• Food Science and Industry
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• v.50 no.3
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• pp.93-104
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• 2017

monosodium L-glutamate (MSG), composed of 88% L-glutamic acid (GLU) and 12% Na, is considered as Generally Recognized as Safe. GLU is accounting for 15% of the total amino acid content in our body. Daily GLU intake is large 3.5-10.6 g from food and 1.3 g from food additive. The daily formed GLU in the body, via degradation of the total protein, is 48-50 g (70 kg of male) and the maintained GLU in the body is total bound GLU (1.4-2.0 kg) and free GLU (10 g). About 88% GLU are consumed at digestive tract, and only 12% GLU enter the blood stream. GLU is generally known to precursors of N-acetyl glutamate and glutamine, substrates for protein synthesis, a neurotransmitter (GABA), and the active site of the enzyme. In addition to protein synthesis, GLU has these key functions within the body, thus this amino acid is critical for healthy body maintenance and function.

• Archives of Pharmacal Research
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• v.23 no.5
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• pp.488-494
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• 2000

Cerebellar granule and glial cells prepared from 7 day-old rat pups were used to investigate the effects of sub-acute nicotine exposure on the glutamatergic nervous system. These cells were exposed to nicotine in various concentrations for 2 to 10 days in situ. Nicotine-exposure did not result in any changes in cerebellar granule and glial cell viability at concentrations of up to 500 $\mu\textrm{M}$. In cerebellar granule cells, the basal extracellular levels of glutamate, aspartate and glycine were enhanced in the nicotine-exposed granule cells. In addition, the responses of N-methyl-D-aspartate (NMDA)-induced glutamate release were enhanced at low NMDA concentrations in the nicotine-exposed granule cells. However, this decreased at higher NMDA concentrations. The glutaminase activity was increased after nicotine exposure. In cerebellar glial cells, glutamate uptake in the nicotine-exposed glial cells were either increased at low nicotine exposure levels or decreased at higher levels. The inhibition of glutamate uptake by L-trans-pyrollidine-2,4-dicarboxylic acid (PDC) was lower in glial cells exposed to 50 $\mu\textrm{M}$ nicotine. Glutamine synthetase activity was lower in glial cells exposed to 100 or 500 $\mu\textrm{M}$ of nicotine. These results indicate that the properties of cerebellar granule and glial cells may alter after subacute nicotine exposure. Furthermore, they suggest that nicotine exposure during development may modulate glutamatergic nervous activity.

• International Journal of Oral Biology
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• v.49 no.1
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• pp.10-17
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• 2024

Glutamate-mediated oxidative stress causes neuronal cell death by increasing intracellular Ca²⁺ uptake, reactive oxidative species (ROS) generation, mitogen-activated protein kinase (MAPK) activation, and translocation of apoptosis-inducing factor (AIF) to the nucleus. In the current study, we demonstrated that corydaline exerts potent neuroprotective effects against glutamate-induced neurotoxicity. Treatment with 5 mmol/L glutamate increased cellular Ca²⁺ influx, ROS generation, MAPK activation, and AIF translocation. In contrast, corydaline treatment decreased cellular Ca²⁺ influx and ROS generation. Western blot analysis revealed that glutamate-mediated MAPK activation was attenuated by corydaline treatment. We further demonstrated that corydaline treatment inhibited the glutamate-mediated translocation of AIF to the nucleus. We propose that corydaline is a promising lead structure for the development of safe and effective neuroprotectants.

