Efeitos do estresse crônico brando e imprevisível sobre aspectos comportamentais e neurobiológicos relacionados à ansiedade e ao pânico

• Ano de defesa: 2016
• Autor(a) principal: Andrade, José Simões de [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Chronic chronic stress; Immunoreactivity to c-fos protein; Hippocampal neurogenesis; Serum corticosterone concentration; Expression of CRF messenger RNA; Estresse crônico brando; Imunorreatividade à proteína c-fos; Neurogênese hipocampal; Concentração sérica de corticosterona; Expressão de RNA mensageiro de CRF
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=4623521; https://repositorio.unifesp.br/handle/11600/46475

Previous results show that elevated T-maze (ETM) avoidance responses are facilitated by acute restraint. Escape, on the other hand, was unaltered. To examine if the magnitude of the stressor is an important factor influencing these results, we investigated the effects of unpredictable chronic mild stress (UCMS) on ETM avoidance and escape measurements. Analysis of Fos protein immunoreactivity (Fos-ir) was used to map areas activated by stress exposure in response to ETM avoidance and escape performance. Additionally, the effects of the UCMS protocol on the number of cells expressing the marker of migrating neuroblasts doublecortin (DCX) in the hippocampus were investigated. Corticosterone serum levels were also measured. Results showed that UCMS facilitates ETM avoidance, not altering escape. In unstressed animals, avoidance performance increases Fos-ir in the cingulate cortex, hippocampus (dentate gyrus) and basomedial amygdala, and escape increases Fos-ir in the dorsolateral periaqueductal gray and locus ceruleus. In stressed animals submitted to ETM avoidance, increases in Fos-ir were observed in the cingulate cortex, ventrolateral septum, hippocampus, hypothalamus, amygdala, dorsal and median raphe nuclei. In stressed animals submitted to ETM escape, increases in Fos-ir were observed in the cingulate cortex, periaqueductal gray and locus ceruleus. Also, UCMS exposure decreased the number of DCX-positive cells in the dorsal and ventral hippocampus and increased corticosterone serum levels. It is interesting to mention that exposure on ETM avoidance increases the expression of CRF mRNA in the PVN, medial amygdala, central amygdala, hippocampus (cornus Ammon), hippocampus (dentante gyrus) and dorsomedial hypothamalus. Escape measurement, increases the expression of CRF mRNA in the PVN, central amygdala, hippocampus (cornus Ammon) and VlPAG. In stressed animals submitted to ETM avoidance, increases the expression of CRF mRNA in the cingulated cortex, BNST, dorsomedial hypothamalus, hippocampus (cornus Ammon), hippocampus (dentante gyrus) and VlPAG. Escape measurement, increases the expression of CRF mRNA in the medial amygdale and VlPAG. These data suggest that the anxiogenic effects of UCMS are related to the activation of specific neurobiological circuits that modulate anxiety and confirm that this stress protocol activates the hypothalamus?pituitary?adrenal axis and decreases hippocampal adult neurogenesis.