NALOXONE POTENTIATES THE EFFECTS OF SUBEFFECTIVE DOSES OF ANXIOLYTIC AGENTS IN MICE

The ability of the opioid receptor antagonist naloxone to potentiate t he effects of subeffective doses of chlordiazepoxide, diazepam and bus pirone was evaluated in Swiss mice tested in an elevated plus maze. Di azepam (0.5 mg/kg), chlordiazepoxide (2.5 mg/kg) and buspirone (2 mg/k g) were ineffective per se but, when combined with naloxone (10 mg/kg) , they increased the proportion of open arm entries as did higher dose s of the anxiolytic agents (diazepam 1.5 mg/kg, chlordiazepoxide 5 mg/ kg and buspirone 4 mg/kg). Naloxone alone (10 mg/kg) had no intrinsic effect. These data suggest that naloxone is able to potentiate the eff ects of anti-anxiety agents.