The possible role of benzodiazepine receptors in morphine analgesia

Diazepam within its therapeutic dose range, was shown to have no effect on nociception, but was shown to antagonize the analgesic action of morphine. This antagonism was found to be statistically significant at 0.5 mg/kg diazepam. To elucidate the mechanism of this inhibitory action of diazepam against morphine analgesia, Ro 15-1788, the specific antagonist of benzodiazepine receptors was used. As a result, Ro 15-1788 was found to partially reverse the inhibitory action of diazepam against morphine analgesia. This overall interaction between the supramolecular GABA receptor complex and morphine is discussed.