5-羟色胺3A受体在成年小鼠海马中间神经元中的分布

Distribution of 5-HT_(3A)R in hippocampal interneurons in adult mice

目的:利用成年5-HT3AR-BACEGFP转基因小鼠,研究5-羟色胺3A受体(5-HT3AR)在海马中间神经元中的分布情况。方法:成年5-HT3AR-BACEGFP转基因小鼠经心脏灌注固定后,利用免疫荧光双标记方法,并结合激光共焦显微镜扫描技术,观察5-HT3AR在成年5-HT3AR-BACEGFP转基因小鼠海马中不同中间神经元内的表达和分布情况。结果:5-HT3AR在成年小鼠整个海马中都有分布,且主要在CA1区、CA2/CA3区和齿状回有大量5-HT3AR免疫阳性细胞;激光共聚焦显微镜下观察到5-HT3AR阳性产物在细胞核、细胞浆和树突上均有表达;免疫荧光双标实验结果表明5-HT3AR阳性产物在CB(calbindin),CR(calretinin),Reelin,Som(somatostatin),NPY(neuropeptide Y)和VIP(vasoactive intestinal peptide)免疫阳性神经元中表达,但在PV(parvalbumin)免疫阳性神经元中不表达。定量结果显示:几乎所有的VIP阳性神经元均表达5-HT3AR阳性,约3/4的CR阳性神经元表达5-HT3AR,约1/2的CB、Reelin、NPY和Som阳性神经元表达5-HT3AR阳性;约1/4的5-HT3AR阳性神经元中表达Reelin,1/5的表达Som,5-HT3AR/CB和5-HT3AR/CR双标神经元各占5-HT3AR阳性神经元的1/10左右。结论:5-HT3AR-BACEGFP转基因小鼠能够作为研究海马中5-HT3AR功能及其在中间神经元中的作用机制研究的工具鼠。

Objective： To investigate the distribution of 5-HT3A R in the hippocampus interneurons of adult 5-HT3A R- BACEGFP transgenic mice. Methods： Adult 5-HT3aR-BACEGFP transgenie mice were intracardiac perfused with 4% paraformaldehyde. Double immunofluoreseenee histochemistry combining with confocal laser scanning microseope were performed to examine the expression and distribution of 5-HT3AR with different intemeurons in the hippocampus of adult 5-HT3A R-BACEGFP transgenic mice. Results ： 5-HT3A R-positive cells distributed throughout the hippoeampus, especially in the CA1, CA3/CA2 and dentate gyrus regions. Under the confocal laser scanning microscope, 5-HT3AR-immunoreae- tivities were mainly located in the nuclear, cytoplasm and dendrites of hippoeampus neurons. The double immunofluores- cence labeling results showed that 5-HT3A R-immunoreactivities were found in CB, CR, Reelin, Som and VIP-positive cells, but not in PV-positive cells. Quantification data showed that nearly all VIP-positive neurons, 3/4 CR-positive cells and half of CB-, Reelin and NPY-positive cells express 5-HT3AR-immunoreactivities. The number of Reelin/5-HT3AR and Som/5-HT3AR double-positive cells was 1/4 and 1/5 of total 5-HT3AR-immunoreactive cells respectively and it was about 1/10 for CR/5-HT3AR and CB/5-HT3AR double-positive cells. Conclusion： 5-HT3AR-BACEGFP transgenic mice will be an useful tool for investigating 5-HT3AR function and the mechanism of action in the intemeurons of the hippocampus.