title: Age-related dopamine D2/D3 receptor loss in extrastriatal regions of the human brain.
abstract: Loss of dopamine D2-like receptors in the striatum has been associated with both normal human aging and impairment of cognitive and motor functions in the elderly. To investigate whether there are age-associated changes in dopamine D2 and D3 receptor subtypes (D2/3Rs) outside the striatum, a D2/3R selective high-affinity radioligand [11C]FLB 457 was used in positron emission tomography (PET) examinations for 24 normal healthy male subjects (age range 19-74 years). Significant age-related declines of D2/3Rs were detected in all the brain regions studied: the anterior cingulate cortex (decline of 13% per increase of a decade in age, P < 0.001). the frontal cortex (11%, P < 0.001), the lateral temporal cortex (10%, P < 0.001), the hippocampus (10%, P < 0.01), the medial temporal cortex (9%, P < 0.001), the amygdala (7%, P < 0.01), the medial thalamus (6%, P < 0.001) and the lateral thalamus (5%, P < 0.01). The rate of D2/3R decline was significantly faster in the frontal cortex as compared to the medial temporal cortex (P < 0.05, Bonferroni corrected) and as compared to the medial thalamus (P < 0.05, Bonferroni corrected). These results indicate that the previously demonstrated age-related decline in striatal dopamine D2 receptors extends to several extrastriatal regions in normal human males. Further, the rate of D2/3R decline may be faster in the frontal cortex as compared to the temporal and thalamic regions.
authors.affiliation: Department of Neurology, University of Turku, Finland. valtteri.kaasinen@pet.tyks.fi
authors.forename: V
authors.initials: V
authors.lastname: Kaasinen
authors.forename: H
authors.initials: H
authors.lastname: Vilkman
authors.forename: J
authors.initials: J
authors.lastname: Hietala
authors.forename: K
authors.initials: K
authors.lastname: Någren
authors.forename: H
authors.initials: H
authors.lastname: Helenius
authors.forename: H
authors.initials: H
authors.lastname: Olsson
authors.forename: L
authors.initials: L
authors.lastname: Farde
authors.forename: J
authors.initials: J
authors.lastname: Rinne
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D002250:Carbon Radioisotopes; D018492:Dopamine Antagonists; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism; D006179:Gyrus Cinguli / Q000000981:diagnostic imaging / Q000378:metabolism; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D050637:Receptors, Dopamine D3; D012457:Salicylamides; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism; D013788:Thalamus / Q000000981:diagnostic imaging / Q000378:metabolism; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D002250:Carbon Radioisotopes; C493593:DRD3 protein, human; D018492:Dopamine Antagonists; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D012457:Salicylamides; C065065:FLB 457