牛磺酸研究进展

牛磺酸具有抗肿瘤、增强免疫、保护心脏、降压、降血脂、降血糖、减轻脂肪肝、降转氨酶、抗衰老等诸多作用。本文查阅国内外相关文献,并将其分析归纳,综述了牛磺酸性质、药理作用的研究进展,以为含有牛磺酸的守宫及含守宫中成药的抗肿瘤等临床作用机理提供研究线索。     

牛磺酸转运体

牛磺酸是机体内含量最丰富的自由氨基酸,具有十分广泛的生物学效应。牛磺酸多集中于可兴奋组织中,且大部分分布在细胞内,这是牛磺酸通过细胞膜上牛磺酸转运体（TAUT）转运至细胞内所致。TAUT有多种类型,各型分布不同,以使牛磺酸发挥其广泛的生物学效应。     

牛磺酸缓解疲劳及提高免疫力研究进展

综述了牛磺酸的生物合成、代谢、缓解疲劳及提高免疫力的作用机制等方面的研究进展,为缓解疲劳及提高免疫力的产品的开发提供科学依据。     

牛磺酸与突触可塑性研究进展

牛磺酸是哺乳动物中枢神经系统中含量最为丰富的自由氨基酸之一,具有许多认定的神经生理功能。最新的研究结果表明,用牛磺酸孵育脑片可以诱导兴奋性突触传递的持久增强效应。虽然牛磺酸引起的这种持久增强不是由于活动或经验所导致的突触效能的改变,但与反映突触可塑性的长时程增强具有许多共同特征,分享部分共同机制。同时,药理学实验提示,神经元对牛磺酸的摄取可能是长时程增强诱导的关键步骤。     

牛磺酸的生物学效应与运动能力的研究进展

牛磺酸是人和动物的重要营养素,具有多种生物学作用,能清除自由基、对抗脂质过氧化、调节渗透压、维持体液平衡和胞内钙离子稳态、参与糖和氨基酸的代谢。在体育运动中,牛磺酸能显著提高运动能力。本文对牛磺酸在人体内的分布和代谢进行介绍,并对牛磺酸在人体内的功能及其与运动能力的关系进行概述。     

珍珠贝母体中牛磺酸的提取

以珍珠贝母为原料 ,通过细胞自溶破壁 ,使牛黄酸溶出 ,以离子交换树脂法提取纯化溶液中牛磺酸。实验结果表明 :细胞自溶破壁的最佳条件为温度 4 0℃ ,p H5.5,自溶时间 4 0 h;纯化可使牛磺酸量占氨基酸总量的 80 .6%,回收率为 87.5%。     

几种海产品中氨基酸及牛磺酸含量的比较

通过对几种海产品进行氨基酸分析,确证海产品中除了含有常见的１８种氨基酸外,还有含量较高的牛磺酸,对其进行了研究探讨。     

Taurine in Developing Rhesus Monkey Brain

The concentrations of taurine in all regions of fetal and neonatal rhesus monkey brain are greater than in the same regions of adult monkey brain. [³⁵S]Taurine injected into pregnant rhesus monkeys is accumulated by the fetus. This process occurs rapidly in most tissues, but occurs slowly in fetal brain. Neonatal rhesus monkey brain also accumulates [³⁵S]taurine slowly compared with other tissues after i.v. injection, and continues to accumulate [³⁵S]taurine for a long period of time. These results suggest that the accumulation and exchange of taurine in developing rhesus monkey brain is slow, as found in neonatal rats, and that if there is a period of development at which rapid exchange of brain taurine occurs in the rhesus monkey, it is before the rapid brain growth spurt.     

Taurine bromamine: a potent oxidant of tryptophan residues in albumin

Taurine is the most abundant free amino acid in leukocytes and can react with HOBr to produce taurine bromamine (Tau-NHBr). The aim of this study was to assess the ability of Tau-NHBr to oxidize tryptophan, either free or as a residue in albumin. We have demonstrated that Tau-NHBr is a powerful oxidant for tryptophan. Importantly, in comparison to taurine chloramine, HOCl or HOBr, Tau-NHBr exhibits a degree of selectivity for tryptophan. Oxidation of albumin by Tau-NHBr resulted in emission of light, and the quantum yield was more than 10-fold more efficient than that of the other oxidants. The fluorescence band corresponding to oxidized albumin (λ_ex 350/λ_em 450), which is characteristic of the formation of formylkynurenine, was significantly higher in reactions using Tau-NHBr. Excitation of the fluorescent probe 8-anilino-1-naphthalenesulfonate at 295 nm was used to assess the depletion of tryptophan residues in albumin. Results from this experiment further supported a higher efficiency of oxidation of tryptophan residues by Tau-NHBr. Other parameters of protein oxidation, including cysteine depletion and formation of carbonyl groups, were not significantly different between the oxidants tested. In conclusion, these results indicate that Tau-NHBr has a higher affinity for tryptophan residues in proteins.     

