Altered ambient temperature and ethanol-induced conditioned place preference in mice

Previous studies with rats exposed to altered ambient temperature (T-a) or with mice selectively bred for their thermal response to ethanol have shown that a reduced hypothermic response is correlated with decreased place aversion and greater place preference, respectively. The present experiment was designed to test whether alterations in T-a would alter ethanol's ability to produce conditioned place preference in genetically heterogeneous mice. Three groups of mice underwent a differential conditioning procedure that paired one distinctive floor texture with ethanol (2.25 g/kg, IF) and a different floor texture with saline. During conditioning, each group was exposed to a different T-a: cold (10 degrees C), normal (21 degrees C), or warm (34 degrees C). Each group was further divided and subgroups were tested for preference at either the conditioning temperature or a different temperature. Consistent with previous findings, mice conditioned and tested at normal T-a developed a conditioned preference for the ethanol-paired floor. In contrast, mice exposed to a warm or cold T-a during conditioning or testing failed to show place conditioning. Although exposure to either warm or cold T-a interfered with place conditioning, only the warm T-a had an effect on hypothermia. These findings suggest that altered T-a produced stimuli that may have interfered with the association between floor cues and ethanol during conditioning or interfered with expression of this association during testing. (C) 1998 Elsevier Science Inc.