Lauriano E R, Pergolizzi S, Gangemi J, Kuciel M, Capillo G, Aragona M, Faggio C
Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, 98166, Italy.
Department of Comparative Anatomy, Institute of Zoology, Jagiellonian University, Krakow, 30-387, Poland.
Microsc Res Tech. 2017 Sep;80(9):1018-1027. doi: 10.1002/jemt.22896. Epub 2017 May 22.
Serotonin [5-hydroxytryptamine (5-HT)] is an important neuromodulator involved in a wide range of physiological functions. The effects of serotonin are mediated by an extended family of receptors coupled to multiple heterotrimeric G-proteins, associated with cellular membrane. G proteins connect receptors to effectors and thus trigger intracellular signaling pathways. These cellular processes several regulate systemic functions such as embryonic development, gonadal development, learning and memory, and organismal homeostasis. Generally, elasmobranch fish dwell a hypersaline environment and utilize a specialized extrarenal salt secreting organ, the rectal gland, to face ionic homeostasis. In this study in addition to the morphological, histochemical and immunohistochemical description of the Scyliorhinus canicula rectal gland, for the first time, the presence of serotonin (5-HT), and distribution of different types of G protein alpha subunits (Gα o, Gα q/11, and Gα s/olf) has been investigated in the rectal gland epithelium by confocal immunofluorescence techniques. Colocalization G proteins and 5-HT in the secretory epithelium of the gland suggests serotonin acts as a hormone and involves G proteins in an autocrine-paracrine control of rectal gland homeostasis.
血清素[5-羟色胺（5-HT）]是一种重要的神经调节剂，参与多种生理功能。血清素的作用由一个与细胞膜相关的、与多种异源三聚体G蛋白偶联的受体大家族介导。G蛋白将受体与效应器连接起来，从而触发细胞内信号通路。这些细胞过程若干调节全身功能，如胚胎发育、性腺发育、学习和记忆以及机体稳态。一般来说，板鳃亚纲鱼类生活在高盐环境中，并利用一个专门的肾外泌盐器官——直肠腺来维持离子稳态。在本研究中，除了对小斑猫鲨直肠腺进行形态学、组织化学和免疫组织化学描述外，首次通过共聚焦免疫荧光技术研究了直肠腺上皮中血清素（5-HT）的存在以及不同类型G蛋白α亚基（Gαo、Gαq/11和Gαs/olf）的分布。腺体分泌上皮中G蛋白和5-HT的共定位表明血清素作为一种激素起作用，并通过自分泌-旁分泌控制直肠腺稳态涉及G蛋白。
