• The Korean Journal of Physiology and Pharmacology
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• v.17 no.2
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• pp.175-180
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• 2013

Resveratrol is a phytoalexin found in grapes, red wine, and berries. Resveratrol has been known to have many beneficial health effects, such as anti-cancer, neuroprotective, anti-inflammatory, and life-prolonging effects. However, relatively little is known about the effects of resveratrol on the regulation of ligand-gated ion channels. We have previously reported that resveratrol regulates subsets of homomeric ligand-gated ion channels such as those of 5-$HT_{3A}$ receptors. The ${\gamma}$-aminobutyric $acid_C$($GABA_C$) receptor is mainly expressed in retinal bipolar cells and plays an important role in visual processing. In the present study, we examined the effects of resveratrol on the channel activity of homomeric $GABA_C$ receptor expressed in Xenopus oocytes injected with cRNA encoding human $GABA_C$ ${\rho}$ subunits. Our data show that the application of GABA elicits an inward peak current ($I_{GABA}$) in oocytes that express the $GABA_C$ receptor. Resveratrol treatment had no effect on oocytes injected with $H_2O$ or with $GABA_C$ receptor cRNA. Co-treatment with resveratrol and GABA inhibited $I_{GABA}$ in oocytes with $GABA_C$ receptors. The inhibition of $I_{GABA}$ by resveratrol was in a reversible and concentration-dependent manner. The $IC_{50}$ of resveratrol was $28.9{\pm}2.8{\mu}M$ in oocytes expressing $GABA_C$ receptor. The inhibition of $I_{GABA}$ by resveratrol was in voltage-independent and non-competitive manner. These results indicate that resveratrol might regulate $GABA_C$ receptor expression and that this regulation might be one of the pharmacological actions of resveratrol on the nervous system.

• Journal of Life Science
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• v.19 no.9
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• pp.1232-1238
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• 2009

Neurotransmitter release is regulated by various proteins of the active zone in the presynaptic nerve terminals. Dopamine (DA) is an essential neurotransmitter associated with the pathophysiology of diverse behavioral and mental illness such as schizophrenia and drug addiction. We measured synaptosomal DA release of knockout (KO) mice which lacked major genes related to neurotransmitter release. Synaptosomal DA uptake and release were performed and measured using [$^3H$]-DA and superfusion experiments. 3 of the 17 KO mice exhibited altered DA release compared to their littermate controls. In $Rim1{\alpha}$ KO, [$^3H$]-DA release evoked by membrane depolarization significantly decreased. Both basal (physiological buffer-evoked) and membrane depolarization-evoked DA release significantly decreased in dopaminergic conditional KO of $Rim1{\alpha}{\beta}$. Dopaminergic conditional KO of neurexin3 demonstrated a significant increase of membrane depolarization-evoked DA release. These data explain the similarities and distinctions between DA and other classical neurotransmitters such as glutamate and GABA ($\gamma$-aminobutyric acid) release. In conclusion, $Rim1{\alpha}$ and neurexin3 may be important regulators of presynaptic DA release and related to disorders of the nervous system.

• The Korean Journal of Food And Nutrition
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• v.27 no.4
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• pp.692-698
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• 2014

In this study, we investigated cancer cell growth inhibitory effects of kimchi extracts obtained from cabbage kimchi. Kimchi extracts (S46h, S47h, S48h) were obtained from the samples fermented at $15^{\circ}C$ for 46 h, 47 h, and 48 h during the first 10 days, which were subsequently stored at $-1.4^{\circ}C$ in kimchi refrigerator (hereinafter DV kimchi extracts). The samples showed a higher anti-proliferative effect against AGS (human, gastric adenocarcinoma) cell lines compared to control kimchi extract (S0h) obtained from sample stored at $-1.4^{\circ}C$ without fermentation. The DV kimchi contained higher levels of ${\gamma}$-aminobutyric acid (GABA) and ornithine compared to the control kimchi extract. Among the DV kimchi extracts, the S46h sample showed a higher anti-proliferative effect against the cancer cell growth and contained higher amount of GABA than the other kimchi samples. These results suggest that the consumption of DV kimchi can be more beneficial, as it is rich in GABA and ornithine. Therefore, it could be helpful in retarding the proliferation of cancer cells compared to the control kimchi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1201-1206
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• 2010

