• The Journal of Korean Medicine
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• v.22 no.4
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• pp.45-57
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• 2001

Objectives : The water extract of Gwibitang (GBT) has been traditionally used for treatment of psychologic disease and brain damage in Oriental Medicine, This study was designed to investigate the effect of GBT on the glutamate-induced toxicity of rat C6 glial cells. Methods : The cultured cells were pretreated with GBT and exposed to glutamate, The cell damage was assessed by using MTT assay and Hoechst, IC-l staining, Results : GBT had protective effects in glutamate-induced cytotoxicity, which was revealed as apoptosis characterized by chromatic condensation and the loss of mitochondrial membrane potential in C6 glial cells. However, GBT and glutamate had no effect in the activation of caspase family cysteine proteases including caspase-3, -8 and -9 proteasesin C6 glial ce]]s, GBT significantly recovered the depletion of GSH and inhibited the generation of $H_2O_2$ by glutamate in C6 glial cells. In addition, both GBT and antioxidants such as GSH and NAC protected the glutamate-induced cytotoxicity in C6 glial cells, indicating that GBT possibly has antioxidative effect. Moreover, GBT also inhibited the glutamate-induced degradation of $IkB{\alpha}$ in C6 glial cells, This result suggest that GBT has some inhibitory effects on the transcriptional activation of $NF-_{k}B$. Conclusions : GBT has protective effects in glutamate-induced cytotoxicity via an antioxidative mechanism.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.4
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• pp.475-482
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• 2012

This study was designed to elucidate the mechanism of the cytoprotective effect of the Palmul-tang (PMT) on glutamate induced cytotoxicity in rat C6 glial cells. We determined the increase of cell viability by PMT on glutamate-induced death of C6 glial cell. On some experiments, glutamate induced cell death to be an apoptotic phenomena characterized by G1 arrest in cell cycle, chromatin condensation, DNA fragmentation in C6 glial cells. However, pre-treatment of PMT inhibited characteristic apoptotic phenomena. One of the main mediator of glutamate-induced cytotoxicity was known to generation of reactive oxigen species. In this study, PMT attenuated generation of reactive oxigen species by glutamate through down-regulation of NOX1 expression in C6 glial cells. Furthermore, PMT regulated Bcl2 families and caspase proteins, which contribute the cell survival or death. This study suggests that PMT may be candidate for both of therapeutic and protective prescription.

• The Journal of Korean Medicine
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• v.25 no.2
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• pp.184-193
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• 2004

Objectives: This study was designed to investigate effects of Gwibitang on the glutamate-induced toxicity of primary rat neonatal astrocytes. Methods and Results: Gwibitang significantly recovered the glutamate-induced apoptosis and inhibited the generation of $H_2O_2$ in astrocytes. In addition, both Gwibitang and antioxidants such as GSH reduced the glutamate-induced cytotoxicity in astrocytes, indicating that Gwibitang possibly had an antioxidative effect. Moreover, Gwibitang also inhibited the glutamate-induced degradation of Bcl-2 protein and poly(ADP)-ribose polymerase (PARP) in astrocytes. Conclusions: We suggest that Gwibitang has protective effects on glutamate-induced cytotoxicity via an antioxidative mechanism.

• Toxicological Research
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• v.18 no.4
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• pp.355-362
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• 2002

