Positron emission tomography of striatal serotonin transporters in Parkinson disease.
BACKGROUND
Little is known about serotonin neurons in Parkinson disease (PD).


OBJECTIVE
To study the serotonin system in PD with positron emission tomography, using the serotonin transporter radioligand [11C](+)McN5652.


METHODS
We measured the density of the serotonin transporter and the density of [11C]WIN35,428-labeled dopamine transporters in the striatum of 13 adults with PD and 13 age- and sex-matched controls. To assess the effects of possible differences in blood flow or brain atrophy, we also measured regional cerebral blood flow and the size of the regions of interest for the caudate nucleus and putamen.


RESULTS
Patients with PD showed reductions in the specific distribution volumes of [11C](+)McN5652 in the caudate (P<.01) and putamen (P<.01), along with the expected reductions in striatal [11C]WIN35,428 binding (P<.01). There were no reductions in regional cerebral blood flow or the sizes of the regions of interest, mitigating against potential confounding effects of blood flow, brain atrophy, or partial volume effects. Reductions in serotonin transporter binding correlated with ratings of disease staging.


CONCLUSIONS
These results suggest that the density of serotonin transporters, like that of dopamine transporters, is reduced in the striatum of patients with PD and that these changes are related to disease stage.
Kerenyi
Levente
L
Department of Neurology, Medical School Debrecen, Hungary.
Ricaurte
George A
GA
Schretlen
David J
DJ
McCann
Una
U
Varga
Jozsef
J
Mathews
William B
WB
Ravert
Hayden T
HT
Dannals
Robert F
RF
Hilton
John
J
Wong
Dean F
DF
Szabo
Zsolt
Z
D000328:Adult; D000368:Aged; D002352:Carrier Proteins / Q000378:metabolism*; D002421:Caudate Nucleus / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D003342:Corpus Striatum / Q000098:blood supply* / Q000378:metabolism* / Q000473:pathology; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D010300:Parkinson Disease / Q000378:metabolism* / Q000473:pathology; D011699:Putamen / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D012701:Serotonin / Q000378:metabolism*; D050486:Serotonin Plasma Membrane Transport Proteins; D012720:Severity of Illness Index; D014055:Tomography, Emission-Computed
D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D012701:Serotonin; D004298:Dopamine