Effects of the novel benzodiazepine agonist quazepam on suppressed behavior of monkeys.

Behavioral effects of the benzodiazepine agonist quazepam were compared with those of lorazepam in squirrel monkeys responding under a fixed-interval schedule of food presentation with a superimposed fixed-ratio schedule of response-produced shock. Low and intermediate i.v. doses of quazepam (0.1-1.0 mg/kg) and lorazepam (0.03-0.3 mg/kg) increased rates of suppressed responding, yet the maximal increases in rate were less after quazepam than after lorazepam. Higher doses of both drugs tended to increase responding less or decrease it and, with quazepam, frequent sleep was observed for 2-3 days afterwards. The dose-response curves for quazepam and lorazepam were shifted to the right following i.v. pretreatment with the benzodiazepine antagonists Ro 15-1788 (0.18-3.0 mg/kg) or AHR-11797 (1.0-5.6 mg/kg); in this regard, AHR-11797 was less potent than Ro 15-1788. Although the effects of quazepam on suppressed responding are likely due to actions at benzodiazepine receptors, these effects may be influenced by or reflect a more prominent sleep-promoting action of the drug.