Noradrenergic enhancement of reconsolidation in the amygdala impairs extinction of conditioned fear in XXXX --a possible mechanism for the persistence of traumatic memories in @entity1005 .

@entity1 @entity1169 @entity1005 @entity3044 @entity35
BACKGROUND: @entity1005 ( @entity1005 ) is associated with enhanced noradrenergic activity. Animal and @entity1 studies demonstrate that noradrenergic stimulation augments consolidation of fear learning. Retrieval of well-established memories by presenting a learned fear cue triggers reconsolidation processes during which memories may be updated, weakened, or strengthened. We previously reported that noradrenergic blockade in the @entity35 amygdala impairs reconsolidation of fear memories. Here we investigated the effects of noradrenergic enhancement on reconsolidation of learned fear. METHODS: Using auditory fear conditioning in @entity35 , we tested the effects of postretrieval intraamygdala infusion of the b-adrenergic receptor agonist @entity3044 or the antagonist @entity1169 on conditioned fear in the amygdala. RESULTS: A single intraamygdala infusion of @entity3044 following a retrieval of a well-consolidated memory enhanced fear memory elicited by the learned fear stimulus and impaired extinction of this memory 48   hr later. Intraamygdala infusion of the b-adrenergic receptor antagonist @entity1169 following a consecutive retrieval trial blocked the enhancing effects of @entity3044 on fear memory. CONCLUSIONS: Postretrieval b-adrenergic stimulation in the amygdala enhances reconsolidation of fear memories, making them resistant to extinction. Noradrenergic augmentation during retrieval of fear memories may thus contribute to persistence and severity of traumatic memories. Reconsolidation may be a useful tool in understanding the pathology of @entity1005 and may thus help in developing new and in modifying existing treatments of traumatic memories.
