Synthesis and initial preclinical evaluation of the P2X<sub>7</sub>receptor antagonist [<sup>11</sup>C]A-740003 as a novel tracer of neuroinflammation
作者:Bieneke Janssen、Danielle J. Vugts、Uta Funke、Arnold Spaans、Robert C. Schuit、Esther Kooijman、Marissa Rongen、Lars R. Perk、Adriaan A. Lammertsma、Albert D. Windhorst
DOI:10.1002/jlcr.3206
日期:2014.6.30
Neuroinflammation, in particular activation of microglia, is thought to play an important role in the progression of neurodegenerative diseases. In activated microglia, the purinergic P2X7 receptor is upregulated. A-740003, a highly affine and selective P2X7 receptor antagonist, is a promising candidate for the development of a radiotracer for imaging of neuroinflammation by positron emission tomography. For this purpose, [11C]A-740003 was synthesised and evaluated in vivo with respect to both tracer metabolism and biodistribution. In plasma, a moderate metabolic rate was seen. In healthy rat brain, only marginal uptake of [11C]A-740003 was observed and, therefore, metabolites in brain could not be determined. Whether the minimal brain uptake is due to the low expression levels of the P2X7 receptor in healthy brain or to limited transport across the blood–brain barrier has yet to be elucidated.
神经炎症,尤其是小胶质细胞的激活,被认为在神经退行性疾病的发展中起着重要作用。在激活的小胶质细胞中,嘌呤能P2X7受体的表达上调。A-740003是一种高度亲和力和选择性的P2X7受体拮抗剂,是有前景的候选物,用于开发正电子发射断层扫描成像的放射性示踪剂,以检测神经炎症。为此,合成了[11C]A-740003,并在体内对其示踪剂代谢和生物分布进行了评估。在血浆中,显示出中等代谢速率。在健康大鼠脑中,仅观察到[11C]A-740003的微量摄取,因此无法确定脑中的代谢物。这种最小脑摄取是由于健康脑中P2X7受体表达水平低,还是由于其跨血脑屏障的转运受限,尚待阐明。