Diazepam-induced impairment of a go-no go successive discrimination

Diazepam (2.0 and 4.0 mg/kg, but not 1.0 mg/kg) administered in eight acquisition sessions significantly impaired the light-cued successive discrimination of male Sprague-Dawley rats. In two postdrug (vehicle) sessions, groups previously treated with the drug demonstrated good recovery in discrimination. An analysis of response components indicated that the impairment was due to the failure of drugged subjects to inhibit or withhold responses during the no go periods of the task. These findings are consistent with a "disinhibitory hypothesis" of drug impairment. The similarity of the present findings to those previously reported with chlordiazepoxide suggests that such effects are a generalized characteristic of the benzodiazepine class of drugs.