The effects of lidocaine on memory in mice

The present study re-investigated our previous findings that the memory of mice was enhanced by a non-convulsant dose of lidocaine, but was impaired by a convulsant dose of lidocaine in an experiment using a multiple maze. The effects of post-training administration of lidocaine on memory in mice was examined using a passive avoidance task. Twenty-four hours after the training, the test trial latency was measured. Male ddY mice treated with lidocaine 80 mg/kg immediately after the training exhibited a shortened test trial latency and a decreased number of mice showed the maximal latency of 300 sec in passive avoidance task using electric shock as a reinforcement. The mice treated with lidocaine 40 mg/kg immediately after training exhibited a lengthened test trial latency and an increased number of mice showed the maximal latency of 300 sec in passive avoidance task using a dislike for water as the reinforcement. The results supported our previous findings.