Parkinson's disease: contemporary state and perspectives.

Parkinson's disease, a classic human degenerative disease, is one of the commonest neurological disorders. Although this movement disorder had been defined a century and a half ago, its aetiology remains unknown. Some environmental factors are suspected to play a key role in induction of slow progressive loss of nigral dopaminergic neurons. Nerve cell death seems to be produced via cytotoxic oxygen radicals which are accumulated in the pars compacta of the substantia nigra. The major biochemical abnormality in parkinsonism is a decrease in the dopamine synthesis although other neurotransmitters are affected too. Several animal models of Parkinson's disease have been introduced to study mechanisms of selective degeneration of the substantia nigra and to assess effectiveness of various therapeutic approaches. Present pharmacological treatment, directed toward replacement of missing dopamine, uses high-dosage of levodopa. However, this therapy helps the symptoms but do not halt the disease. Doses of levodopa have to be increased as symptoms increase in severity, which is associated with severe side effects. Neural transplantation of catecholamine-producing cells seems to be a new promising tool for treatment of Parkinson's disease. Grafts of adrenal medulla, carotid body, pheochromocytoma, sympathetic ganglion and embryonic dopaminergic cells, either in a form of solid pieces or cell suspension, were inoculated into the experimentally denervated striatum of rats and subhuman primates. At present, more than 300 parkinsonian patients have received autologous adrenal medulla or human embryonic nigral grafts but results are still controversial. Attempts for transplantation treatment retreated to the laboratories and researchers are currently seeking to select the best king of cells capable of producing dopamine.(ABSTRACT TRUNCATED AT 250 WORDS)