| Abstract: | Eight experiments were conducted to examine several possible determinants and controls of milk intake in 10-day-old preweanling Sprague-Dawley rats. Results indicate that while the amount of milk the mother provides is a major determinant of milk consumption, pups will individually adjust their intake in response to certain treatments. Deprived pups ingested more milk than nondeprived littermate controls if given access to enough milk. Intragastric intubations of skimmed milk or distilled water reduced milk intake; heavy cream or isotonic saline did not. Injections of polyethylene glycol or formalin, which produced hypovolemia, increased milk consumption, and hypertonic saline decreased it. Results indicate that preweanling rats are behaviorally responsive to certain changes in body fluids and suggest that milk intake involves more than an invariant reflex. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
