Estudo da relação entre sensibilização comportamental ao etanol e estresse de restrição de movimentos: associação com níveis de corticosterona

• Ano de defesa: 2006
• Autor(a) principal: Trindade, Ágatha Asano [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; estresse; efeito estimulante; corticosterona
• Link de acesso: http://repositorio.unifesp.br/handle/11600/9534

The relationship between drugs of abuse and stress has been demonstrated in several studies. On one hand, there are reports on cross sensitization between drugs of abuse and stressful evens. On the other hand, exposure to a stressor may induce sensitized behavioral response to a drug. Repeated administration of drugs may, however, induce a neuroendocrine sensitization of the hypothalamus-pituitaryadrenal axis (HPA) leading to a marked increase in the release of stress-related hormones. The objectives of the present study were to assess whether mice highly sensitized to the stimulant effect of ethanol presented high levels of corticosterone (CORT) after exposure to acute restraint stress (1 h) and whether an acute or repeated (7 days) exposure to this kind of stressor would affect the behavioral response to ethanol administration (acute and repeated). In the first experiment, mice were treated with 2.2 g/kg of ethanol or with saline and submitted to 1 h restraint stress. Blood samples were collected for determination of corticosterone (CORT) plasma levels. Exposure to stress increased CORT levels, but pre-treatment with ethanol or saline did not affect the hormone response. In Experiment 2, mice were first submitted to a 1 h restraint stress and 24 h later a 14-day treatment with ethanol or saline began. The pre-exposure to stress did not alter locomotor response to ethanol or saline, acute or repeatedly administered. On the 14th day of treatment, ethanol-treated mice presented higher CORT levels than saline-treated ones (p<0,05). In Experiment 3, mice were initially submitted to 1 h restraint stress for 7 days. After 24 h, the treatment with 2.2 g/kg of ethanol or saline started. Previous exposure to repeated (7 days) stress did not alter the mice’s locomotor response to ethanol or saline (acute or repeatedly administered). In a challenge carried out 4 days after the end of the treatment, ethanol-treated mice presented higher CORT levels than saline-treated ones (p<0,05). In addition, animals previously submitted to stress presented higher levels of CORT than non-stressed animals (p<0,05). These results suggest that sensitization to the stimulant effect of ethanol did not induce sensitization of the CORT response to restraint stress and that the acute or repeated exposure to restraint stress is not sufficient to alter the mice’s locomotor response to ethanol (acute or repeatedly). In summary, we did not observe cross sensitization between ethanol and 1 h restraint stress.