Cold-adaptation: Neuropeptide Y versus thermal signals in the development of hyperphagia

(1) Chronic cold exposure elicited immediate hyperphagia in rats, while the fasting-induced hyperphagia became enhanced after 3 weeks (but not 1 week) of adaptation. (2) The NPY-induced hyperphagia increased quickly with cold-adaptation, even in tests performed outside the cold chamber. (3) Resting core temperature decreased by about 0.4–0.6 °C after 3 weeks (full adaptation). (4) Peripheral cold signals rather than NPY appear to be important in the fast development of cold-induced hyperphagia. (5) NPY may play a slowly developing, additional role in this hyperphagia and may contribute to mild hypothermia.