RESUMO
Since chronic stress has been used widely for studying clinical depression and that brain energy metabolism and oxidative stress might be involved in the pathophysiology of this illness, the objective of this study was investigate the activities of pyruvate kinase, complex II and IV (cytocrome c oxidase) in hippocampus and prefrontal cortex of rats submitted to chronic variable stress. We also evaluated if vitamins E and C administration could prevent such effects. During 40 days adult rats from the stressed group were subjected to one stressor per day, at a different time each day, in order to minimize predictability. The stressed group had gained less weight while its immobilization time in the forced swimming test was greater than that of the control group. Results showed that stressed group presented an inhibition in the activities of complex II and cytochrome c oxidase in prefrontal cortex, while in hippocampus just complex IV was inhibited. Pyruvate kinase activity was not altered in stressed group when compared to control. Vitamins E and C administration prevented the alterations on respiratory chain caused by stress. These data suggest that the impairment of energy metabolism and oxidative stress could be related with the pathogenic pathways in stress related disorders.
Assuntos
Antioxidantes/uso terapêutico , Encefalopatias Metabólicas/tratamento farmacológico , Metabolismo Energético/efeitos dos fármacos , Hipocampo/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Estresse Psicológico/metabolismo , Estresse Psicológico/prevenção & controle , Animais , Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Ácido Ascórbico/uso terapêutico , Encefalopatias Metabólicas/etiologia , Doença Crônica , Modelos Animais de Doenças , Transporte de Elétrons/efeitos dos fármacos , Transporte de Elétrons/fisiologia , Complexo IV da Cadeia de Transporte de Elétrons/efeitos dos fármacos , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Metabolismo Energético/fisiologia , Hipocampo/efeitos dos fármacos , Hipocampo/enzimologia , Estresse Oxidativo/fisiologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/enzimologia , Piruvato Quinase/metabolismo , Ratos , Ratos Wistar , Estresse Psicológico/complicações , Vitamina E/farmacologia , Vitamina E/uso terapêuticoRESUMO
The stress response is known to lead to behavioral and metabolic changes. Exposure to chronic stress can promote the development of physiological and behavioral dysfunctions, including alterations in feeding behavior. The aim of this study was to verify whether chronic restraint stress alters the consumption of a highly palatable, highly caloric diet (chocolate), chronically offered to the animals. Male rats ate more chocolate than females, and they also exhibited a higher weight gain, abdominal fat deposition, and higher plasma levels of total cholesterol, LDL-cholesterol and glucose. The stress exposure decreased body weight, increased adrenal weight and decreased plasma insulin levels. Overall, female rats had lower plasma insulin levels and chocolate consumption prevented the increased adrenal gland weight after exposure to chronic stress, suggesting a reduction of stress effects induced by palatable food consumption. Taken together, these results suggest a peculiar metabolic pattern, related to energy store and expenditure, in stressed animals receiving a palatable diet. Since these effects were sex-specific, we may also propose that females and males subjected to restraint stress and chocolate consumption are differentially affected.