• The Korean Journal of Pain
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• v.19 no.1
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• pp.33-44
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• 2006

Background: Peripheral nerve injury leads to neuropathic pain, including mechanical hyperalgesia (MH). Nerve discharges produced by an injury to the primary afferents cause the release of glutamate from both central and peripheral terminals. While the role of centrally released glutamate in MH has been well studied, relatively little is known about its peripheral role. This study was carried out to determine if the peripherally conducting nerve impulses and peripheral glutamate receptors contribute to the generation of neuropathic pain. Methods: Rats that had previously received a left L5 dorsal rhizotomy were subjected to a spinal nerve lesion (SNL) or brief electrical stimulation (ES, 4 Hz pulses for 5 min) of the left L5 spinal nerve. The paw withdrawal threshold (PWT) to von Frey filaments was measured. The effects of an intraplantar (i.pl.) injection of a glutamate receptor (GluR) antagonist or agonist on the changes in the SNL- or ES-produced PWT was investigated. Results: SNL produced MH, as evidenced by decrease in the PWT, which lasted for more than 42 days. ES also produced MH lasting for 7 days. MK-801 (NMDAR antagonist), DL-AP3 (group-I mGluR antagonist), and APDC (group-II mGluR agonist) delayed the onset of MH when an i.pl. injection was given before SNL. The same application blocked the onset of ES-induced MH. NBQX (AMPA receptor antagonist) had no effect on either the SNL- or ES-induced onset of MH. When drugs were given after SNL or ES, MK-801 reversed the MH, whereas NBQX, DL-AP3, and APDC had no effect. Conclusions: Peripherally conducting impulses play an important role in the generation of neuropathic pain, which is mediated by the peripheral glutamate receptors.

• Animal cells and systems
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• v.2 no.1
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• pp.139-144
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• 1998

I examined the projection of glutamatergic neurons in the lateral reticular nucleus into ansiform (crus l and ll) and paramedian lobules in the rat cerebellum using immunocytochemical methods with antiserum against glutamate combined with WGA-HRP histochemistry. The projections of glutamatergic neurons from the lateral reticular nucleus to crus l were most extensive in number among the three injection cases and the majority of projections originated at the dorsal to dorsomedial region of the ipsilateral magnocellular nucleus. Glutamate-immunoreactive cells projecting to crus ll were less extensive in number than those projecting to crus l and were mainly localized at the dorsomedial portion of the ipsilateral magnocellular nucleus. Double-labelled neurons projecting to crus l or crux ll were also located at ipsilateral subtrigeminal as well as contralateral magnocellular nuclei. Glutamatergic neurons projecting to paramedian lobules were moderate in number and mainly located at the dorsal area of the ipsilateral magnocellular nucleus. A few double-labelled cells were also found at ipsilateral subtrigeminal or contralateral magnocellular nuclei. The present study suggests that glutamate-immunoreactive neurons at the dorsal to dorsomedial magnocellular division of the lateral reticular nucleus may participate in the excitatory control of target neuronal activities at ipsilateral, posterior hemispheric lobules of the rat cerebellum.

• YAKHAK HOEJI
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• v.36 no.1
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• pp.73-79
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• 1992

To achieve better understanding of the effects of monosodium-L-glutamate(MSG) against $CCl_4$ fatty liver in Wister male rats, 5% MSG solution was given as drinking water and $CCl_4$ 0.1 ml/kg was injected subcutaneously twice a week for four weeks. It was showed that increased hepatic phospholipid and hepatic triacylglycerol levels by $CCl_4$ challenge were significantly decreased by additionnal MSG, respectively. However, MSG had no apparent effect on the elevated hepatic cholesterol level in the presence of $CCl_4$. Histologically, additional MSG markedly inhibited fatty degeneration, spotty necrosis, inflammation and periportal vascular proliferation manifested by $CCl_4$. respectively. These results indicated that effects of MSG against $CCl_4$ induced-fatty liver appeared to be involved with partial restoration of altered hepatic lipid composition.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.4
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• pp.308-313
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• 2016

This study aimed to analyze the use of monosodium L-glutamate (MSG) and disodium 5'-ribonucleotide in processed foods manufactured in Korea. Information about MSG and disodium 5'-ribonucleotide was collected from the ingredients claimed on the food packaging. A total of 412 food items were investigated, and 76 items were found to use MSG, disodium 5'-r ibonucleotide, and/or disodium 5'-inosinate. MSG was the most frequently found in 45 items (10.9%), followed by disodium 5'-ribonucleotide in 27 items (6.6%) and disodium 5'-inosinate in three items (0.7%). Of 29 food categories classified by the Korea Food Code, MSG was used most frequently in others, meat products, seasoned food, fish products, and noodles. In comparison, disodium 5'-ribonucleotide was mostly used in noodles. These results indicate that MSG and disodium 5'-ribonucleotide have been used in various Korean processed foods as a flavor enhancers with an umami taste that intensifies the flavor of food.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.6
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• pp.353-361
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• 2011

