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用细胞内微电极技术观察了马钱子碱（ｂｒｕｃｉｎｅ）对离体豚鼠乳头肌高Ｋ＋除极异丙肾上腺素（Ｉｓｏ）和组织胺（Ｈｉｓ）诱发的慢反应动作电位（ＳＡＰ）的影响。结果表明，低浓度的ｂｒｕｃｉｎｅ延长慢反应动作电位５０％、９０％动作电位时程（ＡＰＤ５０、ＡＰＤ９０），较高浓度的ｂｒｕｃｉｎｅ则抑制ＳＡＰ的幅度（ＡＰＡ）、Ｏ期最大上升速率（Ｖｍａｘ）以及收缩力（Ｆｃ）。将台氏液中Ｃａ２＋浓度由２．０ｍｍｏｌ／Ｌ提高至４．０ｍｍｏｌ／Ｌ时，ｂｒｕｃｉｎｅ对组织胺诱发ＳＡＰ的ＡＰＡ、Ｖｍａｘ以及Ｆｃ的抑制作用反转，提示ｂｒｕｃｉｎｅ可能阻滞心肌Ｃａ２＋通道。
Intracellular microelectrode technique was used to observe the effect of brucine on high-K+ depolarization isoproterenol (Iso) and histamine (His)-induced slow response action potential (SAP) in isolated guinea pig papillary muscles. The results showed that low concentrations of brucine prolonged the slow response action potential 50%, 90% action potential duration (APD50, APD90), and higher concentrations of brucine inhibited SAP amplitude (APA), O phase maximum rate of rise (Vmax) and Contractility (Fc). When Ca2+ concentration in Tyrode’s solution was increased from 2.0 mmol/L to 4.0 mmol/L, brucine reversed the inhibition of histamine-induced SAP APA, Vmax, and Fc, suggesting that brucine may block myocardial Ca2+ channels.