Mutual suppression of cardiovascular effects of some β-adrenoreceptor agonists in the cat

Abstract

Observations were made of the effects of adrenaline, isoprenaline and orciprenaline on the blood pressure, heart rate and configuration of the ECG in cats. The effects of single injections of these amines in producing a rise in heart rate and a fall in blood pressure were reduced during the intravenous infusion of any one of them: the pressor response to injected adrenaline was enhanced during an infusion. Combinations of these amines did not produce changes in the configuration of the ECG. These experiments were motivated by allegations of acute toxic effects on the cardiovascular system of large doses, or of combinations, of sympathomimetic bronchodilators in asthma. No evidence of deleterious effects of interactions was obtained.