[73] It also helps to maintain skin hydration. Palackal T, Moretz R, Wisniewski H, Sturman J. Abnormal visual cortex development in the kitter associated with maternal dietary taurine deprivation. B: The concentrations of five amino acids in each preparation. Without appropriate taurine uptake, cell degeneration is inevitable, and this mouse line experiences birth defects in their mitochondria, and in myocardial and skeletal muscle development, e.g., increased ventricular wall thickness and cardiac atrophy. Copenhagen, D. R. Need rods? It is also found in various dietary supplements aimed towards athletes. The .gov means its official. The -aminobutyric acid transporter and its interaction with taurine in the apical membrane of the bovine retinal pigment epithelium. Heller-Stilb B, van Roeyen C, Rascher K, Hartwig HG, Huth A, Seeliger MW, Warskulat U, Haussinger D. Disruption of the taurine transporter gene (taut) leads to retinal generation in mice. Clearly these findings are highly suggestive, but cannot be considered definitive evidence of the presence of taurine-specific receptors. [16] Serine dehydratase converts serine to 2-aminoacrylate, which is converted to cysteic acid by 3-phosphoadenylyl sulfate:2-aminoacrylate C-sulfotransferase. We suggest that one of the most effective endogenous agents protecting the distal retina from the application of toxic levels of glutamate is the amino acid taurine. [62] Studies suggest the amino acid should be supplied at 10mg/kg of bodyweight/day for domestic cats. Takatani T, Takahashi K, Uozumi Y, Shikata E, Yamamoto Y, Ito T, Matsuda T, Schaffer SW, Fujio Y, Azuma J. Taurine inhibits apoptosis by preventing formation of the Apaf-1/caspase-9 apoptosome. Because RPE cells are extensively interconnected via gap junctions [105], a human RPE cell line (ARPE-19) expressing Cx43 and Cx46 was chosen to conduct an experiment that directly tested the efficacy of taurine in the prevention of cell death [106]. Sulfur belongs to the same group in the periodic table as oxygen but is much less electronegative. [20], The availability of taurine is affected depending on how the food is prepared, raw diets retaining the most taurine, and baking or boiling resulting in the greatest taurine loss. Olson JE, Martinho E., Jr Regulation of taurine transport in rat hippocampal neurons by hypo-osmotic swelling. [21], Taurine levels were found to be significantly lower in vegans than in a control group on a standard American diet. Carruthers-Jones DI, van Gelder NM. Further evidence for the involvement of taurine in retinal development was provided in a recent study showing that under defined culture conditions, taurine (and certain growth factors) can efficiently promote the in vitro generation of putative rod and cone photoreceptors from mouse, monkey, and human embryonic stem cells [123]. [17][18][19] The mean daily intake from omnivore diets was determined to be around 58mg (range from 9 to 372mg) and to be low or negligible from a strict vegan diet. Taurine (2-aminoethanesulfonic acid, Tau), Homotaurine (Htau), and the amino acid gamma aminobutyric acid (GABA), have been recently proposed as natural SIRT1 activators with possible therapeutic . In addition, the taurine antagonist TAG (6-aminomethyl-3-methyl-4H,1,2,4-benzothiadiazine-1,1-dioxide) blocks spinal cord depolarization without affecting the similar response to glycine [145]. Locke D, Stein T, Davies C, Morris J, Harris AL, Evans WH, Monaghan P, Gusterson B. Altered permeability and modulatory character of connexin channels during mammary gland development. At each of these sites, there is evidence of taurines ability to ameliorate certain forms of neuropathology. It may also be necessary to take into consideration that absorption of taurine from beverages may be more rapid than from foods. Nevertheless, considering its broad distribution, its many cytoprotective attributes, and its functional significance in cell development, nutrition, and survival, taurine is undoubtedly one of the most essential substances in the body. Haas HL, Hosli L. The depression of brain stem neurons by taurine and its interaction with strychnine and bicuculline. However, the endogenous . Measurements of amino acid transport in internally dialyzed giant axons. In more physiological circumstances, pathological conditions often lead to mitochondrial dysfunction, triggering the release of cyC, activation of a downstream caspase cascade, and eventual nuclear disruption. is present in the structure of taurine, which makes difficulty . Photoreceptors are considerably richer in taurine than other retinal neurons, but all retinal cells from the outer and inner nuclear layers to the ganglion cell layer, and seemingly the radial glia (Mller cells) as well [86], take up taurine from the extracellular milieu [66,87-91]. In this brief review, we have described several conditions, both normal and pathological, in which taurine has been shown to exert a significant effect. Correspondence to: Harris Ripps, Departments of Ophthalmology and Visual Science, Anatomy and Cell Biology, Physiology and Biophysics, University of Illinois College of Medicine, 1855 West Taylor Street Chicago, IL 60612, The Marine Biological Laboratory, Whitman Investigator 7 MBL Street Woods Hole, MA 05432; Phone: (561) 347-6244; FAX: (561) 347-6244; email: address: Received 2012 Aug 30; Accepted 2012 Nov 8. Unoki K, LaVail MM. De la Puerta C, Arrieta FJ, Balsa JA, Botella-Carretero JI, Zamarrn I, Vzquez C. Taurine and glucose metabolism. Jong CJ, Azuma J, Schaffer S. Mechanism underlying the antioxidant activity of taurine: prevention of mitochondrial oxidant production. These toxins can pass through gap junctions to kill their neighbors, a process referred to as bystander cell death [102-104]. It plays a role in the modulation of intracellular free calcium concentration, and although it is one of the few amino acids not incorporated into proteins, taurine is one of the most abundant amino acids in the brain, retina, muscle tissue, and organs throughout the body. [28], A substantial increase in the plasma concentration of growth hormone was reported in some epileptic patients during taurine tolerance testing (oral dose of 50mg per kg body mass per day), suggesting a potential to stimulate the hypothalamus and to modify neuroendocrine function. Mechanism of neuroprotective function of taurine. Kaczmarek LK, Davison AN. Taurine in the mammalian cerebellum: demonstration by autoradiography with [3H]taurine and immunocyto- chemistry with antibodies against the taurine- synthesizing enzyme, cysteine-sulfinic acid decarboxylase. Berson EL, Hayes KC, Rabin AR, Schmidt SY, Watson G. Retinal degeneration in cats fed casein. Olney JW. More specifically, taurine administration has been shown to prevent high glucose-induced microangiopathy, i.e., vascular endothelial cell apoptosis [48], and in fructose-fed rats, it has been found to restore glucose metabolizing enzyme activities and improve insulin sensitivity by modifying the postreceptor events of insulin action [49]. Taurine can influence defects in nerve blood flow, motor nerve conduction