Differential antagonism of diazepam-induced loss of the righting response.

Ethyl-beta-carboline-3-carboxylate (beta-CCE), inosine and Ro 15-1788 are antagonists of several actions of the benzodiazepines. These compounds can be differentiated, however, according to their ability to reverse the loss of the righting response induced by diazepam. Ro 15-1788 completely reversed effects of diazepam on the righting response of pigeons and squirrel monkeys but was ineffective against comparable effects produced by pentobarbital. Pretreatment with Ro 15-1788 protected against diazepam-induced righting loss. Neither inosine nor beta-CCE reversed diazepam-induced righting loss or acted prophylactically against this effect. Since beta-CCE has been characterized as an inverse agonist at the benzodiazepine receptor, the absence of antagonism we report would suggest that beta-CCE lacks specific pharmacological activity which opposes suppression of the righting response by diazepam. Research with these preferentially-acting antagonists may lead to the development of anxiolytics devoid of the sedative-hypnotic properties inherent in the drugs currently in a clinical use.