation method. In aldosterone group,isolated adult rat ventricular myocytes were exposed for 48 hours to aldosterone 100 nmol/L, the action potential duration （APD） and ICa-L. were recorded by whole cell patch clamp technique. Result APD50 ,APD90 and ICa-L significantly increased in Ald group, while I-V curve of ICa-L downwardly. APD50, APD90 and ICa-L didn＇t changed in control group. Conclusion A1- dosterone on cardiomyocytes increases the APD and ICa-L which may contribute to cardiac arrhythmia.