In this study, cyanidin-3-glucoside (C3G) fraction extracted from the mulberry fruit (Morus alba L.) was investigated for its neuroprotective effects against oxygen-glucose deprivation (OGD) and glutamate-induced cell death in rat primary cortical neurons. Cell membrane damage and mitochondrial function were assessed by LDH release and MTT reduction assays, respectively. A time-course study of OGD-induced cell death of primary cortical neurons at 7 days in vitro (DIV) indicated that neuronal death was OGD duration-dependent. It was also demonstrated that OGD for 3.5 h resulted in approximately 50% cell death, as determined by the LDH release assay. Treatments with mulberry C3G fraction prevented membrane damage and preserved the mitochondrial function of the primary cortical neurons exposed to OGD for 3.5 h in a concentration-dependent manner. Glutamate-induced cell death was more pronounced in DIV-9 and DIV-11 cells than that in DIV-7 neurons, and an application of $50{\mu}M$ glutamate was shown to induce approximately 40% cell death in DIV-9 neurons. Interestingly, treatment with mulberry C3G fraction did not provide a protective effect against glutamate-induced cell death in primary cortical neurons. On the other hand, treatment with mulberry C3G fraction maintained the mitochondrial membrane potential (MMP) in primary cortical neurons exposed to OGD as assessed by the intensity of rhodamine-123 fluorescence. These results therefore suggest that the neuroprotective effects of mulberry C3G fraction are mediated by the maintenance of the MMP and mitochondrial function but not by attenuating glutamate-induced excitotoxicity in rat primary cortical neurons.

• Food Science and Biotechnology
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• v.14 no.5
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• pp.704-708
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• 2005

Poly-y-glutamate (${\gamma}$-PGA) has great potential as a biodegradable polymer in a broad range of industrial fields such as food, cosmetics, medicine and water treatment. In order to isolate ${\gamma}$-PGA producers that are suitable for specific industrial applications, 653 Bacillus-like strains were isolated from 439 varieties of three Korean fermented foods, Cheongkukjang, Doenjang, and Kochujang, which were collected from different regions across Korea. A very high level of ${\gamma}$-PGA production was demonstrated in 4.7%, 1.8%, and 3.0% of the Bacillus-like strains isolated from Cheongkukjang, Doenjang, and Kochujang samples, respectively, which produced a viscous substance to such extent that it overflowed to the lid of the plate on the glutamate-dependent ${\gamma}$-PGA production plates. On glutamate-independent ${\gamma}$-PGA production plates, 5.1%, 5.9%, and 6.1% of Bacillus-like strains isolated from Cheongkukjang, Doenjang, and Kochujang samples, respectively, showed high production. The maximum ${\gamma}$-PGA production yields were 32.5 g/L and 5 g/L, depending on the purification methods in the glutamate-dependent media, with the higher yield resulting from a simple precipitation of ${\gamma}$-PGA by either methanol or ethanol and dialysis. The viscous substance produced by each strain showed different morphological characteristics, suggesting that isolated ${\gamma}$-PGA producers could produce various types of ${\gamma}$-PGA.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.205-207
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• 2002

Experiments were carried out to the effect of various amino acids on the production of tetraacetylphytosphingosine (TAPS). Among various amino acids were tested, cysteine decreased the production of TAPS at 7 days of flask culture. Especially, Serine is precursor of TAPS but didn't affect the production of TAPS. Glycine and glutamate increased the production of TAPS. Especially, glutamate increased 20% of cell mass and 37% of TAPS production.