AJP - Endocrinology and Metabolism, Vol 244, Issue 6 555-E559, Copyright © 1983 by American Physiological Society

ARTICLES

Carotid vascular control of ACTH secretion in lambs

C. E. Wood and A. M. Rudolph

To test the hypothesis that changes in carotid vascular pressure influence ovine ACTH and corticosteroid secretion, we subjected 6- to 7-wk-old conscious lambs to bilateral carotid occlusion with or without prior vagosympathetic blockade. Reversible vagosympathetic blockade, produced by injection of 2% lidocaine onto the vagosympathetic trunks, inhibited the reflex changes in heart rate after intravenous injection of phenylephrine or during carotid occlusion. Vagosympathetic blockade by itself did not alter arterial pressure or heart rate but did increase circulating levels of ACTH and corticosteroids. This suggests that afferent fibers in the vagosympathetic trunks tonically inhibit the secretion of ACTH. Bilateral carotid occlusion did not change plasma ACTH or corticosteroid concentrations. Bilateral carotid occlusion plus prior vagosympathetic blockade stimulated increases in plasma ACTH and corticosteroid concentrations that were larger than responses to vagosympathetic blockade alone. The results demonstrate that changes in carotid vascular pressure influence ovine ACTH and corticosteroid secretion only during vagosympathetic blockade and therefore suggest that carotid vascular mechanoreceptors interact with other mechanoreceptors having vagosympathetic afferent fibers.

This article has been cited by other articles:

				M. J. Powers and C. E. Wood Ketamine inhibits fetal ACTH responses to cerebral hypoperfusion Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2007; 292(4): R1542 - R1549. [Abstract] [Full Text] [PDF]

				H. Tong, F. Lakhdir, and C. E. Wood Endogenous prostanoids modulate the ACTH and AVP responses to hypotension in late-gestation fetal sheep Am J Physiol Regulatory Integrative Comp Physiol, September 1, 1998; 275(3): R735 - R741. [Abstract] [Full Text] [PDF]