Effects of concurrent access to a single concentration or multiple concentrations of ethanol on ethanol intake by periadolescent high-alcohol-drinking rats

The objectives of the current study were to assess the effects of access to different concentrations of ethanol and sex of the animal on ethanol consumption of high-alcohol-drinking (HAD-1 and HAD-2) rats during adolescence [postnatal days (PNDs) 30 through 60]. At the beginning of adolescence (PND 30), the rats were given concurrent access to either a single concentration [15% volume/volume (vol./ vol.)] or multiple concentrations [10%, 20%, and 30% (vol./vol.)] of ethanol and water. Analyses of ethanol consumption data revealed significant (P <.025) main effects of line, ethanol condition, and week, and a significant line by sex by ethanol condition by week interaction. For the first week, both male and female HAD-1 and HAD-2 rats 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 primarily in male and female HAD-1 rats and to a lesser degree in female HAD-2 rats. In general, female rats consumed more fluids than consumed by male rats, and male rats displayed a higher preference for ethanol over water ratio than observed for their female counterparts. In addition, in comparison with HAD-2 rats, HAD-1 rats drank more ethanol and displayed a higher preference for ethanol ratio. Overall, the current study results indicate that, compared with access to a single concentration (which is used in most studies), concurrent access to multiple concentrations of ethanol produced significantly higher ethanol intakes in periadolescent HAD rats, supporting the suggestion that this ethanol drinking condition would have a greater impact on neuronal development. In addition, although the replicate lines were selectively bred by using the same criteria and foundation stock, the higher ethanol intakes of the HAD-1 line, compared with intakes for the HAD-2 line, seen in the current study support the suggestion that there are some differences in their genetic make-up, affecting ethanol intake, which are expressed during periadolescence. (C) 2004 Elsevier Inc. All rights reserved.