are expected during each ethanol access session, when using the present MSA protocol (Bell et al., 2006b, 2008; Murphy et al., 2002). Gene expression was measured 15 hr after the MSA group's last drinking episode when ethanol was also removed from the CA group. It is noteworthy that 10 of these hours occurred during the daily light-cycle, when P rats normally drink limited amounts of ethanol (Bell et al., 2006b, 2006c; Murphy et al., 1986). Nevertheless, it is likely that the CA group experienced symptoms of its first protracted withdrawal at this time point (Kampov-Polevoy et al., 2000; Waller et al., 1982). Therefore, the gene expression differences observed between the CA and W groups may be due in part to ethanol withdrawal. It would be difficult to resolve the issue of withdrawal effects from continuous chronic alcohol drinking without undertaking a more detailed time-course study with this alcohol drinking protocol. However, since the MSA group did not show a significant number of differences in gene expression compared to the W control group (suggesting little effect of repeated BACs, that exceeded 50 mg% per access period, five days per week), the differences between the CA and W groups may reflect the
