Effects of MPTP on the fine structure of neurons in substantia nigra of dogs.

This study evaluates fine structural changes in neurons from pars compacta of substantia nigra in dogs 1 and 4 days after administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. The toxin induced a disruption and high amplitude swelling of mitochondria, and dispersion of rough endoplasmic reticulum at 4 days. Mitochondria in dendrites were less damaged than those in the soma. Swelling of myelinated axons in the nigrostriatal pathway was evident at 1 and 4 days after injection. Similar morphologic changes are produced by axotomy and inhibitors of mitochondrial function.