velocity, and nerve sensory thresholds in experimental diabetic neuropathic rats. Olney JW. Effects of ATP and taurine on calcium uptake by membrane preparations of the rat retina. Lombardini JB. Sturman JA, Moretz RC, French JH, Wisniewski HM. We should stress that experimentally induced cell death by cyC (as used in the foregoing study) simply bypasses the usual mitochondrial pathway to apoptosis. Although taurine possesses many functions in mammals, its cytoprotective actions have attracted the most attention, as they dramatically alter the health and nutritional status of various species. FOIA Wen R, Song Y, Matthes MT, Yasumura D, LaVail MM, Steinberg RH. This mode of action has been described by Schaffer and coworkers [135] in cases of diabetes. Why had the nerve cells in the distal layers been spared? A pathway for taurine biosynthesis from serine and sulfate is reported in microalgae,[14] developing chicken embryos,[15] and chick liver. Thirunavukkarasu, Anuradha CV. Smith KE, Borden LA, Wang CH, Hartig PR, Branchek TA, Weinshank RL. These transport mechanisms, regarded as responsible for clearing L-glutamate from the synaptic cleft [4,5] and for terminating the excitatory signal [6], represent the first step in the recycling of the transmitter through the glutamine cycle [7,8]. Regulation of the cellular content of the organic osmolyte taurine in mammalian cells. Most of the time, your body. Young TL, Cepko CL. Kaczmarek LK, Davison AN. Perhaps even more relevant are the striking results from the Cepko laboratory, where it was shown that taurine stimulates rod development when added to media containing rat retinal cultures [120]. It is named after Latin taurus (cognate to Ancient Greek , taros) meaning bull or ox, as it was first isolated from ox bile in 1827 by German scientists Friedrich Tiedemann and Leopold Gmelin. [40][41] The United States Department of Agriculture has found a link between cataract development and lower levels of vitamin B6, folate, and taurine in the diets of the elderly. Moreover, equivalent amounts of taurine and GABA depressed the firing rate of brainstem neurons almost equally [148], and similar specific, carrier-mediated transport systems are known to operate at brain cell membranes [149,150]. Ehinger B. Glial uptake of taurine in the rabbit retina. Taurine in the brain and liver of the developing human and monkey. However, it should be noted that this study was clearly too small and of too short a duration to have any clinical significance. Timbrell JA, Seabra V, Waterfield CJ. Lake N, Verdone-Smith C. Immunocytochemical localization of taurine in mammalian retina. In the retina, taurine is critical for photoreceptor development and acts as a cytoprotectant against stress-related neuronal damage and other pathological conditions. Clearly, endogenous taurine is crucial for preventing retinal neurodegeneration. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Protection of mouse photoreceptors by survival factors in retinal degenerations. The intercellular junctional complexes of retinal pigment epithelia. and transmitted securely. Findings such as these, although difficult to interpret precisely, add to an appreciation of the importance of taurine in the cell biology of the retina. Taurine; its selective action on neuronal pathways in the rabbit retina. Note also that destruction of the inner retina by glutamate has little effect on taurine concentration. Taurine and central nervous system disorders. [. Taurine (2-aminoethane- sulfonic acid), an organic osmolyte involved in cell volume regulation, provides a substrate for the formation of bile salts, and plays a role in the modulation of intracellular free calcium concentration [15,16]. The biology of taurine in nutrition and development. Schousboe A, Hertz L. Role of astroglial cells in glutamate homeostasis. [57] A taurine deficiency in cats can lead to retinal degeneration and eventually blindness a condition known as central retinal degeneration (CRD),[58][59] as well as hair loss and tooth decay. A similar situation arose with the inhibitory neurotransmitter GABA, another -amino acid whose molecular structure is strikingly similar to that of glycine and taurine. [6] The sulfonic acid has a low pKa[7] ensuring that it is fully ionized to the sulfonate at the pHs found in the intestinal tract. Taurine is a -amino acid found in very high concentration in most cells, with levels particularly high in excitable tissues. Therefore, it is not surprising that depleting endogenous taurine by the genetic knockout of TauT or by blocking the taurine transporter with GES has been shown to cause ganglion cell loss, along with degenerative changes in the distal retina [75,85]. The enzyme cysteine dioxygenase (CDO) catalyzes the conversion of L-cysteine to cysteine sulfinate, and the oxidation of hypotaurine (2-aminoethane sulfinate) results in taurine. Molecular characterization and, Bulley S, Shen W. Reciprocal regulation between taurine and glutamate response via Ca. Reymond I, Sergeant A, Tappaz M. Molecular cloning and sequence analysis of the cDNA encoding rat liver cysteine sulfinate decarboxylase (CSD). Curtis DR, Watkins JC. Currently, perhaps the best hope for establishing the molecular structure of a taurine receptor stems from the elegant work of Anderson and Trapido-Rosenthal [156], who discovered a unique taurine receptor candidate at a fast excitatory synapse in the motor nerve net (MNN) of the jellyfish Cyanea capillata. However, not only did cyC induce the death of cells along the scrape, but it also caused apoptosis in cells remote from the site of injury. Credit: Columbia University Irving Medical Center . Most of these enterprises employ the ethanolamine method to produce a total annual production of about 3,000tonnes. The authors are extremely grateful to Dr. Thoru Pederson (University of Massachusetts Medical School) for a critical reading of the manuscript, and the many helpful suggestions that have been incorporated in the text. According to a third study, taurine consumption was estimated to vary between 40 and 400mg/day. Anderson PAV, Trapido-Rosenthal HG. There is obviously a broad array of mechanisms by which taurine serves its cytoprotective role, but the molecular identity of a taurine-selective receptor remains a mystery. [54], Mice with a genetic taurine deficiency had a nearly complete depletion of skeletal and cardiac muscle taurine levels and a reduction of more than 80% of exercise capacity compared to control mice. Reddy DVN. Increasing taurine levels restores respiratory chain activity and increases the synthesis of ATP at the expense of superoxide anion production. Lake N, Malik N. Retinal morphology in rats treated with a taurine transport antagonist. Structurally, taurine is 2-aminoethane sulfonic acid and it is a nonprotein amino acid with many vital functions in physiological processes. In their initial studies on the action of taurine on neuronal pathways in the rabbit retina, Cunningham and Miller [140] showed that taurine was able to separate the On and Off channels of the parallel pathways identified in recordings of the