• Animal cells and systems
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• v.1 no.3
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• pp.467-473
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• 1997

Taurine (2-aminoethanesulfonic acid), one of bioactive amino acid in the mammalian brain, is known to exert inhibitory effects on neurons via GABA receptor. In the present study, we examined effects of taurine on glutamateinduced neurotoxicity on hippocampal neuron cell culture using cell counting method and lactate dehydrogenase (LDH) assay. After 10 d of culture, cells were stimulated with appropriate drugs. Only 43% of cultured neuronal cells survived at one day after stimulation with 500 uM L-glutamate for 10 min. Survival rate was enhanced by 82% in the presence of 10 mM taurine. LDH activity from the culture supernatant incubated with a combination of L-glutamate and taurine was less than half of that with L-glutamate alone. In the next series of experiments, interleukin-6 (IL-6) mRNA expression in cultured astrocytes was investigated using reverse tanscription-PCR (RT-PCR). IL-6 mRNA was detected in the astrocytes stimulated with L-glutamate in a dose-dependent manner, while not detected in the unstimulated control astrocytes. The expression of IL-6 mRNA caused by 10 mM glutamate was inhibited by taurine, but not by GABA. These findings demonstrated a neuroprotective action of taurine against glutamate-induced toxicity.

• KSBB Journal
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• v.16 no.1
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• pp.36-40
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• 2001

In order to study the molecular mechanism of $\gamma$-aminobutyric acid (GABA) production in plants, we cloned and sequenced a partial glutamate decarboxylase (GAD) cDNA from the Arabidopsis thaliana cDNA library, using primers targeted at highly conserved sequences of the petunia GAD gene. The cDNA fragment was inserted into TA cloning vector with T7 promoter and the recombinant plasmid obtained was used to transform E. coli. The plasmid DNA purified from the transformed E. coli was digested with EcoRI and the presence of the insert was confirmed. Nucleotide sequence analysis showed that the fragment is a partial Arabidopsis thaliana GAD gene and that the sequence showed 98% and 78% identity to the region of the putative Arabidopsis thaliana GAD sequences deposited in GenBank, Accession nos: U46665 and U10034, respectively. The amino acid sequence deduced from the partial Arabidopsis thaliana GAD gene showed 99% and 91% identities to the GAD sequences deduced from the genes of the U46665 and U10034, respectively. The partial cDNA sequence determined may facilitate the study of the molecular mechanism of GABA metabolism in plants.

• Natural Product Sciences
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• v.18 no.2
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• pp.67-75
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• 2012

Zizyphi Spinosi Semen (ZSS) have been widely used for the treatment of insomnia in Asia. This experiment was performed to investigate whether methanol extract of ZSS (MEZSS) has hypnotic effects through the ${\gamma}$-amino butyric acid (GABA)ergic systems. MEZSS inhibited the locomotor activity. MEZSS enhanced pentobarbital-induced sleep behaviors. However, MEZSS itself did not induce sleep at higher dose, similar to muscimol. On the other hand, both pentobarbital and MEZSS increased the non rapid eye move (NREM) sleep, especially reducing the -wave electroencephalogram (EEG) activity in REM sleep. MEZSS showed similar effects with muscimol on potentiating chloride influx induced by pentobarbital. MEZSS significantly increased GABAA receptors ${\gamma}$-subunit expression and slightly decreased ${\beta}$-subunit expression in hypothalamus and thalamus, showing that subunit-expression was similar to diazepam. In addition, MEZSS enhanced the expression of glutamic acid decarboxylase (GAD). In conclusion, it is suggested that MEZSS might augment pentobarbital-induced sleep behaviors through the modification of GABAergic systems.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.4
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• pp.614-619
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• 2011

Nelumbo nucifera(NN) is a oriental medicinal herb which has been used traditionally for the treatment of antidiarrhea, sedative action and various brain diseases including convulsion and epilepsy. In order to examine the mechanism of anticonvulsive effect, we treated the methanol extract of NN(100, 200 mg/kg, P.0) to the sleeping time and pentylenetetrazole(PTZ)-induced convulsive mice. The methanol extract of NN prolonged sleep time by pentobarbital. Methanol extracts of NN were not effected the concentration of GABA and GABA-T activity in the brain of PTZ-induced mice. Methanol extracts of NN significantly inhibited the convulsion state as well as the level of lipid peroxidation in the brain. The butanol and dichloromethane fraction of methanol extracts among the others effectively inhibited in vitro lipid peroxidation dose dependently($5.0{\times}10^{-6}\sim2.0{\times}10^{-5}\;g/ml$). These results suggest that the anticonvulsive effect of NN is possibly due to the antioxidative effects of the free radical formation at brain for the PTZ-induced convulsion if it were by due to generating system.

