Serotonin (5-HT) plays pivotal roles in many physiological processes including reproduction of crustaceans, which are mediated 5-HT receptors. The distributions of 5-HT and its receptor have never been explored in Portunus pelagicus. To validate the targets which indirectly indicate the roles of 5-HT in this crab, we have investigated the distribution of 5-HT in the central nervous system (CNS) and ovary using immunohistochemistry and tissue expression of its receptor by RT-PCR. In the brain, 5-HT immunoreactivity (-ir) was detected in clusters 6, 7, 8, 11, 14, 15 and the fibers. In the ventral nerve cord (VNC), 5-HT-ir was detected in pairs of neurons and the fibers connected to the neurons. In the ovary, 5-HT-ir was intense in the oocyte step 1 (Oc1) and Oc2, and its intensity was slightly decreased in Oc3 and Oc4. The 5-HT receptor was molecularly characterized to be type 7, and it was strongly expressed in the eyestalk, brain, VNC, mature ovary and muscle. Due to the presence of 5-HT receptor we suggest that 5-HT acts primarily at the CNS and ovary, thus implicating its role in reproduction especially in the development of oocytes though its exact function in this crab needed to be explored further.

中文翻译：

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5-羟色胺及其受体在中枢神经系统中的存在以及蓝色游泳蟹Portunus pelagicus的新型蟹形5-羟色胺受体的卵巢和分子克隆。

5-羟色胺（5-HT）在许多生理过程中起着关键作用，包括甲壳类动物的繁殖，它们是介导的5-HT受体。5-HT及其受体的分布从未在远古Portunus中进行过探索。为了验证间接表明5-HT在该蟹中的作用的靶标，我们使用免疫组化技术及其RT-PCR受体的组织表达，研究了5-HT在中枢神经系统（CNS）和卵巢中的分布。在大脑中，在簇6、7、8、11、14、15和纤维中检测到5-HT免疫反应性（-ir）。在腹神经索（VNC）中，在成对的神经元和连接到神经元的纤维中检测到5-HT-ir。在卵巢中，5-HT-ir在卵母细胞第1步（Oc1）和Oc2中强烈，在Oc3和Oc4中其强度略有降低。5-HT受体在分子上被鉴定为7型，并且在眼球，大脑，VNC，成熟的卵巢和肌肉中强烈表达。由于5-HT受体的存在，我们建议5-HT主要作用于中枢神经系统和卵巢，因此暗示其在生殖中的作用，特别是在卵母细胞的发育中，尽管其在螃蟹中的确切功能尚待进一步探讨。