Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
Sci Rep. 2017 Mar 9;7:42884. doi: 10.1038/srep42884.
Of the many serotonin receptors, the type 3 receptors (5-HT3R) are the only ionotropic ones, playing a key role in fast synaptic transmission and cognitive and emotional brain function through controlled neuronal excitation. To better understand the various functions of 5-HT3Rs, it is very important to know their expression pattern in the central nervous system (CNS). To date, many distributional studies have shown localized 5-HT3R expression in the brain and spinal cord. However, an accurate pattern of 5-HT3R expression in the CNS remains to be elucidated. To investigate the distribution of 5-HT3R in the mouse brain in detail, we performed immunofluorescent staining using 5-HT3AR-GFP transgenic mice. We found strong 5-HT3AR expression in the olfactory bulb, cerebral cortex, hippocampus, and amygdala; and partial expression in the pons, medulla, and spinal cord. Meanwhile, the thalamus, hypothalamus, and midbrain exhibited a few 5-HT3AR-expressing cells, and no expression was detected in the cerebellum. Further, double-immunostaining using neural markers confirmed that 5-HT3AR is expressed in GABAergic interneurons containing somatostatin or calretinin. In the present study, we built a 5-HT3AR expression map in the mouse brain. Our findings make significant contributions in elucidating the novel functions of 5-HT3R in the CNS.
在众多的 5-羟色胺受体中，5-羟色胺受体 3（5-HT3R）是唯一的离子型受体，通过控制神经元兴奋，在快速突触传递和认知及情绪脑功能中发挥关键作用。为了更好地了解 5-HT3R 的各种功能，了解其在中枢神经系统（CNS）中的表达模式非常重要。迄今为止，许多分布研究表明 5-HT3R 在大脑和脊髓中有局部表达。然而，中枢神经系统中 5-HT3R 的准确表达模式仍有待阐明。为了详细研究 5-HT3R 在小鼠大脑中的分布，我们使用 5-HT3AR-GFP 转基因小鼠进行了免疫荧光染色。我们发现 5-HT3AR 在嗅球、大脑皮层、海马体和杏仁核中表达较强；在脑桥、延髓和脊髓中有部分表达。同时，丘脑、下丘脑和中脑有少量表达 5-HT3AR 的细胞，小脑无表达。进一步用神经标志物进行双免疫染色证实 5-HT3AR 表达于含有生长抑素或钙结合蛋白的 GABA 能中间神经元。在本研究中，我们构建了小鼠大脑中 5-HT3AR 的表达图谱。我们的研究结果对阐明 5-HT3R 在中枢神经系统中的新功能具有重要意义。
