@article{oai:repo.qst.go.jp:00047354,
 author = {Yamasaki, Tomoteru and Fujinaga, Masayuki and Yui, Joji and Wakizaka, Hidekatsu and Ohya, Tomoyuki and Nengaki, Nobuki and Ogawa, Masanao and Ikoma, Yoko and Hatori, Akiko and Xie, Lin and Kawamura, Kazunori and Zhang, Ming-Rong and 山崎 友照 and 藤永 雅之 and 由井 譲二 and 脇坂 秀克 and 大矢 智幸 and 念垣 信樹 and 小川 政直 and 生駒 洋子 and 羽鳥 晶子 and 謝 琳 and 河村 和紀 and 張 明栄},
 issue = {6},
 journal = {PloS one},
 month = {Jun},
 note = {Metabotropic glutamate receptor subtype 1 (mGluR1) is a crucial target in the development of new medications to treat central nervous system (CNS) disorders. Recently, we developed N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-4-[11C]methoxy-N-methyl-benzamide ([11C]ITMM) as a useful positron emission tomography (PET) probe for mGluR1 in clinical studies. Here, we aimed to improve visualization and threshold of specific binding for mGluR1 using [11C]ITMM with ultra-high specific activity (SA) of > 3,500 GBq/μmol in rat brains. A two-tissue compartment model indicated large differences between the two SAs in the constants k3 and k4, representing binding ability for mGluR1, while constants K1 and k2 showed no differences. The total distribution volume (VT) values of conventional and ultra-high SA were 9.1 and 11.2 in the thalamus, 7.7 and 9.7 in the striatum, and 6.4 and 8.5 mL/cm3 in the substantia nigra, respectively. The specific binding of [11C]ITMM with ultra-high SA was significantly higher than the conventional SA, especially in the basal ganglia. Parametric PET images scaled with VT of the ultra-high SA clearly identified regional differences in the rat brain. In conclusion, PET studies using [11C]ITMM with ultra-high SA could sufficiently improve visualization and specific binding for mGluR1, which could help further understanding for mGluR1 functions in CNS disorders.},
 title = {Improved Visualization and Specific Binding for Metabotropic Glutamate Receptor Subtype 1 (mGluR1) Using [11C]ITMM with Ultra-High Specific Activity in Small-Animal PET.},
 volume = {10},
 year = {2015}
}