Intrastriatal administration of a 21-mer phosphorothioate antisense oligodeoxynucleotide targeting the adenosine A1 receptor blocked ethanol-induced motor incoordination in the rat and reduced striatal adenosine A1 receptor content, as judged by specific binding of the A1-specific ligand 8-cyclopentyl-1,3-dipropylxanthine (Bmax = 0.350 +/- 0.07, Kd = 1.87 +/- 0.50 nM). No effect upon striatal adenosine A2 receptor content was observed (Bmax = 0.415 +/- 0.04, Kd = 13.13 +/- 1.25 nM) with the A2-specific ligand 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine. A mismatched control oligodeoxynucleotide of identical G-C base composition and general sequence structure was without effect on adenosine A1 receptor (Bmax = 0.666 +/- 0.11, Kd = 1.32 +/- 0.27 nM) or adenosine A2 receptor content (Bmax = 0.501 +/- 0.08; Kd = 14.65 +/- 1.82 nM) or ethanol-induced motor incoordination. These results confirm an important role of the striatal adenosine A1 receptor in mediating certain motor-related physiological effects of ethanol.