AJP - Regulatory, Integrative and Comparative Physiology, Vol 261, Issue 5 1226-R1233, Copyright © 1991 by American Physiological Society
Mechanism of drinking-induced inhibition of vasopressin secretion in dehydrated dogs
B. H. Appelgren, T. N. Thrasher, L. C. Keil and D. J. Ramsay
Department of Physiology and Oral Clinical Physiology, Karolinska Institute, Stockholm, Sweden.
Ingestion of water stimulates a powerful inhibitory input to secretion of
arginine vasopressin (AVP) in many species. A previous study in dogs has
suggested that the stimulus arises from activation of oropharyngeal
receptors, but the nature of the stimulus is unknown. The objectives of
this study were to determine if the taste, osmolality, or temperature of
the solution ingested constituted an important element in the inhibitory
mechanism and if these same attributes affected the volume ingested in
response to 24 h of water deprivation in conscious dogs. Experiments
consisted of a control period, a 6-min period of access to fluid, and a
60-min period after drinking, with blood samples taken frequently to assess
changes in plasma AVP. Dogs were placed in a sling that allowed them to
stand or lie supported with easy access to a bowl. The solutions were water
at 20 and 38 degrees C; 0.9% NaCl at 20 and 38 degrees C; 1.8 and 2.7% NaCl
at 20 degrees C; 5% glucose and mannitol and 10% mannitol at 20 degrees C;
and liquified food at 20 degrees C. In the time-control experiment dogs
were allowed to see but not drink water for 6 min.(ABSTRACT TRUNCATED AT
250 WORDS)
