Long-term suppression in mice of the development of complementary memory storage sites: effect of a muscarinic antagonist.

Bitemporal injections of puromycin consistently induce amnesia of aversive maze-learning in mice when administered within 3 days of training. These bitemporal puromycin injections lose their amnestic effectiveness, if the latency between training and injection is extended beyond 6 days. Consistent with other evidence, we conclude that in our experimental paradigm, complementary memory storage sites normally develop in additional cerebral areas during the 6 days following training. Previous experiments have indicated that the central adrenergic system is critically involved in this process. We now present evidence that the central cholinergic system is also critically involved. This conclusion is based upon our results with the muscarinic receptor antagonists, scopolamine and methyl scopolamine.