Effect of brain-derived neurotropic factor released from hypoxic astrocytes on gamma-aminobutyric acid type A receptor function in normal hippocampal neurons

Astrocytes can release increased levels of brain-derived neurotrophic factor during cerebral ischemia, but it is unclear whether brain-derived neurotrophic factor affects y-aminobutyric acid type A receptor function in normal neurons. Results from this study demonstrated that y-aminobutyric acid at 100 pmol/L concentration raised the intracellular calcium level in neurons treated with medium from cultured hypoxic astrocytes, and the rise in calcium level could be inhibited by y-aminobutyric acid type A receptor antagonist bicuculline or brain-derived neurotrophic factor receptor antagonist k252a, y-aminobutyric acid type A-gated current induced by 100 IJmol/L y-aminobutyric acid was in an inward direction in physiological conditions, but shifted to the outward direction in neurons when treated with the medium from cultured hypoxic astrocytes, and this effect could be inhibited by k252a. The reverse potential was shifted leftward to -93 mV, which could be inhibited by k252a and Na＋-K＋-CI cotransporter inhibitor bumetanide. Brain-derived neurotrophic factor was released from hypoxic astrocytes at a high level. It shifted the reverse potential of y-aminobutyric acid type A-gated currents leftward in normal neurons by enhancing the function of Na＋-K＋-CI- cotransporter, and caused y-aminobutyric acid to exert an excitatory effect by activating y-aminobutyric acid type A receptor.

Gamma-aminobutyric acid promotes human hepatocellular carcinoma growth through overexpressed gamma-aminobutyric acid A receptor α3 subunit

AIM:To investigate the expression pattern of gamma-aminobutyric acid A(GABAA) receptors in hepatocellular carcinoma(HCC) and indicate the relationship among gamma-aminobutyric acid(GABA),gamma-aminobutyric acid A receptor α3 subunit(GABRA3) and HCC.METHODS:HCC cell line Chang,HepG2,normal liver cell line L-02 and 8 samples of HCC tissues and paired non-cancerous tissues were analyzed with semiquantitative polymerase chain reaction(PCR) for the expression of GABAA receptors.HepG2 cells were treated with gamma-aminobutyric acid(GABA) at serial concentrations(0,1,10,20,40 and 60 μmol/L),and their proliferating abilities were analyzed with the 3-(4,5-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay,cell doubling time test,colon formation assay,cell cycle analysis and tumor planted in nude mice.Small interfering RNA was used for knocking down the endogenous GABRA3 in HepG2.Proliferating abilities of these cells treated with or without GABA were analyzed.RESULTS:We identified the overexpression of GABRA3 in HCC cells.Knockdown of endogenous GABRA3 expression in HepG2 attenuated HCC cell growth,suggesting its role in HCC cell viability.We determined the in vitro and in vivo effect of GABA in the proliferation of GABRA3-positive cell lines,and found that GABA increased HCC growth in a dose-dependent manner.Notably,the addition of GABA into the cell culture medium promoted the proliferation of GABRA3-expressing HepG2 cells,but not GABRA3-knockdown HepG2 cells.This means that GABA stimulates HepG2 cell growth through GABRA3.CONCLUSION:GABA and GABRA3 play important roles in HCC development and progression and can be a promising molecular target for the development of new diagnostic and therapeutic strategies for HCC.

Synthesis and Anti-tumor Activity of Novel Amide Derivatives of Ursolic Acid

Ursolic acid was modified at C3 and C28 position to obtain fourteen derivatives including twelve novel compounds, and their chemical structures were characterized by IR, ^1H NMR and MS. Cell growth inhibitory effects of the derivatives against Hela cell were evaluated by MTT assay. All these derivatives were found to have stronger cell growth inhibitory than their parent compound, ursolic acid. The derivatives with a substituted acetyl group at C3 hydroxyl group show better activities than those with an unsubstituted hydroxyl group.

