Department of Biology, Center for Developmental Neuroscience, College of Staten Island, Staten Island, NY, USA.
Adv Exp Med Biol. 2019;1155:977-985. doi: 10.1007/978-981-13-8023-5_81.
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.
牛磺酸（2-氨基乙磺酸）是一种含硫氨基酸。它是许多兴奋组织（包括大脑、骨骼和心肌）中最丰富的游离氨基酸之一。牛磺酸的生理作用广泛，包括调节血浆葡萄糖水平、胆汁酸结合、解毒、膜稳定、血压调节、渗透压调节、神经传递以及调节线粒体功能和细胞内钙离子水平。牛磺酸在调节谷氨酸和 GABA 神经传递以及防止体外细胞毒性方面起着重要作用，主要通过调节细胞内钙离子稳态来实现。牛磺酸补充可预防认知功能随年龄增长而下降。由于牛磺酸的广泛作用，其水平通过酶生物合成或饮食摄入进行高度调节。此外，内源性牛磺酸耗竭或外源性牛磺酸补充已被证明对多个器官产生广泛作用。半胱氨酸磺酸脱羧酶（CSAD）最初在肝脏中被鉴定为，被认为是牛磺酸生物合成的限速酶。CSAD mRNA 在大脑中的星形胶质细胞中表达。缺乏 CSAD 的纯合敲除小鼠（CSAD-KO）牛磺酸含量非常低，并且在视觉系统、骨骼系统、心脏、胰腺和大脑中表现出严重的功能组织病理学。相反，牛磺酸的饮食补充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元质膜、形成血脑屏障的内皮细胞和肾脏近端细胞中的牛磺酸转运体表达水平发生变化。这表明存在一种高度调节的机制来维持牛磺酸的动态平衡和器官系统的功能。在这里，我们展示了牛磺酸水平的变化如何直接影响一个器官系统的功能，以及通过功能相互作用和代偿性适应，这些影响扩展到另一个器官系统，重点是神经系统。
