OSMOREGULATORY THIRST IN RATS AFTER LATERAL PREOPTIC LESIONS

Conducted 5 experiments using a variety of dehydrational procedures to characterize drinking behavior in rats with lesions of the lateral preoptic area (LPO). In confirmation of previous observations, lesions of the LPO in male albino Sprague-Dawley rats abolished water ingestion during a 4-hr test following an ip injection of hypertonic NaCl solution. These Ss increased their water intakes when tests were prolonged to 24 hrs and drank almost exactly what they needed for osmoregulation. Furthermore, they increased their water intakes normally when NaCl was given in their diet, when NaCl was administered iv, or when they were water deprived and given preloads of isotonic saline to remove hypovolemia. These findings indicate that rats with lateral preoptic lesions do experience osmoregulatory thirst, and raise new doubts about whether osmoreceptors located in the lateral preoptic area mediate thirst following the administration of osmotic loads. (34 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1978 American Psychological Association.