Article
作者: Hoyle, Danielle E. ; Li, Yinlong ; Kumata, Katsushi ; Xie, Lin ; Zhang, Ming-Rong ; Hu, Qilong ; Fujinaga, Masayuki ; Li, Xiaoyan ; Li, Chongjiao ; Kokufuta, Tomomi ; Yamasaki, Tomoteru ; Zhang, Yiding ; Zhao, Taoqian ; Chen, Jiahui ; Song, Zhendong ; Mori, Wakana ; Sun, Zhenkun ; Hu, Kuan ; Yuan, Hongjie ; Patel, Jimmy S. ; Liang, Steven H. ; Zhou, Xin ; Gao, Yabiao
Phosphodiesterase 2A (PDE2A) plays a vital role in regulating cyclic nucleotide signaling by hydrolyzing cAMP and cGMP in the central nervous system (CNS). This enzymatic activity is essential for neuronal function, and PDE2A has emerged as a molecular target for neuroimaging in neuropsychiatric disorders and neurodegenerative diseases. In this study, we evaluated the novel 11C-labeled positron emission tomography (PET) radioligand [11C]1 derived from a pyrazolopyrimidine-based PDE2A inhibitor. The radiosynthesis of [11C]1 was accomplished via [11C]-methyl iodide-mediated methylation of precursor 9 under mild conditions, yielding [11C]1 with high purity (99%) and high molar activity (154 ± 66 GBq/μmol). In vitro autoradiography demonstrated high radiotracer accumulation in regions with abundant PDE2A expression, including the striatum and substantia nigra. However, dynamic PET imaging in rats showed a relatively uniform distribution throughout the brain and no significant blocking effects. Further optimization in medicinal chemistry is necessary to improve the in vivo performance of the pyrazolopyrimidine-based PDE2A tracer scaffold.