Molecular forms of acetylcholinesterase in senile dementia of Alzheimer type: selective loss of the intermediate (10S) form.

Using density gradient centrifugation, three molecular forms of acetylcholinesterase have been distinguished in both normal and senile dementia of Alzheimer-type (SDAT) postmortem neocortex. Whilst the levels of the light and heavy forms were unaltered in SDAT there was a selective and extensive loss of the intermediate form. This form is predominantly hydrophobic and its loss from the cerebral cortex in SDAT may reflect degeneration of cholinergic axonal processes. This is the first report of an altered distribution of acetylcholinesterase molecular forms in a disease of the central nervous system.