Ledda F, Mantelli L, Manzini S, Amerini S, Mugelli A
J Cardiovasc Pharmacol. 1981 Nov-Dec;3(6):1162-73. doi: 10.1097/00005344-198111000-00002.
Propafenon, a new antiarrhythmic drug, caused a 30% decrease in maximal driving frequency and a 65 ms net increase in functional refractory period of isolated guinea pig atria at a concentration as low as 0.5 microgram/ml. The spontaneous rate of isolated atria and the contractility of electrically driven ventricular strips were reduced after treatment with propafenon 1 microgram/ml. Propafenon 0.5 microgram/ml also altered action potentials of sheep Purkinje fiber. It reduced the action potential and overshoot amplitudes, decreased the maximum rate of depolarization of the action potential upstroke in a frequency-dependent fashion, shortened the action potential and effective refractory period, and depressed the membrane responsiveness. Moreover, propafenon antagonized the chronotropic and inotropic effects of isoprenaline in isolated guinea pig heart preparations; the pA2 value was about 6.4. Finally, propafenon possessed very weak calcium antagonist properties, being about 100 times less potent than verapamil in this respect. We conclude that propafenon is an antiarrhythmic drug with beta-adrenoceptor blocking and "membrane stabilizing" activities in the same range of concentrations and that it has a calcium antagonistic activity only at much higher concentrations.
普罗帕酮是一种新型抗心律失常药物，在浓度低至0.5微克/毫升时，可使离体豚鼠心房的最大驱动频率降低30%，功能不应期净增加65毫秒。用1微克/毫升普罗帕酮处理后，离体心房的自发频率和电驱动心室条的收缩力降低。0.5微克/毫升的普罗帕酮也改变了绵羊浦肯野纤维的动作电位。它降低了动作电位和超射幅度，以频率依赖的方式降低了动作电位上升支的最大去极化速率，缩短了动作电位和有效不应期，并降低了膜反应性。此外，普罗帕酮拮抗异丙肾上腺素对离体豚鼠心脏标本的变时性和变力性作用；pA2值约为6.4。最后，普罗帕酮具有非常弱的钙拮抗特性，在这方面其效力比维拉帕米弱约100倍。我们得出结论，普罗帕酮是一种在相同浓度范围内具有β-肾上腺素能受体阻断和“膜稳定”活性的抗心律失常药物，并且仅在高得多的浓度下才具有钙拮抗活性。