electroretinogram, the proximal negative response of amacrine cells [141], and the spontaneous activity of ganglion cells. Membrane perturbations and mediation of gap junction formation in response to taurine treatment in normal and injured alveolar epithelia. [159], Schaffer et al. Nandhini AT, Anuradha CV. Kudo Y, Akiyoshi E, Akagi H. Identification of two taurine receptor subtypes on the primary afferent terminal of frog spinal cord. In addition, passive diffusion of such a small molecule as taurine would allow it to traverse the plasma membrane of retinal cells without the aid of an active transport mechanism, and there is experimental evidence that both path length and matrix components (collagen and elastic tissue) influence the diffusion of taurine across human and bovine tissues comprised of Bruchs membranechoroid [95]. Scientific American Books, 1990, pp 1105. Taurine (2-aminoethane sulfonic acid; C2H7NO3S) is a nonprotein sulfur-containing -amino acid present in nearly all mammalian tissues and the most ubiquitous free endogenous biomolecule in human cells. The major route for the biosynthesis of taurine, shown in Figure 1B is from methionine and cysteine via cysteinesulfinic acid decarboxylase (CSD), and typically requires oxidation of . If it could be described at the molecular level, this would be a major achievement, and a significant step toward unraveling the pathway(s) by which taurine provides cytoprotection, osmoregulation, neuromodulation, and the myriad of important functions it serves in humans and animals. Darnell J, Lodish H, Baltimore D. Molecular cell biology. Voss JW, Pedersen SF, Christensen ST, Lambert IH. Sturman JA, Kashdan C. Fate of axonally transported taurine and proteins in the developing rabbit visual system following optic nerve section. Udawatte C, Qian H, Mangini NJ, Kennedy BG, Ripps H. Taurine suppresses the spread of cell death in electrically coupled RPE cells. Ostwald TJ, Steinberg RH. (iv) The presence on postsynaptic cells of a receptor that specifically binds the putative neurotransmitter. [65], In a study analyzing ocular tissue extracts of rat eyes, it was found that taurine was the most abundant amino acid present within the retina, vitreous humor, lens, cornea, iris, and ciliary body. Paskowitz DM, Donohue-Rolfe KM, Yang H, Yasumura D, Matthes MT, Hosseini K, Graybeal CM, Nune G, Zarbin MA, Lavail MM, Duncan JL. Imaki H, Jacobson SG, Kemp CM, Knighton RW, Neuringer M, Sturman J. Retinal morphology and visual pigment levels in 6- and 12-month-old rhesus monkeys fed a taurine-free human infant formula. Careers, Unable to load your collection due to an error. In the presence of taurine, 5-Arylidene (thio) barbituri Hillenkamp J, Hussain AA, Jackson TL, Cunningham JR, Marshall J. [63], Taurine appears essential to the development of passerine birds. It is an unusual example of a naturally occurring sulfonic acid. However, neither of these studies attempted to determine the molecular structure of a taurine receptor at the respective sites. Indeed, preliminary experiments in human epileptic subjects confirm the anticonvulsive effect of taurine, but the effects are not robust, nor are they consistent [59]. Subsequent studies have implicated the ligand-gated glycine 2 receptor in photoreceptor development [121], since mice with targeted deletion of this receptor no longer experienced proper normal photoreceptor development. 8600 Rockville Pike Lake N. Taurine depletion leads to loss of rat optic axons. Considering its broad distribution, its many cytoprotective attributes [29,30], and its functional significance in cell development, nutrition, and survival [31,32], these are clearly misnomers. Taurine in the central nervous system and the mammalian actions of taurine. [26] It is a biosynthetic precursor to the bile salts sodium taurochenodeoxycholate and sodium taurocholate. A: The chemical formula of taurine is C2H7NO3S MW=125.15. In the preface to the second edition of their fine text on Molecular Cell Biology [171], James Darnell, Harvey Lodish, and David Baltimore state that the quest in all biologic disciplines is the same: to discover proteins that could carry out specific biologically important tasks. A rephrasing of that statement might well include all molecules that engage in such tasks, even the nonessential amino acid taurine, which participates in so many vital biological functions. Manganese exposure inhibits the clearance of extracellular GABA and influences taurine homeostasis in the striatum of developing rats. Taurine-treated diabetic rats had a decrease in the formation of advanced glycation end products (AGEs) and AGEs content. Taurine is present in breast milk, and has been added to many infant formulas, as a measure of prudence, since the early 1980s. Both in retina and isolated synaptosomes, strychnine suppressed the action of taurine but not that of GABA, whereas the GABA antagonist bicuculline had no effect on the inhibitory action of taurine, but blocked the depressant action of GABA. Anuradha CV, Balakrishnan SD. Adobe. Wu JY, Wu H, Jin Y, Wei J, Sha D, Prentice H, Lee HH, Lin CH, Lee YH, Yang LL. Accumulation in the rabbit lens. Subsequently, the elevated levels of NO were shown to cause upregulation of the taurine transporter gene and a concomitant increase in taurine uptake in human retinal pigment epithelial cells [51]. [28], Taurine functions as an antioxidant, suppressing the toxicity of hypochlorite and hypobromite produced physiologically. Hypotaurine is enzymatically oxidized to yield taurine by hypotaurine dehydrogenase. Taurine serves a wide variety of functions in the central nervous system, from development to cytoprotection, and taurine deficiency is associated with cardiomyopathy, renal dysfunction, developmental abnormalities, and severe damage to retinal neurons. There is no shortage of publications claiming to have detected one or more putative taurine receptors. Overview Taurine is a type of chemical called an amino sulfonic acid. [10], In the laboratory, taurine can be produced by alkylation of ammonia with bromoethanesulfonate salts. Injury-induced upregulation of bFGF and CNTF mRNAs in the rat retina. Yarbrough GG, Singh DK, Taylor DA. The fact that this array of responses to both taurine and glycine were blocked by strychnine suggests that a single glycinergic receptor may be sensitive to both agents. Kennedy AJ, Voaden MJ. However, this finding has not been independently confirmed, nor as we have already mentioned is it likely to be its sole mode of action. Lake N. Electroretinographic deficits in rats treated with guanidinoethyl sulfonate, a depletor of taurine. Taurines effect on renal function [52], particularly as it relates to streptozotocin-induced diabetic animal models, is also noteworthy. It was first identified and isolated from the bile of the ox (Bos [30][31], Taurine crosses the bloodbrain barrier[32][33] and has been implicated in a wide array of physiological phenomena including inhibitory neurotransmission,[34] membrane stabilization[35] feedback inhibition of neutrophil/macrophage respiratory burst, adipose tissue regulation and calcium