Bell et al. (2006) examined the effects of chronic alcohol drinking by alcohol-preferring (P) rats on protein levels in the ACB and amygdala, and reported a small number of changes in each region with chronic alcohol drinking. Recently, Rodd et al. (2008) examined the effects of operant ethanol self-administration on changes in gene expression in the ACB and amygdala of inbred P rats 24 hr after the last 1-hr session. In the ACB, approximately 200 genes significantly differed between the ethanol and water control groups, whereas, in the amygdala, few significant differences were observed. In another recent study (Bell et al., 2009), gene expression changes were determined in the ACB of P rats following two different alcohol drinking conditions, i.e., continuous 24-hr access and multiple 1-hr daily scheduled access periods. Significant differences in expression of genes involved in intracellular signaling pathways and transcription factors were found between the continuous access and water control groups, whereas no significant differences were observed in the ACB between the multiple scheduled access and the water control groups, when measured the day after the last
