Cold-adapted rats (unlike non-adapted animals) respond to an acute exposure
to external cold by an overshoot increase in metabolic rate and a paradoxi
cal increase in body core temperature. In contrast to external cooling, int
ernal cooling with the aid of a chronically implanted intravenous heat exch
anger elicited comparable increase in metabolic rate, coupled with a large
fall in core temperature. It is concluded that cold adaptation alters perip
heral thermosensitivity (enhances cold sensitivity), while the thermosensit
ivity of the core is not affected by the adaptation process. (C) 2000 Elsev
ier Science Ltd. All rights reserved.