Release of renin by the carotid baroreflex in anesthetized dogs. Role of cardiopulmonary vagal afferents and renal arterial pressure.

Abstract

In 3 of 10 anesthetized dogs with aortic nerves sectioned and renal arterial pressure maintained constant, reduction to 40 mm Hg of the pressure in the vascularly isolated carotid sinuses resulted in an increase in renin secretion. After section of the vagus nerves, carotid sinus hypotension resulted in an increase in renin secretion in 9 of the 10 dogs. Vagal nerve section in these 10 dogs with carotid sinuses vascularly isolated and maintained at a pressure equal to existing aortic pressure resulted in significant increases in basal levels of plasma renin activity and renin secretion. The increase in renin secretion found during carotid sinus hypotension in vagotomized dogs was totally or substantially inhibited when renal arterial pressure was not maintained constant but allowed to increase equally with systemic arterial pressure. The increase in renin secretion observed during carotid hypotension in vagotomized dogs with renal arterial pressure held constant was abolished by renal denervation. The carotid baroreflex is involved in the neural control of renin release. A concomitant activation of cardiopulmonary receptors and/or a substantial rise in renal arterial pressure can suppress the reflex increase in the secretion of renin induced by carotid sinus hypotension.