Memory enhancing effect of low-dose sevoflurane does not occur in basolateral amygdala-lesioned rats.

Background: Certain anesthetics might enhance aversive memory at doses around 0.1 minimum alveolar concentration. This issue was investigated in a rat model of learning and memory.

Does the amygdala mediate anesthetic-induced amnesia? Basolateral amygdala lesions block sevoflurane-induced amnesia.

Background: Amnesia for aversive events caused by benzodiazepines or propofol depends on the basolateral amygdala (BLA). Whether the amnesia of volatile anesthesia is also mediated through the BLA is unknown. If so, a general principle of anesthetic-induced amnesia may be emerging.

Basolateral amygdala interacts with other brain regions in regulating glucocorticoid effects on different memory functions.

Extensive evidence indicates that acutely administered glucocorticoid hormones influence cognitive performance. Posttraining activation of glucocorticoid-sensitive pathways involving glucocorticoid receptors dose-dependently enhance long-term memory consolidation. We previously reported that such glucocorticoid effects on memory consolidation rely on noradrenergic activation of the basolateral complex of the amygdala (BLA) and interactions of the BLA with other brain regions.

Glucocorticoid effects on memory retrieval require concurrent noradrenergic activity in the hippocampus and basolateral amygdala.

Previous findings indicate that administration of abeta-adrenoceptor antagonist systemically blocks glucocorticoid impairment of memory retrieval. Here, we report that beta-adrenoceptor activation in the hippocampus and the basolateral complex of the amygdala (BLA) is implicated in the impairing effects of glucocorticoids on memory retrieval. The specific glucocorticoid receptor (GR) agonist 11beta,17beta-dihydroxy-6,21-dimethyl-17alpha-pregna-4,6-trien-20yn-3-one (RU 28362) (15 ng) infused into the hippocampus of male Sprague Dawley rats 60 min before water maze retention testing, 24 hr after training, impaired probe trial retention performance, as assessed by quadrant search time and initial latency to cross the platform location.