红霉素对豚鼠单心室肌细胞APD及主要跨膜离子电流的作用

Effects of erythromycin on APD and main currents involved in action potentional in single guinea pig ventricular myocytes

目的 通过观察红霉素对豚鼠单心室肌细胞动作电位时程 (APD)及动作电位形成过程中主要跨膜离子电流的作用 ,探讨其诱发室性心律失常的电生理学机制 .方法 采用膜片钳全细胞技术记录红霉素对 ADP及主要电流的影响 .结果 红霉素可使 APD明显延长 ,并选择性地抑制了延迟整流钾电流 (IK)中的快速激活成份 IKr.红霉素对心室肌细胞直接的电生理作用较弱 ,只有在较高浓度时才会对单心室肌细胞 APD及 IKr产生抑制作用 .结论 红霉素通过选择性抑制IKr而使 APD延长 ,这可能是临床应用红霉素诱发室性心律失常的机制 .

AIM To explain the ventricular tachycardia induced by administration of erythromycin by observing the its effects on action potential duration (APD) and main ion channel currents in guinea pig ventricular myocytes. METHODS Whole cell patch clamp techniques were used. RESULTS Erythromycin prolonged APD and selectively blocked the rapid activating component of the delayed rectifier potassium current ( I Kr ). The electrophysiological effects of erythromycin on ventricular myocytes were weak. It prolonged APD and inhibited I Kr only at relatively high concentrations. CONCLUSION Erythromycin could prolong APD by selectively blocking the rapid activating component of the delayed rectifier potassium current ( I Kr ), which may be the mechanisms of ventricular tachycardia induced by erythromycin.