红霉素的心脏电生理效应

目的研究大环内酯类抗生素红霉素对心脏快反应动作电位的影响,初步探讨其诱发心律失常的机制。方法应用细胞内微电极技术,研究红霉素对心肌细胞快反应动作电位的影响;利用钾通道特异性阻断剂chromonal 293B和dofetilide研究红霉素对延迟整流钾电流Ikr和Iks的影响。结果红霉素可使豚鼠心室乳头肌快反应动作电位时程和有效不应期延长,0期最大除极速率降低;在chromanol 293B作用基础上,红霉素仍可显著延长动作电位时程;在应用dofetilide完全阻断Ikr的基础上,观察到它并不延长动作电位时程。结论根据红霉素对动物心脏电生理活动的影响,初步推测其可能通过抑制钠和钾离子通道,而且是通过特异性阻断Ikr而产生诱发心律失常效应。

Cardiac Electrophysiological Effect of Erythromycin

Objective To explore effects of crythromycin on fast response action potential. Methods Conventional microelectrode technique was employed to record the fast response action potenital of the isola- ted papillary muscles of guinea pigs. Specific blockers of potassium channels such as chromanol 293B and dofetilide were used to study the effects of erythromycin on the Ikr and Iks. Results Erythromycin could prolong action potential duration and effective refractory period in the fast response action potential of the guinea pigs. The maximum depolarization velocity of 0 phase decreased. Erythromycin prolonged action potential duration on the basis of chromanol 293B,but it didn＇t prolong action potential duration after using dofetilide. Conchlsion Erythmmycin may induce arrhythmia by inhibiting sodium and potassium ion channels, especially Ikr.