Additionally, we have demonstrated that SD rats will consume significantly higher amounts of 20% ethanol (0.96 ± 0.10 g/kg/30min) compared to 10% ethanol (0.39 ± 0.10 g/kg/30min) with pharmacologically relevant BECs in an operant self-administration paradigm. These results coincide with previous evidence in the literature that suggests that out-bred rats may consume greater amounts of ethanol when higher concentrations of ethanol are presented (Amit et al., 1970; Samson et al., 1999; Samson et al., 1988; Simms et al., 2010; Wise, 1973, 1975). However, it is difficult to prove that the SD rats in the present study have an inherent preference for higher ethanol concentrations because of the long-term ethanol exposure these animals experienced in their home cage. In the future, it would be interesting to observe the performance of ethanol-naive, adult SD rats in the operant setting to evaluate the impact of prior chronic ethanol exposure on subsequent operant self-administration.
