MITOCHONDRIAL ABNORMALITIES IN NIGRAL NEURONS OF THE MARMOSET AND MACACA-FASCICULARIS TREATED WITH MPTP

In a previous study we observed the processes determining the cellular death in nigral neurons of Macaca fascicularis and common Marmoset tr eated with MPTP. The purpose of this study is to consider, in substant ia nigra neurons of the same animals, mitochondrial abnormalities caus ed by neurotoxin. Three Macaca fascicularis and 5 common Marmosets, re spectively treated with 3 and 4 mg/kg of MPTP dissolved in saline + 10 % ethanol, were suppressed by means of an i.v. injection phenobarbital . The substantia nigra, isolated from the mesencephalon, has been exam ined under Electron Microscope. Different mitochondrial abnormalities have been observed in nigral neurons: crystal abnormalities occur more frequently than other alterations. They are correlated with various d egrees of mitochondrial enlargement. Dissolution of the matrix induces formation of spherical highly electron-dense inclusions of various vo lume and in different number; they are probably lipoprotein. Laminar b odies and myelin-like figures are determined by alterations of the ext ernal membrane. Particular roundish organules, placed near normal mito chondria, are limited by fragments of membrane with a granular materia l, occasionally flowing in the cytoplasm. The biochemical hypothesis c oncerning the genesis of the observed abnormalities is discussed in th e present study.