Function of sigma1 receptors in Parkinson's disease.
OBJECTIVE
The objective of this study was to investigate the mapping of sigma1 receptors in Parkinson's disease (PD) using [11C]SA4503 and positron emission tomography (PET), and to assess whether sigma1 receptors are involved in the damaged dopaminergic system in PD patients.


METHODS
We studied seven normal volunteers and six PD patients. The low density of dopamine transporters and the normal or high density of dopamine receptors were confirmed in the putamen of all patients using [11C]CFT and [11C]RAC PET. A dynamic series of PET data acquisition was performed with arterial blood sampling. We computed the binding potential (BP) of [11C]SA4503.


RESULTS
In PD patients, the BP was significantly lower on the more affected than the less affected side of the anterior putamen, although there was no significant difference with respect to the BP between patients and controls.


CONCLUSIONS
Release of dopamine is reduced asymmetrically in the putamen of early PD. [11C]SA4503 PET is an indicator of presynaptic dopaminergic damage in PD.
Mishina
M
M
The Department of Neurology, Neurological Institute, Nippon Medical School Chiba-Hokusoh Hospital, Inba-Gun, Chiba, Japan. mishina@nms.ac.jp
Ishiwata
K
K
Ishii
K
K
Kitamura
S
S
Kimura
Y
Y
Kawamura
K
K
Oda
K
K
Sasaki
T
T
Sakayori
O
O
Hamamoto
M
M
Kobayashi
S
S
Katayama
Y
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001667:Binding, Competitive / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D002250:Carbon Radioisotopes; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D018697:Nootropic Agents / Q000378:metabolism; D010300:Parkinson Disease / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D010879:Piperazines / Q000378:metabolism; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D017729:Presynaptic Terminals / Q000378:metabolism; D011699:Putamen / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D011954:Receptors, Dopamine / Q000378:metabolism; D017480:Receptors, sigma / Q000378:metabolism*; D013378:Substantia Nigra / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D000097605:Sigma-1 Receptor
D002250:Carbon Radioisotopes; D004298:Dopamine; D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D018697:Nootropic Agents; D010879:Piperazines; D011954:Receptors, Dopamine; D017480:Receptors, sigma; D000097605:Sigma-1 Receptor; C101789:SA 4503