Fig. 5.

Chronic administration of varenicline significantly decreases ethanol consumption in rats chronically consuming ethanol (intermittent access to 20% ethanol). Varenicline (2 mg/kg s.c.) or vehicle was administered to two different groups of rats on each of 6 consecutive days, 30 min before the start of the ethanol- or water-drinking session. The effect of varenicline or vehicle on ethanol consumption was measured on days 1, 3, and 6 and compared with baseline drinking levels. Varenicline but not vehicle administration significantly decreased ethanol consumption (g/kg) compared with baseline drinking levels at 30 min (A) and 6 h (B) after the onset of drinking. Vehicle administration had no significant effect on the ethanol consumption compared with baseline drinking levels at 30 min (A) or 6 h (B) after the onset of drinking. There was no difference between baseline and posttreatment baseline drinking levels within either the varenicline or vehicle group, respectively (A and B). The values are expressed as mean ± SEM (repeated-measures ANOVA within each treatment group followed by Newman–Keuls post hoc test). **, P < 0.01; ***, P < 0.001 compared with baseline drinking levels, n = 5.