Neural cell adhesion molecules play a role in rat memory formation in appetitive as well as aversive tasks

A polyclonal antibody (R1), raised against chick synaptic membrane glycoproteins and recognizing the neural cell adhesion molecule (NCAM) caused amnesia for avoidance tasks when injected into day-old chicks and adult rats 5.5 h post-training. We investigated the effects of R1 antibody on memory formation in a non-aversive task, where stress is minimal: a massed trial odour discrimination task in rats. Preimmune serum or R1 antibody was injected i.c.v. 5.5 h after the last training session. Forty-eight hours after the training session, control rats showed very good retention whereas R1 antibody injection significantly disrupted retention. The results suggest that glycoproteins recognized by R1 in the rat play a specific role in memory formation for appetitive events as well as in memory formation for aversive situations.