title: Acetylcholine esterase activity in mild cognitive impairment and Alzheimer's disease.
abstract: OBJECTIVE
  Impairment of cholinergic neurotransmission is a well-established fact in Alzheimer's disease (AD), but there is controversy about its relevance at the early stages of the disease and in mild cognitive impairment (MCI).
  
  
  METHODS
  In vivo positron emission tomography imaging of cortical acetylcholine esterase (AChE) activity as a marker of cholinergic innervation that is expressed by cholinergic axons and cholinoceptive neurons has demonstrated a reduction of this enzyme activity in manifest AD. The technique is also useful to measure the inhibition of cerebral AChE induced by cholinesterase inhibitors for treatment of dementia symptoms.
  
  
  RESULTS
  A reduction of cortical AchE activity was found consistently in all studies of AD and in few cases of MCI who later concerted to AD.
  
  
  CONCLUSIONS
  The in vivo findings in MCI and very mild AD are still preliminary, and studies seem to suggest that cholinergic innervation and AChE as the main degrading enzyme are both reduced, which might result in partial compensation of their effect.
authors.affiliation: Wolfson Molecular Imaging Centre, Clinical Neuroscience, University of Manchester, 27 Palatine Road, Manchester, UK. karl.herholz@manchester.ac.uk
authors.forename: Karl
authors.initials: K
authors.lastname: Herholz
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000544:Alzheimer Disease / Q000175:diagnosis / Q000201:enzymology*; D001921:Brain / Q000201:enzymology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000201:enzymology*; D003952:Diagnostic Imaging / Q000379:methods; D004789:Enzyme Activation; D006801:Humans; D008959:Models, Neurological; D015336:Molecular Probe Techniques; D014018:Tissue Distribution
chemical_list: D000110:Acetylcholinesterase