Changing oral cues in suckling of weaning-age rats: Possible contributions to weaning.

Abstract

The relative contribution of oral and nutritional stimuli in the control of suckling in 20 and 25 day old rat pups was assessed. Oral factors were critical to suckling satiety, since the initiation of a suckling bout in weanling pups is not retarded by food infused directly into the stomach. As late as 20 days of age, suckling deprivation induces suckling largely through its stimulus-deprivation effects rather than through its food-deprivation effects. By 25 days of age, the type of oral stimulation that leads to suckling satiety expands; oral stimulation provided by independent feeding acquires characteristics that allow it also to inhibit suckling. This developmental change in the stimuli that modulates suckling does not appear to be critically dependent upon sensory changes in the dam or experiential events within the litter. The behavioral change may represent a maturation of neural systems that facilitate the transition from suckling to independent feeding.