title: Striatal dopamine D1 and D2 receptors in burning mouth syndrome.
abstract: Animal studies have indicated that the nigrostriatal dopaminergic system is involved in central pain modulation. In a recent positron emission tomography (PET) study, we demonstrated presynaptic dysfunction of the nigrostriatal dopaminergic pathway in burning mouth syndrome, which is a chronic pain state. The objective of the present study was to examine striatal dopamine D1 and D2 receptors in these patients. We used 11C-NNC 756 and 11C-raclopride to study D1 and D2 receptor binding in a PET study in ten burning mouth patients and 11 healthy controls. Patients underwent a structured psychiatric evaluation and an electrophysiological test for the excitability of the blink reflex. The striatal uptake of 11C-NNC 756 did not differ between patients and controls. In a voxel-level analysis, the uptake of 11C-raclopride was statistically significantly higher in the left putamen in burning mouth patients (corrected P-value 0.038 at cluster-level). In the region of interest analysis, the D1/D2 ratio was 7.7% lower in the right putamen (0.64+/-0.04 vs. 0.69+/-0.04, P=0.01) and 6.4 % lower in the left putamen (0.65+/-0.05 vs. 0.70+/-0.05, P=0.05) when compared to controls. Increased 11C-raclopride uptake and the subsequent decrease in the D1/D2 ratio may indicate a decline in endogenous dopamine levels in the putamen in burning mouth patients.
authors.affiliation: Department of Anesthesiology and Intensive Care, Turku University Central Hospital, PO Box 52, FIN-20521, Turku, Finland.
authors.forename: Nora
authors.initials: N
authors.lastname: Hagelberg
authors.forename: Heli
authors.initials: H
authors.lastname: Forssell
authors.forename: Juha O
authors.initials: JO
authors.lastname: Rinne
authors.forename: Harry
authors.initials: H
authors.lastname: Scheinin
authors.forename: Tero
authors.initials: T
authors.lastname: Taiminen
authors.forename: Sargo
authors.initials: S
authors.lastname: Aalto
authors.forename: Sinikka
authors.initials: S
authors.lastname: Luutonen
authors.forename: Kjell
authors.initials: K
authors.lastname: Någren
authors.forename: Satu
authors.initials: S
authors.lastname: Jääskeläinen
mesh_terms: D000328:Adult; D000368:Aged; D001552:Benzazepines; D001572:Benzofurans; D002054:Burning Mouth Syndrome / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002250:Carbon Radioisotopes; D002908:Chronic Disease; D003342:Corpus Striatum / Q000502:physiology*; D018492:Dopamine Antagonists; D006801:Humans; D008875:Middle Aged; D020891:Raclopride; D017447:Receptors, Dopamine D1 / Q000502:physiology*; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D014055:Tomography, Emission-Computed
chemical_list: D001552:Benzazepines; D001572:Benzofurans; D002250:Carbon Radioisotopes; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D020891:Raclopride; C075357:odapipam