Disponibilidade de aminoacidos livres e expressão de receptores de glicocorticoides em cerebro de ratos com desnutrição proteica pre e pos-natal : correlações morfologicas e comportamentais

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

The central nervous system of mammals is especially vulnerable to the protein malnutrition. In the present work was studied the consequences of severe pre and postnatal protein malnutrition on rats. Five weeks before the pregnancy, female Wistar rats started to receive hypoproteic diet (6% protein) or normoproteic diet (18% protein). These were maintained during the whole gestation and lactation period. A group of pups was sacrificed afier 8 (P8) or 16 (P16) days of life. Another group was maintained with their respective mothers diet starting from weans to 12 weeks of age. At this age they were submitted to the Elevated Plus-Maze test. In ali the animais the concentration of free amino acids was evaluated (AA) in the central nervous system (SNC). In the animais P8 and P16 the expression of the glucocorticoids receptors (GR) was investigated and the reactivity of the cortical neurons and hyppocampal to the demarcation with Fluoro-Jade (FJ). Our results showed that the protein malnutrition modified in a significant way the availability of the free amino acids implicated in the neurotransmission such as GABA and glutamate. In the animais P8 and P16 submitted to the protein malnutrition there was a significant reduction of the expression of GR in the areas of the amygdala, when compared to the animais control. The number of neurons reagents to FJ was larger in dentate gyrus of I hyppocampus in protein malnutrition group at P8. On the other hand, this difference was not observed between protein malnutrition and control animais in the cortical areas. The results of the Plus-Maze test, accomplished with the adult animais, showed that the animais submitted to the severe protein malnutrition exhibit lower anxiety due to aversive situations if compared with the control animais. The behavior modifications verified in the adult animal were correlated with the smallest expression of GR in the amygdala and the largest number of FJ positive neurons associated to the alterations in the AA concentration implicated in the neurotransmission present in the malnourished animais during the period of maturation of the nervous system. These results showed that pre and postnatal protein malnutrition modified important physiological and behavioral parameters as well as opened new perspectives for the study of the mechanisms involved in the genesis of such effects in both timing short term or long-term periods

ASSUNTO(S)

desnutrição proteica sistema nervoso central aminoacidos na desnutrição

ACESSO AO ARTIGO

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