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Hippocampal dopamine D2 receptors correlate with memory functions in Alzheimer's disease
Author(s) -
Kemppainen N.,
Laine M.,
Laakso M. P.,
Kaasinen V.,
Någren K.,
Vahlberg T.,
Kurki T.,
Rinne J. O.
Publication year - 2003
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.2003.02716.x
Subject(s) - dopamine receptor d2 , hippocampus , neuroscience , hippocampal formation , psychology , dopamine receptor d3 , dopamine , dopamine receptor , dopaminergic , temporal lobe , receptor , medicine , epilepsy
Post mortem studies have revealed a loss of dopamine D2 receptors in the temporal lobes in Alzheimer's disease (AD). Moreover, the role of hippocampal D2 receptors on memory performance has been suggested in experimental studies. However, there are no previous in vivo studies on extrastriatal D2 receptors in AD. Our aim was to examine in vivo whether hippocampal or temporal cortical dopamine D2 receptors are affected in AD and whether D2 receptor availability is associated with the memory dysfunction seen in AD. Fourteen patients with probable AD and 11 age‐ and sex‐matched controls were studied with positron emission tomography using a dopamine D2/D3 receptor antagonist [ 11 C]FLB 457. The D2 receptor binding potentials (BPs) were measured in extrastriatal brain regions and a neuropsychological investigation was performed on the patients with AD. In AD, the D2 receptor availability was reduced in the hippocampus: by 34% ( P = 0.03) in the right hippocampus and by 14% ( P = 0.78) in the left hippocampus as compared with controls. Multiple linear regression analysis showed that the BP in the right hippocampus had a significant positive association with verbal memory performance (Wechsler Memory Scale – Revised) ( P = 0.001) and picture naming (the Boston Naming Test) ( P = 0.002). Our findings suggest a role for temporal lobe D2 receptors in the memory and naming performance in AD, and suggest that studies to evaluate the efficiency of dopaminergic medication on patients with early AD might be warranted.