RESTORATION OF MNEMONIC FUNCTION IN RATS WITH GLUTAMERGIC TEMPORAL SYSTEMS DISRUPTED - DOSE AND TIME OF GLYCINE INJECTIONS

Disruption of the connections between the temporal cortex (TC) and lat eral entorhinal cortex (LEC) in rats causes impaired memory accompanie d by decreased levels of glutamate in these neocortical areas. Adminis tration of glutamergic agonists to rats with TC/LEC disruptions improv es retroactive memory. The purpose of this study was to test effects o f glycine on proactive memory. The results show that a relatively larg e dose of glycine (750 mg/kg) injected just prior to training enhanced both acquisition and retention of a discrimination task in TC/LEC rat s. Glycine given 1 day prior to training impaired the initial phase of acquisition but improved retention (Experiment 1). Injection of glyci ne immediately following training or just prior to retrieval reinstate d normal mnemonic function in TC/LEC animals, whereas glycine given mi dway between learning and retention had no such effect (Experiment 2). A potential mnemonic model function of TC/LEC lesion is suggested, an d possible beneficial effects of glycine on patients with Alzheimer's disease are discussed.