Efeito do suporte social na extinção da memória de medo condicionado ao contexto : aprendizagem sem evocação, e dependência de síntese de proteínas no córtex pré-frontal mas não no hipocampo

Abstract

Memories of fear when dysfunctional can lead to pathologies associated with anxiety, such as depression, panic disorder and posttraumatic stress disorder. Thus, it becomes essential to understand biological and behavioral mechanisms that may contribute to the treatment of these disorders. The general objective of this research was to evaluate the impact of social support on the extinction of a fear memory and to verify the participation of different brain areas in this memory. For this, Wistar rats were used between 300 - 330g with cannulas implanted in the CA1 regions of the hippocampus or PFCm, submitted to MCC theophyte alone. Twenty-four hours later, the extinction training was carried out with a duration of 10 minutes, either alone (S) or in the presence of a familial coexistent (SS) and immediately infused intra- CA1 or intra-PFCin saline solution 0.9% (Vehicle), anisomycin (Ani, 80 μg per side, protein synthesis inhibitor), rapamycin (Rapa, 5 μg per side, mTOR protein inhibitor) or 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (DRB , 8 ng per side, inhibitor of gene expression). After twenty-four hours the animals S or SS were submitted to the extinction test, all alone, for 3 minutes. As results, it was found that the MCC in the presence of a family member who did not undergo the aversive task (social support) can occur independently of the original memory being evoked during the extinction training. Social support generates a different form of learning from extinction acquired without social support in terms of the brain structures involved. It has been observed that the extinction of fear memory with social support depends on protein synthesis in the PFCm region, but not in the ca1 region of the Hippocampus. These findings may lead to a better understanding of the brain mechanisms involved in the influence of social support in memories and in therapies for disorders related to dysfunctional fear memories.