Age-related changes in human D1 dopamine receptors measured by positron emission tomography.
The effects of age on the binding parameters of 11C-SCH23390, the highly selective ligand for central D1 dopamine receptors, at specific binding sites in the brain were studied. Seventeen healthy male volunteers (20-72 years old) participated. Regional radioactivity in the brain was followed for 40 min by positron emission tomography (PET). A high accumulation of radioactivity was observed in the striatum and there was a conspicuous accumulation in the neocortex. A two-compartment model was used to obtain quantitative estimates of rate constants of association (K3) and dissociation (k4). The binding potential (k3/k4) of the dopamine D1 receptors in the striatum and frontal cortex decreased by 35% and 39%, respectively, with age. The value of k3 decreased by 58% in the striatum and 83% in the frontal cortex, whereas the value of k4 decreased by 35% in the striatum and 72% in the frontal cortex with age.
Suhara
T
T
Division of Clinical Research, National Institute of Radiological Sciences, Chiba-shi, Japan.
Fukuda
H
H
Inoue
O
O
Itoh
T
T
Suzuki
K
K
Yamasaki
T
T
Tateno
Y
Y
D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D001552:Benzazepines / Q000494:pharmacology; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000378:metabolism; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism*; D017447:Receptors, Dopamine D1; D014055:Tomography, Emission-Computed
D001552:Benzazepines; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1