APStracts 2:0017R, 1995.

Npy increases food intake in white-crowned sparrows: effect in short and long photoperiods. Richardson, Ralph D., Timothy Boswell, Brian D. Raffety, Randy J. Seeley, John C. Wingfield, and Stephen C. Woods. Departments of Psychology and Zoology, University of Washington, Seattle, WA 98195

APStracts 2:0017R, 1995.

NPY Increases Food Intake in White-Crowned Sparrows: Effect in Short and Long Photoperiods. Am. J. Physiol.: To determine if altered sensitivity to NPY underlies premigratory fattening, white-crowned sparrows held on short daylength (9L15D) received 3rd intraventricular (ivt) injections of saline or several doses of NPY. An inverted-U function occurred with food intake increasing following 1.0 and 2.0 [mu]g after 30 and 60 minutes. When photostimulated (18L6D) birds increased daily caloric intake and gained weight rapidly. Birds maintained on long daylengths significantly increased food intake following 0.25 and 0.5 [mu]g of NPY, and did not respond to higher doses. The effective dose range for NPY to increase food intake moved to the left, suggesting an increase in sensitivity to the peptide on long daylengths. In summary, white-crowned sparrows, consume more food when administered NPY ivt and have increased sensitivity when photostimulated and gaining weight. Hence, NPY may be a natural stimulator of food intake in this species.

Received 3 October 1994; accepted in final form 10 January 1995.
APS Manuscript Number R570-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative Comp.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 February 1995.