Noradrenergic Action in Prefrontal Cortex in the Late Stage of Memory Consolidation
Erratum in
Learn Mem. 2004 Sep-Oct;11(5):658.
These experiments investigated the role of the noradrenergic system in the late
stage of memory consolidation and in particular its action at beta receptors in
the prelimbic region (PL) of the prefrontal cortex in the hours after training.
Rats were trained in a rapidly acquired, appetitively motivated foraging task
based on olfactory discrimination. They were injected with a beta adrenergic
receptor antagonist into the PL 5 min or 2 h after training and tested 48 h
later. Rats injected at 2 h showed amnesia, whereas those injected at 5 min had
good retention, equivalent to saline-injected controls. Monitoring extracellular
noradrenaline efflux in PL by in vivo microdialysis during the first hours after
training revealed a significant increase shortly after training, with a rapid
return to baseline, and then another increase around the 2-h posttraining time
window. Pseudo-trained rats showed a smaller early efflux and did not show the
second wave of efflux at 2 h. These results confirm earlier pharmacological and
immunohistochemical studies suggesting a delayed role of noradrenaline in a late
phase of long-term memory consolidation and the engagement of the PL during these
consolidation processes.