Chlordiazepoxide impairs the performance of a learned discrimination

Chlordiazepoxide (CDP) (5 mg/kg) administered on four of eight sessions significantly impaired the performance of a previously learned, reinforcement-cued discrimination in male Sprague-Dawley rats. On four interspersed vehicle-injection sessions, the performance of subjects demonstrated immediate recovery and was indistinguishable from that of controls (0 mg/kg). An analysis of response components indicated that the impairment in discrimination performance was due to a "disinhibitory" effect of the drug on responding during "no-go" phases of the task. The results are discussed in the context of similarities and differences in the effect of CDP on performance and acquisition.