Monoamine oxidase-B in motor cortex: changes in amyotrophic lateral sclerosis

The occurrence of monoamine oxidase-B in cerebral cortex and white matter in brains from three patients with the diagnosis of amyotrophic lateral sclerosis and three controls was quantified by means of an autoradiographical method. [3H]L-Deprenyl, an irreversible and selective monoamine oxidase-B inhibitor, was used as ligand and the autoradiographs were analysed by computer-assisted densitometry. In both amyotrophic lateral sclerosis and control cerebral cortex, lamina I showed the highest, laminae II and III intermediate, laminae IV, V and VI the lowest [3H]L-deprenyl binding. White matter showed about one-third of the binding in the cortex. Amyotrophic lateral sclerosis cases showed significantly higher binding of [3H]L-deprenyl in all the cortex laminae of the pre- and postcentral gyri. There was no difference in the binding between the amyotrophic lateral sclerosis cases and the controls in area 7 of the occipital cortex, an area which is relatively spared in amyotrophic lateral sclerosis.