中文摘要：

目的：观察5-羟色胺（5-HT）纤维和5-HT2A受体在大鼠海马CA1、CA2和CA3三个区域的分布特点。方法：用5-HT递质和5-HT2A受体特异性抗体的免疫组织化学显色以及图像处理与分析。结果：在海马内，抗5-HT2A受体的免疫反应阳性产物主要位于锥体细胞的细胞膜和树突，树突染色较深；5-HT2A受体的阳性胞体在CA1、CA2和CA3的分布不均匀，以锥体层细胞分布最多，CA2〉CA3〉CA1，CA2与CA1之间，CA3与CA1之间比较差异有统计学意义；在海马的CA1、CA2和CA3区可见呈线状的5-HT递质阳性神经纤维及其终末；在海马的CA1、CA2和CA3未见呈点状或线状的5-HT2A受体阳性神经纤维及终末表达。结论：5-HT2A受体广泛分布在海马CA1、CA2和CA3区，可以接受外来5-HT递质的调控。

英文摘要：

Objective.. To observe the distribution of the serotoninergic （5-HT） fibers and 5-HT2A receptor in CA1, CA2 and CA3 regions of the rat hippcampus. Methods： The distribution and expression of 5-HT and 5-HT2A receptor were detected by immunohistochemical staining against 5-HT transmitter and 5-HT2A antibodies, and then analyzed with image system. Results.. In the hippocampus, the immunoreactive products of 5-HT2A was located in the cell membrane and dendrites of pyramidal cells, especially in dendrites. The 5-HT2A receptor immunoreactive neurons were distributed dominantly in pyramidal cells in CA1, CA2 and CA3 （CA2〉CA3〉CA1） （P〈0.01）. The linear positive products against 5-HT were found in nerve fibers and terminals in CA1, CA2 and CA3 of hippocampus. No positive products of 5-HT2A receptor were found in nerve fibers and terminals in CA1, CA2 and CA3 of hippocampus. Conclusion： 5-HT2A widely distributes in the hippocampus CA1, CA2 and CA3, and can response the regulation of extrinsic 5-HT neurotransmitter.