Amerini S, Giotti A, Mugelli A
Br J Pharmacol. 1985 May;85(1):89-96. doi: 10.1111/j.1476-5381.1985.tb08834.x.
The effects of verapamil and diltiazem on normal action potentials, abnormal automaticity at depolarized membrane potential and oscillatory afterpotentials were compared in sheep cardiac Purkinje fibres. Concentrations of verapamil and diltiazem exerting the same action on abnormal automaticity due to slow action potentials, caused different effects on action potential characteristics and on oscillatory afterpotentials. Diltiazem significantly shortened action potential duration whereas verapamil slightly lengthened it (NS). Diltiazem appeared to be more effective than verapamil in preventing the development of oscillatory afterpotentials induced by barium or by strophanthidin. In 50% of barium-treated preparations, verapamil caused the appearance of spontaneous activity due to enhanced normal diastolic depolarization, while diltiazem had no such effect. The observed differences were explained in terms of the different effects of the two drugs on currents other than the slow inward current, since diltiazem was more potent than verapamil in depressing Vmax.
在绵羊心脏浦肯野纤维中比较了维拉帕米和地尔硫䓬对正常动作电位、去极化膜电位时的异常自律性以及振荡后电位的影响。维拉帕米和地尔硫䓬对因慢动作电位导致的异常自律性发挥相同作用的浓度，对动作电位特征和振荡后电位产生了不同影响。地尔硫䓬显著缩短动作电位时程，而维拉帕米使其稍有延长（无统计学差异）。在预防钡或毒毛花苷诱导的振荡后电位的发生方面，地尔硫䓬似乎比维拉帕米更有效。在50%的经钡处理的标本中，维拉帕米因增强正常舒张期去极化而导致自发活动的出现，而地尔硫䓬没有这种作用。观察到的差异根据这两种药物对除慢内向电流之外的其他电流的不同作用来解释，因为地尔硫䓬在抑制最大去极化速度方面比维拉帕米更有效。
