Discriminative stimulus effects of alprazolam and diazepam: generalization to benzodiazepines, antidepressants and buspirone
Wettstein, J..G..; Gauthier, B..
Behavioural Pharmacology 3(3): 229-237
Rats in one group were trained to discriminate alprazolam (1.0mg/kg, i.p.) and in another group diazepam (3.0mg/kg, i.p.) from saline in a two-lever drug discrimination procedure. Food presentation occurred after 10 consecutive responses on the lever associated either with the training drug or with saline. Alprazolam, diazepam, lorazepam and chlor diazepoxide increased responding on the drug-associated lever in a comparable dose-related manner in both groups of rats: the relative order of potency was lorazepam >/= alprazolam > diazepam >/= chlordiazepoxide. Flumazenil (10.0mg/kg, i.p.) attenuated the effects of the training drugs. A range of doses of buspirone and four drugs having antidepressant properties (amitriptyline, fluoxetine, cericlamine, imipramine) then were studied in both groups of rats. All five drugs caused approximately 40% increases (group mean) in drug-appropriate responding in alprazolam-trained rats whereas only amitriptyline partially substituted for diazepam. The results indicate that alprazolam has interoceptive stimulus effects that overlap with the stimulus effects of diazepam, yet the effects of alprazolam may not be identical to those of diazepam because the antidepressant drugs and buspirone substituted partially for alprazolam but generally not for diazepam.