Effects of Intra-arterial and Intravenous Epinephrine on Disappearance of Nal 131 from Calf Muscle and on Calf Blood Flow

Abstract

The effects of intra-arterial and intravenous infusions of epinephrine on total blood flow in the calf and on capillary blood flow in calf muscle were determined in human subjects rising venous occlusion plethysmography and radioisotope disappearance rates respectively. The two technics usually demonstrated similar changes with both intravenous and intraarterial routes of administration. Since intravenous epinephrine affected the radioisotope disappearance rates, the hypothesis that epinephrine acts on arteriovenous shunts alone does not appear to apply in these experiments. Intra-arterial epinephrine often produced a sustained increase in blood flow similar to that produced by intravenous epinephrine, indicating that the initial and sustained actions could be explained by local effects of the agent. These studies also add further support for using the radioisotope disappearance rate as a qualitative measure of skeletal muscle blood flow.