As a means to increase the production and consumption of the brown colored rice with high content of GABA ($\gamma$-aminobutyric acid), this study was conducted to develop brown colored rice tea. After roasting at various temperatures and times, color values and GABA content of the brown colored rice were analyzed. Physicochemical properties such as browning, turbidity, reducing sugar, soluble solid, total polyphenol and pH of brown colored rice tea were determined after the rice powder was put into tea bags and leached in hot water. Sensory characteristics were investigated for three kinds of tea roasted at $170^{\circ}C$ for 10, 20 and 30 min. As the roasting temperature and time increased, L, a and b values decreased as well as GABA content. The brown colored rice roasted at $170^{\circ}C$ for 10 min contained the highest content of GABA. Browning, turbidity, reducing sugar, soluble solid and total polyphenol of the brown colored rice tea increased as the roasting temperature and time increased, on the contrary, pH decreased. The brown colored rice tea roasted for 30 min was preferred the most in color, flavor, taste and overall acceptance. From this result, the brown colored rice tea needs to be manufactured by a combination of the brown colored rice roasted at $170^{\circ}C$ for 10 min and 30 min to satisfy the consumer's preference and high content of GABA.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.7
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• pp.963-969
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• 2012

This study evaluated the physicochemical properties of brown rice (BR) and germinated brown rice (GBR) in Korea. The protein content of BR was significantly higher than that of GBR. The amylose content of BR and GBR ranged from 17.42 to 18.48% and from 17.50 to 19.69%, respectively. The GBR contained higher ${\gamma}$-aminobutyric acid (GABA) content than that of BR. In an RVA examination, pasting temperatures of BR and GBR were $67.97{\sim}68.03^{\circ}C$. Texture analysis test showed that GBR Yeonghojinmi had the lowest hardness and highest stickiness. In conclusion, this study showed that compared to BR, GBR has a much softer texture, improved eating quality and increased GABA content.

• Plant Biotechnology Reports
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• v.5 no.3
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• pp.225-234
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• 2011

Arabidopsis mutants with T-DNA insertion in seven calmodulin genes (CAM) were used to determine the specific role of CAM in the tolerance of plants to oxidative stress induced by paraquat and hydrogen peroxide ($H_2O_2$) treatments. Arabidopsis calmodulin mutants (cam) were screened for seedling growth, seed germination, induced oxidative damage, and levels of ${\gamma}$-aminobutyric acid (GABA) shunt metabolites. Only the cam5-4 and cam6-1 mutants exhibited an increased sensitivity to paraquat and $H_2O_2$ during seed germination and seedling growth. In response to treatments with $3{\mu}M$ paraquat and 1 mM $H_2O_2$, only the cam5-4, cam6-1 mutants showed significant changes in malonaldehyde (MDA) levels in root and shoot tissues, with highly increased levels of MDA. In terms of the GABA shunt metabolites, GABA was significantly elevated in root and shoot tissues in response to the paraquat treatments in comparison to alanine and glutamate, while the levels of all shunt metabolites increased in root tissue but not in the shoot tissue following the $H_2O_2$ treatments. GABA, alanine and glutamate levels were significantly increased in root and shoot of the cam1, cam4, cam5-4, and cam6-1 mutants in response to paraquat (0.5, 1 and $3{\mu}M$), while they were increased only in the root tissue of the cam1, cam4, cam5-4, and cam6-1 mutants in response to $H_2O_2$ (200 and $500{\mu}M$, 1 mM). These data show that the cam5-4 and cam6-1 mutants were sensitive to the induced oxidative stress treatments in terms of seed germination, seedling growth, and oxidative damage. The accumulation of GABA shunt metabolites as a consequence of the induced oxidative stress treatments (paraquat and $H_2O_2$ treatments) suggests that the GABA shunt pathway and the accumulation of GABA metabolites may contribute in antioxidant machinery associated with reactive oxygen species and in the acquisition of tolerance in response to induced oxidative stress in Arabidopsis seedlings.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.72-77
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• 2000

