Participação do sistema da orexina na sensibilização comportamental ao efeito estimulante do etanol em camundongos machos

• Ano de defesa: 2011
• Autor(a) principal: Macedo, Giovana Camila de [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Etanol; Camundongos; Dependência de substâncias; Imuno-histoquímica; SB 334867; Sensibilização comportamental; Área tegmentar ventral; Orexina; Ethanol; Substance dependence; Mice; Ventral tegmental area; Behavioral sensitization; Orexin; Immunohistochemistry
• Link de acesso: http://repositorio.unifesp.br/handle/11600/9914

Orexins are two neuropeptides, orexin-A and orexin-B, derived from the same precursor gene (pre-pro-orexin) produced by a few thousand neurons located in the perifornical area of the lateral hypothalamus. Despite having a restricted production, orexinergic neurons project widely to brain structures that regulate a number of endocrine and homeostatic functions. Recent evidence suggests the involvement of the orexin system in the reward circuit. We evaluated the role of this system in ethanol-induced behavioral sensitization. In Experiment 1 was used the behavioral sensitization model (development), in which animals were chronically treated for 14 days with saline, acute ethanol after saline treatment or with ethanol (seven administration) to induce behavioral sensitization; at the end of the treatment animals were perfused and immunohistochemistry technique was used to determine double staining for orexin and c-Fos (ORX+c-Fos-IR). In Experiment 2 behavioral sensitization was induced and SB 334867, an orexin-1 receptor antagonist, was used to examine whether it could block the expression of this phenomenon. The results of Experiment 1 showed no statistical difference among the groups (saline, acute and chronic) as to ORX+c-Fos-IR, although animals chronically treated with EtOH exhibited an trend to more double staining of orexin neurons indicating that this treatment regimen activates this neuropeptide system. In the second experiment, SB 334867 blocked the expression of this phenomenon. The orexin system seems to influence the process of behavioral sensitization, since systemic administration of SB 334867 blocked the expression of this phenomenon induced by a stimulant dose of ethanol in male mice.