Posttraining or pretest administration of nimodipine fails to affect retention of a simple learned association

Abstract

In previous experiments, the antagonist of voltage-sensitive calcium channels, nimodipine, given before training, enhanced the retention of an acquired preference for white-left relative to black-right in a two compartment apparatus. In the present experiments we attempted to determine if the retention effects produced by the drug could be attributed to effects occurring in the posttraining period. Various groups of rats received posttraining injections of nimodipine or its vehicle and two hours prior to testing received a second injection of nimodipine or its vehicle or no injection at all. All rats were tested for retention of the association twice, both 24 and 48 hr after acquisition. No posttraining or pretesting drug effects were found. This would support the view that the enhanced retention found after treatment with nimodipine found by ourselves and by others is due to a change in the animals at the time of acquisition.