Cannabinoid receptor CB2 (CB2R) is upregulated on activated microglia and astrocytes in the brain under inflammatory conditions and plays important roles in many neurological diseases, such as Alzheimer's disease, amyotrophic lateral sclerosis, and ischemic stroke. The advent of positron emission tomography (PET) using CB2R radiotracers has enabled the visualization of CB2R distribution in vivo in animal models of central nervous system inflammation, however translation to humans has been less successful. Several novel CB2R radiotracers have been developed and evaluated to quantify microglial activation. In this review, we summarize the recent preclinical and clinical imaging results of CB2R PET tracers and discuss the prospects of CB2R imaging using PET.

中文翻译：

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2 型大麻素受体的正电子发射断层扫描用于检测中枢神经系统的炎症。

在炎症条件下，大麻素受体 CB2 (CB2R) 在大脑中激活的小胶质细胞和星形胶质细胞上表达上调，并在许多神经系统疾病中发挥重要作用，例如阿尔茨海默病、肌萎缩侧索硬化症和缺血性中风。使用 CB2R 放射性示踪剂的正电子发射断层扫描 (PET) 的出现使得中枢神经系统炎症动物模型中 CB2R 体内分布的可视化成为可能，但应用于人类却不太成功。几种新型 CB2R 放射性示踪剂已被开发和评估，以量化小胶质细胞的激活。在这篇综述中，我们总结了 CB2R PET 示踪剂的最新临床前和临床成像结果，并讨论了使用 PET 进行 CB2R 成像的前景。