AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 3 589-R594, Copyright © 1984 by American Physiological Society
Carotid arterial control of vasopressin secretion in sheep
C. E. Wood, L. C. Keil and A. M. Rudolph
The purpose of this study was to test the role of carotid arterial
mechanoreceptors in the control of vasopressin secretion in conscious 6- to
7-wk-old lambs. Bilateral carotid occlusion decreased lingual arterial
pressure and stimulated reflex increases in heart rate and femoral arterial
blood pressure but did not significantly alter plasma concentrations of
vasopressin. Acute vagosympathetic blockade, produced by injection of 2%
lidocaine onto the vagosympathetic trunks, did not significantly alter
heart rate or blood pressure but did stimulate a slow increase in plasma
vasopressin concentration, suggesting that afferent vagal fibers tonically
inhibit vasopressin secretion. Bilateral carotid occlusion after
vagosympathetic blockade stimulated a brisk increase in plasma vasopressin
that was larger than the response to vagosympathetic blockade alone. These
results suggest that vasopressin secretion in lambs is partially controlled
by arterial mechanoreceptors in the carotid sinus and by extracarotid
receptors with vagosympathetic afferent fibers.
