Effects of Context Shift on Tolerance to Alcohol and Peak-interval Behavior in Rats

The current study used 64 rats to examine the effect of context shift on tolerance to alcohol, assessed by performance on a peak-interval task. Past research has extensively studied chronic alcohol intake and the mechanisms that underlie development of tolerance to alcohol in both humans and animals (McCusker & Brown, 1990; White, Roberts, & Best, 2002). Specifically, prior research has examined the effect of context-specific tolerance to alcohol on animal’s motor functioning and body temperature (Siegel & Sdao-Jarvie, 1986), with the general pattern of findings suggesting that tolerance is maintained only in a particular context previously associated with a drug. The current study extended previous findings on contextspecific drug tolerance by examining whether a context change has an effect on tolerance to alcohol, assessed through examining an animal’s internal clock. A peak-interval task was used to demonstrate the accuracy and precision with which animals time their responses. The subjects trained in an alcohol-related context were predicted to show tolerance to alcohol in the same context as indicated by a stable response curve on a peak-interval task. However, the response curve was predicted to shift to the left, indicating an increased number of premature responses for the subjects when moved to a different environment. The results indicated that the animals that received alcohol overestimated time in a novel environment compared to those receiving alcohol in the familiar context (and to control groups that received water). However, the amount of alcohol consumed was not associated with an increase in the number of premature responses, and, contrary to the original prediction, gender was found to have no effect on the amount of alcohol that the subjects drank. The limitations of the study and the directions for future research are also addressed.