Antagonism of selected ethanol-enhanced brain stimulation properties by Ro 15-4513

Low doses of ethanol increase responding for brain stimulation. Recently, other intoxicating effects of ethanol have been reversed by the imidazobenzodiazepine, Ro 15-4513. Possibly, Ro 15-4513 blockade also acts on reward-enhancing properties of ethanol. Rats trained to alternately shuttle between nose poke and lever operanda for rewarding stimulation to the medial forebrain bundle, were tested following intragastric intubations of ethanol (18%, 1.35 g/kg), Ro 15-4513 (3 mg/kg in 18% ethanol), or vehicle. Ro 15-4513 reversed ethanol-enhanced effects on reinforced responses. Because Ro 15-4513 did not completely block instrumental responding for brain stimulation, we conclude its effects on ethanol were not acting on the same reward substrate as the current and consummatory response.