QSAR and Pharmacophore Studies of Thiazolidine-4-carboxylic Acid Derivatives as Novel Influenza Neuraminidase Inhibitors Using HQSAR, Topomer CoMFA and CoMSIA

In order to understand the chemical-biological interactions governing their activities toward neuraminidase （NA）, QSAR models of 28 thiazolidine-4-carboxylic acid derivatives with inhibitory influenza A virus were developed. The obtained HQSAR （hologram quantitative structure activity relationship）, Topomer CoMFA and CoMSIA （comparative molecular similarity indices analysis） models were robust and had good exterior predictive capabilities. Moreover, QSAR modeling results elucidated that hydrogen bonds highly contributed to the inhibitory activity, then electrostatic and hydrophobic factors. Squared multiple correlation coefficients （R2） of HQSAR, Topomer CoMFA and CoMSIA models were 0.994, 0.978 and 0.996, respectively. Squared cross-validated correlation coefficients （Q2） of HQSAR, Topomer CoMFA and CoMSIA models were in turn 0.951, 919 and 0.820. Furthermore, squared multiple correlation coefficients for the test set （R2test） of HQSAR, CoMFA and CoMSIA models were 0.879, 0.912 and 0.953, respectively. Squared cross-validated correlation coefficients for the test set （Q2ext） of HQSAR, Topomer CoMFA and CoMSIA models were 0.867, 0.884 and 0.899, correspondingly.

Synthesis of Tetrahydrofuran and Tetrahydropyran Derivatives Catalyzed by Tungstophosphoric Acid in Ionic Liquid

Synthesis of tetrahydrofuran and tetrahydropyran derivatives catalyzed by tungstophosphoric acid （H3PW12040） were conveniently performed with high yield from the corresponding unsaturated alcohols in ionic liquid. Sufuric acid （H2SO4）, trifluoromathanesulfonic acid （TfOH） and p-toluenesulfonic acid （TsOH） were also explored for preparing these products in ionic liquid. The catalysts and ionic liquid can be easily recovered and reused.

Synthesis and biological evaluation of novel N-(alkoxyphenyl)-aminocarbonylbenzoic acid derivatives as PTP1B inhibitors

Based on the fact that petroselinic acid showed good inhibitory activity（IC50 = 6.99μmol/L） against protein tyrosine phophatase 1B（PTP1B） in vitro,a series of novel N-（alkoxyphenyl）-aminocarbonylbenzoic acid derivatives were designed and synthesized.The results indicated that most of the derivatives showed more potent activities against PTP1B.Especially,compound 13 had obvious activity with an IC50 of 106 nmol/L in vitro.

Synthesis of phenol-class azo derivatives of 4-aminosalicylic acid

To explore the better prodrug of 4-aminosalicylic acid（4-ASA）with higher activity and less side effects against the inflammatory bowel disease.4-ASA,after a succession of synthesis process,was conjugated with various carder molecules to get seven azo derivatives of 4-ASA.All compounds were characterized by FT-IR,^1H NMR,^13C NMR spectras in detail.New derivatives of 4-ASA were definituded.

A Two-stage pH and Temperature Control with Substrate Feeding Strategy for Production of Gamma-aminobutyric Acid by Lactobacillus brevis CGMCC 1306

Methods to optimize the production of gamma-aminobutyric acid （GABA） by Lactobacillus brevis CGMCC 1306 were investigated. Results indicated that cell growth was maximal at pH 5.0, while pH 4.5 was pref-erable to GABA formation. The optimal temperature for cell growth （35 °C） was lower than that for GABA forma-tion （40 °C）. In a two-stage pH and temperature control fermentation, cultures were maintained at pH 5.0 and 35 °C for 32 h, then adjusted to pH 4.5 and 40 °C, GABA production increased remarkably and reached 474.79 mmol·L-1 at 72 h, while it was 398.63 mmol·L-1 with one stage pH and temperature control process, in which cultivation con-ditions were constantly controlled at pH 5.0 and 35 °C. In order to avoid the inhibition of cell growth at higher L-monosodium glutamate （L-MSG） concentrations, the two-stage control fermentation with substrate feeding strat-egy was applied to GABA production, with 106.87 mmol （20 g） L-MSG supplemented into the shaking-flask at 32 h and 56 h post-inoculation separately. The GABA concentration reached 526.33 mmol·L-1 at 72 h with the fer-mentation volume increased by 38%. These results will provide primary data to realize large-scale production of GABA by L. brevis CGMCC 1306.

