AJP - Regulatory, Integrative and Comparative Physiology, Vol 238, Issue 5 333-R339, Copyright © 1980 by American Physiological Society

ARTICLES

Thirst and vasopressin release in the dog: an osmoreceptor or sodium receptor mechanism?

T. N. Thrasher, C. J. Brown, L. C. Keil and D. J. Ramsay

The effects of intravenous infusion of hypertonic NaCl, sucrose, glucose, urea, or isotonic NaCl solution on thirst and plasma arginine vasopressin concentration (AVP) were studied in five conscious dogs. The changes in osmolality and sodium concentration of plasma and cerebrospinal fluid (CSF) were measured at the threshold of drinking, or after 45 min if no drinking occurred. Hypertonic NaCl and sucrose stimulated drinking in all dogs and significantly elevated plasma AVP. Equally hypertonic glucose, urea, or isotonic NaCl failed to stimulate any drinking or vasopressin secretion. All hypertonic solutions caused significant and similar increases in the osmolality and sodium concentration of CSF. Plasma osmolality was increased by the hypertonic solutions. Plasma sodium was increased by hypertonic NaCl, decreased by sucrose and glucose, and not changed by urea. Isotonic NaCl had no effect on either plasma or CSF composition. These data are not consistent with either a sodium or an osmoreceptor mechanism located within the blood-brain barrier (BBB) or with a peripheral sodium receptor mechanism. An intracranial osmoreceptor located on the blood side of the BBB is proposed to explain these results.

This article has been cited by other articles:

				J. M. Ho, D. K. Zierath, A. V. Savos, D. J. Femiano, J. E. Bassett, M. J. McKinley, and D. A. Fitts Differential effects of intravenous hyperosmotic solutes on drinking latency and c-Fos expression in the circumventricular organs and hypothalamus of the rat Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2007; 292(4): R1690 - R1698. [Abstract] [Full Text] [PDF]

				V. L. Brooks, Y. Qi, and T. L. O'Donaughy Increased osmolality of conscious water-deprived rats supports arterial pressure and sympathetic activity via a brain action Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2005; 288(5): R1248 - R1255. [Abstract] [Full Text] [PDF]

				J. A. Freece, J. E. Van Bebber, D. K. Zierath, and D. A. Fitts Subfornical organ disconnection alters Fos expression in the lamina terminalis, supraoptic nucleus, and area postrema after intragastric hypertonic NaCl Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2005; 288(4): R947 - R955. [Abstract] [Full Text] [PDF]

				D. A. Fitts, J. A. Freece, J. E. Van Bebber, D. K. Zierath, and J. E. Bassett Effects of forebrain circumventricular organ ablation on drinking or salt appetite after sodium depletion or hypernatremia Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2004; 287(6): R1325 - R1334. [Abstract] [Full Text] [PDF]

				V. L. Brooks, K. L. Freeman, and T. L. O'Donaughy Acute and chronic increases in osmolality increase excitatory amino acid drive of the rostral ventrolateral medulla in rats Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2004; 287(6): R1359 - R1368. [Abstract] [Full Text] [PDF]