title: [The [18F]-FNECA serves as a suitable radioligand for PET investigation of purinergic receptor expression].
abstract: The well known and widely used P1 adenosine agonist, 5'-N-ethyl-carboxamidoadenosine (NECA), was labelled with 18F isotope for the in vivo PET investigation of A1, A2 and A3 adenosine receptor expression. The precursor 2-[18F]fluoroethylamine was reacted with 2',3'-O-isopropylideneadenosine-5'-uronic acid. Specific activity of the [18F]-FNECA was (2.3 +/- 1.1) TBq/mmol (60 Ci/mmol). Dynamic PET measurements were carried out in rabbits to study the in vivo kinetics of the receptor saturation with the labelled ligand. The time dependent accumulation was followed up in the heart, lungs, liver, brain and testis. The radiotracer uptake was rapid and reached its maximum in less than two minutes in the heart and testes after v. injection of the radiopharmaceutical, while it took about 6 minutes in the brain, lungs and liver. High [18F]-FNECA accumulation was detected in the intestines, too. The specific binding of the [18F]-FNECA was tested in competition experiments in brain and heart sections using autoradiographic technique. The outlined synthesis provided sufficient amounts of [18F]-FNECA to map adenosine receptor expression under physiological conditions.
authors.affiliation: Debreceni Egyetem, Orvos- és Egészségtudományi Centrum, PET Centrum, Debrecen. marian@pet.dote.hu
authors.forename: Teréz
authors.initials: T
authors.lastname: Márián
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Lehel
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Lengyel
authors.forename: László
authors.initials: L
authors.lastname: Balkay
authors.forename: Géza
authors.initials: G
authors.lastname: Horváth
authors.forename: Pál
authors.initials: P
authors.lastname: Mikecz
authors.forename: Tünde
authors.initials: T
authors.lastname: Miklovicz
authors.forename: István
authors.initials: I
authors.lastname: Fekete
authors.forename: A József
authors.initials: AJ
authors.lastname: Szentmiklósi
mesh_terms: D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000138:chemical synthesis; D000818:Animals; D001345:Autoradiography; D001773:Blood Cells / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D019788:Fluorodeoxyglucose F18; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D051379:Mice; D009206:Myocardium / Q000378:metabolism; D010949:Plasma / Q000378:metabolism; D011869:Radioligand Assay / Q000379:methods*; D019275:Radiopharmaceuticals / Q000138:chemical synthesis; D018047:Receptors, Purinergic P1 / Q000378:metabolism*; D013737:Testis / Q000378:metabolism; D013997:Time Factors; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D018047:Receptors, Purinergic P1; D019788:Fluorodeoxyglucose F18; D019830:Adenosine-5'-(N-ethylcarboxamide)