Anthranilic acid derivatives from Inula japonica

Three new anthranilic acid derivatives, N-heneicosanoylanthranilic acid （1b）, N-tricosanoylanthranilic acid （1d）, N-tetracosanoylanthranilic acid （1e）, and two known N-arachidylanthranilic acid （1a） and N-docosanoylanthranilic acid （1c） were isolated from the aerial parts of lnula japonica Thunb. Their structures were established by spectroscopic and chemical methods.

Evolution of neurotransmitter gamma-aminobutyric acid,glutamate and their receptors

Gamma-aminobutyric acid(GABA)and glutamate are two important amino acid neurotransmitters widely present in the nervous systems of mammals,insects,round worm,and platyhelminths,while their receptors are quite diversified across different animal phyla.However,the evolutionary mechanisms between the two conserved neurotransmitters and their diversified receptors remain elusive,and antagonistic interactions between GABA and glutamate signal transduction systems,in particular,have begun to attract significant attention.In this review,we summarize the extant results on the origin and evolution of GABA and glutamate,as well as their receptors,and analyze possible evolutionary processes and phylogenetic relationships of various GABAs and glutamate receptors.We further discuss the evolutionary history of Excitatory/Neutral Amino Acid Transporter(EAAT),a transport protein,which plays an important role in the GABA-glutamate“yin and yang”balanced regulation.Finally,based on current advances,we propose several potential directions of future research.

A green method for the synthesis of bis-indolylmethanes and 3,3'-indolyloxindole derivatives using cellulose sulfuric acid under solvent-free conditions

A highly efficient green protocol for the preparation of bis-indolylmethanes,bis-2-methylindolylmethanes,bis-1-methylindolylmethanes and 3,3 -diindolyloxindole derivatives from the reaction of indoles with various aldehydes and ketones in the presence of cellulose sulfuric acid under solvent-free conditions is reported.The significant features of this procedure are high yields of the products,mild reaction,solvent-free condition and non-toxicity of the catalyst.

Hippocampal and cortical expression of gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein in pentylenetetrazol-induced chronic epileptic rats

BACKGROUND： Gamma-aminobutyric acid transporter plays an important role in gamma-aminobutyric acid metabolism, and is highly associated with epilepsy seizures. Pathologically, astrocytes release active substances that alter neuronal excitability, and it has been demonstrated that astrocytes play a role in epileptic seizures. OBJECTIVE： To observe changes in gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein expression in the hippocampus and cortex of the temporal lobe in rats with pentylenetetrazol-induced chronic epilepsy. DESIGN, TIME AND SETTING： Randomized, controlled, animal experiment was performed at the Department of Neurobiology, Third Military University of Chinese PLA between January 2006 and December 2007. MATERIALS： Pentylenetetrazol was purchased from Sigma, USA; rabbit anti-rat gammaaminobutyric acid transporter 1 and glial fibrillary acidic protein were from Chemicon, USA. METHODS： A total of 40 Sprague Dawley rats were divided into model and control groups. Rat models of chronic epilepsy were created by pentylenetetrazol kindling, and were subdivided into 3-, 7-, and 14-day kindling subgroups. MAIN OUTCOME MEASURES： Gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein expression, as well as the number of positive cells in the hippocampus and cortex of temporal lobe of rats, were determined by immunohistochemistry and Western blot analyses. RESULTS： Compared with the control group, the number of gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein -positive cells in the hippocampus and cortex of rats with pentylenetetrazol-induced epilepsy significantly increased, gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein expression increased after 3 days of kindling, reached a peak on day 7, and remained at elevated levels at day 14 （P〈 0.05）. CONCLUSION： Astrocytic activation and gamma-aminobutyric acid transporter 1 overexpression may contribute to pentylenetetrazol-induced epilepsy.

