Lu X D, Zhao G S, Zhao Y Q
Department of Pharmacology, Xi-an Medical University, China.
Zhongguo Yao Li Xue Bao. 1991 Mar;12(2):170-2.
The effects of metoclopramide (Met) on the action potential of rabbit sinus node cells and slow response action potential of guinea pig papillary muscles were studied with the intracellular microelectrodes. Met 10 mumol.L-1 prolonged the action potential duration at 90% repolarization (APD90) of SA node cell and sinus cycle length (SCL). Met 100 mumol.L-1 caused a decrease in action potential amplitude (APA), Vmax and the slope of phase 4 of action potential of SA node cell. APD90 and SCL were prolonged further. For slow response action potential induced by KCl (25 mmol.L-1), Met 100 mumol.L-1 produced a decrease in APA and depolarization rate. Met 10 mumol.L-1 began to suppress the spontaneous electrical activities induced by barium ion. These findings suggest that Met probably has the effect of blocking calcium inward current in myocardium.
采用细胞内微电极技术，研究了甲氧氯普胺（Met）对家兔窦房结细胞动作电位及豚鼠乳头肌慢反应动作电位的影响。10 μmol.L-1的Met可延长窦房结细胞90%复极化动作电位时程（APD90）和窦性周期长度（SCL）。100 μmol.L-1的Met可使窦房结细胞动作电位幅度（APA）、最大上升速率（Vmax）及动作电位4期斜率降低，APD90和SCL进一步延长。对于由25 mmol.L-1氯化钾诱发的慢反应动作电位，100 μmol.L-1的Met可使APA及去极化速率降低。10 μmol.L-1的Met开始抑制钡离子诱发的自发电活动。这些结果提示，Met可能具有阻断心肌内向钙电流的作用。
