Post-training infusions of drugs, including noradrenergic agonists and antagonists, into the basolateral amygdala (BLA) influence the consolidation of memory for training in several tasks, including inhibitory avoidance. There is, however, conflicting evidence concerning whether post-training intra-BLA drug infusions modulate the consolidation of contextual fear conditioning (CFC). In the present study, norepinephrine (NE) was infused bilaterally into the BLA of male Sprague Dawley rats immediately after training on two CFC tasks: a Y-maze and a straight alley. Post-training intra-BLA infusions enhanced memory of CFC training in the Y-maze, as assessed by percentage of time spent freezing and shock arm entrance latencies. Post-training intra-BLA infusions of NE enhanced 48 hr retention of CFC training in the straight alley, as assessed by shock compartment entrance latencies and the number of shocks required to learn to avoid entering the shock compartment. These findings indicate that the consolidation of memory for CFC, like that for inhibitory avoidance training, is influenced by post-training neuromodulatory influences within the BLA. Thus, the findings provide additional evidence consistent with the hypothesis that the BLA has a general role in modulating memory consolidation.

In conditioned taste aversion (CTA), a subject learns to associate a novel taste (conditioned stimulus, CS) with visceral malaise (unconditioned stimulus, US). Considerable evidence indicates that the noradrenergic system in the amygdala plays an important role in memory consolidation for emotionally arousing experiences. The specific aim of the present set of experiments was to determine the involvement of noradrenergic activity in the basolateral amygdala (BLA) during the US presentation and consolidation of CTA as well as during the consolidation of a nonaversive/incidental gustatory memory. Selective bilateral microinfusions of the beta-adrenergic antagonist propranolol administered into the BLA immediately before intraperitoneal (i.p.) lithium chloride (LiCl) injections disrupted CTA memory. Additionally, propranolol infused into the BLA immediately after a pre-exposure to the saccharin (CS) significantly attenuated latent inhibition. The present findings indicating that alterations in noradrenergic function in the BLA affect taste memory formation, provide additional evidence that the BLA plays a critical role in modulating the consolidation of memory and that the influence is mediated by interactions with other brain regions that support memory for different kinds of experiences.