Synthesis of azo derivatives of 4-aminosalicylic acid

For searching a better 4-aminosalicylic acid derivative with higher activity and less side effects against the inflammatory bowel disease, 4-aminosalicylic acid (4-ASA) was protected by benzyloxycarbonyl and acetyl, respectively. The resultant was hydrogenized to remove protective group of amino group, then the product was reacted with NaNO2 to give diazonium salt, which was conjugated with salicylic acid, hydroxybenzene, N-salicyloyl glycine acid to get azo derivatives of 4-ASA. The azo derivatives were hydrolyzed under the alkaline condition to get the target products. All compounds were characterized by FT-IR, (1)H NMR, (13)C NMR spectra in details. New derivatives of 4-ASA were characterized. The synthetic route was reasonable and feasible.

2D-QSAR Studies on Anthranilic Acid Derivatives: A Novel Class of Allosteric Inhibitors of Hepatitis C NS5B Polymerase

Quantitative structure activity relationship （QSAR） studies were performed on 45 anthranilic acid derivatives for their potent allosteric inhibition activities of HCV NSSB polymerase. Genetic algorithm based genetic function approximation （GFA） method of variable selection was used to generate the model. Highly statistically significant model with r^2 = 0.966 and r^2cv = 0.951 was obtained when the number of descriptors in the equation was set to 5. High r^2pred value of 0.884 indicates the good predictive power of the best model. Spatial descriptors of radius of gyration （RadOfGration）, molecular volume （Vm）, length of molecule in the z dimension （Shadow-Zlength）, thermodynamic descriptors of the octanol/water partition coefficient （LogP） and molecular refractivity index （MR） showed enormous contributions to HCV NS5B polymerase inhibition. The validation of the model was done by leave-one-out （LOO） test, randomization tests and external test set prediction. The model gives insight on indispensable structural requirements for the activity and can be used to design more potent analogs against HCV NSSB polymerase.

Effects of Gamma-Aminobutyric Acid on Performance of Lactating Sows during Heat Weather

[ Objective] To study the effects of gamma-aminobutyric acid （GABA） on performance of lactating sows during heat stress. [ Metbod] A total of 14 sows at the same parity and with close expected date of childbirth and similar body we：,ght were randomly divided into control group and experimental group. They were fed a common basal diet and a GABA （300 mg/kg） supplementary diet, respectively. The trial lasted for 21 d. [ Result ] The daily feed intake, lactation yield and average daily gain of piglets in the experimental group were increased by 9.4%, 28.5% and 10.7%, respectively. The backfat of lactating sows was decreased less, and the same with the weaning-oestrus interval. The survival ratio of piglets was increased by 4.5%. Compared with the control group, the content of lactose and fat increased significantly, but other components almost did not change. [Conclusien] Supplementing GABA in diet can improve the performance of lactating sows and promote the growth of piglets effectively.

SYNTHESIS AND ANTI－LIPID PEROXIDATION ACTIVITY OF AMINO ACID DERIVATIVES OF EBSELEN

There Ebselen derivatives (Ⅲ1-3) were desihned and synthesized with amino acid attached to the p-position of 2-phenyl moiety, Effect of compound Ⅱ,Ⅲ1,Ⅲ2,Ⅲ2, as well as Ebselen on the Fe2+/cysteine-induced rat microsomal lipid peroxidation were investigated. And their I C50 were 30,17.7,22.7,22.2,and 24 mol/L respectively.

Three New Heptelidic Acid Derivatives from the Culture of Mushroom Lentinellus ursinus

Three new heptelidic acid derivatives(1-3)including two new dimeric esters and two known heptelidic acid analogues(4 and 5)were isolated from the solid culture of mushroom Lentinellus ursinus.The structures of new compounds were confirmed by the analysis of NMR and HRESIMS spectroscopic data.The biosynthetic origin of compounds 1-5 was postulated.Compounds 1-5 exhibited no antibacterial activity against Staphylococcus aureus and Escherichia coli at the dose of 100 μM.

