Altered Ambient Temperature and Ethanol-Induced Conditioned Place Preference in Mice

Abstract

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, IP) and a different floor texture with saline. During conditioning, each group was exposed to a different T a: cold (10°C), normal (21°C), or warm (34°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.