Addiction Biology Unit, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, 21224, USA.
Addiction Biology Unit, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, 21224, USA.
Neurosci Biobehav Rev. 2019 Mar;98:208-220. doi: 10.1016/j.neubiorev.2018.12.026. Epub 2019 Jan 3.
The type 2 cannabinoid receptor (CB2R) was initially regarded as a peripheral cannabinoid receptor. However, recent technological advances in gene detection, alongside the availability of transgenic mouse lines, indicate that CB2Rs are expressed in both neurons and glial cells in the brain under physiological and pathological conditions, and are involved in multiple functions at cellular and behavioral levels. Brain CB2Rs are inducible and neuroprotective via up-regulation in response to various insults, but display species differences in gene and receptor structures, CB2R expression, and receptor responses to various CB2R ligands. CB2R transcripts also differ between the brain and spleen. In the brain, CB is the major transcript isoform, while CB and CB transcripts are present at higher levels in the spleen. These new findings regarding brain versus spleen CB2R isoforms may in part explain why early studies failed to detect brain CB2R gene expression. Here, we review evidence supporting the expression and function of brain CB2R from gene and receptor levels to cellular functioning, neural circuitry, and animal behavior.
2 型大麻素受体（CB2R）最初被认为是一种外周大麻素受体。然而，随着基因检测技术的进步和转基因小鼠系的出现，表明 CB2R 在生理和病理条件下存在于大脑中的神经元和神经胶质细胞中，并在细胞和行为水平上参与多种功能。脑 CB2R 可通过各种刺激的上调而诱导和神经保护，但在基因和受体结构、CB2R 表达以及对各种 CB2R 配体的受体反应方面存在种间差异。脑和脾脏中的 CB2R 转录本也存在差异。在大脑中，CB 是主要的转录本亚型，而 CB 和 CB 转录本在脾脏中表达水平更高。这些关于大脑与脾脏 CB2R 亚型的新发现部分解释了为什么早期研究未能检测到大脑 CB2R 基因表达。在这里，我们从基因和受体水平到细胞功能、神经回路和动物行为，综述了支持大脑 CB2R 表达和功能的证据。
