Differential interactions of Ro 15-4513 with benzodiazepines, ethanol and pentobarbital

The effects of the imidazobenzodiazepine Ro 15-4513 in combination with three CNS depressants (ethanol, benzodiazepine agonists and pentobarbital) were examined in three different experiments. Full antagonism of classical benzodiazepines by Ro 15-4513 was seen in all three situations. Partial antagonism of ethanol occurred in the pull up test of muscle relaxation in rats, but not in the inhibition of ultrasounds produced in rat pups by mild stress. The depressant effect of ethanol on twitching of the urethane-anaesthetised rat suprahyoid muscles was reversed. No attenuation of the effects of pentobarbital was seen in any test.