ADMINISTRATION OF DL-2-AMINO-5-PHOSPHONOVALERIC ACID (AP5) INDUCES TRANSIENT INHIBITION OF REMINDER-ACTIVATED MEMORY RETRIEVAL IN DAY-OLD CHICKS

DL-2-Amino-5-phosphonovaleric acid (50 mu M) administered immediately after a Visual reminder presented to day-old chickens between 7.5 min and 24 h following a single trial passive avoidance learning task prod uced transient losses of memory on retention test, an effect not obser ved in the absence of a reminder or when the reminder was given 48 h p ost learning. The duration of the transient deficits decreased with in creasing interval between training and the reminder trial. The time of onset of memory loss after the reminder trial appeared to increase wi th increasing interval between the training and the reminder trials. T he results suggest that, for a period of at least up to 24 h after pas sive avoidance training, retrieval of memory may lead to processes whi ch are sensitive to inhibition by the NMDA receptor antagonist AP5, wi th the duration of sensitivity post retrieval decreasing as the period of memory consolidation increases. The results extend previously repo rted findings and suggest the possibility that consolidation of a stab le memorial representation of a learning experience may take over seve ral days and may entail the concurrent laying down of a stable retriev al mechanism.