A comparison of the anti-arrhythmic actions of I.C.I. 50172 and (--)-propranolol and their effects on intracellular cardiac action potentials and other features of cardiac function.

摘要: Abstract 1. I.C.I. 50172 had marked quinidine-like effects on intracellular cardiac action potentials at concentrations above 20 mg/l. (6·61 × 10-5M). The rate of rise and overshoot the potential, conduction velocity contractions were decreased. (—)-Propranolol similar less than 1/30 this concentration. 2. 1/100 activity (—)-propranolol as a local anaesthetic. Since is also ratio their in vitro β-receptor blocking activities, provides no net increase specificity blockade. 3. In contrast, vivo protecting anaesthetized guinea-pigs against ouabain-induced ventricular fibrillation was 40% that (—)-propranolol. 4. Structure-activity relations drugs are discussed.