Effects of acute and chronic maprotiline administration on inhibitory avoidance in male mice

The effects of acute and chronic administration of maprotiline (5, 10 or 20 mg/kg, intraperitoneally) were assessed on inhibitory avoidance in male mi ce. Acute administration of maprotiline before training did not effect trai ning phase latencies, but impaired performance (i.e. produced shorter laten cies) in the test at doses of 5 and 20 mg/kg. When given after training, th e drug did not modify test latencies at any of the doses used. Chronic admi nistration for 21 days (interrupted 24 h before training) also shortened la tencies in the test but not in training. An experiment on the acute effects of maprotiline on analgesia (determination of flinch and jump thresholds f or increasing electric foot shock levels), at the doses stated, was carried out on naive animals. No analgesic effect of the drug was found. Taken tog ether, the results indicate that acute maprotiline produces anterograde amn esia, and tolerance does not appear after 21 days of treatment. (C) 2000 El sevier Science B.V. All rights reserved.