Decoding the nexus:branched-chain amino acids and their connection with sleep,circadian rhythms,and cardiometabolic health

The sleep-wake cycle stands as an integrative process essential for sustaining optimal brain function and,either directly or indirectly,overall body health,encompassing metabolic and cardiovascular well-being.Given the heightened metabolic activity of the brain,there exists a considerable demand for nutrients in comparison to other organs.Among these,the branched-chain amino acids,comprising leucine,isoleucine,and valine,display distinctive significance,from their contribution to protein structure to their involvement in overall metabolism,especially in cerebral processes.Among the first amino acids that are released into circulation post-food intake,branched-chain amino acids assume a pivotal role in the regulation of protein synthesis,modulating insulin secretion and the amino acid sensing pathway of target of rapamycin.Branched-chain amino acids are key players in influencing the brain's uptake of monoamine precursors,competing for a shared transporter.Beyond their involvement in protein synthesis,these amino acids contribute to the metabolic cycles ofγ-aminobutyric acid and glutamate,as well as energy metabolism.Notably,they impact GABAergic neurons and the excitation/inhibition balance.The rhythmicity of branchedchain amino acids in plasma concentrations,observed over a 24-hour cycle and conserved in rodent models,is under circadian clock control.The mechanisms underlying those rhythms and the physiological consequences of their disruption are not fully understood.Disturbed sleep,obesity,diabetes,and cardiovascular diseases can elevate branched-chain amino acid concentrations or modify their oscillatory dynamics.The mechanisms driving these effects are currently the focal point of ongoing research efforts,since normalizing branched-chain amino acid levels has the ability to alleviate the severity of these pathologies.In this context,the Drosophila model,though underutilized,holds promise in shedding new light on these mechanisms.Initial findings indicate its potential to introduce novel concepts,particularly in elucidating the intricate connections between the circadian clock,sleep/wake,and metabolism.Consequently,the use and transport of branched-chain amino acids emerge as critical components and orchestrators in the web of interactions across multiple organs throughout the sleep/wake cycle.They could represent one of the so far elusive mechanisms connecting sleep patterns to metabolic and cardiovascular health,paving the way for potential therapeutic interventions.

Electroacupuncture (EA) Speeds Up the Regulation of Hypothalamic Pituitary Adrenal Axis Dysfunction in Acute Surgical Trauma Rats: Mediated by Hypothalamic Gamma-Aminobutyric Acid (GABA)_AReceptors

Hypothalamic Corticotropin-releasing factor (CRF) directly activates the hypothalamic pituitary adrenal axis (HPA axis) during the surgical trauma induced stress response. Electroacupuncture (EA) has been demonstrated to have stress relieving effects in breast surgery, colorectal surgery, prostatectomy and craniotomy. This study was aimed to investigate the hypothesis that EA could regulate hypothalamic CRF in surgical trauma rats. In experiment one, Sprague-Dawley (SD) male rats were divided into intact, model (10% partial hepatectomy), sham EA and EA group. Rats from the Sham EA and EA group were stimulated at ST36-Zusanli and SP6-Sanyiniiao acupoints twice, 24 hours before the surgery and immediately after the surgery. Expressions of hypothalamic CRF and CRFR, GABA receptors, glutamate decarboxylase (GAD), serum adrenocorticotropic hormone (ACTH) and Corticosterone (CORT) were observed at 2, 4, 8 and 24 h after the surgery by radioimmunoassay (RIA), western blot, real-time PCR and immunohistochemistry. In the experiment two, SD male rats were divided into the intact, model, model + vehicle, model + L-838,417 EA and EA + L838,417 group. It was found that hypothalamus CRF, serum ACTH and CORT levels were increased in model group compared with the intact group, and those in the EA group decreased in comparison with the model group. Compared with the model group, hypothalamus-aminobutyric acid (GABA) receptor Aα3 mRNA and protein expressions of the EA group raised strikingly. In conclusion, EA alleviated surgical stress response by improving the GABA synthesis in hypothalamus, thus enhancing GABA receptors’ inhibitory regulation of the HPA axis dysfunction in rats with acute surgical trauma.

