@article{oai:repo.qst.go.jp:00045842,
 author = {Yanamoto, Kazuhiko and Konno, Fujiko and Odawara, Chika and Yamasaki, Tomoteru and Kawamura, Kazunori and Hatori, Akiko and Yui, Joji and Wakizaka, Hidekatsu and Nengaki, Nobuki and Takei, Makoto and Zhang, Ming-Rong and 柳本 和彦 and 昆野 富士子 and 小田原 知佳 and 山崎 友照 and 河村 和紀 and 羽鳥 晶子 and 由井 譲二 and 脇坂 秀克 and 念垣 信樹 and 武井 誠 and 張 明栄},
 issue = {5},
 journal = {Nuclear Medicine and Biology},
 month = {Jul},
 note = {Introduction: Developing positron emission tomography (PET) ligands for imaging metabotropic glutamate receptor type 1 (mGluR1) is
important for studying its role in the central nervous system. N-cyclohexyl-6-{[N-(2-methoxyethyl)-N-methylamino]methyl}-Nmethylthiazolo[
3,2-a]benzimidazole-2-carboxamide (YM-202074) exhibited high binding affinity for mGluR1 (Ki=4.8 nM), and selectivity
over other mGluRs in vitro. The purpose of this study was to label YM-202074 with carbon-11 and to evaluate in vitro and in vivo
characteristics of [11C]YM-202074 as a PET ligand for mGluR1 in rodents.
Methods: [11C]YM-202074 was synthesized by N-[11C]methylation of its desmethyl precursor with [11C]methyl iodide. The in vitro and in
vivo brain regional distributions were determined in rats using autoradiography and PET, respectively.
Results: [11C]YM-202074 (262–630 MBq, n=5) was obtained with radiochemical purity of N98% and specific activity of 27–52 GBq/micromol
at the end of synthesis, starting from [11C]CO2 of 19.3–21.5 GBq. In vitro autoradiographic results showed that the high specific binding of
[11C]YM-202074 for mGluR1 was presented in the cerebellum, thalamus and hippocampus, which are known as mGluR1-rich regions. In ex
vivo autoradiography and PET studies, the radioligand was specifically distributed in the cerebellum, although the uptake was low.
Furthermore, the regional distribution was fairly uniform in the whole brain by pretreatment with JNJ16259685 (a mGluR1 antagonist).
However, radiometabolite(s) was detected in the brain.
Conclusions: From these results, especially considering the low brain uptake and the influx of radiometabolite(s) into brain, [11C]YM-
202074 may not be a useful PET ligand for in vivo imaging of mGluR1 in the brain.
© 2010 Elsevier Inc. All rights reserved.},
 pages = {615--624},
 title = {Radiosynthesis and evaluation of [11C]YM-202074 as a PET ligand for imaging the metabotropic glutamate receptor type 1},
 volume = {37},
 year = {2010}
}