Altered dopamine D2 receptor binding in atypical facial pain.
Animal studies suggest that the dopaminergic system plays a role in central pain modulation. We have previously demonstrated with positron emission tomography (PET) that striatal dopaminergic hypofunction may be involved in the burning mouth syndrome. The aim of the present study was to evaluate the nigrostriatal dopaminergic system in patients with atypical facial pain using PET. In seven patients with atypical facial pain, striatal presynaptic dopaminergic function was assessed with [18F]FDOPA and dopamine D1 and D2 receptor availabilities with [11C]NNC 756 and [11C]raclopride, respectively. The results were compared with those of healthy controls. A quantitative region-of-interest analysis showed that the uptakes of [18F]FDOPA and [11C]NNC 756 did not differ between patients and controls. There was a tendency of increased D2 receptor availability in the left putamen (P=0.056), and the D1/D2 ratio in the putamen was decreased bilaterally by 7.7% (P=0.002) in patients when compared to controls. In a voxel-based analysis, the uptake of [11C]raclopride was increased in the left putamen (P=0.025). In conclusion, the increase in D2 receptor availability in the left putamen and the decrease in D1/D2 ratio imply that alterations in the striatal dopaminergic system as evaluated by PET may be involved in chronic orofacial pain conditions.
Hagelberg
Nora
N
Department of Anesthesiology and Intensive Care, Turku University Central Hospital, P.O. Box 52, FIN-20521 Turku, Finland.
Forssell
Heli
H
Aalto
Sargo
S
Rinne
Juha O
JO
Scheinin
Harry
H
Taiminen
Tero
T
Någren
Kjell
K
Eskola
Olli
O
Jääskeläinen
Satu K
SK
D000368:Aged; D001552:Benzazepines; D001572:Benzofurans; D002250:Carbon Radioisotopes; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D018492:Dopamine Antagonists; D005157:Facial Pain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged; D011699:Putamen / Q000378:metabolism; D020891:Raclopride; D017447:Receptors, Dopamine D1 / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D014055:Tomography, Emission-Computed
D001552:Benzazepines; D001572:Benzofurans; D002250:Carbon Radioisotopes; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C043437:fluorodopa F 18; D020891:Raclopride; D004295:Dihydroxyphenylalanine; C075357:odapipam