Adaptation to cold swim stress-induced hypothermia: Absence of Pavlovian conditional tolerance

Mice subjected to cold swim stress developed pronounced hypothermia. Exposure to warm water swim, however, had little or no effect on body temperature. After repeated exposure to cold swim, the stress-induced hypothermia was attenuated. The finding that cold swim resulted in hypothermia, whereas warm swim had no effect in this respect, provided a useful experimental design by which to assess the role of conditioning factors in the adaptation to the thermic effects of cold swim. In two subsequent experiments, mice received cold swim either in a familiar environment or in a novel environment. Adaptation to the thermic effects of cold swim was observed when mice were tested in the distinctive environment, regardless of the environmental cues previously paired with repeated exposure to the cold swim stress. These findings suggest that contextual cues were not of primary importance in the development of tolerance to the thermic effects of cold swim stress.