氨氯地平对豚鼠心房肌动作电位及早期后除极的影响

用标准玻璃微电极技术观察氨氯地平对豚鼠左房肌快反应动作电位和异丙肾上腺素诱发的早期后除极作用。结果发现氨氯地平5μmol／L对动作电位无影响；10μmol／L可明显缩短动作电位时程（APD），但对动作电位幅度（APA）、0相上升速率（Vmax）、有效不应期（ERP）和三相时程（DP3）无影响；25μmol／L氨氯地平可显著抑制异丙肾上腺素诱发的早期后除极活动。提示：①L型钙电流在异丙肾上腺素诱发的早期后除极活动中起主要作用；②氨氯地平可预防和治疗异丙肾上腺素所致的触发性心律失常。

EFFECTS OF AMLODIPINE ON ACTION POTENTIAL AND EARLY AFTERDEPOLARIZATION IN LEFT ATRIUM MYOCARDIUM OF GUINEA PIG

Standard microelectrode techniqueswere used to study the effects of Amlodipine on fastaction potential and early afterdepolarization inducedby Isoproternenol in left atrium myocardium ofguinea pig. At 5 μmol/L, it had no effect on the action potential; at 10 μmol/L, it caused a significantshortening of the action potential duration and nosignificant changes in action potental duration and nosignificant changes in action potentials amplitude(APA), the maximal rate of rise of phase 0(Vmax), effective refractory period (ERP) and duration of phase 3(DP3); at 25 μmol/L, it markedlyattenuated the development of EAD induced by 50μmol/L Isoporoternenol in left atrium myocardium.The results indicate that Amlodipine may prevent orcure Isoproternenol induced triggered arrhythmias.