NSU-MD Faculty Articles

Carotid sinus reflex vasoconstriction in right coronary circulation of dog and pig.

Publication Title

The American journal of physiology

Publisher

American Physiological Society

ISSN

0002-9513

Publication Date

8-1-1981

Keywords

Animals, Carotid Artery Diseases, Carotid Sinus, Constriction, Pathologic, Coronary Circulation, Dogs, Electric Stimulation, Isoproterenol, Perfusion, Phenylephrine, Propranolol, Reflex, Stellate Ganglion, Swine, Sympathetic Nervous System, Vasoconstriction

Abstract

This study was designed to evaluate the effects of the sympathetic nervous system on right ventricular and right coronary hemodynamics in the anesthetized vagotomized dog and pig during constant-pressure coronary perfusion. Carotid occlusion in the dog resulted in an increase in heart rate, aortic pressure, right ventricular dP/dt, and a sustained 13% decrease in right coronary artery blood flow and a 14% increase in coronary vascular resistance. This coronary vasoconstriction was not modified during beta-blockade with propranolol but was prevented by alpha- blockade with phentolamine. Similar hemodynamic data was obtained in the pig and, in addition, it was found that the O2 consumption of the right ventricle is low (4.8 +/- 0.4 ml O2.min-1.100 g-1) and is only slightly increased (5.l5 +/- 0.8 ml.min-1.100 g-1) during carotid occlusion. These data suggest that baroreflex-mediated sympathetic stimulation to the heart evokes only a minor increase in metabolic activity in the right ventricular myocardium so that the direct neural (alpha-vasoconstrictor) effect predominates over the metabolic vasodilator mechanism.

DOI

10.1152/ajpheart.1981.241.2.H149

Volume

241

Issue

2

First Page

H149

Last Page

H154

Disciplines

Medicine and Health Sciences

Link to Full Text
Peer Reviewed

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