homeostasis,[36] recovery from osmotic shock,[37] protection against glutamate excitotoxicity,[38] and prevention of epileptic seizures. official website and that any information you provide is encrypted The molecular structure of taurine differs from that of amino acids by the presence of a sulfonic acid, instead of the more common carboxylic acid group in the structure of amino acids. Taurine (/trin/), or 2-aminoethanesulfonic acid, is a non-proteinogenic amino sulfonic acid that is widely-distributed in animal tissues. Perhaps the most enigmatic question regarding taurine is whether it is a neurotransmitter. We suggest that the high concentration of endogenous taurine throughout the retina can better serve the role of neuroprotectant against glutamate-induced excitotoxicity. Glutamate as a CNS transmitter. Distribution of free amino acids and related compounds in ocular fluids, lens, and plasma of various mammalian species. van Gelder NM, Koyama I, Jasper HH. Sanz MM, Johnson LE, Ahuja S, Ekstrom PAR, Romero J, VanVeen T. Significant photoreceptor rescue by treatment with a combination of antioxidants in an animal model for retinal degeneration. Development of normal and injury-induced gene expression of aFGF, bFGF, CNTF, BDNF, GFAP and IGF-I in the rat retina. Further experimental and clinical studies will be of importance in evaluating taurines therapeutic potential in the management of diabetes in humans [45]. Jack Taylor/Getty Images. They tested the effects of 28 candidate neurotransmitters including glycine, GABA, dopamine, epinephrine, acetylcholine, and a variety of neuropeptides and nucleotides. These are as follows: (i) Evidence that the substance, together with the enzymes and related chemical machinery required for its synthesis are present within the presynaptic neurons; (ii) Evidence that the substance is released by a calcium-dependent mechanism in response to presynaptic depolarization, and that it exerts an effect on postsynaptic cells; (iii) The presence of a mechanism to terminate the action of the transmitter (e.g.., degradation, high-affinity uptake), and the availability of a relatively specific antagonist; and. Neurons and glia have been shown to sequester glutamate via high-affinity uptake systems. CSD levels are very low in cats, as well as humans and other primates, but the ingestion of meat and seafoodor taurine supplementshelps to maintain normal tissue concentrations of taurine. Many passerines seek out taurine-rich spiders to feed their young, particularly just after hatching. Regulation of taurine biosynthesis and its physiological significance in the brain. Taurine attenuates hypertension and improves insulin sensitivity in the fructose-fed rat, an animal model of insulin resistance. . II. Taurine is a compound that is similar to amino acids. To ensure that the taurine effect was not due to the blockage of gap junctions, voltage clamp recordings from electrically coupled Xenopus oocytes transfected with Cx43 showed that junctional communication was not affected by taurine [106]. An ultrastructural study of nutritionally induced and reversed retinal degeneration in cats. The chemical structure of taurine, shown in Figure 1A, reveals that it lacks the carboxyl group typical of other amino acids, but does contain a sulfonate group. This may be because taurine does not readily cross the blood-brain barrier, and several taurine analogs that do are currently under investigation for their therapeutic potential [60]. It has many biological roles, such as conjugation of bile acids, antioxidation, osmoregulation, membrane stabilization, and modulation of calcium signaling. Osakada F, Ikeda H, Mandai M, Wataya T, Watanabe K, Yoshimura N, Akaike A, Sasai Y, Takahashi M. Toward the generation of rod and cone photoreceptors from mouse, monkey and human embryonic stem cells. Marcinkiewicz J, Kontny E. Taurine and inflammatory diseases. 2012; [Epub ahead of print]. Characterization of mice with targeted deletion of glycine receptor alpha 2. However, the quest may end before too long. Feline maternal taurine deficiency: effects on retina and tapetum of the offspring. Once again it was difficult to clearly distinguish between their neuronal actions. Taurine is one of the most abundant amino acids in the brain and spinal cord, leukocytes, heart and muscle cells, the retina, and indeed almost every tissue throughout the body. Crompton M, Andreeva L. On the involvement of mitochondrial pore in reperfusion injury. Plasma taurine was 78% of control values, and urinary taurine was 29%. Using primary neuronal cultures from the fetal rat brain, these researchers showed that taurine suppresses glutamate-induced toxicity through several pathways: (i) it inhibits calcium influx through L-, N- and P/Q-type voltage-gated calcium channels, (ii) it prevents the downregulation of Bcl-2 and the upregulation of Bax, the protein products of which otherwise would translocate to the mitochondria and result in the release of the highly toxic cytochrome C (cyC), (iii) it protects neurons from oxidative stress, and (iv) it inhibits glutamate-induced calpain activation, thereby preventing the cleavage of Bcl-2 (see also [99]). For the bovine sub-species, see, InChI=1S/C2H7NO3S/c3-1-2-7(4,5)6/h1-3H2,(H,4,5,6), InChI=1/C2H7NO3S/c3-1-2-7(4,5)6/h1-3H2,(H,4,5,6), Except where otherwise noted, data are given for materials in their. Lake N. Depletion of retinal taurine by treatment with guanidoethyl sulfonate. In addition, the reader may wish to consult the many insightful studies on the effects of taurine on intercellular communication (cf. Das J, Sil PC. Protective effects of taurine against oxidative stress in the heart of MsrA knockout mice. Inclusion in an NLM database does not imply endorsement of, or agreement with, The best food sources are meat, fish, and eggs. [75], This article is about the chemical compound. Leon R, Wu H, Jin Y, Wei J, Buddhala C, Prentice H, Wu J-Y. Frosini M, Sesti C, Saponara S, Ricci L, Valoti M, Palmi M, Machetti F, Sgaragli GA. [44][45], A study published in 2023 suggests that the blood concentration of taurine declines during the aging process, as measured in mice, monkeys, and humans. Note that in the normal (control) retina, taurine exceeds the concentration of each of the other amino acids by tenfold or more, whereas in the photoreceptorless C3H mouse, its concentration is about one-third of its value in the control retina. II Supplementation with methionine, cysteine, or taurine. Despite this diversity of pathophysiology in so varied a group of seemingly unrelated disorders, there is a growing consensus that oxidative stress is linked to mitochondrial dysfunction [127,130-133], and that the beneficial effects of taurine are a result of its antioxidant properties [126,128,129], as well as its ability to improve mitochondrial function by stabilizing the electron transport chain and inhibiting the generation of reactive oxygen species [134,135]. As Sinwell and Gorodischer [21] have shown, there is an increased incidence of pediatric problems in children being raised on the totally vegetarian diets of vegan communities. Cao W, Li F, Steinberg RH, Lavail MM. Another study examining proteins that interact with taurine used the cross-linker bis-(sulfosuccinimidyl) suberate (BS3) to covalently bind 3H-taurine to cell surface proteins on membranes from the olfactory organ of the spiny lobster [155]. I. Taurine deficiency. Bridges CC, Ola MS, Prasad PD, El-Sherbeny A, Ganapathy V, Smith SB. Protective effect of taurine on the light-induced disruption of isolated frog rod outer segments. Uptake and release of taurine from rat brain slices. 