[PET study of cholinergic system in the brain].
Recently, we have developed a method to measure acetylcholinesterase (AChE) activity, a functional marker for cholinergic system, by positron emission tomography (PET) and carbon-11 labeled N-methyl-4-piperidyl acetate. Kinetic analysis of the radioactivity in the brain and the plasma yielded a rate constant "k 3" as an index of AChE activity. The ratios for the k 3 values for the cerebral cortex/thalamus/cerebellum/striatum found in healthy participants were 1/3/8/10, respectively, corresponding well with AChE activity ratios in the brain at necropsy (1/3/8/38), except for the striatum. In 23 healthy volunteers (age range: 24-89 years), there was no age-related decline of k 3 values in the cerebral cortex, suggesting AChE activity is preserved in aged cerebral cortex. In 11 patients with Alzheimer's disease, there was a significant reduction (-24%) of k 3 values in the cerebral cortex and hippocampus, suggesting a loss of ascending cholinergic system from the basal forebrain to the cerebral cortex and hippocampus. In 16 patients with Parkinson's disease, there was a significant reduction (-18%) of k 3 values in the cerebral cortex. In 10 patients with progressive supranuclear palsy, there was a significant reduction (-38%) of k 3 values in the thalamus. This technique is useful for investigating central cholinergic system in neurodegenerative disorders with dementia.
Shinotoh
H
H
Department of Neurology, Chiba University School of Medicine.
D000110:Acetylcholinesterase / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D001921:Brain / Q000000981:diagnostic imaging / Q000201:enzymology / Q000503:physiopathology*; D002799:Cholinergic Fibers / Q000502:physiology*; D006801:Humans; D019636:Neurodegenerative Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014055:Tomography, Emission-Computed / Q000379:methods*
D015415:Biomarkers; D000110:Acetylcholinesterase