Cardiovascular effects of dopamine in the anesthetized cat

Abstract

Noncannulating electromagnetic probes were used to determine the effects of intravenous dopamine on blood flow in the ascending aorta; superior and inferior venae cavae; and in the celiac, left gastric, hepatic, splenic, superior mesenteric, inferior mesenteric, renal, and femoral arteries of cats anesthetized with pentobarbitone. Dopamine produced vasodilatation in the vascular beds of the left gastric, superior mesenteric, and inferior mesenteric arteries and vasoconstriction in the vascular beds supplied by the hepatic and splenic arteries. Vasodilatation commonly occurred in the innervated hindlimb but the denervated limb showed only constriction. Renal vasodilatation was slight and inconstant. Heart rate and stroke volume increased. Arterial pressure changes were variable. A pressor effect usually occurred but, especially with low doses, a depressor component was seen. [beta]-Adrenergic blockade prevented the cardiac effects of dopamine but not the peripheral vasodilatation or the depressor component of the pressure response. Dopamine therefore possesses the unusual characteristic of being a cardiac [beta]-adrenergic receptor stimulator which produces peripheral vasodilatation by a non-[beta]-adrenergic mechanism.