01 June 2006 PDF Split View Cite Permissions Share ABSTRACT Methionine, cysteine, homocysteine, and taurine are the 4 common sulfur-containing amino acids, but only the first 2 are incorporated into proteins. Taurine, a -amino acid that is abundantly available in the tissues of human and animals, is efficiently used as a green bio-organic catalyst in the preparation of some of the biologically active barbituric and thiobarbituric acid derivatives. Taurine has been shown to be tissue-protective in many . The major route for the biosynthesis of taurine, shown in Figure 1B is from methionine and cysteine via cysteinesulfinic acid decarboxylase (CSD), and typically requires oxidation of hypotaurine to taurine as the final step [19]. Transport of taurine, L-methionine and 3- o-methyl-D-glucose across frog retinal pigment epithelium. Brain lesions, obesity, and other disturbances in mice treated with monosodium glutamate. Taurine concentrations in land plants are very low or undetectable, but up to 1000 nmol/g wet weight have been found in algae.[4][5]. Taurine, L-theanine, and L-citrulline are non-essential amino acids that are increasingly gaining attention as nutritional supplements in HS animals. Taurine: Retinal function. Wu JY, Tang XW, Schloss JV, Faiman MD. [71], A review published in 2008 found no documented reports of negative or positive health effects associated with the amount of taurine used in energy drinks, concluding, "The amounts of guarana, taurine, and ginseng found in popular energy drinks are far below the amounts expected to deliver either therapeutic benefits or adverse events". Moreover, contrary to the results from animal experiments, a study of 20 obese human subjects with a genetic predisposition for Type 2 diabetes demonstrate that taurine supplementation (1.5 g for 8 weeks) had no effect on insulin secretion or sensitivity [54]. USA TODAY 0:00 0:35 The amino acid taurine appears to improve health and extend the lifespan of worms, mice and monkeys, according to a new study, though further research is needed to confirm. Heinmki AA, Muhonen AS, Piha RS. Bethesda, MD 20894, Web Policies Glutamate uptake by brain slices and its relation to the depolarization of neurons by acidic amino acids. The influence of path length and matrix components on ageing characteristics of transport between the choroid and the outer retina. The https:// ensures that you are connecting to the Intracellular recording from these relatively large cells in the MNN showed that only taurine (a -sulfonic acid) and -alanine (a -carboxylic acid), both of which are present in the neurons and released on depolarization, produced responses consistent with those of the normal excitatory post-synaptic potentials (EPSPs) in these cells. Foos TM, Wu JY. In contrast, when the cells were preincubated in taurine, or the gap junctions were blocked with octanol, cell death was confined to those cells that were injured by the scrape. Similar issues have clouded the relationship between taurine and epilepsy, although there is little doubt that taurine has antiepileptic activity in experimental animals. Rather, it seems likely that there are one or more endogenous substances that serve to protect the outer retina from the typically severe reaction to glutamate. Chesney RW, Han X, Patters AB. Olney JW, Ho OL. Hernndez-Bentez R, Ramos-Mandujano G, Pasantes-Morales H. Taurine stimulates proliferation and promotes neurogenesis of mouse adult cultured neural stem/progenitor cells. Schaffer SW, Azuma J, Mozaffari M. Role of antioxidant activity of taurine in diabetes. As Trachtman et al. The major route for the biosynthesis of taurine, shown in Figure 1B is from methionine and cysteine via cysteinesulfinic acid decarboxylase (CSD), and typically requires oxidation of . In this connection, it is important to note that taurine was shown to reduce insulin secretion by cells in vitro [53]. As the authors noted, while it is evident that glycine is not a transmitter at the MNN synapse, the features of the taurine response are unlike that typically seen in mammalian preparations, i.e., a hyperpolarizing, inhibitory response. Taurine reacts with these halogenating agents to form N-chloro- and N-bromotaurine, which are less toxic than their precursors hypohalides. Brns C, Spohr C, Storgaard H, Dyerberg J, Vaag A. (a) Taurine or 2-aminoethane-sulfonic acid is a -sulfonic amino acid as it has a sulfonyl group rather than a carboxyl group attached to the alpha carbon and an amino group on the beta carbon; (b) a standard amino acid contains an alpha carbon, to which an both an amino group and a carboxyl group are attached. They propose that the dysfunctional respiratory chain accumulates electron donors, thereby diverting electrons from the respiratory chain to oxygen, and forming superoxide anion in the process. Taurine receptor: kinetic analysis and pharmacological studies. Electrophysiological analysis of taurine and glycine action on neurons of the mudpuppy retina. Taurine11.4.1. In: Taurine in Health and Disease, 2012: 215254 Editors: A. El Idrissi and W. LAmoreaux, pp. Freeman SM, Abboud CN, Whartenby KA, Packman CH, Koeplin DS, Moolten FL, Abraham GN. Taurine (2-amino-ethanesulfonic acid) is a naturally occurring amino sulfonic acid derived from cysteine and methionine metabolism. The slow, long-lasting nature of these depolarizing responses suggests that they may be mediated by metabotropic receptors rather than the ionotropic receptors acting at the fast excitatory synapses of the MNN. High affinity uptake sites for taurine in the retina. Taurine treatment of spontaneous chronic epilepsy in a cat. Get glycine receptors and taurine. Kinney GA. GAT-3 transporters regulate inhibition in the neocortex. Oja SS, Lhdesmki P. Is taurine an inhibitory neurotransmitter? As we have attempted to show, this ubiquitous amino acid is a potent cytoprotective agent; moreover, it is considered to be a neurotransmitter candidate, is clearly a modulator of neuronal activity, and is a molecule that deserves significantly more attention than it has received thus far. The group led by Freitas has studied taurine's antioxidant and anti-inflammatory effects for ten years or more, initially in high-performance athletes and later in obese individuals, with daily . In their inhibition studies, only taurine inhibited the crosslinkage of 3H-taurine to the membrane, and the taurine-evoked behavioral search response was significantly reduced following treatment of their antennules with BS3 + taurine as compared with animals treated with BS3 alone. Its common name derives from the ox, as it was first isolated from the bile of an ox (Froger et al., 2014). However, unlike the findings with glycine, there are significant differences between taurine and GABA. The physiological role of taurine. Hypotaurine is then oxidized to taurine as described above.