Effects of concurrent access to a single concentration or multiple concentrations of ethanol on the intake of ethanol by male and female periadolescent alcohol-preferring (P) rats

The objectives of this study were to assess the effects of access to different concentrations of ethanol and sex of the animal on ethanol consumption during periadolescence [postnatal days (PNDs) 30-60] in alcohol-preferring (P) rats. On PND 28, female and male P pups were single housed in hanging stainless steel cages with ad libitum access to water and food. Beginning on PND 30, the rats were also given access to either a single concentration [15% volume/volume (vol./vol.)] or multiple concentrations [10%, 20%, and 30% (vol./vol.)] of ethanol. Differences between sex (male vs. female) and ethanol conditions (single concentration vs. multiple concentrations), for the average amount of ethanol consumed for each week (starting on PND 33) of access, were examined. Analyses of the data for ethanol drinking revealed significant (P <.025) main effects of week and ethanol condition, as well as a significant week x ethanol condition interaction. For the first week, both male and female P pups consumed more ethanol under the multiple-ethanol-concentration condition than under the single-ethanol-concentration condition. However, across the second through fourth weeks, this pattern was seen only in female P pups. When preference for one concentration of ethanol over the other concentrations was assessed, it was found that male P pups tended to choose the 30% concentration over the 10% and 20% concentrations, whereas female P pups did not display a preference. The findings of this study corroborate previous work indicating that periadolescent P rats readily acquire high-ethanol-drinking behavior and that, similar to adult P rats, concurrent access to multiple concentrations of ethanol further enhances ethanol intake. These findings suggest to us that innate genetically influenced mechanisms promoting high ethanol intake are present at this stage of development. (C) 2003 Elsevier Inc. All rights reserved.