LOW SELENIUM DIET INCREASES THE DOPAMINE TURNOVER IN PREFRONTAL CORTEX OF THE RAT

It has been proposed that interaction of catecholamines and indoleamin es with free radicals may result in the formation of endogenous neurot oxins. In order to better understand the mechanisms involved in neurod egenerative disorders showing evidence of oxidative stress, we have st udied the basal concentrations and the turnover rates of dopamine, nor adrenaline, serotonin and their metabolites in the prefrontal cortex o f rats that were fed on control or low selenium diets. Nutritional def icit of selenium decreases the brain antioxidant protection in experim ental conditions by the decrease in glutathione peroxidase activity. T he dopamine and serotonin turnover increased and noradrenaline and 5-h ydroxy-3-indoleacetic acid turnover decreased compared to experimental control animals. The increase of dopamine turnover in experimental ra ts was accompanied by an increase in tyrosine hydroxylase activity. Th ese results suggest that the decrease of brain protection against oxid ative damage could induce brain damage by disturbing the turnover rate of some monoamines. (C) 1997 Elsevier Science Ltd.