Neuropeptide Y (NPY) increases food intake when administered into the third ventricle (i3vt). In the usual experimental paradigm, the approach or appetitive phase and the ingestive or consummatory phase are necessarily confounded. To determine if NPY has a differential effect on these two phases of food intake, we utilized the intraoral intake paradigm in which liquid food is infused directly into the mouth and the animal need only engage in the stereotyped oro-motor movements associated with ingestion. Rats with indwelling intraoral cannulas received i3vt saline or NPY. Intake of pelleted chow or of 0.1 M sucrose in a bottle were significantly increased by 9.5 μg of NPY. Intake of 0.1 M sucrose, when delivered intraorally, was not affected by doses of 0, 3.0, 9.5 or 30 μg of NPY. Additionally, 24-h food deprivation nearly doubled intake in the intraoral intake paradigm in the same rats. These results suggest that NPY does not alter the consummatory phase of food intake, and that if the appetitive phase of food intake is elicited, the consummatory phase is secondarily increased. Finally, since food deprivation but not NPY increases intraoral intake, NPY administration does not completely mimic the stimulus state associated with food deprivation.
ASJC Scopus subject areas
- Nutrition and Dietetics