Anti-arrhythmic and beta-adrenoceptor blocking activities of vanilol

Vanilol (1-(2-methoxy-4-methyoxycarbonyl-1-phenoxy)-3-isopropylamino-2-propanol) is a derivative of protocatechuic acid with the same side chain as that of propranolol. In the isolated rabbit left atria, the effective refractory period (ERP) could be prolonged by 16% y vanilol 10(-5) M. The aconitine-induced arrhythmia in rats and ouabain-induced arrhythmia in guinea pigs could be antagonized by the constant iv cumulative dose of vanilol 30 mg/kg. The epinephrine-induced arrhythmia in anesthetized dogs and rabbits could be prevented by iv vanilol 2 and 10 mg/kg, respectively. In anesthetized cats, the beta-adrenergic blocking potency of propranolol was approximately 73 times that of vanilol. The acute LD50 (+/-SD) in mice given by po, ip and iv were 401+/-102, 207+/-53 and 50+/-13 mg/kg, respectively. In subacute toxicity test in rats, vanilol was ip at daily doses of 50 and 100 mg/kg for 14 days. No noticeable changes of the blood picture, SGPT, morphology of liver and kidneys were observed.