Evidence for a new G protein-coupled cannabinoid receptor in mouse brain
Evidence for a new G protein-coupled cannabinoid receptor in mouse brain
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DOI：
10.1124/mol.60.1.155
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发表时间：
2001-07-01
影响因子：
3.6
通讯作者：
Martin, BR
中科院分区：
文献类型：
--
作者：
Breivogel, CS;Griffin, G;Martin, BR
这些研究的目的是为了支持大脑中存在未被发现的大麻素受体的假设。[S-35] anandamide和WIN55212-2刺激CB1+/+和CB1-/-小鼠脑膜GTP gammaS结合。相比之下，许多其他已知能激活CB1受体的化合物，包括CP55940、HU-210和Delta(9)-四氢大麻酚，都不能刺激[S-35]GTP γ在CB1-/-膜上的结合。在CB1-/-膜中，SR141716A仅在浓度大于1mum时影响基础和anandamide或win55212 -2诱导的[S-35]GTP γ - ma结合的刺激。在CB1+/+膜中，SR141716A仅抑制84%的anandamide和67%的WIN55212-2刺激的[S-35]GTP γ - ma结合，其亲和力适合CB1受体介导（K-B约为0.5 nM）。剩余的刺激似乎以较低的效力（IC50约为5mum）被抑制，类似于CB1-/-膜或缺乏激动剂时的情况。进一步实验确定anandamide与WIN55212-2的作用不具有相加性，而mu阿片、腺苷A1和大麻素配体的作用具有相加性。最后，对不同中枢神经系统（CNS）区域的实验表明，大麻素在脑干、皮质、海马、间脑、中脑和脊髓的CB1-/-膜中有显著活性，但在基底节区和小脑中没有活性。此外，这些相同的中枢神经系统部分区域也显示出[H-3]WIN55212-2的显著结合，但没有[H-3]CP55940的结合。因此，anandamide和WIN55212-2似乎通过一种具有不同中枢神经系统分布的常见G蛋白偶联受体在CB1-/-小鼠脑膜中具有活性，这意味着脑中存在一种未知的大麻素受体亚型。
The purpose of these studies was to support the hypothesis that an undiscovered cannabinoid receptor exists in brain. [S-35]GTP gammaS binding was stimulated by anandamide and WIN55212-2 in brain membranes from both CB1+/+ and CB1-/- mice. In contrast, a wide variety of other compounds that are known to activate CB1 receptors, including CP55940, HU-210, and Delta (9)-tetrahydrocannabinol, failed to stimulate [S-35]GTP gammaS binding in CB1-/- membranes. In CB1-/- membranes, SR141716A affected both basal and anandamide- or WIN55212-2-induced stimulation of [S-35]GTP gammaS binding only at concentrations greater than 1 muM. In CB1+/+ membranes, SR141716A inhibited only 84% of anandamide and 67% of WIN55212-2 stimulated [S-35]GTP gammaS binding with an affinity appropriate for mediation by CB1 receptors (K-B approximate to 0.5 nM). The remaining stimulation seemed to be inhibited with lower potency (IC50 approximate to 5 muM) similar to that seen in CB1-/- membranes or in the absence of agonist. Further experiments determined that the effects of anandamide and WIN55212-2 were not additive, but that the effect of mu opioid, adenosine A1, and cannabinoid ligands were additive. Finally, assays of different central nervous system (CNS) regions demonstrated significant activity of cannabinoids in CB1-/- membranes from brain stem, cortex, hippocampus, diencephalon, midbrain, and spinal cord, but not basal ganglia or cerebellum. Moreover, some of these same CNS regions also showed significant binding of [H-3]WIN55212-2, but not [H-3]CP55940. Thus anandamide and WIN55212-2 seemed to be active in CB1-/- mouse brain membranes via a common G protein-coupled receptor with a distinct CNS distribution, implying the existence of an unknown cannabinoid receptor subtype in brain.