Efeito da privação de sono paradoxal na expressão de receptores para glicocorticoides no hipocampo e no aprendizado e memória

• Ano de defesa: 2012
• Autor(a) principal: Araujo, Paulo Cesar da Costa
• Orientador(a): Almeida, Olga Maria Martins Silva de
• Banca de defesa: Costa, Frank Tenório de Almeida , Filgueiras, Cláudio Carneiro , Rocha, Mônica Santos
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade do Estado do Rio de Janeiro
• Programa de Pós-Graduação: Programa de Pós-Graduação em Biociências
• Departamento: Centro Biomédico::Instituto de Biologia Roberto Alcantara Gomes
• País: BR
• Palavras-chave em Português: Sono Paradoxal; Privação de sono; Receptor de Glicocorticóide; Hipocampo; Memória; Privação do sono Complicações; Receptores de Glucocorticóides Fisiologia; Distúrbios cognitivos; Distúrbios da memória
• Palavras-chave em Inglês: Paradoxical sleep; Sleep deprivation; Glucocorticoid receptor; Hippocampus; Memory
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::FARMACOLOGIA
• Link de acesso: http://www.bdtd.uerj.br/handle/1/16278

Several studies have shown a relation between sleep and memory. In this way, an important role in memory consolidation by sleep and a negative effect induced by sleep deprivation have been described. Hippocampus is a region responsible for consolidation of spatial memory and contains a high expression of corticosteroids receptors. In the hippocampus, the corticosteroids actions are crucial for memory acquisition and depend on an adequate balance between Glucocorticoid (GR) and Mineralocorticoid receptors (MR). Studies have demonstrated that an increased expression of MR promotes memory acquisition while an increased expression of GR has negatives effects. In spite of the circulating levels of glucocorticoids in paradoxical sleep deprivation (PSD) are not responsible for the PSD induced memory impairments, do not exist studies about the expression of the GR and MR in hippocampus after PSD. In this study we investigate the expression of GR in the hippocampus and evaluate learning and memory in PSD rats. Wistar male rats (250-350g) were paradoxical sleep deprived by the multiple platform method for 96 hours. After 96h of sleep deprivation, the animals were anesthetized and perfused. Slices of 25 micron of the area of the hippocampus were obtained and reacted with antibodies against GR. We evaluated the areas CA1, CA3 and dentate gyrus (GD). Learning and spatial memory were evaluated in Radial water maze before and after PSD. We evaluated the escape latency and the number of errors obtained. PSD group showed an increased expression of GR in CA1 and GD. However, in the CA3 area there was no significant difference in expression. The PSD prior to the tests of learning and memory did not provoke significant alterations. The sleep deprivation after learning also did not produce statistically significant differences, but an increase in the time of escape latency and number of errors suggests impairment in the memory consolidation. The increase in the RGc expression in the studied areas can be consequent to an alteration in the balance between corticosteroid receptors in the hippocampus and be responsible for alterations in the learning and memory in PSD rats.