Influence of Propranolol on Hemodynamic Changes and Plasma Catecholamine Levels Following Cigarette Smoking and Nicotine. ∗

Summary

Cigarette smoke inhalation or intravenous infusion of nicotine produced a marked increase in cardiac output, stroke volume, arterial blood pressure and plasma epinephrine and norepinephrine levels with a reflex decrease in heart rate in the morphine-pentobarbital anesthetized dog. Following beta adrenergic blockade with 0.2 mg/kg propranolol intravenously, cigarette smoke inhalation and nicotine infusion resulted in a marked alteration of cardiac output, stroke volume, heart rate and mean arterial pressure without significant changes in caval plasma catecholamine levels. It is concluded that beta adrenergic blockade produced by propranolol does not modify the release of catecholamines from the adrenal glands of dogs in response to smoking and nicotine and that the “unmasking” of alpha receptor activity causes a marked increase in systemic peripheral resistance and compromises left ventricular function.