Involvement of AChergic systems in chlordiazepoxide induced impairment of passive avoidance response.

The chlordiazepoxide (CDP)-induced impairment of the passive avoidance response was attenuated by Ro 15-4513, a benzodiazepine inverse agonist, physostigmine and scopolamine at low doses. In a biochemical approach, CDP increased, but Ro 15-4513 decreased the acetylcholine (ACh) levels of cerebral cortex. After the training of passive avoidance, the ACh levels in the hippocampus and cerebral cortex decreased. This change disappeared by pretraining administration of CDP. These results suggest that the effect of CDP on the passive avoidance response was related to AChergic neuronal systems.