Decreased messenger RNA expression of key markers of the nigrostriatal dopaminergic system following vitamin E deficiency in the rat

We have evaluated the effect of a vitamin E-deficient diet on the rat nigro striatal dopaminergic system. After 15 days of deficient diet, the amount a nd activity of striatal and nigral tyrosine hydroxylase increased, which co ntrasted with a decreased messenger RNA expression for tyrosine hydroxylase and the dopamine transporter in the ventral mesencephalon. When we prolong ed the deficiency of vitamin E for 30 days, dopamine levels did not differ in both areas. In contrast, messenger RNA levels for tyrosine hydroxylase a nd the dopamine transporter were markedly reduced in 30-day deficient rats. In addition, the number of oxidatively modified proteins significantly inc reased in the striatal and nigral areas studied. Overall, we propose that these changes suggest an important role of vitamin E in maintaining the normal equilibrium of the dopaminergic nigrostriatal system. (C) 2000 IBRO. Published by Elsevier Science Ltd. All rights reserv ed.