Pathophysiological elevation of intracellular calcium concentration ($[Ca^{2+}]_1$) in the neuron has been considered as an important responsible factor in the neuronal cell damages. However the mechanism of increase of $[Ca^{2+}]_1$ and the relationship between $[Ca^{2+}]_1$ level and cytotocixity have not been fully demonstrated. In the present study, real-time alteration of $[Ca^{2+}]_1$and cellular response (cell damages) in the pheochromocytoma cells (PC12) stimulated by glutamate were investigated. Glutamate dose dependently decreased cell viability determined propidium iodide fluorescence method and morphology change. Conversely related with cell damages, glutamate dose dependently increased the level of［Ca$^{2+}$］$_{i}$ . To investigate the mechanism of glutamate-induced increase of $[Ca^{2+}]_1$,$[Ca^{2+}]_1$, was first measured in the cell cultured in calcium free media and in the presence of dantrolene, an inhibitor of calcium release from ryanodine receptor located in endoplasmic reticulum (ER). Similar to the increase$[Ca^{2+}]_1$ in the calcium-containing media, glutamate dose dependently increased $[Ca^{2+}]_1$ in the cell cultured in free calcium media. However pretreatment (2 hr) with 20~50 $\mu\textrm{M}$ dantrolene substantial lowered glutamate-induced increase of $[Ca^{2+}]_1$, suggesting that release of calcium from ER may be major sourse of increase of $[Ca^{2+}]_1$ in PC12 cells. Dantrolene-induced inhibition of $[Ca^{2+}]_1$ resulted in recovery of cytotoxicity by glutamate. Relevance of N-methy-D-aspartate (NMDA) receptor, a type of glutamte receptor on glutamate-induced incense of $[Ca^{2+}]_1$,$[Ca^{2+}]_1$ was also determined in the cells pretreated (2 hr) with NMDA receptor antagonist MK-80l. Glutamate-induced increase of $[Ca^{2+}]_1$ was reduced by MK-801 dose dependently. Furthermore, glutamate-induced cytotoxicity was also prevented by MK-80l. These results demonstrate that glutamte increase $[Ca^{2+}]_1$ dose dependently and thereby cause cytotoxicity. The increase of $[Ca^{2+}]_1$ may release from ER, especially through ryanodine receptor and/or through NMDA receptor Alteration of calcium homeostasis through disturbance of ER system and/or calcium influx through NMDA receptor could contribute glutamate-induced cell damages.s.

• Korean Journal of Acupuncture
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• v.38 no.1
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• pp.32-42
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• 2021

Objectives : In this study, we investigated the neuroprotective effects of ethanol extract of Lonicera japonica flower buds (EELJ) on glutamate-induced neurotoxicity in mouse hippocampus-derived neuronal HT22 cells. Methods : After analyzing the cytoprotective effect of EELJ on glutamate in HT22 cells, the inhibitory effect of apoptosis was studied using flow cytometry. In order to analyze the antioxidant efficacy of EELJ, the levels of reactive oxygen species (ROS) and glutathione (GSH) were investigated, and the effects on the activities of superoxide dismutase (SOD) and catalase (CAT) were also analyzed. Furthermore, the effect of EELJ on the expression of apoptosis regulators such as Bax and Bcl-2 in glutamate-treated HT22 cells was investigated. Results : According the current results, pretreatment with EELJ significantly reduced glutamate-induced loss of cell viability and release of lactate dehydrogenase. EELJ also markedly attenuated glutamate-induced generation of intracellular ROS, which was associated with increased levels of GSH, and activity of SOD and CAT in glutamate-stimulated HT22 cells. In addition, EELJ was strikingly inhibited glutamate-induced apoptosis in HT22 cells. Furthermore, the expression of pro-apoptotic Bax was increased and the expression of anti-apoptotic Bcl-2 was decreased in glutamate-treated HT22 cells, while in the presence of EELJ, their expressions were maintained at the control levels. Conclusions : These findings indicate that EELJ protects glutamate-induced cytotoxicity in HT22 hippocampal neurons through antioxidant activity. Therefore, although identification of biologically active substances of EELJ and re-evaluation through animal experiments is necessary, this natural substance is a promising candidate for further research in preventing and treating oxidative stress-mediated neurodegenerative diseases.

