Choline acetyltransferase immunohistochemistry in brains of Alzheimer's disease patients and controls.

Choline acetyltransferase (ChAT)-containing neuronal structures of the basal forebrain were studied by ChAT immunohistochemistry in the brains of persons dying with Alzheimer's disease (SDAT), as well as age-matched controls dying without neurological disorder. A loss of greater than 50% in ChAT-containing neurons was found in the substantia innominata in the SDAT group. In contrast, there was no reduction in the number of ChAT-containing neurons of the putamen as compared with controls. The data confirm the reason for the reduction of ChAT as measured biochemically in the neocortex of SDAT cases, and support the cholinergic hypothesis of memory.