Taurine Regulation of Neuroendocrine Function
Taurine Regulation of Neuroendocrine Function
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DOI：
10.1007/978-981-13-8023-5_81
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发表时间：
2019-01-01
期刊：
影响因子：
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通讯作者：
El Idrissi, Abdeslem
中科院分区：
文献类型：
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作者：
El Idrissi, Abdeslem
牛磺酸（2-氨基乙磺酸）是一种含硫氨基酸。它是许多可兴奋组织中最丰富的游离氨基酸之一，包括大脑、骨骼和心肌。牛磺酸的生理作用广泛，包括调节血糖水平、胆汁酸结合、解毒、膜稳定、血压调节、渗透调节、神经传递以及线粒体功能和细胞钙水平的调节。牛磺酸在调节谷氨酸和GABA神经传递中起重要作用，并主要通过调节细胞内钙稳态来防止体外兴奋性毒性。补充牛磺酸可以防止认知功能的年龄依赖性衰退。由于牛磺酸的广泛作用，其水平通过酶的生物合成或饮食摄入受到高度调节。此外，内源性或膳食补充外源性牛磺酸的消耗已被证明会对多个器官产生广泛的作用。半胱氨酸磺酸脱羧酶（CSAD）首先在肝脏中被发现，被认为是牛磺酸生物合成中的限速酶。CSAD mRNA在脑星形胶质细胞中表达。缺乏CSAD的纯合子敲除小鼠（CSAD- ko）牛磺酸含量非常低，在视觉系统、骨骼系统、心脏、胰腺和大脑中表现出严重的功能性组织病理学。相反，饮食中补充牛磺酸会通过相同的器官系统产生显著的健康益处。牛磺酸生物利用度的波动导致神经质膜、形成血脑屏障的内皮细胞和肾近端细胞中牛磺酸转运蛋白表达水平的变化。提示维持牛磺酸稳态和器官系统功能的高度调控机制。在这里，我们展示了牛磺酸水平的改变如何直接影响一个器官系统的功能，并通过功能相互作用和代偿适应；这些影响延伸到其他器官系统，重点是神经系统。
Taurine (2-aminoethanesulfonic acid) is a sulfur-containing amino acid. It is one of the most abundant free amino acids in many excitable tissues, including the brain, skeletal and cardiac muscles. Physiological actions of taurine are widespread and include regulation of plasma glucose levels, bile acid conjugation, detoxification, membrane stabilization, blood pressure regulation, osmoregulation, neurotransmission, and modulation of mitochondria function and cellular calcium levels. Taurine plays an important role in modulating glutamate and GABA neurotransmission and prevents excitotoxicity in vitro primarily through modulation of intracellular calcium homeostasis. Taurine supplementation prevents age-dependent decline of cognitive functions. Because of the wide spread actions of taurine, its levels are highly regulated through enzymatic biosynthesis or dietary intake. Furthermore, depletion of endogenous or dietary supplementation of exogenous taurine have been shown to induce wide spread actions on multiple organs. Cysteine sulfonic acid decarboxylase (CSAD) was first identified in the liver and is thought to be the rate-limiting enzyme in taurine biosynthesis. CSAD mRNA is expressed in the brain in astrocytes. Homozygous knockout mice lacking CSAD (CSAD-KO) have very reduced taurine content and show severe functional histopathology in the visual system, skeletal system, heart, pancreas and brain. Conversely, dietary supplementation of taurine results in significant health benefits acting through the same organ systems. Fluctuation of taurine bioavailability lead to changes in the expression levels of taurine transporters in neuronal plasma membranes, endothelial cells forming the blood-brain barrier and proximal cells of the kidneys. Suggesting a highly regulated mechanism for maintaining taurine homeostasis and organ systems function. Here we show how alterations in taurine levels directly affect the function of one organ system and through functional interaction and compensatory adaptation; these effects extend to another organ systems with focus on the nervous system.