title: PET shows that striatal dopamine D1 and D2 receptors are differentially affected in AD.
abstract: OBJECTIVE
  To study dopamine D1 and D2 receptors in the putamen and the caudate nucleus in patients with AD and age-matched healthy controls by means of PET.
  
  
  METHODS
  A dopamine D1 receptor antagonist ([11C]NNC 756) and a D2 receptor antagonist ([11C]raclopride) were used as ligands. The uptake of these ligands was calculated as a distribution volume ratio of the putamen and the caudate nucleus to the cerebellum.
  
  
  RESULTS
  The mean [11C]NNC 756 uptake in AD was reduced by 14% from the mean control value both in the putamen (p = 0.004) and the caudate nucleus (p = 0.009). There was no significant reduction in the mean [11C]raclopride uptake in either the putamen or the caudate nucleus in AD. There was no correlation between [11C]NNC 756 or [11C]raclopride uptake and Mini-Mental State Examination or motor Unified PD Rating Scale scores in patients with AD.
  
  
  CONCLUSIONS
  There are changes in striatal D1 but not in D2 receptors in AD.
authors.affiliation: Department of Neurology, University of Turku, Finland.
authors.forename: N
authors.initials: N
authors.lastname: Kemppainen
authors.forename: H
authors.initials: H
authors.lastname: Ruottinen
authors.forename: K
authors.initials: K
authors.lastname: Nâgren
authors.forename: J O
authors.initials: JO
authors.lastname: Rinne
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001931:Brain Mapping; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000503:physiopathology; D003342:Corpus Striatum / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D011699:Putamen / Q000000981:diagnostic imaging / Q000503:physiopathology; D017447:Receptors, Dopamine D1 / Q000502:physiology*; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D014055:Tomography, Emission-Computed
chemical_list: D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2