NANOSYMPOSIUM N 3 MALADAPTIVE ASSOCIATIVE MEMORIES: FROM NEUROBIOLOGY TO TREATMENT CHAIRc EMILIANO MERLO NS.3.1 - THE TRANSITION FROM RECONSOLIDATION TO EXTINCTION OF FEAR MEMORY IS DEPENDENT ON NEWLY SYNTHESIZED CALCINEURIN IN THE AMYGDALA

neuronal plasticity and the active epigenetic machinery cooperate during this period to translate environmental inputs into long-lasting changes in gene expression. The purpose of our study was to explore how a social isolation stress (IS) during peri-adolescence in the mouse (third week of life) can impact adult behaviour and increase the susceptibility to develop psycho-pathological conditions. Moreover we intended to explore the role of epigenetic modifications in the long-term effects of early environmental experiences. Our results show that IS mice develop adult depression-like phenotype, social avoidance, anhedonia and increased cocaine dependence. Furthermore, in order to assess the contribution of epigenetic modifications, we have analysed adult levels of expression of 40 genes involved in epigenetic mechanisms in IS compared to unhandled mice. Interestingly we have found a 40% decrease in the expression level of an enzyme with histone deacetylase activity both in the brain and blood lymphocytes of IS mice. Our results open new intriguing perspectives in the identification of peripheral/brain biomarkers of the early traumainduced susceptibility to develop psycho-pathologies.