Γ-Aminobutyric acid promotes methionine-choline deficient diet-induced nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis（NASH） is one of the most common liver diseases and a major cause of liver fibrosis worldwide.r-Aminobutyric acid（GABA） is one of the most abundant inhibitory neurotransmitters in the central nervous system.Recently,it has been reported that GABAergic signaling pathways are found in various non-neuronal tissues including the immune system and play a functional role.In the present study,we investigated whether administration of GABA has effects on NASH through its immunomodulatory effects.To test this hypothesis,C57BL/6 mice were fed a methionine-choline-deficient（MCD） diet for 8 weeks.After four weeks into MCD feeding,mice were provided with plain water（control） or water containing 2 mg/mL of GABA for the subsequent 4 weeks.Using this MCD diet-induced NASH model,we found that mice receiving GABA showed more severe steatohepatitis and liver fibrosis than control mice.This increased liver damage was confirmed by higher levels of serum alanine transaminase（ALT） and aspartate aminotransferase（AST） compared to the control group.In accordance with increased liver steatohepatitis,NASH-related and inflammatory gene expression（collagen al,tissue inhibitor of metalloproteinase-1,TNF-α） in the liver was markedly increased in GABA-treated mice.Furthermore,GABA directly enhanced production of inflammatory cytokines including IL-6 and TNF-α in LPS activated RAW macrophage cells and increased TIB-73 hepatocyte death.Such effects were abolished when GABA was treated with bicuculline,a competitive antagonist of GABA receptors.These results suggest that oral administration of GABA may be involved in changes of the liver immune milieu and conferred detrimental effects on NASH progression.

Coexistence of nitric oxide synthase with γ-aminobutyric acid during seizure induced by kainic acid in SD rats

Objective: Functional significance of NO and central inhibitory neurotransmitter γ-aminobutyric(GABA) during seizures were investigated morphorlogically. Methods: A kainate-induced complex partialseizure model was used in our experiment. Twenty SD rats were randomly divided into KA 30, 60, 90, 200min and control groups. The brain sections were stained by NADPh (nicotinamide adenine dinucleotide phosphate ) diaphorase (Nd ) histochemically, and were further stained by GABA immunohistochemically.Results: Histological and immunohistochemical study revealed that in KA groups the number of Nd and GABA-positive double labelled neurons in CA3 region, CA3 region and dentate gyms was significantly reduced,compared with the control group. Conclusion: Nd coexisted with GABA in the brain. Reduction of GABA release led to relief of GABA-ergic inhibition and in the same way, reduction of NO release weakened its negative feedback modulation. Therefore neuronal synchronous paroxysmal discharges increased. GABA and NO,both having antiepileptic action, acted through different ways or different link in the same way. NO may involve in the effect of GABA-ergic neurons and play cooperative antiepileptic action with GABA.

Construction of Free Amino Acids Composition Data Base for Food

Significant amounts of free amino acids exist in commercially sold vegetables and fruits. Despite of the fact, only a little information is available about the free amino acid contents in foods. To utilize information of free amino acids in food, we have carried out the experiments to quantitate the free amino acids by derivatized with NBD-F （4-fluoro-7-nitrobenzofurazan） and analyzed on reversed-phase UHPLC （ultra-high pressure liquid chromatography） equipped with ultraviolet visible detector. Almost all of food extracts contained free amino acids including GABA （T-amino butyrate）. Contents of free amino acids vary considerably depending upon vegetables and fruits. Principal free amino acids found in vegetables and fruits were asparagine, glutamine, arginine and GABA, which are involved in important metabolic pathways in human. About 140 species of vegetables and fruits were subjected for the data base. All of the plants and fruits we examined exhibit significant amount of free amino acids, those are clearly distinct from data bases obtained after acid hydrolysis treated food samples. Since glutamate and GABA act as excitatory and inhibitory neurotransmitters in CNS, respectively; free amino acids in vegetables and fruits that we eat daily, should be an important source for the cellular metabolic activities.

The role of γ-aminobutyric acid and its receptors in the nucleus of basal optic root in pigeons

The effects of γ-aminobutyric acid (GABA) and its antagonists bicuculline and 2-hydroxysaclofen on neuronal firings in the nucleus of basal optic root (nBOR) in pigeons were studied by using extracellular recording and microiontophoretic techniques. The results suggest that GABA may be an inhibitory neurotransmitter or modulator within nBOR, functioning by means of main mediation of GABAA receptors and of minor mediation of GABAB receptors. Furthermore, GABA and its GABAA receptors are involved in the modulation of directional selectivity in part of nBOR neurons.

