Saji H, Tsutsumi D, Magata Y, Iida Y, Konishi J, Yokoyama A
Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
Ann Nucl Med. 1992 Feb;6(1):63-7. doi: 10.1007/BF03164644.
A potent mu-opioid agonist, [11C]carfentanil, was prepared by the methylation of carfentanil carboxylic acid with [11C]methyl iodide in order to study brain mu-opioid receptors by positron emission tomography. Synthesis (including purification) was completed within 25 min and the radiochemical yield was approximately 40%. The radiochemical purity of the product was more than 99% and its specific activity was 3.7-7.4 GBq/mumol. Biodistribution studies performed in mice after intravenous injection showed a high brain uptake and rapid blood clearance, so a high brain/blood ratio of 1.5-1.8 was found from 5 to 30 min. Regional cerebral distribution studies in the mouse showed a significantly higher uptake of [11C]carfentanil by the thalamus and striatum than by the cerebellum, with the radioactivity in the striatum disappearing more rapidly than that in the thalamus. Treatment with naloxone significantly reduced the uptake of [11C]carfentanil by the thalamus and striatum. These results indicate that [11C]carfentanil binds specifically to brain mu-opioid receptors.
一种强效的μ-阿片受体激动剂[11C]卡芬太尼，是通过卡芬太尼羧酸与[11C]甲基碘进行甲基化反应制备而成，目的是利用正电子发射断层扫描技术研究脑内μ-阿片受体。合成（包括纯化）在25分钟内完成，放射化学产率约为40%。产物的放射化学纯度超过99%，比活度为3.7 - 7.4 GBq/μmol。对小鼠进行静脉注射后的生物分布研究表明，[11C]卡芬太尼在脑内摄取量高且血液清除迅速，因此在5至30分钟内脑/血比高达1.5 - 1.8。对小鼠进行的脑区分布研究显示，丘脑和纹状体对[11C]卡芬太尼的摄取量明显高于小脑，纹状体内的放射性消失速度比丘脑更快。用纳洛酮处理可显著降低丘脑和纹状体对[11C]卡芬太尼的摄取。这些结果表明，[11C]卡芬太尼能特异性结合脑内μ-阿片受体。
