Managanese neurotoxicity: Effects of L-DOPA and pargyline treatments

Single, monolateral injection into rat substantia nigra of managanese chloride produced within two weeks from its administration a loss of dopamine in the striatum ipsilatera to the injected side. When L-DOPA + carbidopa or pargyline were given to these animals the decrease of striatal dopamine was more marked. The stimulatory effects of apomorphine were more relevant in striatum where presynaptic dopaminergic neurons were not affected by manganese chloride. The data indicate that the alterations of dopaminergic postsynaptic receptors may be different in parkinosonian and in manganese-intoxicated patients and that current therapy used for Parkinson's disease could be a hazard in treating manganese poisoning.