title: Decrease in human striatal dopamine D2 receptor density with age: a PET study with [11C]raclopride.
abstract: The effect of age on human striatal dopamine D2 receptors was investigated with positron emission tomography (PET) using [11C]raclopride as a radioligand. Twenty-one healthy volunteers aged from 20 to 81 years were studied. An equilibrium method was applied and two separate PET scans with different specific activities of [11C]raclopride were performed. The maximal number of receptors (Bmax) and their dissociation constant (Kd) were calculated using Scatchard analysis. There was an age-dependent decline in the Bmax (r = -0.49; p = 0.02) of striatal D2 receptors while the Kd remained unchanged. The results show that there is an age-related loss of striatal D2 receptors, which, together with other changes in the brain nigrostriatal dopaminergic system, may contribute to extrapyramidal symptoms associated with aging.
authors.affiliation: Department of Neurology, University of Turku, Finland.
authors.forename: J O
authors.initials: JO
authors.lastname: Rinne
authors.forename: J
authors.initials: J
authors.lastname: Hietala
authors.forename: U
authors.initials: U
authors.lastname: Ruotsalainen
authors.forename: E
authors.initials: E
authors.lastname: Säkö
authors.forename: A
authors.initials: A
authors.lastname: Laihinen
authors.forename: K
authors.initials: K
authors.lastname: Någren
authors.forename: P
authors.initials: P
authors.lastname: Lehikoinen
authors.forename: V
authors.initials: V
authors.lastname: Oikonen
authors.forename: E
authors.initials: E
authors.lastname: Syvälahti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002250:Carbon Radioisotopes; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000378:metabolism; D065127:Dopamine D2 Receptor Antagonists; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020891:Raclopride; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D012457:Salicylamides; D013378:Substantia Nigra / Q000000981:diagnostic imaging / Q000378:metabolism*; D014055:Tomography, Emission-Computed
chemical_list: D002250:Carbon Radioisotopes; D065127:Dopamine D2 Receptor Antagonists; D017448:Receptors, Dopamine D2; D012457:Salicylamides; D020891:Raclopride