Calcineurin immunoreactivity in striatonigral degeneration.

The basal ganglia (including substantia nigra) of two patients with striatonigral degeneration, who had clinical histories of Parkinson's disease, were studied immunohistochemically using a purified antibody to calcineurin (CaN). Marked loss of CaN-immunoreactive neurons in the putamen and neuromelanin-pigmented neurons in the zona compacta of the substantia nigra was seen in both cases. A small number of CaN-immunoreactive neurons remained dispersed in "clusters" or "islands" in the medial portion of the putamen. In one case there was loss of CaN-immunoreactive neurons in the caudate nucleus to a lesser degree than that in the putamen. In addition, both cases showed marked depletion of CaN-immunoreactive afferent nerve fibers in the external and internal segments of the globus pallidus and the zona reticulata of the substantia nigra. This report emphasizes the usefulness of the CaN-immunostaining technique for assessing the striatal efferents in human basal ganglia, and shows the neuropathological changes in the basal ganglia with striatonigral degeneration which were not possible to ascertain with previous techniques.