Decreased sensitivity to ethanol reward in adolescent mice as measured by conditioned place preference.

Background: Many preclinical studies have demonstrated age-related differential sensitivity to various effects of ethanol between adolescent and adult animals. However, published data addressing possible differences in ethanol's motivational effects are sparse, particularly in mice. The present study examined age-related differences in the conditioned rewarding effects of ethanol in DBA/2J mice.

Methods: In the first experiment an unbiased place conditioning procedure was used to determine the rewarding effects of 2 g/kg ethanol in adult and adolescent DBA/2J mice. In a subsequent place conditioning experiment, the effects of 2 and 4 g/kg were assessed in adolescent mice.

Results: Adolescents demonstrated a place preference with the high dose of 4 g/kg but not with a more moderate dose of 2 g/kg. In contrast, 2 g/kg was sufficient to produce place preference in adult mice.

Conclusions: Adolescents are less sensitive than adults to the rewarding effects of ethanol but can experience reward with high doses. These results extend the current literature on ethanol's effects in adolescent animals.