Context-specific tolerance to the ataxic effects of alcohol

Tolerance to alcohol and many other drugs can become conditioned to specific contextual cues present at the time of drug administration. Context-specific tolerance occurs to a variety of alcohol's effects, including changes in hormone levels, body temperature and locomotor activity. The present study investigated whether context-specific tolerance can occur to the ataxic effects of alcohol. Baseline levels of motor coordination were assessed using a tilting plane apparatus. During a 7-day tolerance acquisition phase, subjects received an injection of either alcohol (1.5 g/kg i.p.) or saline (15 ml/kg i.p.) in a novel testing room and were then placed in the tilting plane apparatus for a period of 20 min. Approximately 5 h after the first injection, subjects received a second injection in the colony room and were then placed in their home cages. One group of subjects, the paired group, received alcohol in the testing room and saline in the colony room. An unpaired group received saline in the testing room and alcohol in the colony room. A no alcohol control group received saline in both environments. Following the tolerance acquisition phase, all subjects were injected with alcohol (1.5 g/kg i.p.) and tested for ataxia in the tilting plane apparatus. Subjects in the paired group were less ataxic than subjects in the control group during all four testing blocks following alcohol administration. In contrast, subjects in the unpaired group were less ataxic than the control subjects only during the 15-min testing block. Relative to baseline scores, the paired group exhibited deficits only during the 5- and 10-min testing blocks, while subjects in the unpaired and control groups exhibited deficits during all four testing blocks. These data strongly suggest that tolerance to the ataxic effects of alcohol can become conditioned to contextual cues present at the time of alcohol administration.