Age-related Changes of Glu/GABA Expression in the Primary Visual Cortex of Cat

Recent studies show that a reduced effect of inhibitory transmitter system in the visual cortex may underlie aged visual function degradation. Whether excitatory transmitter system changes with age and hence affects intracortical excitation-inhibition balance is not clear. To explore this issue, we used Nissl staining and immunohistochemical methods as well as Image-Pro Express software to examine the density of Nissl-stained neurons, Glutamie acid-immunoreactive （Glu-IR） neurons and T-Aminobutyric acid-immunoreactive （GABA-IR） neurons in the primary visual cortex of young adult and aged cats. The results showed that there was no significant difference in the density of Nissl-stained neurons between young and old cats （2〉0.05）. However, the density of Glu-IR neurons and GABA-IR neurons in the primary visual cortex of aged cats was significantly lower than that of young ones （P〈0.01）. The ratio between Glu-IR neurons and GABA-IR neurons was significantly increased in old cats compared to that in young adult ones （P〈0.01）. These results indicated that the effect of excitatory transmitter system in the old visual cortex was increased relative to the inhibitory transmitter system, which might cause an imbalance between cortical excitation and inhibition and might be an important factor mediating the visual function decline during aging.

比色法测定茶叶GABA含量的可行性研究

应用比色法、HPLC和氨基酸自动分析仪法同时测定了六大茶类共45个样品的GABA含量,结果表明,HPLC与氨基酸分析仪测定结果基本一致,比色法和HPLC法测定的普洱茶、红茶、白茶、黄茶的结果差异极显著(P<0.01),应用比色法测得的普洱茶和黑茶中GABA含量比HPLC测定结果高,而其他茶类测定结果低,推测茶叶中含有化学物质(色素、氨基酸等)干扰比色法测定。目前比色法不能应用于茶叶GABA测定,需要进一步改进方法以排除如氨基酸、茶色素等的干扰。

发芽苦荞GABA的富集及氨基酸等含氮物的变化

研究了苦荞发芽过程中γ-氨基丁酸(GABA)、谷氨酸脱羧酶(GAD)活力及可溶性蛋白、氨基酸等含氮物含量的变化。结果表明:随着发芽时间的延长,GABA含量在发芽4d时达到最高,子叶和胚中GAD活力均呈先升后降趋势。可溶性蛋白呈下降趋势,游离氨基酸含量先升高后降低,总氨基酸含量不断升高。除蛋氨酸外,异亮氨酸及缬氨酸等几种人体必需氨基酸均呈现上升趋势,谷氨酸(Glu)含量升高,这些变化均有利于发芽苦荞中GABA的富集。

乳酸菌ML7生长及其产GABA特性的研究

通过分析时间、温度、pH和底物添加量对发酵过程的影响,从而进一步对ML7的生长及其产GABA两方面特性进行研究。实验结果表明,ML7的生长最适温度为37℃;最适初始pH为7;培养20 h活菌数达到最大值。而ML7产GABA的最佳温度为30℃;GABA的产量随着初始pH的降低而逐渐增加;培养55 h后GABA积累量达到最大;Glu添加量为5%时获得最大GABA产量。

低氧胁迫对不同品种发芽糙米GABA含量及生理指标变化的影响

目的:研究不同品种糙米在低氧胁迫条件下发芽γ-氨基丁酸(GABA)含量及各生理指标的变化。方法:以糙米作为研究对象,分析低氧胁迫对7种糙米发芽后GABA、还原糖、可溶性蛋白含量、呼吸强度、千粒重和谷氨酸脱羧酶(GAD)活力的变化的影响。结果:不同品种发芽糙米在低氧胁迫3 d时的GABA含量存在明显差异,最高达329.15 mg/100 g,最低为191.43 mg/100 g,平均含量为235.64 mg/100g,是未发芽糙米的8.12倍。结论:低氧胁迫条件下发芽糙米中GABA含量与呼吸强度、可溶性蛋白含量、还原糖含量、谷氨酸脱羧酶(GAD)活力均呈极显著正相关(P<0.01),与千粒重呈显著负相关(P<0.05),3号(f两优6876)品种可作为富集GABA的良好原料。

γ-氨基丁酸(GABA)在食品工业中的应用研究

γ-氨基丁酸(GABA)是一种天然存在的功能性蛋白质。介绍了GABA的理化性质、生理功能及制备方法,并对其在食品工业中的应用及发展前景进行了综述与展望。

大鼠展神经核和前庭神经核内GABA反应神经元向动眼神经核的投射

用辣根过氧化物酶(horseradish peroxidase,HRP)逆行标记结合γ-氨基丁酸(γ-amino-butyric acid,GABA)的免疫组织化学双标技术观察大鼠的展神经核和前庭神经核内GABA阳性神经元的分布,以及其向动眼神经核的投射。结果表明:注射HRP于大鼠动眼神经核内直肌亚核后,在对侧展神经核区以及前庭神经核、脑桥旁正中网状结构中发现HRP单标记细胞;在前庭神经核内,可见HRP单标记、GABA阳性和HRP/GABA双标记三类神经元,其中HRP/GABA双标记细胞占HRP标记细胞总数的47.1%。结果表明GABA在前庭神经核向动眼神经核的抑制性投射中起一定作用,而在展神经核向动眼神经核投射的核间通路中,可能不是起主要作用的抑制性神经递质。