Gamma-aminobutyric acid A receptors in Alzheimer＇s disease： highly localized remodeling of a complex and diverse signaling pathway

Alzheimer＇s disease （AD）, the predominant form of dementia, is a chronic, incurable neurodegenerative disorder presenting with symptoms includ- ing progressive memory loss and disturbed emotional state. It has been estimated that dementia affects over 47 million people worldwide （Prince et al., 2015）, and with 60-80% of cases attributable to AD.

Gamma-aminobutyric acid A receptor and N-methyl-D-aspartate receptor subunit expression in rat spiral ganglion neurons

BACKGROUND： Gamma-aminobutyric acid A （GABAA） and N-methyl-D-aspartate （NMDA） receptors are significant receptors in the central nervous system. An understanding of GABAA and NMDA receptor expression in spiral ganglion neurons （SGN） provides information for the functional role of these receptors in the auditory system. OBJECTIVE： To investigate mRNA expression of GABAA receptor （GABAAR） and NMDA receptor （NMDAR） subunits in the rat SGN. DESIGN, TIME AND SETTING： This in vitro, molecular biological study was performed at the Laboratory of Otolaryngology-Head and Neck Surgery, Guangxi Medical University, China from July 2007 to May 2008. MATERIALS： Reverse Transcriptase Kit and Taq DNA polymerase were purchased from Fermentas Burlington, ON, Canada; GABAAR and NMDAR primers were purchased from Shanghai Sangon, Shanghai, China. METHODS： SGN from 3-5 day postnatal Wistar rats was collected for primary cultures, mRNA expression of GABAAR and NMDAR subunits in the SGN was determined by reverse transcription polymerase chain reaction. MAIN OUTCOME MEASURES： Expression levels of GABAAR and NMDAR subunits were determined by quantitative analysis. RESULTS： GABAAR subunits （αl 6, β1 3, and y1 3） and NMDAR subunits （NR1, NR2A, NR2B, NR2C, NR2D, NR3A, and NR3B） were detected in the SGN. In α subunit genes of GABAAR, α1 and α3 expression was similar （P 〉 0.05） and greater than the other subunits. Of the β subunit genes, β1 subunit mRNA levels were greater than β2 and β3. Of the y subunit genes, y2 subunit mRNA levels were greater than y1 and y3. NR1 mRNA expression was the greatest of NMDAR subunits. CONCLUSION： GABAAR subunits （α1 6, β1-3, and y1-3） and NMDAR subunits （NR1, NR2A, NR2B, NR2C, NR2D, NR3A, and NR3B） were expressed in the rat SGN. Through comparison of GABAAR and NMDAR subunit expression, possible GABAAR combinations, as well as highly expressed subunit combinations, were estimated, which provided information for pharmacological and electrophysiological characteristics of GABAAR in the auditory system.

Evolution of neurotransmitter gamma-aminobutyric acid, glutamate and their receptors

Gamma-aminobutyric acid （GABA） and glutamate are two important amino acid neurotransmitters widely present in the nervous systems of mammals, insects, round worm, and platyhelminths, while their receptors are quite diversified across different animal phyla. However, the evolutionary mechanisms between the two conserved neurotransmitters and their diversified receptors remain elusive, and antagonistic interactions between GABA and glutamate signal transduction systems, in particular, have began to attract significant attention. In this review, we summarize the extant results on the origin and evolution of GABA and glutamate, as well as their receptors, and analyze possible evolutionary processes and phylogenetic relationships of various GABAs and glutamate receptors. We further discuss the evolutionary history of Excitatory/Neutral Amino Acid Transporter （EAAT）, a transport protein, which plays an important role in the GABA-glutamate ＂yin and yang＂ balanced regulation. Finally, based on current advances, we propose several potential directions of future research.