title: Central in vivo nicotinic acetylcholine receptor imaging agents for positron emission tomography (PET) and single photon emission computed tomography (SPECT).
abstract: Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are useful for non-invasive investigation of brain receptors. With these imaging techniques, changes in brain receptor densities and distributions during chronic drug treatments and disease progressions can be tracked for a long period. Appropriate radiolabeled imaging agents are necessary for PET and SPECT molecular imaging. Nicotinic acetylcholine receptors (nAChRs) play important roles in brain functions. The alpha4beta2 and alpha7 are the major nAChR subtypes in the brain. To date, several subtype selective radiolabeled ligands for nAChR have been reported. For the alpha4beta2 subtype, some agents are already applied for human studies, but only a few agents are developed for the alpha7 subtype. Here, we overview our results of [(125/123)I]5-iodo-3-(2(S)-azetidinylmethoxy)pyridine and 5-[11C]methyl-3-(2-(S)-azetidinylmethoxy)pyridine ([11C]5MA) for alpha4beta2 subtype imaging, and [11C](R)-2-methylamino-benzoic acid 1-aza-bicyclo[2.2.2]oct-3-yl ester ([11C](R)-MeQAA) for alpha7 subtype imaging.
authors.affiliation: Photon Medical Research Center, Hamamatsu University School of Medicine, Japan.
authors.forename: Mikako
authors.initials: M
authors.lastname: Ogawa
authors.forename: Hideo
authors.initials: H
authors.lastname: Tsukada
authors.forename: Kentaro
authors.initials: K
authors.lastname: Hatano
authors.forename: Yasuomi
authors.initials: Y
authors.lastname: Ouchi
authors.forename: Hideo
authors.initials: H
authors.lastname: Saji
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Magata
mesh_terms: D000818:Animals; D001384:Azetidines / Q000493:pharmacokinetics; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D002250:Carbon Radioisotopes; D007457:Iodine Radioisotopes; D049268:Positron-Emission Tomography; D011725:Pyridines / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D011978:Receptors, Nicotinic / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: C540131:5-(11C)methyl-3-(2-(S)-azetidinylmethoxy)pyridine; C104288:A 85380; D001384:Azetidines; D002250:Carbon Radioisotopes; D007457:Iodine Radioisotopes; D011725:Pyridines; D019275:Radiopharmaceuticals; D011978:Receptors, Nicotinic