Alterations in gene expression produced by exposure to alcohol have been reported in several studies with rats and mice. Acute ethanol injections (6 g/kg; i.p.) produced changes in whole brain of C57BL/6J and DBA/2J mice (high and low alcohol drinkers, respectively) in expression of genes involved in regulating cell signaling, gene regulation, and homeostasis/stress response (Treadwell and Singh, 2004). Kerns et al. (2005) reported that acute i.p. ethanol injections altered expression of genes involved in glucocorticoid signaling, neurogenesis, myelination, neuropeptide signaling, and retinoic acid signaling in the nucleus accumbens (ACB), prefrontal cortex and ventral tegmental area (VTA) of C57BL/6J and DBA/2J mice. Differences in expression of genes coding for oxido-reductases and ADP-ribosylation factors were found in the dorsal hippocampus of Lewis rats given 12% ethanol or water for 15 months (Saito et al., 2002). In contrast, Saito et al. (2004) found no statistically significant effects of chronic free-choice alcohol drinking on gene expression in the striatum of C57BL/6By mice. The above studies were conducted using ethanol injections or 24-hr free-choice drinking. Moreover, other then the study of Kerns et al.
