Adolescent and adult rats appear to exhibit differential sensitivity to the motivational effects of ethanol when assessed by means of a second order conditioning (SOC) procedure. In adolescents, the association between an intraoral CS1 and ethanol’s postabsorptive consequences successfully endowed the CS1 with reinforcing properties. Specifically, CS1 later acted as an appetitive second-order reinforcer, mediating the expression of conditioned place preferences. Adult animals, in contrast, did not show significant changes in tactile preferences as a function of the preceding associations between ethanol (0.5 or 2.0 g/kg, yielding BELs between 47 and 150 mg%; Fig. 4) and the CS1. Adolescent and adult subjects had similar ethanol levels in blood and brain across doses and postadministration time, except in the case of the higher ethanol dose at the later sampling interval, where BELs and BrELs were found to be lower in adult rats. The effects obtained at each age were neither dose-dependent nor did they vary significantly as a function of postadministration time.
