Neuropeptide Y administration into the amygdala suppresses ethanol drinking in alcohol-preferring (P) rats following multiple deprivations

The present experiment examines the effects of NPY administered into the amygdala on ethanol drinking by alcohol-preferring P rats following long-term continuous ethanol access, with and without multiple periods of imposed ethanol abstinence. P rats had access to 15% (v/v) ethanol and water for 11 weeks followed by 2 weeks of ethanol abstinence, re-exposure to ethanol for 2 weeks, 2 more weeks of ethanol abstinence, and a final ethanol re-exposure. Immediately prior to the second ethanol re-exposure, 4 groups of rats received bilateral infusions NPY (0.25, 0.5, 1.0 μg) or artificial cerebrospinal fluid (aCSF) into the amygdala. Two additional groups were given uninterrupted ethanol access and were infused with a single NPY dose (1.0 μg) or aCSF. The highest NPY dose (1.0 μg) suppressed ethanol intake for 24 h in rats with a history of ethanol abstinence (i.e. deprivation) periods, but had no effect in rats with a history of continuous ethanol access. Water and food intakes were not altered. These results suggest that the amygdala mediates the suppressive effects of centrally administered NPY on ethanol drinking, and that NPY may block relapse-like drinking by opposing the anxiogenic effects of ethanol abstinence.