Taurine in the Central Nervous System

2 Taurine in the Central Nervous System There is a relatively high concentration of taurine in the central nervous system - higher than would be expected for a neurotransmitter and without a specific anatomical localization. As in the retina, the main function of taurine in the central nervous system seems to be as an osmolyte (Hussy et al., 2000 Saransaari and Oja, 2000). 

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S.J. Watson, Behavioral neurochemistry neuroregulators and behavioral states. Science 2oo 96 (1978). 29 S.S. Oja and P. Kontro, Neurotransmitter actions of taurine in the central nervous system, in "Taurine and Neurological Disorders", A, Barbeau and R.J. Huxtable, eds.. Raven Press, New York (1978). 

Is a Neurotransmitter Role the Main Function of Taurine in the Central Nervous System ... 

In the last years there have been increasing interest in the role of taurine in the central nervous system (CNS), because of its possible association with the mechanisms regulating nervous excitability . After the finding of the generalized anticonvulsant action of taurine ", as well as of its effects on human epilepsies... 

Olive ME. 2002. Interactions between taurine and ethanol in the central nervous system. Amino Acids 23(4) 345-357. 

For many years it was assumed that a single neuron released only a single transmitter. We know now that this is incorrect.616 For example, enzymes in neuromuscular junctions synthesize not only acetylcholine but also catecholamines, taurine, and GABA.617 Some synapses in the central nervous system release both glycine and GABA.618... 

Amino acids are involved in many metabolic processes and m protein synthesis. In the central nervous system, they also function as neurotransmitters or neuromodulators (Davidson, 1976 Corradetti et al., 1983 Fonnum, 1981, 1984). Numerous studies have demonstrated the excitatory effects of aspartate and glutamate (Watkins and Evans, 1981) the inhibitory effects of glycine, y-aminobutyric acid (GABA), and taurine (Schaffer et al., 1981 Lloyd et al., 1983 Roberts, 1984), and the precursor roles of tryptophan in serotonin synthesis and of tyrosine and phenylalanine in the biosyntheses of catecholamines (Sved, 1983). It is not surprising, therefore, to see an ever-increasing interest in amino acid analysis in biological samples. 

Recently, it was found that unconjugated bile acids (CA, CDCA, and DCA) are present at high (nmol/g tissue) levels in the rat brain cytoplasmic fraction, but their functions in the central nervous system are unclear. To clarify this point, a profile analysis of file rat serum bile acids (eight common bile acids and their glycine and taurine conjugates) has been demonstrated. ... 

The role of taurine in the retina has been thoroughly reviewed elsewheref( and is the subject of several papers at this meeting It is of interest that taurine uptake into platelets from patients with retinitis pigmentosa has recently been shown to be decreased-. Platelets are considered to be useful models for synaptosomes in the central nervous system and have been much used in tudies of the uptake mechanisms of various biogenic amines. Since retinitis pigmentosa may also be found in patients with Friedreich s ataxia, it would be of interest to examine the transport and content of taurine in platelets from patients. 

Lima L, Obregon F, Cubillos S, Fazzino F, and Jaimes I (2001) Taurine as a micronutrient in development and regeneration of the central nervous system. Nutritional Neuroscience 4, 439-43. 

We focused our attention on L-Cys (Scheme 19.2) because of its importance as a sulfur-containing semiessential amino acid, which can be biosynthesized in humans and yet, due to its relatively low content in food, it is also used as a food additive (denoted as E920). L-Cys is an important building block of proteins that are used throughout the body, and it can physiologically be transformed to glutathione (a powerful antioxidant [22]), or taurine (essential for cardiovascular function, development and function of skeletal muscles, the retina, and the central nervous system [23]). Thus, the main aim of this study [14] was to employ TLC-densitometry and TLC-ESI-MS in order to demonstrate an ability of L-Cys to spontaneously undergo chiral conversion and condensation, when dissolved in 70% aqueous acetonitrile. 

Chemical stimulants caffeine and others. Stimulants of the central nervous system - such as caffeine, taurine, and amphetamines - are often used to counteract the effects of fatigue. As noted in many surveys of driver coping behaviors, one of the more common approaches to counteract fatigue is to ingest a stimulant, especially caffeine typically in the form of coffee (Lucidi et al., 2006 Nguyen et aL, 1998). 

While taurine may not fulfill all the criteria for being a neurotransmitter strong evidence, reviewed elsewhere " has accumulated over the past years implicating taurine as an inhibitory neurotransmitter in certain parts of the central nervous system. The most convincing evidence is probably the work by McBride Fre-derickson, who in a series of elegant experiments have shown with a high degree of probability that taurine is the... 

Outside the central nervous system, taurine in high concentrations is present in the heart, in striated muscle, in the adrenal gland, and in platelets and lymfocytes, but all tissues contain some taurine. 

Hosli E, Hosli L (1980) Cellular localization of the uptake of [3H]taurine and [3H]beta-alanine in cultiu-es of the rat central nervous system. Nemoscience 5(1) 145-152... 

Taurine - A glyclne-like, sulphur containing amino acid, taurine (12) is found in reasonably high concentrations throughout the mammalian central nervous system and in heart.In brain, taurine is formed as a result of the decarboxylation of cysteine sulphinic acid (15) to hypotau-rlne (8 ), which in turn is oxidized to form taurine.Like other transmitter candidates, taurine is accumulated and released by brain tissue and the accumulation can be inhibited by ouabain. Clinically, significant alterations in taurine levels may be associated with retinitis pigmentosa, epilepsy, mongolism, and possibly heart disease. 

Collins GG. 1974. The rates of synthesis, uptake and disappearance of [14C]-taurine in eight areas of the rat central nervous system. Brain Res 76 447-459. 

Collins G. G. S. (1977) On the Role of Taurine m the Mammalian Central Nervous System, m Essays in Neurochemistry and Neuropharmacology, Vol. 1 (Youdini M.B.H., Lovenberg W, Sharman D F, and Lagnado J.R., eds.), John Wiley, London... 

Pasantes-Morales, H., Loriette, C., and Chatagner, F., 1977, Regional and subcellular distribution of taurine-synthesizing enzymes in the rat central nervous system, Neurochem. Res., 2 671. 

Glutamate is the main excitatory amino acid neurotransmitter in central and peripheral nervous systems. Its concentration in brain is higher than in other body tissues. In the brain, the concentration of glutamate is 3- to 4-fold greater than that of aspartate, taurine, or glutamine (McGeer et al., 1987). The most abundant amino acid... 

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