Ro15-4513 differentially affects ethanol-induced hypnosis and hypothermia.

Recent reports of in vivo antagonism of the acute anti-conflict, ataxic, and lethal effects of ethanol with the partial inverse agonist imidazobenzodiazepine Ro15-4513 implicate the GABAa/benzodiazepine receptor in mediating several acute effects of ethanol. These data raise the question as to whether all of the acute effects of ethanol can be antagonized by Ro15-4513. The present study addressed this issue by investigating the effect of Ro15-4513 on ethanol-induced loss of righting reflex and hypothermia in mice. We found that Ro15-4513 antagonized the hypnotic, but not the hypothermic, effects of ethanol when tested under identical conditions. These results suggest that the GABAa/benzodiazepine receptor may not be involved in mediating all pharmacological effects of ethanol.