CONICET | Buscador de Institutos y Recursos Humanos

Influence of the fear memory labilization/reconsolidationprocess on the hippocampal structural plasticity. ComasMutis RG, Espejo P, Ortiz V, Martijena ID,Calfa GD and Molina VA.IFEC-CONICET, Departamento de Farmacología,Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba,Argentina. Under certain conditions, the reactivation of aconsolidated fear memory induces a labile state followed by a stabilization process(reconsolidation). During destabilization, the memory trace is vulnerable to interferingagents such as propranolol (PROP).Weevaluated whether the reactivation of a fear memory impact on the dendriticspines remodeling in CA1 dorsal Hipocampus (DH) associated with contextual fearmemory. Stressed and control animals were fear conditioned and 24hs postconditioning or post retrieval, were sacrificed. Additionally, animals were BasolateralAmygdala complex (BLA) cannulated and PROP administered after fear reactivation.One day later the animals were sacrificed. Independentlyfrom the reactivation session, conditioned animals -but not stressed- exhibiteda higher number of dendritic spines in comparison to non-conditioned animals. Priorstress exposure prevented such increase; even the behavioral freezing responsewas similar. Likewise, the intra-BLA PROP administration prevented the increasein the number of dendritic spines in comparison to SAL administration.Fearconditioning induced structural remodeling in DH is not affected by memoryreactivation. However, stress-induced resistance to memory reconsolidation orthe blockade of this process prevented the structural plasticity suggestingthat destabilization/reconsolidation following reactivation is a critical stepto induce spines remodeling after reactivation in fear conditioned animals.