Mass Spectrometric Analyses of Brain Synaptic Peptides Containing Taurine

The structure of a number of low-molecular-weight acidic peptides containing taurine prepared from calf brain synaptosomes and their subcellular vesicles was studied using electron impact mass spectrometry. At least seven sequences could be identified: N-acetylaspartyl-glutamyl-taurine, N-acetylaspartyl-taurine, N-acetylglutamyl-taurine, glutamyl-taurine, aspartyl-taurine, seryl-glutamyl-seryl-taurine, and seryl-taurine.     

A Possible Role for Taurine in Osmoregulation Within the Brain

Intracranial microdialysis was used to measure changes in extracellular amino acids within the rat brain during local osmotic alteration of the extracellular microenvironment or during systemic water intoxication. Increased cellular hydration produced by either of these methods was accompanied by a marked increase in extracellular taurine levels without affecting the other amino acids measured. With local osmotic alteration, this increase was osmolarity dependent and reversible. The specificity, sensitivity, and reversibility of the increase in extracellular taurine strongly suggest a functional role in osmoregulation in the brain under normal as well as pathological conditions.     

Taurine deficiency,synthesis and transport in the mdx mouse model for Duchenne Muscular Dystrophy

The amino acid taurine is essential for the function of skeletal muscle and administration is proposed as a treatment for Duchenne Muscular Dystrophy (DMD). Taurine homeostasis is dependent on multiple processes including absorption of taurine from food, endogenous synthesis from cysteine and reabsorption in the kidney. This study investigates the cause of reported taurine deficiency in the dystrophic mdx mouse model of DMD. Levels of metabolites (taurine, cysteine, cysteine sulfinate and hypotaurine) and proteins (taurine transporter [TauT], cysteine deoxygenase and cysteine sulfinate dehydrogenase) were quantified in juvenile control C57 and dystrophic mdx mice aged 18 days, 4 and 6 weeks. In C57 mice, taurine content was much higher in both liver and plasma at 18 days, and both cysteine and cysteine deoxygenase were increased. As taurine levels decreased in maturing C57 mice, there was increased transport (reabsorption) of taurine in the kidney and muscle. In mdx mice, taurine and cysteine levels were much lower in liver and plasma at 18 days, and in muscle cysteine was low at 18 days, whereas taurine was lower at 4: these changes were associated with perturbations in taurine transport in liver, kidney and muscle and altered metabolism in liver and kidney. These data suggest that the maintenance of adequate body taurine relies on sufficient dietary intake of taurine and cysteine availability and metabolism, as well as retention of taurine by the kidney. This research indicates dystrophin deficiency not only perturbs taurine metabolism in the muscle but also affects taurine metabolism in the liver and kidney, and supports targeting cysteine and taurine deficiency as a potential therapy for DMD.     

Taurine in toad brain and blood under different conditions of osmolality: An immunohistochemical study

The concentrations of taurine in blood and brain regions of the toadBufo boreas have been measured. Most of these values are considerably lower than those found in mammals. Using an antibody prepared against conjugated taurine, the distribution of taurine in three brain regions of the toad has been visualized. The possible osmoregulatory functions of taurine have been investigated by making toads hyper- or hypo-osmotic in vivo. Induction of hypoosmolality is accompanied by a massive taurine tide in blood plasma, but has no immediate effects upon the taurine concentrations in the brain areas studied. However, histochemical visualization indicates a marked redistribution of taurine between cellular components and extracellular space of brain tissues. This may indicate that taurine has an osmoregulatory function in brain tissue under hypo-osmotic conditions. Hyperosmolality results in no elevation of the taurine concentration in blood plasma of toads, but rather in a very gradual decline of total plasma taurine content over a prolonged time period. Histochemical studies reveal little change in frontal cortex after 1 hour but deeper staining of many neurons in optic lobe accompanied by greater staining in the extracellular fluid. By 3 hours there is a depletion of taurine from all compartments of cerebral cortex tissues. No evidence of any prolonged direct osmoregulatory role for taurine is indicated under hyperosmotic conditions. A possible indirect osmoregulatory function of taurine is discussed.Special issue dedicated to Dr. Claude Baxter.