Effects of Ro 15-4513 on ethanol discrimination in C57BL/6 mice.

Ro 15-4513, a partial benzodiazepine receptor inverse agonist, counteracts many of the effects of ethanol, however, its effects on ethanol discrimination in operant paradigms remains unclear. The present study examined the effects of Ro 15-4513 on ethanol discrimination by female C57BL/6 mice in a food-reinforced behavior-operant paradigm. Under the time and dosing conditions used in previous reports, Ro 15-4513 did not alter ethanol discrimination whether given prior to or after ethanol exposure. The drug did, however, attenuate ethanol discrimination for brief periods (less than 8 min) when injected after ethanol and at doses and postinjection times which also disrupted responding. The present study confirmed that Ro 15-4513 attenuated ethanol discrimination, but not to the extent as previously reported. The results indicate that postinjection time is a very critical factor in whether Ro 15-4513 attenuates ethanol discrimination.