3-((+/-)-2-CARBOXYPIPERAZIN-4-YL)PROPYL-1-PHOSPHONIC ACID (CPP) AND PHENCYCLIDINE PRODUCE A DEFICIT OF PASSIVE-AVOIDANCE RETENTION IN RATS

3-((±)-2-Carboxypiperazin-4-yl)propyl-1-phosphonic acid (CCP), phencyclidine (PCP) and diazepam were evaluated for their ability to produce a deficit for a single trial step-through passive avoidance response in rats. Pretraining administration with CCP at doses ranging from 2.0 to 10.0 mg/kg s.c. significantly decreased retention latencies 24 h after passive avoidance training. Similar effects were found with PCP at doses ranging from 0.5 to 1.7 mg/kg s.c. and diazepam at doses between 5.0-18.0 mg/kg s.c. Pretraining administration with the benzodiazepine antagonist, RO15-1788 at doses between 0.1-15 mg/kg s.c., did not alter retention latencies. Co-administration of RO15-1788 (0.01-15.0 mg/kg s.c.) with CCP (6.0 mg/kg s.c.) or PCP (1.0 mg/kg s.c.) failed to block decreases in latencies. However, when RO15-1788 was co-administered with diazepam (9.0 mg/kg s.c.) a dose-related antagonism of diazepam's effects were found. These results suggest that the behavioral actions of CCP and PCP on passive avoidance retention are not mediated via the benzodiazepine receptor complex. © 1990.