噪声暴露对大鼠听皮层兴奋性及GABA和NMDA受体表达的影响

目的观察噪声暴露对大鼠听皮层兴奋性以及听皮层γ-氨基丁酸(γ-amino butyric acid,GABA)和N-甲基-天冬氨酸(N-methyl-D-aspartic acid,NMDA)受体表达的影响。方法将14只SD大鼠随机分为噪声暴露高剂量组(3只)、中剂量组(4只)、低剂量组(4只)和正常对照组(3只),高、中、低剂量噪声暴露组大鼠分别于125dB SPL白噪声暴露2小时、120dB SPL白噪声暴露1小时和90dB SPL白噪声暴露1小时,正常对照组不给予噪声暴露;在噪声暴露前、暴露后1小时、1天、3天、1周、2周行听性脑干反应(ABR)和声诱发听皮层放电率检测;运用蛋白免疫印迹技术检测听皮层兴奋性增强的大鼠以及对照组大鼠听皮层组织中GABA和NMDA两种受体亚型(GABAA、GABAB和NR2A、NR2B)的蛋白表达水平。结果所有噪声暴露组大鼠在暴露后1小时各频率ABR反应阈较暴露前显著提高,脱离噪声环境2周后,低、中剂量噪声暴露组各频率ABR反应阈恢复至暴露前水平,高剂量噪声暴露组ABR阈移未恢复。与暴露前相比,低剂量噪声暴露后大鼠听皮层放电率在各时间点未升高;中剂量噪声暴露后1小时听皮层放电率升高,2周后降低至暴露前水平;高剂量组噪声暴露后听皮层放电率在各时间点均降低。与对照组相比,噪声暴露后听皮层放电率升高的大鼠听皮层GABAA、GABAB、NR2A、NR2B受体表达水平均降低。结论 120dB SPL噪声暴露1小时可导致大鼠听皮层兴奋性增强,这可能与听皮层通过减少GABA抑制作用增强听觉中枢兴奋性来补偿外周听觉系统信号输入的减少有关。

Suppression of Human Liver Cancer Cell Migration and Invasion via the GABA_A Receptor

Objective To investigate the roles of the y-aminobutyric acid （GABA） in the metastasis of hepatocellular carcinoma （HCC） and to explore the potential of a novel therapeutic approach for the treatment of HCC. Methods The expression levels of GABA receptor subunit genes in various HCC cell lines and patients＇ tissues were detected by quantitative real-time polymerase chain reaction and Western blot analysis. Transwell cell migration and invasion assays were carried out for functional analysis. The effects of GABA on liver cancer cell cytoskeletal were determined by immunofluorescence staining. And the effects of GABA on HCC metastasis in nude mice were evaluated using an in vivo orthotopic model of liver cancer. Results The mRNA level of GABA receptor subunits varied between the primary hepatocellular carcinoma tissue and the adjacent non-tumor liver tissue. GABA inhibited human liver cancer cell migration and invasion via the ionotropic GABAA receptor as a result of the induction of liver cancer cell cytoskeletal reorganization. Pretreatment with GABA also significantly reduced intrahepatic liver metastasis and primary tumor formation in vivo. Conclusions These findings introduce a potential and novel therapeutic approach for the treatment of cancer patients based on the modulation of the GABAergic system.

GABA(γ-氨基丁酸)的功能性

γ-氨基丁酸(GABA)富含于蔬菜、水果及发酵食品中,是日常摄取的氨基酸的一种。作为抑制性神经物质在人的大脑中枢神经系统中起作用。关于GABA的功能性,以前曾报道其具有抑制血压上升作用,但是在日常生活中摄取的GABA的量很少,所以,光从食物中很难获取能发挥其功能性的需要量。因此,我们注重研究有饮食生活经验的发酵食品中的微生物,开发了由微生物发酵的高效GABA生产技术。而且,经过一系列试验确认了GABA的有效作用,如抗压力作用等新功能。