[13]. More inclusive reviews can be found in excellent accounts by Huxtable [157], Lombardini [158], Timbrell et al. Fonnum F. Glutamate: a neurotransmitter in the mammalian brain. This is consistent with the findings that animals (e.g., cats, monkeys, man) that do not produce adequate levels of taurine experience severe degenerative changes in their photoreceptors and retinal pigment epithelium (RPE) when deprived of dietary taurine [36,69-75]. [67][68][69] The molecular structure of taurine differs from that of amino acids by the presence of a sulfonic acid . These dynamic structures are condensates of macromolecules that are reversibly assembled in a process termed liquid-liquid phase separation . Taurine in the developing rabbit visual system: changes in concentration and axonal transport including a comparison with axonally transported proteins. Effect of taurine treatment on insulin secretion and action,and on serum lipid levels in overweight men with a genetic predisposition for type II diabetes mellitus. Maar T, Moran J, Schousboe A, Pasantes-Morales H. Taurine deficiency in dissociated mouse cerebellar cultures affects neuronal migration. It is synthesized endogenously from cysteine and methionine in the kidney, liver, and white adipose tissue (Craig, 2004). The impetus for this review dates back more than a few decades, having originated with a curious malady, i.e., the severe headaches that were often suffered by diners who had ingested monosodium glutamate, a common food additive in general use in homes and restaurants. Hernndez-Bentez R, Pasantes-Morales H, Saldaa IT, Ramos-Mandujano G. Taurine stimulates proliferation of mice embryonic cultured neural progenitor cells. Researchers compared the behaviours and development of birds fed a taurine-supplemented diet to a control diet and found the juveniles fed taurine-rich diets as neonates were much larger risk takers and more adept at spatial learning tasks. Hayashi T. The inhibitory action of beta-hydroxy-gamma-aminobutyric acid upon the seizure following stimulation of the motor cortex of the dog. Rapid postmortem changes in the cellular localisation of amino acid transmitters in the retina as assessed by immunocytochemistry. CSD was initially cloned and identified in the liver as the rate-limiting enzyme in the biosynthesis of taurine [20], and was later shown to be present in the kidney as well as the brain, where it is localized in glial cells. Hamberger AC, Chiang GH, Nylen ES, Scheff SW, Cotman CW. Sun M, Xu C. Neuroprotective mechanism of taurine due to up-regulating calpastatin and down-regulating calpain and caspase-3 during focal cerebral ischemia. 1Departments of Ophthalmology and Visual Science, Anatomy and Cell Biology, Physiology and Biophysics, University of Illinois College of Medicine, Chicago, IL, 2The Marine Biological Laboratory, Woods Hole, MA, 3Department of Biomedical Science, College of Medicine, Florida Atlantic University, 777 Glades Road, Boca Raton, FL. Treatment with combinations of antioxidants has also proven to effectively rescue photoreceptors in an animal model (rd1) of retinal degeneration [14], but here too the agents were applied exogenously. However, the pathway linking the GABAB receptor to its physiologic action has yet to be identified, and there is a high level of uncertainty regarding the existence or nature of a taurine-specific receptor (see below). Taurine may help to promote healthy metabolism, protect various organs,. The human body uses taurine for actions in cells. Taurine modulates kallikrein activity and glucose metabolism in insulin resistant rats. Because it is one of the few amino acids not used in protein synthesis, taurine is often referred to as a nonessential amino acid, or more generously as a conditionally essential amino acid. [64], Taurine has been used in some cryopreservation mixes for animal artificial insemination. The preparation of this review was supported by grants from the National Eye Institute (EY14161, WS) and the National Science Foundation (IOS 1,021,646, WS). One example is that taurine is used for energy production. The issue is of more than academic interest, since glutamate-triggered neuronal damage is known to occur when the glutamate concentration of interstitial fluids reaches abnormally high levels as a result of hypoxia, ischemia, or brain trauma. Taurine ameliorates alloxan-induced diabetic renal injury, oxidative stress-related signaling pathways and apoptosis in rats. Proximal negative response of frog retina. Protective function of taurine in glutamate- induced apoptosis in cultured neurons. All ocular tissues contain taurine, and quantitative analysis of ocular tissue extracts of the rat eye revealed that taurine was the most abundant amino acid in the retina, vitreous, lens, cornea, iris, and ciliary body. Lake N, Marshall J, Voaden MJ. They find that in this condition, there occurs a decline in the levels of endogenous taurine, and suggest that this taurine deficiency reduces the expression of the respiratory chain components required for normal translation of mitochondrial-encoded proteins. Although there is no shortage of nonhuman neuronal systems in which taurine is a prominent component, e.g., the squid giant axon [168], the mollusk Aplysia [169], and the migratory locust [170], results obtained from the jellyfish motor nerve net suggest that a taurine-specific receptor may be present in this unusual beast [156]. Taurine plays an important role as a basic factor for maintaining cellular integrity in the heart, muscle, retina, and throughout the CNS. Accessibility Taurine is an organic osmolyte involved in cell volume regulation, and provides a substrate for the formation of bile salts. Sturman JA, Moretz RC, French JH, Wisniewski HM. The efficacy of taurine has been demonstrated in both naturally occurring and drug-induced epilepsy in cats [55], mice [56], rats [57], and dogs [58], and evidence that taurine blocks dentato-hippocampal synapses, a locus of importance in epileptogenesis, indicates a specific action in epilepsy. Mammalian taurine synthesis occurs in the pancreas via the cysteine sulfinic acid pathway. Taurine in the pineal gland. Sivakami S, Ganapathy V, Leibach FH, Miyamoto Y. In an impressive series of papers, they showed that when applied topically or by injection, glutamate and its analogs (aspartate, kainate, N-methyl-d-aspartate [NMDA], -amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid [AMPA]) were cytotoxic to nerve cells in every part of the central nervous system (CNS) [1-3]. About 50 years ago, K.C. Many contain 1000mg per serving,[24] and some as much as 2000mg.