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目的：探讨Ｏ（４乙氧基丁基）小檗胺（ＥＢＢ）对离体蛙心的影响．方法：应用Ｓｔｒａｕｂ法制备离体蛙心；使用ＬＭＳ２Ａ记录仪经张力换能器描记心脏活动．结果：ＥＢＢ１－１００μｍｏｌ·Ｌ－１剂量依赖性增强蛙心收缩与舒张活动，但不影响心率；ＥＢＢ２５０－５００μｍｏｌ·Ｌ－１则引起心跳减慢，甚至停搏．ＥＢＢ的正性肌力作用不受西咪替丁１０μｍｏｌ·Ｌ－１和哌唑嗪１００μｍｏｌ·Ｌ－１影响；但可被维拉帕米０．０１μｍｏｌ·Ｌ－１所拮抗．ＥＢＢ能增强ＣａＣｌ２的正性肌力作用．与咖啡因和异丙肾上腺素比较，ＥＢＢ起效较慢，作用持续时间较长；但室温为（２１．０±０．５）℃时，与哇巴因比较却恰好相反．结论：ＥＢＢ的正性肌力作用至少部分是通过促进外Ｃａ２＋内流而非促进内Ｃａ２＋释放所致．
Objective: To investigate the effect of O (4ethoxybutyl) berbamine (EBB) on isolated frog heart. Methods: Straub method was used to prepare isolated frog heart; LMS A2A was used to record heart activity via tension transducer. Results: EBB1-100μmol·L-1 dose-dependently enhanced the contractile and diastolic activity of the frog but did not affect the heart rate. EBB250-500μmol·L-1 caused a slow heartbeat or even a cardiac arrest. The inotropic effect of EBB was not affected by cimetidine 10μmol·L-1 and prazosin 100μmol·L-1; however, it was antagonized by verapamil 0.01μmol·L-1. EBB enhances the positive inotropic effect of CaCl2. Compared with caffeine and isoproterenol, EBB has a slower onset of action and a longer duration of action. However, at room temperature (21.0 ± 0.5) ° C, EBB has the opposite effect compared with ouabain. CONCLUSION: Intrinsic inotropic action of EBB is at least partly due to the promotion of extracellular Ca2 + influx rather than the promotion of intracellular Ca2 + release.