Acetylcholinesterase activity in cerebrospinal fluid of patients with Alzheimer's disease and senile dementia.

Acetylcholinesterase (AChE) in the cerebrospinal fluid (CSF) from patients with Alzheimer-type dementia and control subjects was analyzed by centrifugation on a sucrose density gradient, and by column chromatography on Sephadex G-200. The sedimentation coefficient and molecular weight of CSF AChE were calculated as 10S and 380,000, respectively, which corresponded to those of G4 isozyme in the brain. Other isozymes of AChE were not detected in the CSF of either patients with Alzheimer-type dementia or the controls. Sufficient activity of AChE was observed in the CSF of a patient with familial pseudocholinesterase deficiency, although the pseudocholinesterase activity was not found either in the serum or in the CSF. CSF AChE activity in control subjects increased with advancing age (P less than 0.02). AChE activity in the CSF was significantly lower in patients with presenile dementia (Alzheimer's disease), compared with age-matched control subjects (P less than 0.001). However, AChE activity in the CSF showed a wide variation among patients of Alzheimer-type dementia with a late onset (senile dementia).