2 TIME WINDOWS OF ANISOMYCIN-INDUCED AMNESIA FOR PASSIVE-AVOIDANCE TRAINING IN THE DAY-OLD CHICK

The antibiotic anisomycin (ANP), a protein synthesis inhibitor, was us ed to investigate the time-related changes in protein synthesis follow ing passive avoidance training in the day-old chick. Retention of memo ry for this simple learning task is known to be prevented by protein s ynthesis inhibitors within the first hour posttraining. Here we report a second, later time window during which inhibition of protein synthe sis results in amnesia following one-trial passive avoidance training. Birds were given bilateral intracranial injections of ANI (10 mu 1/he misphere of a 30 mM solution) at various times relative to training an d tested 24 h later. Injections given between 0.5 h prior to 1.5 h pos t-training or 4-5 h posttraining, but not at later or at intervening t imes, resulted in amnesia. These results are discussed in the context of earlier findings, using the inhibitor of glycoprotein synthesis 2-d eoxygalactose, that memory formation shows two glycoprotein-synthesis- dependent periods of sensitivity (Scholey, Rose, Zamani, Beck, and Sch achner, 1993). The time windows of susceptibility of ANI and 2-Dgal ar e consistent with a model in which there are two waves of neural activ ity following training; during the second, commencing 4 h after traini ng, proteins are synthesized and then glycosylated as part of the esta blishment of an enduring memory trace. (C) 1995 Academic Press, Inc.