• Biomolecules & Therapeutics
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• v.26 no.5
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• pp.432-438
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• 2018

Worldwide, caffeine is among the most commonly used stimulatory substances. Unfortunately, significant caffeine consumption is associated with several adverse effects, ranging from sleep disturbances (including insomnia) to cardiovascular problems. This study investigates whether treatment with the Evodia rutaecarpa aqueous extract (ERAE) from berries and its major molecular component, evodiamine, can reduce the adverse caffeine-induced sleep-related and excitation effects. We combined measurements from the pentobarbital-induced sleep test, the open field test, and the locomotor activity test in mice that had been dosed with caffeine. We found that ERAE and evodiamine administration reduced the degree of caffeine-induced sleep disruption during the sleep test. Additionally, we found that evodiamine significantly inhibits caffeine-induced excitation during the open field test, as well as decreasing hyperlocomotion in the locomotor activity test. Additional in vitro experiments showed that caffeine administration decreased the expression of ${\gamma}$-aminobutyric acid $(GABA)_A$ receptor subunits in the mouse hypothalamus. However, evodiamine treatment significantly reversed this expression reduction. Taken together, our results demonstrate that ERAE and its major compound, evodiamine, provide an excellent candidate for the treatment or prevention of caffeine-induced sleep disturbances and excitatory states, and that the mechanism of these beneficial effects acts, at least in part, through the $GABA_A$-ergic system.

• The Journal of Korean Medicine
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• v.21 no.1
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• pp.11-19
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• 2000

The present study was carried out to investigate the effects of Woowhangcheongshim-won(WCW) on the extracellular concentrations of amino acid neurotransmitters(glutamate, aspartate, GABA, glycine, taurine, alanine, and tyrosine) and organic acid (lactate and pyruvate) in striatum and cerebral infarction volume in rats subjected to permanent focal cerebral ischemia induced by 2 hours of middle cerebral artery occlusion(MCAO), using intracerebral microdialysis as the sampling technique, Microdialysis probes were inserted into the lateral part of the caudate-putamen 2 hours before the experiment and microdialyzates were collected at 20min intervals and analyzed by high performance liquid chromatography, WCW significantly decreased the infarction volume with reducing focal cerebral ischemia-induced increase of extracellular glutamate, asparate, and tyrosine. On the other hand, the increase of GABA and taurine was enhanced after treatment of WCW in the ischemia-induced rats, These results suggest that WCW can produce a neuroprotective effect against cerebral ischemia by regulating extracellular excitatory and inhibitory amino acid levels in relation to the concept of excitotoxicity in brain ischemia.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.643-646
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• 2002

The succinic semialdehyde dehydrogenase (SSADH) inhibitory component was isolated from the EtOAc fraction of Lactuca sativa through repeated column chromatography; then, it was identified as phytol, a diterpenoid, based on the interpretation of several spectral data. Incubation of SSADH with the phytol results in a time-dependent loss of enzymatic activity, suggesting that enzyme modification is irreversible. The inactivation followed pseudo-first-order kinetics with the second-rate order constant of $6.15{\times}10^{-2}mM^{-1}min^{-1}.$ Complete protection from inactivation was afforded by the coenzyme $NAD^{+}$, whereas substrate succinic semialdehyde failed to prevent the inactivation of the enzyme; therefore, it seems likely that phytol covalently binds at or near the active site of the enzyme. It is postulated that the phytol is able to elevate the neurotransmitter GABA levels in central nervous system through its inhibitory action on one of the GABA degradative enzymes, SSADH.