[25]. Pasantes-Morales H, Klethi J, Urban PF, Mandel P. The physiological role of taurine in retina: uptake and effect on electroretinogram (ERG). The results showed that either NO- synthase activity is increased or NO sensitivity is decreased in Type 1 patients, a good indication that the L-arginineNO system is involved in the pathophysiology of diabetes and its sequelae, e.g., diabetic retinopathy. Adding to this is the fact that there is a rapid calcium-dependent efflux of taurine after electrical stimulation of cortical slices of rat brain, and the presence of uptake mechanisms to terminate its action [137-139]. Metabolism of sulfur-containing amino acids. Neuringer M, Palackal T, Kujawa M, Moretz RC, Sturman JA. It is likely that the multiple functions of taurine we have described are mediated at different loci on both extracellular sites (e.g., to participate in neuronal activity, stimulate rod production) and intracellular targets (e.g., to fulfill its role in development and cytoprotection). Taurine occurs naturally in foods with protein, such as meat or fish. In this pathway, cysteine is first oxidized to its sulfinic acid, catalyzed by the enzyme cysteine dioxygenase. Shank RP, Aprison MH. Cunningham R, Miller RF. Taurine (2-aminoethane-sulfonic acid) is a sulfur-containing amino acid which is not used for protein synthesis and is therefore the most abundant free amino acid in mammalian tissues, with the exception of human liver in which aspartate is the most abundant one [ 1, 2 ]. Electrophysiological analysis of taurine and glycine action on neurons of the mudpuppy retina. Mechanism for modulation of gating of. Cloning and expression of a high affinity taurine transporter from rat brain. In this context, taurinechloramine, an oxidant produced by activated macrophages, inhibits the response of NFB to cytokines, inhibition that is mediated by the oxidation of Met45 from IB. Trnquist P, Alm A. Carrier-mediated transport of amino acids through the blood-retinal and the blood-brain barriers. In the neonatal mouse retina, for example, he reported that a 30 min exposure to parenterally administered glutamate (1 mM) produced a histopathological lesion characterized by swollen cell bodies in the ganglion cell layer, the proximal half of the inner nuclear layer, and extending to the inner plexiform layer. In this report, we present a broad overview of the functional properties of taurine, some of the consequences of taurine deficiency, and the results of studies in animal models suggesting that taurine may play a therapeutic role in the management of epilepsy and diabetes. Omura Y, Inagaki M. Immunocytochemical localization of taurine in the fish retina under light and dark adaptations. . It should also be noted that the actions of taurine on adult subventricular stem cells and progenitor cells are not mimicked by glycine, GABA, or alanine [114]. [11], Taurine is naturally derived from cysteine. The overproduction of reactive oxygen specie and the bodys inability to stem the accumulation of highly reactive free radicals have been implicated in cardiovascular disease [126], diabetes-induced renal injury [127], inflammatory disease [128], light-induced lipid peroxidation in photoreceptors [38], reperfusion injury [129], and several of the major disorders of the CNS [130,131]. Taurine has a unique chemical structure that implies important physiological functions: bile acid conjugation and cholestasis prevention, antiarrhythmic/inotropic/chronotropic effects, central nervous system neuromodulation, retinal development and function, endocrine/metabolic effects and antioxidant/antiinflammatory properties. Influence of taurine dosage on cobalt epilepsy in mice. Taranukhin AG, Taranukhina EY, Saransaari P, Podkletnova IM, Pelto-Huikko M, Oja SS. ERG, PNR and Muller cell recordings. The cause remained a mystery until 1969, when John Olney and his colleagues unequivocally demonstrated the neurotoxic effects of monosodium glutamate. This article is devoted to taurine and its influence on water structure and protein stability. It occurs naturally in the body. Sturman JA, Hayes KC. Synthetic taurine is obtained by the ammonolysis of isethionic acid (2-hydroxyethanesulfonic acid), which in turn is obtained from the reaction of ethylene oxide with aqueous sodium bisulfite. [39], Taurine acts as a glycation inhibitor. Franconi F, Di Leo MAS, Bennardini F, Ghirlanda G. Is taurine beneficial in reducing risk factors for diabetes mellitus? Other studies purporting to have detected taurine receptors in rabbit brain [152] and in RPE cells in culture [153] have been similarly inconclusive. Huxtable RJ. Depletion of taurine in rats treated with GES leads to a marked and progressive reduction in the amplitude of the electroretinogram [82] and severe degenerative changes in photoreceptors and the RPE [83], effects that can be reversed by intravenous infusion of taurine [84]. [1] It is a major constituent of bile and can be found in the large intestine, and accounts for up to 0.1% of total human body weight. Perfeito R, Cunha-Oliveira T, Cristina Rego A. Revisiting oxidative stress and mitochondrial dysfunction in the pathogenesis of Parkinson disease - resemblance to the effect of amphetamine drugs of abuse. Similarly, betaine is an amino acid derivative that possesses favorable biological properties which contributes to its role as a functional additive during HS. [34]. Taurine ( / trin / ), or 2-aminoethanesulfonic acid, is a non-proteinogenic amino sulfonic acid that is widely-distributed in animal tissues. Taurine and the renal system. In sum, these observations suggest that taurine and GABA are acting on different receptors, and thus, there is no convincing evidence that the electrophysiological actions of taurine are mediated via binding to an ionotropic GABA receptor. Taurine, also known as 2-aminoethanesulfonic acid, is a conditional amino acid that is found in natural dietary sources, biosynthesized in the body and produced by chemical . However, this practice has never been rigorously studied, and as such it has yet to be proven to be necessary, or even beneficial. Reddy VN. Taurine is an amino acid with . The distribution of taurine in the vertebrate retina. Taurine is undoubtedly one of the most essential substances in the body. It plays a role in several essential body functions. Considering the chemical structure, this group of molecules includes: polyols, amino acids, amines, urea and its derivatives, etc. These and other members of the transforming growth factor- family help to protect retinal neurons from ischemia, free radical formation, light damage, and related forms of neuronal insult. This conclusion was based on their observation that the application of 10 mM taurine caused a biphasic response consisting of a hyperpolarization followed by a slow onset depolarization. Side Effects What is taurine? Menzie J, Pan C, Prentice H, Wu JY. Retinal changes associated with taurine depletion in pigmented rats. Chan-Palay V, Lin C-T, Palay S, Yamamoto M, Wu J-Y. A striking curiosity was seen when Olneys studies were extended to the visual system. Young-Pearse TL, Ivic L, Kriegstein AR, Cepko CL. Interestingly, taurine satisfies many of the criteria considered essential for inclusion in the inventory of neurotransmitters, but evidence of a taurine-specific receptor has yet to be identified in the vertebrate nervous system. [2] It was discovered in human bile in 1846 by Edmund Ronalds.