Effects of diazepam, ethanol and Ro 15-1788 on ultrasonic vocalization, locomotor activity and body righting in the neonatal rat.
It has been suggested that ethanol, besides its stimulating, sedative and ataxic effects, also exerts anxiolytic effects similarly to diazepam. In the present study we tested this hypothesis on ultrasonic distress crying in neonatal rats separated from mother and litter-mates. The results showed that both ethanol and diazepam reduced crying in a dose-dependent manner and at doses not affecting the level of motor activity. It was found that the effects of diazepam, but not that of ethanol, was antagonized by the specific benzodiazepine-receptor-antagonist Ro 15-1788. The effects of ethanol were antagonized by the GABA-ergic antagonist picrotoxin. Assessing the sedative/ataxic effects of ethanol and diazepam by the surface body righting response, it was found that the effect of diazepam, but not of ethanol, was antagonized by Ro 15-1788. The results support the hypothesis that ethanol exerts similar anxiolytic actions as diazepam, but that the effects are mediated by different mechanisms.
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D003975:Diazepam / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D005442:Flumazenil / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D011187:Posture; D051381:Rats; D011919:Rats, Inbred Strains; D012018:Reflex / Q000187:drug effects*; D014465:Ultrasonics; D014828:Vocalization, Animal / Q000187:drug effects*
D000431:Ethanol; D005442:Flumazenil; D003975:Diazepam