• BMB Reports
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• v.32 no.3
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• pp.254-258
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• 1999

The NADPH-dependent succinic semialdehyde reductase is one of the key enzymes in the brain GABA shunt, and it catalyzes the formation of the neuromodulator $\gamma$-hydroxybutyrate from succinic semi aldehyde. This enzyme was inactivated by diethylpyrocarbonate (DEP) with the second-order rate constant of $1.1{\times}10^3\;M^{-1}min^{-1}$ at pH 7.0, $25^{\circ}C$, showing a concomitant increase in absorbance at 242 nm due to the formation of N-carbethoxyhistidyl derivatives. Complete inactivation of succinic semialdehyde reductase required the modification of five histidyl residues per molecule of enzyme. However, only one residue was calculated to be essential for enzyme activity by a statistical analysis of the residual enzyme activity. The inactivation of the enzyme by DEP was prevented by preincubation of the enzyme with the coenzyme NADPH but not with the substrate succinic semialdehyde. These results suggest that an essential histidyl residue involved in the catalytic activity is located at or near the coenzyme binding site of the brain succinic semialdehyde reductase.

• Journal of Life Science
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• v.25 no.5
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• pp.594-600
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• 2015

Protein-protein interactions have a critical role in the regulation of many cellular functions. Postsynaptic density-95/disks large/zonula occludens-1 (PDZ) domain is one of domains that mediate protein-protein interactions. PDZ domains typically bind to the specific motif at the carboxyl (C)-terminal end of partner proteins. Multi-PDZ domain protein 1 (MUPP1), which has 13 PDZ domains, serves a scaffolding function for structure proteins and signaling proteins, but the cellular function of MUPP1 has not been fully elucidated. We used the yeast two-hybrid system to identify proteins that interact with PDZ domains of MUPP1. We found an interaction between MUPP1 and muskelin. Muskelin was recently identified as a GABA_A receptor (GABA_AR) α1 subunit binding protein and known to have a role in receptor endocytosis and degradation. Muskelin bound to the 3^rd PDZ domain, but not to other PDZ domains of MUPP1. The C-terminal end of muskelin was essential for the interaction with MUPP1 in the yeast two-hybrid assay. When co-expressed in HEK-293T cells, muskelin but not the C-terminal deleted muskelin was co-immunoprecipitated with MUPP1. In addition, MUPP1 co-localized with muskelin at the same subcellular region in cells. These findings collectively suggest that MUPP1 or its interacting proteins could modulate GABA_AR trafficking and turnover through the interaction with muskelin.

• BMB Reports
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• v.32 no.4
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• pp.339-344
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• 1999

We studied the effects of ginsenosides in immature rats based upon the previous results that ginseng has a suppressive or anticonvulsive activity. To examine the suppressive effect of ginsenosides on kainic acid-induced seizures, the severities and frequencies were observed for 4 h after injection of kainic acid (KA; i.p., 2 mg/kg b.w.) using 10-day-old male Sprague-Dawley rats ($22{\pm}2\;g$). Protopanaxadiol saponins such as ginsenoside-Rb1 (Rb1), ginsenoside-Rb2 (Rb2), ginsenoside-Rc (Rc), and ginsenoside-Rd(Rd) generally reduced the seizure activities while protopanaxatriol saponins such as ginsenoside-Rg1 (Rg1) and ginsenoside-Re (Re) rather increased stereotypic "paddling-like" movements. When vinyl-GABA (v-G) was injected together with Rb1 or Rc, KA-induced seizure severities were additionally reduced only by the injection of Rc, but not by Rb1. The level of gamma isozyme of protein kinase C (PKC-${\gamma}$) in the hippocampus increased about three times as much as that of normal rats at 4 h after KA injection. The increased level of PCK-${\gamma}$ by KA was significantly reduced to about 35% by the coinjection with v-G alone, but it was not changed by v-G together with Rb1 or Rc. The increased level of PKC-${\gamma}$ at 4 h after injection of KA was not consistent with the reduction of seizure severities between Rb1 and Rc. These results suggest that Rc and Rb1 may reduce seizure severity independent of PKC-${\gamma}$ levels, and Rc may additionally act with v-G regarding the GABA metabolism during the stage of KA-induced seizures in the immature rats.