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The adult rats received both neurotoxin 6-hidroxidophamine and neurotoxin and melatonin. It was investigated a link between the disturbances of the brain antioxidant enzymes activity and thymic endocrine function, as possible pathogenic factors of parkinsonism, with changes in the number of neural stem cells (NSC) in the bulbus olfactorius. Rats with motor asymmetry in the apomorphine test and significant damage of the dopaminergic neurons in the-substantia nigra have decreased levels of superoxide dismutase, catalase and glutathione peroxidase activities in striatum (1.3-1.4 times) and blood thymulin content (8 times) compared to control group. On the contrary, examined indices were not changed in rats without motor asymmetry and correspondingly partly damaged neurons. The number of nestin(+)-cells in the bulbus olfactorius of rats without motor asymmetry increased from 91.2% to 99.3% and remained unchanged after melatonin administration course (10 mg/kg during 18 days). Melatonin administration resulted in the decrease in the number of nestin(+)-cells along with significant elevation of the decreased antioxidant enzymes activity and blood thymulin content in rats with circulatory movements. Possibilities of the enhancement of NSC differentiation in bulbus olfactorius into neuronal direction in such animals has been discussed. The conclusion about the potential use of melatonin as a neuroprotector in parkinsonism therapy has been made.

We studied the influence of antioxidants (trolox, melatonin and coenzyme Q10) on 6-hydroxydopamine-induced degeneration in the substantia nigra dopaminergic neurons from the left brain hemisphere. In rats, the level of unilateral degeneration of nigrostriatal dopaminergic system was estimated on the base of an intensity of rotation movements which were contralateral to denervated hemishere and resulted from systemic injections of a dopamine receptor agonist apomorphine. It has been shown that all tested antioxidants reduced a number of animals with apomorphine-induced behavioral asymmetry in a different degree: coenzyme Q10 reduced it twofold, trolox - fivefold and melatonin - sevenfold. We suggest that a neuroprotective effects of trolox, melatonin and coenzyme Q10 are associated with their ability to block the mitochondrial pore openings in the nervous cells under exploration, and this is the way to prevent apoptotic death. An oxidative stress has been proved to take part in the apoptosis in dopamine-producing neurons in the substantia nigra, and tested antioxidants have been shown to be effective in preventing neurodegeneration.