Water regulation in weanling hypodipsic dorsomedial hypothalamic-lesioned rats.
Weanling rats with dorsomedial hypothalamic nuclei lesions (DMN-L) are hypodipsic and hypophagic when compared to sham-operated rats. When tested for interdependence of food and water intake (WI) the DMN-L rats drank in the absence of food and ate in the absence of water. The data suggest DMN-L rats are not prandial drinkers. On testing for intracellular thirst (5.8 or 5.4% NaCl, 1 ml/100 g body wt), extracellular thirst [polyethylene glycol (PG), 25% wt/vol, 0.5 ml/35 g body wt], or a combination of both thirsts, the DMN-L rats responded as well or better than the control animals when the test data were expressed as a percentage of the rat's base-line WI. Both groups were more responsive to PG when tested in the light phase. When injected with angiotensin II (200 micrograms/100 g body wt) both groups responded similarly. Therefore, whereas the DMN-L rats were hypodipsic in comparison to controls, they respond as well or better than control animals when classical thirst testing procedures are utilized. It is suggested that DMN-L may have "reset" WI similarly to the previously proposed reset for body weight and food intake.
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001835:Body Weight; D004327:Drinking Behavior / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D007031:Hypothalamus / Q000502:physiology*; D007033:Hypothalamus, Middle / Q000502:physiology*; D051381:Rats; D013894:Thirst / Q000502:physiology*
D000804:Angiotensin II