Animal models have been used to study the influence of genetic factors on the effects of alcohol and on alcohol drinking behavior (reviewed in Bell et al., 2005; McBride and Li, 1998; Murphy et al., 2002). Demonstrating that animals will drink alcohol for its CNS effects and will attain relevant blood alcohol concentrations (BACs) is crucial for establishing a valid animal model to study brain mechanisms leading to the development and maintenance of excessive alcohol drinking. Among the rodent models, only the P line has been shown to satisfy all of the perceived criteria for an animal model of alcoholism (reviewed in McBride and Li, 1998; Murphy et al., 2002; Bell et al., 2005). In addition, innate differences in levels of gene expression in 5 CNS regions, including the ACB, have been reported between inbred P and inbred alcohol-non-preferring (NP) rats (Kimpel et al., 2007). Previously, it was established that P rats, given one-hour access to 10% ethanol 4 times during the dark cycle (water available ad lib), will consume nearly as much alcohol as rats given 24-hr free-choice access
