Degeneration of tyrosine hydroxylase-immunoreactive neurons in the cerebral cortex and hippocampus of patients with dementia with Lewy bodies.

We immunohistochemically investigated the degeneration of tyrosine hydroxylase (TH)-positive neurons in the cerebral cortex and hippocampus of dementia with Lewy bodies (DLB) brains. TH-positive neurons in the cerebral cortex and hippocampus were decreased in number, and were rarely associated with Lewy bodies (LB) or neurofibrillary tangles (NFT). A mild to moderate loss of TH-positive neurons was observed in both the cerebral cortex and substantia nigra. In addition, most brains showing low NFT stages and lacking amyloid deposits (AM), corresponding to pure-form DLB brains, demonstrated a moderate to severe loss of TH-positive neurons. These findings suggest that TH-positive neurons in the cerebral cortex degenerate by a pathomechanism similar to that in the substantia nigra, and that the degeneration of these neurons is partly related to LB or NFT formation in either the substantia nigra or cerebral cortex.