Chromatographic Studies of the Effect of Intravenous Injections of Tyramine on the Concentrations of Adrenaline and Noradrenaline in Plasma

Abstract

Abstract Intravenous injections of tyramine, increased the concentrations of adrenaline and noradrenaline in the plasma of heparinised blood withdrawn from the lower aortae of chloralosed cats, which had been rested for 30–40 minutes after induction of lasting ganglion block with hexamethonium and exclusion of the adrenals from the circulation. Both the pressor response to tyramine and this increase in catechol amine was abolished either by pretreatment of the animal with reserpine or by the intramuscular injection of cocaine. Only one tenth of the increase in adrenaline and noradrenaline in the plasma of the lower aorta reached the inferior vena cava, and there was only a very small accompanying rise in the catechol amine content of plasma from blood taken from the base of the carotid arteries when the tyramine injected did not exceed 120 μg./kg.