Generalization between benzodiazepine- and triazolopyridazine-elicited discriminative cues.

Using a milk reinforced two-lever operant procedure, rats were trained to discriminate 3 mg/kg chlordiazepoxide (CDP) from saline. Following this, generalization experiments were conducted with the triazolopyridazine CL 218,872, a synthetic non-benzodiazepine (BDZ) ligand for the BDZ receptor. CL 218,872 produced CDP lever selection in a dose related fashion and thus generalized to the standard CDP treatment. However, this generalization was antagonized by the concurrent administration of pentylenetetrazol or amphetamine, but not by strychnine or bicuculline. Also, there was evidence for cross tolerance for a sedative effect between CDP and CL 218,872.