Effects of hydrational state on ingestion in infant rats: is dehydration the only ingestive stimulus?
The physiological stimulus for deprivation-enhanced ingestion was studied in developing rats. During an overnight deprivation period, continuous gastric infusions of isotonic saline or milk were made to 6- and 15-day-old rat pups in order to preferentially maintain hydrational or hydrational and nutritional status, respectively. Pups' ingestion was then studied in oral-infusion tests. In 6-day-old pups that received either milk or saline infusions, ingestion was depressed relative to intake in pups that were simply deprived. But in 15-day-old pups, only milk infusions reduced intake. These findings suggest that the increased ingestion stimulated by deprivation in pups less than a week of age results primarily from dehydration, and thus that nutrient-related feeding does not emerge until later in development.
Phifer
C B
CB
Louisiana Scholars' College, Northwestern State University, Natchitoches 71497.
Ladd
M D
MD
Hall
W G
WG
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D003259:Consummatory Behavior / Q000502:physiology*; D004327:Drinking Behavior / Q000502:physiology; D005508:Food Deprivation / Q000502:physiology; D009752:Nutritional Status / Q000502:physiology*; D051381:Rats; D013894:Thirst / Q000502:physiology*; D014868:Water Deprivation / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000502:physiology*