AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 1 143-R148, Copyright © 1990 by American Physiological Society

ARTICLES

Spontaneous drinking: is it stimulated by hypertonicity or hypovolemia?

T. R. Houpt and C. R. Anderson
Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.

Ten young female pigs were allowed to eat and drink whenever they wanted, and blood samples were taken without disturbance to the pig. Samples were divided into four categories: 1) base line, i.e., taken when not drinking and not eating; 2) preprandial, i.e., taken when starting to drink just before eating; 3) postcibal, i.e., taken when starting to drink after any eating; and 4) nonprandial, i.e., taken when starting to drink but not in association with eating. Osmolality (mosmol/kgH2O), plasma protein (g/dl), and packed cell volume (%) were, respectively, as follows (mean +/- SE): base line 294.9 +/- 1.8, 6.2 +/- 0.1, and 30.0 +/- 1.2; preprandial 295.1 +/- 1.7, 6.1 +/- 0.2, and 29.7 +/- 1.4; postcibal 295.0 +/- 3.3, 6.5 +/- 0.2, and 31.7 +/- 1.3; and nonprandial 295.2 +/- 1.4, 6.3 +/- 0.1, and 30.0 +/- 1.3. None of the parameters associated with drinking were significantly different from base-line parameters, except for the postcibal rise of packed cell volume. Calculated blood volume differences from base line were as follows: preprandial 0.7 +/- 1.2% fall; postcibal 0.2 +/- 1.7% increase; and nonprandial 0.8 +/- 0.9% fall. It is unlikely that either plasma hypertonicity or hypovolemia stimulates drinking under spontaneous conditions.

This article has been cited by other articles:

				T. R. Houpt, H. Yang-Preyer, J. Geyer, and M. L. Norris A rapid feedback signal is not always necessary for termination of a drinking bout Am J Physiol Regulatory Integrative Comp Physiol, April 1, 1999; 276(4): R1156 - R1163. [Abstract] [Full Text] [PDF]