Pathogenesis of Parkinson's disease
D. M. Mann and P. O. Yates
Nucleolar volume and melanin pigment were measured in nerve cells of the
substantia nigra in cases of idiopathic Parkinson's disease and in other
cases of parkinsonism associated with cerebrovascular disease. In
cerebrovascular parkinsonism, nucleolar volume is reduced by 16%, whereas
melanin content is unchanged, reflecting local deficiencies in circulation
on function of nerve cells, otherwise normal for age. In idiopathic
parkinsonism, remaining cells are atrophied, and nucleolar volume is
reduced by 16%. Melanin content is decreased by 22% because of preferential
loss of the highly pigmented cells. The pathogenesis of idiopathic
parkinsonism may lie with a secondary aggravation of changes that occurs,
as part of the "normal process of aging," in relation to the cytotoxic
effects of dopamine metabolism and melanin accumulation.
