THIRST-HUNGER INTERACTION .I. EFFECTS OF BODY-FLUID RESTORATION ON FOOD AND WATER INTAKE IN WATER-DEPRIVED RATS

Deprived 28 female Wistar albino rats of water for 211/2 hr. and gave, in sequence, (1) intraperitoneal injection of 2, 4, 6, or 8 cc. of water, of .45% NaCl, or of .9% NaCl solution; (2) sham injection; or (3) 30-min free access to water. 30 min. after injections, or immediately after the 30-min free drinking period, either food or water was presented for 1 hr. to assess the effect of the treatments. This period was followed by a 1-hr recovery period when both food and water were provided. Results indicated that injection of isotonic saline did not reduce water intake nor increase food intake beyond sham control level, but water and hypotonic saline reduced water and increased food intake proportionally to the amount injected. Injection of .45% saline was half as effective as water injection on both food and water intake. Complex thirst induced by water deprivation cannot be reduced by extracellular volume restoration alone; intracellular hydration is needed to reduce thirst and stimulate appetite. Water deprivation appears to inhibit feeding through activation of the osmotic thirst system. (30 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.