title: Search for PET probes for imaging the globus pallidus studied with rat brain ex vivo autoradiography.
abstract: We have evaluated the feasibility of using four positron emission tomography (PET) tracers for imaging the globus pallidus by ex vivo autoradiography in rats. The tracers investigated were [11C]KF18446, [11C]SCH 23390 and [11C]raclopride for mapping adenosine A2A, dopamine D1 and dopamine D2 receptors, respectively, and [18F]FDG. The highest uptake by the globus pallidus was found for [11C]SCH 23390, followed by [18F]FDG, [11C]KF18446 and [11C]raclopride. The receptor-specific uptake by the globus pallidus was observed in [11C]KF18446 and [11C]SCH 23390, but not in [11C]raclopride. Uptake ratios of globus pallidus to the striatum for [18F]FDG and [11C]KF18446 were approximately 0.6, which was twice as large as that for [11C]SCH 23390. In a rat model of degeneration of striatopallidal gamma-aminobutyric acid-ergic-enkephalin neurons induced by intrastriatal injection of quinolinic acid, the uptake of [11C]KF18446 by the striatum and globus pallidus was remarkably reduced. To prove the visualization of the globus pallidus by PET with [18F]FDG and [11C]KF18446, PET-MRI registration technique and advances in PET technologies providing high-resolution PET scanner will be required. The metabolic activity of the globus pallidus could then be measured by PET with [18F]FDG, and [11C]KF18446 may be a candidate tracer for imaging the pallidal terminals projecting from the striatum.
authors.affiliation: Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Japan. ishiwata@pet.tmig.or.jp
authors.forename: K
authors.initials: K
authors.lastname: Ishiwata
authors.forename: N
authors.initials: N
authors.lastname: Ogi
authors.forename: J
authors.initials: J
authors.lastname: Shimada
authors.forename: W
authors.initials: W
authors.lastname: Wang
authors.forename: K
authors.initials: K
authors.lastname: Ishii
authors.forename: A
authors.initials: A
authors.lastname: Tanaka
authors.forename: F
authors.initials: F
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Senda
mesh_terms: D000818:Animals; D001345:Autoradiography / Q000379:methods; D001552:Benzazepines / Q000493:pharmacokinetics; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D002250:Carbon Radioisotopes; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D005917:Globus Pallidus / Q000000981:diagnostic imaging* / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009928:Organ Specificity; D020891:Raclopride / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D051381:Rats; D017208:Rats, Wistar; D043705:Receptor, Adenosine A2A; D017447:Receptors, Dopamine D1 / Q000032:analysis*; D017448:Receptors, Dopamine D2 / Q000032:analysis*; D018047:Receptors, Purinergic P1 / Q000032:analysis*; D013926:Thrombopoietin; D014055:Tomography, Emission-Computed; D014970:Xanthines / Q000493:pharmacokinetics
chemical_list: D001552:Benzazepines; D002250:Carbon Radioisotopes; C405422:KF18446; D019275:Radiopharmaceuticals; D043705:Receptor, Adenosine A2A; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D018047:Receptors, Purinergic P1; D014970:Xanthines; D019788:Fluorodeoxyglucose F18; D020891:Raclopride; D013926:Thrombopoietin