L-TYROSINE HYDROXYLASE-ACTIVITY IN THE RAT-BRAIN AFTER CHRONIC ORAL-ADMINISTRATION OF MANGANESE CHLORIDE

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  • 1 January 1980
    • journal article
    • research article
    • Vol. 2  (1) , 37-41
Abstract
In rats chronically treated with high oral load of MnCl2 a significant increase in activity of L-Tyr hydroxylase was observed in neostriatum, midbrain and hippocampus 1 mo. after the beginning of the experiment. Augmented enzymatic activity persisted in neostriatum, midbrain and hypothalamus on 3rd mo. and remained elevated only in neostriatum on 6th mo. After 8 mo. a significant decrease in enzyme activity was found in neostriatum with no changes in the remaining regions. These findings are interesting since human Mn intoxication starts with a psychiatric phase bearing similarities to schizophrenia in which the primary disturbance was suggested to be an overactivity of dopamine neurons. On the contrary, the permanent neurological phase was associated with reduced striatal dopamine due to a decrease in L-Tyr hydroxylase activity.