Clonidine-ethanol synergistic behavioral interaction requires activation of the α2A-adrenergic receptor. Rotorod time courses (A), corresponding area under the curve (AUC, B), and LORR durations (C) are shown for groups pretreated with the selective α2A-receptor antagonist RX821002 (RX, 0.3 mg, i.c.) 10 min prior to 2 i.v. injections of: (i) saline + saline (RX), (ii) 60 μg/kg clonidine + saline (RX + Clonidine), (iii) saline + 1 g/kg ethanol (RX + Ethanol), or (iv) 60 μg/kg clonidine + 1 g/kg ethanol (RX + Clon + EtOH). All other aCSF i.c. pretreated groups (Sal, Clon, EtOH, and Clon + EtOH) are replotted for comparison from Fig. 1. The number of animals per group is shown in parentheses above the bar graphs. p < 0.05, * differs from Sal, RX, Clon, RX + Clon, and EtOH (rotorod trends also differed); #differs from Clon. LORR data did not reach significance due to unequal variance.