The repeated silica gel colum chromatographies of EtOAc fraction, showing anticonvulsant activity, obtained from MeOH extracts of Schizandra chinensis B. fruits led to isolation of a sesquiterpenoid, four lignans and a sterol glycoside. Their chemical structures were determined to be chamigrenal, gomisin A, gomisin H, gomisin N. schizandrin and daucosterol. Among them, schizandrin and daucosterol inhibited GABA degrative enzymes, succinic semialdehyde dehydrogenase and succinic semialdehyde reductase, respectively. It is postulated that the schizandrin and daucosterol are able to elevate the neurotransmitter GABA levels in central nervous system by inhibitory action on GABA degrative enzymes and act as anticonvulsant drugs.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.315-320
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• 2011

Germination conditions were evaluated to obtain barley containing a high content of gamma-aminobutyric acid (GABA), and quality characteristics of saccharified materials manufactured using germinated barley were investigated. Water absorption content of barley increased but pH of the steeping solution decreased with increasing steeping time at all steeping temperatures. The changes in water absorption content and pH were highest at a steeping temperature of $25^{\circ}C$. The highest GABA content was obtained at a steeping condition of $25^{\circ}C$ for 20 h. The highest GABA content was obtained for a germination condition of $5^{\circ}C$ for 36 h after steeping, resulting in an increase of 7.4 times more GABA contents than that in raw material. The pH of saccarified materials decreased but titratable acidity, amino type nitrogen content, and ammonia type nitrogen content increased during the saccharification period. GABA content of saccarified materials increased with increasing saccharification period, resulting in the highest GABA content from saccarified materials containing germinated barley.

• Applied Microscopy
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• v.42 no.1
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• pp.9-16
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• 2012

The goal of this study was to identify neurotransmitters in endings (p-endings) presynaptic to low-threshold mechanoreceptive vibrissa afferents in the laminae III/IV of cat trigeminal caudal nucleus (Vc). Rapidly-adapting vibrissa afferents were intra-axonally labeled after electrophysiological identification, and postembedding immunogold staining with antisera against ${\gamma}$-aminobutyric acid (GABA) and glycine was performed, followed by quantitative ultrastructural analysis of p-endings presynaptic to the labeled vibrissa afferent terminals. Sixteen p-endings, which are presynaptic to the HRP-labeled vibrissa afferent terminals, were analyzed in this study: Eight p-endings (50%, 8/16) were immunopositive to GABA but immunonegative to glycine (GABA+ p-ending), and remaining 8 p-endings (50%, 8/16) exhibited immunoreactivity to both GABA and glycine. Bouton volume of the p-endings was not significantly different between the two groups. However, the p-endings differed from each other in relative content of GABA and glycine. These findings suggest that low-threshold mechanoreceptive information conveyed through vibrissa afferent at Vc is presynaptically modulated by GABA and/or glycine, and that degree of presynaptic modulation may differ among each vibrissa afferent terminal.

• Journal of Life Science
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• v.28 no.5
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• pp.597-604
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• 2018

Although the core mechanisms of Attention Deficit/Hyperactivity Disorder (ADHD) are unknown, several ADHD-associated proteins have been studied. G-protein - coupled receptor kinase interacting protein-1 (GIT1) is a multifunctional adapter protein that affects neuron growth and dendrite formation. GIT1-deficient mice have shown ADHD-like behavior and also recovered through amphetamine treatment. In this study, gliotransmitters were investigated in both intracellular and extracellular space from GIT1-deficient mice. To measure the amount of gliotransmitters, primary astrocyte cultures were taken from the cerebral and cerebellar cortices of wild (WT), hetero (HE), and knock-out (KO) mice. Major gliotransmitters were analyzed using high-performance liquid chromatography. It was observed that the amount of excitatory and inhibitory gliotransmitters were dependent on genotype and showed a change in excitation/inhibition ratios. Interestingly, the major excitatory gliotransmitter, glutamate, existed at the lowest level in WT mice, but the amount of inhibitory gliotransmitters, gamma-aminobutyric acid (GABA) and glycine, varied depending on brain region. Remarkably, an increased amount of GABA was measured at the intracellular cerebrum in WT mice compared with KO mice. It was presumed that KO mice would secrete more inhibitory gliotransmitters to compensate for GIT1 depletion or else acquire a defect to reuptake-secreted GABA. This may be a possible mechanism for ADHD pathology.