Figure 1.

Acute guanfacine treatment (0.3 and 0.6 mg/kg) significantly decreased voluntary alcohol intake compared with vehicle in rats voluntarily consuming (a) high (4.3±0.2 g/kg per 24 h; n=11) but not (b) low (1.9±0.2 g/kg per 24 h; n=7) amounts of alcohol for ∼5 months before the treatment. (c) There was no rebound increase in alcohol intake during the first drinking session after treatment in rats consuming high amounts of alcohol. All values are expressed as mean±SEM; **P<0.01, ***P<0.001 compared with corresponding vehicle ((a, b) two-way repeated-measures ANOVA followed by planned comparisons; (c) one-way repeated-measures ANOVA followed by Newman–Keuls multiple comparison test).