EFFECT OF HISTAMINE AND OTHER ENDOGENOUS AMINES ON THE PERIPHERAL HEMODYNAMICS IN RABBITS UNDER THE CONTROLLED CARDIAC OUTPUT

1. The mode of action of histamine and other endogenous amines on the peripheral hemodynamics in rabbits was investigated using a mechanical left ventricle according to J.C. Rose. 2. The arterial and peripheral venous pressure together with the left auricular outflow were recorded under the controlled cardiac output, thereby arterial pressure represented the total peripheral resistance and the left auricular outflow to the reservoir indicated the venous return. 3. Histamine injected intra-aortically increased the total peripheral resistance and acted also on the veins to increase the venous pressure and left auricular outflow, but the latter two decreased in the following period. The pulmonary vessels were affected by intravenously injected histamine to produce a significant decrease in the left auricular outflow. 4. Adrenaline and noradrenaline administered intra-aortically raised the total peripheral resistance and venous pressure and increased the left auricular outflow significantly, but their action on the right ventricle and the pulmonary circulation to affect the left auricular outflow was not so significant. The action of these catecholamines on the capacitance vessels was noted. 5. Serotonin administered intra-aortically increased the total peripheral resistance in most of the cases, the effect on the venous pressure and left auricular outflow resembling that of histamine. But serotonin administered intravenously produced characteristic von Bezold-like effect to lower the total peripheral resistance and vonous pressure together with the left auricular outflow.