N-甲基小檗胺对豚鼠单一心肌细胞慢内向离子电流的作用

Effect of N-methyl berbamine on slow inward current in single cardiac cell of guinea pigs

N-甲基小檗胺（N-methyl berbamine,NMB）是从陕西省凤县产小檗属植物中提取的一种双苄基异喹啉生物碱,结构与小檗胺（berbamine）相似,为黄连素的同系物,动物实验表明,黄连素及小檗胺具有抗心律失常作用,大剂量可抑制心肌收缩,本文用膜片钳术（patch clamp technique）全细胞记录（whole cell recording）方法,观察了NMB对豚鼠单一心肌细胞慢内向离子电流(Ⅰsi的影响,从离子通道水平对NMB的抗心律失常作用机理进行了初步探讨。

The effect of N-methyL berbamine (NMB) at three different concentrations (0.1, 1.0 and 10μmol·L-1) on the Isi in single cardiac ventricular cell of guinea pigs was studied with patch clamp technique and whole-cell recording method. The holding potential was -30 mV in the experiment. The results show that NMB can reduce Isi in a dose-dependent manner and the Isi is decreased to 1.6± 5 0.27, 1.26± s 0.29 and 0.28± s 0.08 nA at concentrations of 0.1, 1.0 and 10μmol ·L-1 of NMB, respectively, compared with control (2.42 ± s 0.41 nA).According to the current- voltage (Ⅰ-Ⅴ) relationship curve, the reversal potential of lsi in the control was 51.8± s 1.8 mV. It was decreased to 45.0± s 2.7, 39.4± s 1.4 and 23.4± s 1.5 mV at 0.1, 1.0 and 10 μmol· L-1 of NMB, respectively. The results suggest that NMB may be a calcium channel blocker.