THE EFFECTS OF INTRA-ARTERIAL EPINEPHRIN ON THE BLOOD FLOW IN AN EXTREMITY

Abstract

Small doses of epinephrin diluted in whole blood were given in the femoral artery in dogs, and the arterial blood flow measured. The most frequent type of response was a combined dilatation and constriction, and these 2 phases varied in their time relationship according to the rate of flow. This correlation indicates that the site of the dilatation is in the capillary, and that the constriction is in the artery and arteriole. No pure dilator effects were observed, though the dosage was minimal to produce a measurable effect by the method used. The local effect of epinephrin upon the muscle blood vessels is, probably, in all physiologic doses, dilatation of the capillaries and constriction of the arterioles, rather than a reversal of the capillary effect with increased concentrations.