Measuring age-related changes in dopamine D2 receptors with 11C-raclopride and 18F-N-methylspiroperidol.
This study investigates the rate of age-related dopamine D2 receptor loss as determined by positron emission tomography (PET) and 11C-raclopride and compares it with D2 loss previously estimated with 18F-N-methylspiroperidol (NMS). Dopamine D2 receptors were measured with 11C-raclopride in 24 healthy volunteers (24-73 years of age) using the ratio of the distribution volume in striatum to that in cerebellum (Bmax/Kd + 1). The results were compared with those obtained in 20 healthy male volunteers (20-49 years of age) in whom D2 receptors were measured with NMS using the ratio index (slope of the striatum-to-cerebellum ratio as a function of time). Findings of correlational analysis between age and dopamine D2 receptor availability were significant for both ligands. Estimates of dopamine D2 receptor loss per decade corresponded to 7.9% for the 11C-raclopride study and 7.8% for the NMS study. Both ligands documented significant age-related decreases in dopamine D2 receptors that occurred relatively early in life (40 years of age).
Volkow
N D
ND
Medical Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
Wang
G J
GJ
Fowler
J S
JS
Logan
J
J
Gatley
S J
SJ
MacGregor
R R
RR
Schlyer
D J
DJ
Hitzemann
R
R
Wolf
A P
AP
D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000378:metabolism*; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism*; D018491:Dopamine Agonists / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D008024:Ligands; D008297:Male; D008875:Middle Aged; D009410:Nerve Degeneration; D020891:Raclopride; D017448:Receptors, Dopamine D2 / Q000187:drug effects*; D012457:Salicylamides / Q000493:pharmacokinetics*; D013134:Spiperone / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D014055:Tomography, Emission-Computed
D018491:Dopamine Agonists; D008024:Ligands; D017448:Receptors, Dopamine D2; D012457:Salicylamides; D020891:Raclopride; D013134:Spiperone; C039167:3-N-methylspiperone