Calcineurin in human brain and its relation to extrapyramidal system. Immunohistochemical study on postmortem human brains.

Calcineurin immunoreactivity has been successfully detected in formalin-fixed paraffin-embedded postmortem human brain tissue using the peroxidase-antiperoxidase method. We have examined two autopsy cases with Huntington's disease (HD), three cases with Parkinson's disease, and two senile patients as controls. In the controls, calcineurin immunoreactivity was present in neuronal cells only and highly concentrated in the caudate nucleus, putamen, globus pallidus (striato-pallidal pathway), substantia nigra (striato-nigral pathway) and hippocampal formation. These localizations were similar to those identified in rat brain. There was a marked depletion of neurons containing calcineurin in the caudate nucleus and putamen, and a marked reduction of calcineurin-immunoreactive nerve fibers in the globus pallidus and substantia nigra were found in the cases with HD, but not in those with Parkinson's disease. These findings suggest that calcineurin can be a useful and specific index of neuronal degeneration in the caudato-putamen resulting from extrapyramidal disease, and that the calcineurin-immunostaining method can be a valuable tool for clarifying the anatomy of the human extrapyramidal system.