Regional skin temperature changes in a rat model for the menopausal hot flush.
Administration of naloxone to morphine-dependent male and female rats produced a significant rise in both tail skin temperature and foot temperature with a subsequent fall in colonic temperature. The magnitudes of the skin temperature surges were similar in the two regions, with the elevation in foot temperature preceding the rise in tail skin temperature. These regional skin temperature surges were similar in magnitude, duration and temporal pattern in both the male and female rat, and are similar to those exhibited in men and women undergoing flushing episodes. Castration of males did not alter these temperature responses. The only difference in response between male and female rats was the more pronounced fall in colonic temperature observed in morphine-dependent female rats following administration of naloxone. Neither the administration of naloxone to placebo-treated animals nor that of saline to morphine-dependent animals produced any changes in skin or colonic temperature in either male or female rats. These results suggest that the pattern of skin temperature alterations associated with morphine withdrawal in both the male and female rat is similar to the pattern of skin temperature surges associated with the hot flush in men and women, which provides additional evidence for the morphine-dependent rat as a model for women who exhibit flushing episodes. Additionally, this is the first report of a potential model for men who exhibit flushing episodes.