Comparison of two pet radioligands for imaging extrastriatal dopamine transporters in human brain.
We compared the sensitivity of two dopamine transporter (DAT) ligands ([C-11]cocaine and [C-11]d-threo-methylphenidate) for measurement of extrastriatal DAT availability using positron emission tomography (PET) on separated groups of 10 age matched male volunteers (age range, 21-49 years). DAT availability was obtained using the ratio of the distribution volume in the region of interest to that in the cerebellum (Bmax'/Kd'+ 1). DAT availability measured with [C-11]d-threo-methylphenidate was highest in basal ganglia, followed by thalamus > temporal insula, cingulate > orbitofrontal, frontal and occipital cortices. A similar ranking order for DAT availability was obtained with [C-11]cocaine. Specific binding (Bmax'/Kd') of [C-11]cocaine in thalamus was 25-33% that of basal ganglia and [C-11]d-threo-methylphenidate in thalamus was 11-13% that of basal ganglia. The regional measures with [C-11]cocaine were significantly correlated with those of [C-11]d-threo-methylphenidate (p < or = 0.0001). These results document extrastriatal binding in human brain with two different DAT ligands.
Wang
G J
GJ
Medical Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
Volkow
N D
ND
Fowler
J S
JS
Ding
Y S
YS
Logan
J
J
Gatley
S J
SJ
MacGregor
R R
RR
Wolf
A P
AP
D000328:Adult; D001923:Brain Chemistry; D002250:Carbon Radioisotopes; D002352:Carrier Proteins / Q000032:analysis*; D003042:Cocaine; D004298:Dopamine; D050483:Dopamine Plasma Membrane Transport Proteins; D006801:Humans; D008024:Ligands; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D008774:Methylphenidate; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D011869:Radioligand Assay / Q000379:methods*; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed
D002250:Carbon Radioisotopes; D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D008024:Ligands; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493214:SLC6A3 protein, human; D008774:Methylphenidate; D003042:Cocaine; D004298:Dopamine