G protein-coupled receptor 50 (GPR50) belongs to the G protein-coupled receptor which is highly homologous with the sequence of melatonin receptor MT1 and MT2. GPR50 expression has previously been reported in many brain regions, like cortex, midbrain, pons, amygdala. But, the distribution of GPR50 in the hippocampus and cortex and the cell types expressing GPR50 is not yet clear. In this study, we examined the distribution of GPR50 in adult male mice by immunofluorescence. Our results showed that GPR50 was localized in the CA1-3 pyramidal cells and the granule cells of the dentate gyrus. GPR50 was also expressed in excitatory and inhibitory neurons. As inhibitory neurons also contain many types, we found that GPR50 was localized in some interneurons in which it was co-expressed with the calcium-binding proteins calbindin, calretinin, and parvalbumin. Besides, similar results were seen in the cortex. The widespread expression of GPR50 in the hippocampus and cortex suggests that GPR50 may be associated with synaptic plasticity and cognitive function.

G蛋白偶联受体50（GPR50）属于与褪黑激素受体MT1和MT2的序列高度同源的G蛋白偶联受体。以前在许多大脑区域，如皮层，中脑，脑桥，杏仁核中都报道过GPR50表达。但是，GPR50在海马和皮质中的分布以及表达GPR50的细胞类型尚不清楚。在这项研究中，我们通过免疫荧光检查了成年雄性小鼠中GPR50的分布。我们的结果表明，GPR50定位在齿状回的CA1-3锥体细胞和颗粒细胞中。GPR50在兴奋性和抑制性神经元中也有表达。由于抑制性神经元也包含多种类型，我们发现GPR50定位于某些中间神经元中，其中它与钙结合蛋白calbindin，calretinin，和小白蛋白。此外，在皮质中也观察到了类似的结果。GPR50在海马和皮层中的广泛表达表明，GPR50可能与突触可塑性和认知功能有关。