[3]. Izumi K, Donaldson J, Minnich JL, Barbeau A. Ouabain-induced seizures in rats: suppressive effects of taurine and gamma-aminobutyric acid. Taurine prevents high glucose-induced human vascular endothelial cell apoptosis. On the other hand, it was surprising to learn that the early in vivo experiments on the active transport of taurine through the frog RPE showed the main flux to be in the retina to choroid direction [92]. [52][53] Likewise, taurine administration to diabetic rabbits resulted in 30% decrease in serum glucose levels. Neurotrophic factors minimize the retinal toxicity of verteporfin photodynamic therapy. Within the retina, taurine is necessary for the development of photoreceptors. Federal government websites often end in .gov or .mil. [42], A 2022 systematic review of literature found that across 5 relevant studies, taurine supplementation reduced levels of HbA1c, fasting blood sugar level, and HOMA-IR. Although there is considerable evidence that, in specific circumstances, taurine can interact with GABAB receptors to activate a metabotropic pathway, neither the intracellular link nor a taurine-specific receptor has yet to be identified at the molecular level. The close relationship between taurine levels and nutritionally induced degeneration is supported further in that taurine supplementation can inhibit light-induced lipid peroxidation, and thereby protect isolated rod outer segments from photic damage [37,38]. The suggestion that taurines ability to promote photoreceptor development may be mediated by GlyR2 subunit-containing glycine receptors [124] is apparently at odds with the evidence that neither the addition of glycine nor GABA to the media had the same effect as taurine [125]. Interaction of taurine with GABA. An analysis of taurine uptake at this site showed that uptake was severely depressed in the presence of GABA, and conversely, GABA uptake was suppressed by the presence of taurine [81]. In mammalian tissues, taurine is ubiquitous and is the most abundant free amino acid in the heart, retina, skeletal muscle, brain, and leukocytes. The subventricular zone is one of the few regions in the brain in which neurogenesis continues throughout adulthood, and the cells from this region can proliferate and migrate via the rostral migratory stream to the olfactory bulb where they differentiate into neurons [115]. Gordon RE, Heller RF, Del Valle JR, Heller RE. Protection of the rat retina from ischemic injury by brain-derived neurotrophic factor, ciliary neurotrophic factor, and basic fibroblast growth factor. The binding was completely abolished by 0.1mM cobalt, zinc, or mercury, suggesting the presence of free sulfhydryl groups near or at the ligand-binding site. Shellfish offer the biggest dose, Yadav said, but taurine is also found in beef and poultry . Regulation of the expression and subcellular localization of the taurine transporter TauT in mouse NIH3T3 fibroblasts. HHS Vulnerability Disclosure, Help Here's a detailed look at how it works, sources and potential side effects. [160-163]), the axonal transport of taurine in the retina and CNS [25,164-166], and a comprehensive review devoted solely to the actions of taurine in the retina [167]. Taurine occurs naturally in fish and meat. Interestingly, both a GABA transporter and a taurine transporter are active at apical membrane vesicles from bovine RPE; they both require Na+ and Cl- and exhibit a similar stoichiometry. The chemical structure of taurine, shown in Figure 1A, reveals that it lacks the carboxyl group typical of other amino acids, but does contain a sulfonate group. Taurine modifies insulin signaling enzymes in the fructose-fed insulin resistant rats. Thus, although taurine is released after electrical stimulation, and at physiologic concentrations it exerts a powerful inhibitory effect on the bioelectric activity of the retina and on synaptic transmission in retinotectal pathways, the one crucial criterion that has not yet been met is the presence of a taurine-specific receptor on postsynaptic cells. [23], Taurine is an ingredient in some energy drinks. The suggestion that nitric oxide (NO) may be implicated in the pathogenesis of diabetes prompted a study to determine whether endogenous NO synthesis or local reactivity to endogenous NO might be impaired in patients with Type 1 insulin-dependent diabetes mellitus [50]. What is Taurine? Thus, although the actions of glycine and taurine overlap at similar receptors, there is reason to suspect that the receptor populations are not the same [146]. [70] Even so, a study by the European Food Safety Authority found no adverse effects for up to 1,000mg of taurine per kilogram of body weight per day. Gaucher D, Arnault E, Husson Z, Froger N, Dubus E, Gondouin P, Dherbcourt D, Degardin J, Simonutti M, Fouquet S, Benahmed MA, Elbayed K, Namer IJ, Massin P, Sahel JA, Picaud S. Taurine deficiency damages retinal neurones: cone photoreceptors and retinal ganglion cells. Sturman JA, Gargano AD, Messing JM, Imaki H. Feline maternal taurine deficiency: effect on mother and offspring. Taurine is a -amino acid, however, instead of the carboxylic group it has the sulfonate one. A case in point is its role in diabetes. However, there is some evidence to the contrary. Wu QD, Wang JH, Fennessy F, Redmond HP. However, the ship was righted with evidence of bidirectional transport [93], and the demonstration of taurine transport from the blood to retina direction [94]. A precipitous loss of taurine is also seen after genetic disruption of TauT in mice. The pharmacology of amino acids related to gamma-aminobutyric acid. taurus), from which it derives its name [17,18]. In short, these findings do not support the view that dietary supplementation with taurine can be used to prevent the development of Type 2 diabetes. In each case, taurine, by virtue of its antioxidant activity, has been shown to play a crucial role as a cytoprotectant and in the attenuation of apoptosis. Physiological and chemical analysis of neurotransmitter candidates at a fast excitatory synapse in the jellyfish. It also helps modulate intracellular free calcium concentrations. The highest level of taurine was, of course, in the vertebrate retina, and an ingenious experiment involving a judicious selection of normal and diseased mouse retinas enabled Cohen and coworkers [68] to quantify the distribution of taurine and other amino acids across the layers of retinal cells (Figure 2). Perhaps the most exhaustive body of experimental work on the neuroprotective properties of taurine was performed by Wu and colleagues [29,30,96-98]. Evaluation of glucose and glutamine as precursors for the synthesis of preferentially released glutamate. Sung DY, Walthall WW, Derby CD. Tiedemann F, Gmelin L. Einige neue Bestandteile der Galle des Ochsen. Redmond HP postsynaptic cells of a receptor that specifically binds the putative neurotransmitter a.. 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Wu and colleagues [ 29,30,96-98 ] bromoethanesulfonate salts mouse cerebellar cultures affects neuronal migration, Saldaa it, G!