@misc{oai:repo.qst.go.jp:00072762,
 author = {Yamasaki, Tomoteru and Mori, Wakana and Zhang, Yiding and Hatori, Akiko and Kurihara, Yusuke and Ogawa, Masanao and Nengaki, Nobuki and Wakizaka, Hidekatsu and Fujinaga, Masayuki and Lu, Wang and Liang, Huan and Zhang, Ming-Rong and 山崎 友照 and 森 若菜 and 張 一鼎 and 羽鳥 晶子 and 栗原 雄祐 and 小川 政直 and 念垣 信樹 and 脇坂 秀克 and 藤永 雅之 and 王 璐 and 梁 歓 and 張 明栄},
 month = {Apr},
 note = {Background: Monoacylglycerol lipase (MGL) is a key enzyme for regulation of the endocannabinoid system, which relates to pain and multiple neurotransmissions in the central nervous system (CNS). Recently, [11C]SAR127303 was developed as a promising radioligand for MGL imaging. Herein, we aimed to quantify regional MGL activities using positron emission tomography (PET) with [11C]SAR127303.
Methods: PET studies with artery blood sampling were conducted using seven Sprague Dawley rats (male, 8-10 wk). To estimate quantitative parameters (k3, Ki, and lambda k3) for MGL activity, kinetic analyses were performed by the irreversible two tissue compartment model (2-TCMi, k4 = 0) and Patlak plot. Subsequently, in vitro autoradiography using rat brain sections was carried out for determination of regional distribution of MAL with [11C]SAR127303. All animal experiments were approved by the Committee for the Care and Use of Laboratory Animals in National Institutes for Quantum and Radiological Science and Technology and performed according to the ARRIVE guidelines. 
Results: In PET study, quantitative parameters (k3, Ki, and lambda k3) based on 2-TCMi were successfully obtained with high identifiability (< 10%COV), with ranked order as follows: cingulate cortex > striatum > hippocampus > thalamus > cerebellum > hypothalamus ≈ pons. In vitro autoradiograms using [11C]SAR127303 showed heterogeneous distribution of radioactivity as seen in PET images. The highest correlation with in vitro bindings was determined in the Ki value. Additionally, the Ki values based on Patlak plot showed high correlation with low underestimation compared to Ki values based on 2-TCMi. Using Ki value based on Patlak plot, we constructed parametric PET image, which succeeded in visualization of regional MGL activities in rat brain. 
Conclusion: We succeeded in in vivo mapping of MGL activity in rat brain regions for the first time by using PET with [11C]SAR127303., 12th Congress of the World Federation of Nuclear Medicine and Biology},
 title = {In vivo mapping for monoacylglycerol lipase activity using PET with [11C]SAR127303},
 year = {2018}
}