Pathology
Degeneration of pigmented neurons in this region is the principal pathology that underlies Parkinson's disease. In a few people, the cause of Parkinson's disease is genetic, but in most cases, the reason for the death of these dopamine neurons is unknown. Parkinsonism can also be produced by viral infections such as encephalitis or a number of toxins, such as MPTP, an industrial toxin which can be mistakenly produced during synthesis of the meperidine analog MPPP. Many such toxins appear to work by producing reactive oxygen species. Binding to neuromelanin by means of charge transfer complexes may concentrate radical-generating toxins in the substantia nigra.
Pathological changes to the dopaminergic neurons of the pars compacta are also thought to be involved in schizophrenia (see the dopamine hypothesis of schizophrenia) and psychomotor retardation sometimes seen in clinical depression.
Read more about this topic: Pars Compacta
Famous quotes containing the word pathology:
“It is often said that Poland is a country where there is anti-semitism and no Jews, which is pathology in its purest state.”
—Bronislaw Geremek (b. 1932)