The effects of clonidine treatment on alcohol intake during the daily 2-h freechoice between alcohol and water in a 2-day treatment trial are presented in Fig. 1. There was no significant difference among treatment groups on the pre-drug day. During the 2 treatment days there was a significant effect of dose [F(4,46) = 17.95, p < 0.001] but no significant effect of day and no significant dose × day interaction. Further pairwise comparisons using the Fisher’s LSD test revealed that alcohol intake was decreased (p < 0.001) by clonidine at doses of 40 or 80 µg/kg relative to treatment with vehicle, independent of day. On post-treatment days 1 and 2, there was a significant effect of dose [F(4,46) = 4.51, p < 0.01] but no significant effect of day and no significant dose × day interaction. Further pairwise comparisons using the Fisher’s LSD test revealed that alcohol intake was decreased (p ≤ 0.05) by previous treatment with clonidine 40 or 80 µg/kg relative to previous treatment with vehicle, independent of day.