GABA富化处理的大米产品的成分分析与营养评价

近年来随着人们生活水平的迅速改善,人们更加关注膳食营养健康。在本研究中,为了分析经过GABA富化装置处理前后稻谷的营养成分和功能组分变化,测定了GABA、游离氨基酸、蛋白质、还原糖、抗性淀粉和总淀粉等指标的含量。经过GABA富化处理后,精米中的还原糖含量由1.53 mg/g减少到0.341 mg/g;淀粉含量由746 mg/g减少到728 mg/g;而抗性淀粉含量由1.96%增加到2.30%;GABA含量由84.1μg/g增加到111μg/g;游离氨基酸含量由1114μg/g增加到1123μg/g;必需氨基酸含量由419μg/g增加到426μg/g。总蛋白含量几乎不变,且蛋白质组成符合理想蛋白质的要求。

超声辅助吐温80提取发芽小米GABA和多酚的工艺优化

采用超声辅助吐温80优化发芽小米γ-氨基丁酸(gamma-amino butyric acid,GABA)和多酚提取工艺。以GABA和多酚得率为考察指标,通过单因素试验探究吐温80质量分数、超声温度、超声时间、料液比、超声功率对GABA得率的影响,设计正交试验优化GABA提取工艺;通过单因素试验探究吐温80添加量、超声温度、超声时间、料液比4个因素对多酚得率的影响,以响应面试验设计优化多酚提取工艺。结果表明:超声辅助吐温80提取GABA的最佳工艺条件为吐温80质量分数6%、超声温度35℃、超声时间25 min、料液比1∶18(g/mL)、超声功率126 W,此条件下GABA得率为4.70 mg/g;提取多酚的最佳工艺条件为吐温80质量分数9%、超声温度42℃、超声时间19 min、料液比1∶12.5(g/mL),此条件下多酚得率为1.99 mg/g。

Neuroprotective effects of Shaoyao Gancao decoction against excitatory damage in PC12 cells based on the Src-NR2-nNOS pathway

Objective:To explore the neuroprotective effects of the Shaoyao Gancao decoction(SGD)against excitatory damage in PC12 cells and the role of the Src-NR2-nNOS pathway mediation by SGD in regulatingγ-aminobutyric acid(GABA)-glutamate(Glu)homeostasis.Methods: N-Methyl-d-aspartic acid(NMDA)was used to establish a PC12 cell excitability injury model.To investigate the neuroprotective effect of SGD,a cell counting kit-8(CCK-8)assay was used to determine PC12 cell viability,Annexin V/Propidium Iodide(Annexin V/PI)double staining was used to determine PC12 cell apoptosis,and Ca^(2+)concentration was observed using laser confocal microscopy.GABA receptor agonists and antagonists were used to analyze the neuroprotective interactions betweenγ-aminobutyric acid(GABA)and NMDA receptors.Additionally,molecular biology techniques were used to determine mRNA and protein expression in the Src-NR2-nNOS pathway.We analyzed the correlations between the regulatory sites of GABA and NMDA interactions,excitatory neurotoxicity,and brain damage at the molecular level.Results: NMDA excitotoxic injury manifested as a significant decrease in cell activity,increased apoptosis and caspase-3 protein expression,and a significant increase in intracellular Ca^(2+)concentration.Administration of SGD,a GABAA receptor agonist(muscimol),or a GABAB receptor agonist(baclofen)decreased intracellular Ca^(2+)concentrations,attenuated apoptosis,and reversed NMDA-induced upregulation of caspase-3,Src,NMDAR2A,NMDAR2B,and nNOS.Unexpectedly,a GABA_(A)receptor antagonist(bicuculline)and a GABA_(B)receptor antagonist(saclofen)failed to significantly increase excitatory neurotoxicity.Conclusions: Taken together,these results not only provide an experimental basis for SGD administration in the clinical treatment of central nervous system injury diseases,but also suggest that the Src-NR2A-nNOS pathway may be a valuable target in excitotoxicity treatment.

不同产地妃子笑荔枝果汁的氨基酸组分

为评价荔枝的营养价值,采用全自动氨基酸分析仪测定广东、广西、海南和福建4个产区共5个妃子笑荔枝果汁样品的氨基酸组分。结果表明:妃子笑荔枝果汁富含氨基酸组分,不同产区样品的氨基酸组分总量介于341.51～455.42mg/100mL之间,其中广西钦州产区样本的氨基酸组分含量最高为455.42mg/100mL,广东阳西产区样本的氨基酸组分含量最低为341.51mg/100mL;5个样品妃子笑荔枝果汁的氨基酸组分总量平均为396.38mg/100mL;其中γ-氨基丁酸为妃子笑荔枝果汁中的主要氨基酸,其平均含量为104.69mg/100mL,占氨基酸组分总量的26.57%;其次为丙氨酸,平均为67.37mg/100mL,占16.87%。基于对荔枝果汁中氨基酸组分的初步评价,认为荔枝是一种具有富含γ-氨基丁酸的潜在功能性食品资源。