• Journal of Life Science
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• v.19 no.7
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• pp.963-967
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• 2009

This study evaluated the neuroprotective effect of extracts from the root bark of Morus alba (MA) against glutamate-induced cytotoxicity in neuronal cells. Glutamate-induced cytotoxicity was shown by MTT reduction assay. The neuroprotective effects of methanol, ethanol, and acetone extracts from MA against glutamate-induced cytotoxicity were measured. Among the three extracts, the methanolic extracts showed the highest protective effect, as determined by the results of an morphological assay, a lactate dehydrogenase release assay. Furthermore, the methanol extracts were fractionated sequentially with hexane, diethyl ether, ethyl acetate, and water layer according to degree of polarity. The hexane fractions exhibited a neuroprotective effect against glutamate-stressed N18-RE-105 cells. Therefore, these results suggest that extracts of MA could be a new potential candidate as a protective substance against glutamate-induced cytotoxicity.

• Biomolecules & Therapeutics
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• v.20 no.3
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• pp.306-312
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• 2012

Resveratrol (trans-3,5,4'-trihydroxystilbene) has received considerable attention recently for the potential neuroprotective effects in neurodegenerative disorders where heme oxygenase-1 (HO-1) and sirtuin 1 (SIRT1) represent promising therapeutic targets. Resveratrol has been known to increase HO-1 expression and SIRT1 activity. In this study, the effects of resveratrol and trans-3,5,4'-trimethoxystilbene (TMS), a resveratrol derivative, on cytotoxicity caused by glutamate-induced oxidative stress, HO-1 expression, and SIRT1 activation have been investigated by using murine hippocampal HT22 cells, which have been widely used as an in vitro model for investigating glutamate-induced neurotoxicity. Resveratrol protected HT22 neuronal cells from glutamate-induced cytotoxicity and increased HO-1 expression as well as SIRT1 activity in a concentration-dependent manner. Cytoprotection afforded by resveratrol was partially reversed by the specific inhibition of HO-1 expression by HO-1 small interfering RNA and the nonspecific blockage of HO-1 activity by tin protoporphyrin IX, but not by SIRT1 inhibitors. Surprisingly, TMS, a resveratrol derivative with methoxyl groups in lieu of the hydroxyl groups, and trans-stilbene, a non-hydroxylated analog, failed to protect HT22 cells from glutamate-induced cytotoxicity and to increase HO-1 expression and SIRT1 activity. Taken together, our findings suggest that the cytoprotective effect of resveratrol was at least in part associated with HO-1 expression but not with SIRT1 activation and, importantly, that the presence of hydroxyl groups on the benzene rings of resveratrol appears to be necessary for cytoprotection against glutamate-induced oxidative stress, HO-1 expression, and SIRT1 activation in HT22 neuronal cells.

• Natural Product Sciences
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• v.15 no.3
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• pp.162-166
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• 2009

Oxczaasssaidative stress plays an important role in neuronal cell death, which is associated with neurodegenerative conditions such as Alzheimer's and Parkinson's disease. This study evaluated the neuroprotective effect of Euryale ferox (EF) extracts against glutamate-induced cytotoxicity in hybridoma N18-RE-105 cells. Specifically, neuroprotective effects of methanol and ethanol extracts were evaluated by the MTT reduction assay. The ethanol extracts of EF displayed dose dependent protection against neuronal cell death induced by 20 mM of glutamate. Furthermore, the ethanol extracts of EF was sequentially fractionated with hexane, diethyl ether, ethyl acetate, and water layer according to degree of polarity. The hexane fractions exhibited neuroprotective effect against glutamate-stressed N18-RE-105 cells. Overall, results suggest that EF extracts can potentially be used as chemotherapeutic agents against neuronal diseases.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.79-83
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• 2008

The present study describes glutamate which is known as excitatory neurotransmitter is related with oxidative damages and the Viola mandshurica extracts. Showed protective effects against glutamate-induced cytotoxicity. The protective effect of antioxidant on the glutamate treated N18-RE-I05 cells was determined by a MTT reduction assay. The neuroprotective effect of methanol, ethanol, and acetone extracts from V. mandshurica against glutamate-induced cytotoxicity was assessed by the results of an MTT reduction assay. Among the three extracts, the acetone extract showed the highest protective effect by the results of an lactate dehydrogenase release assay. Therefore, these results suggest that V. mandshurica extracts could be a new potential candidate against glutamate-induced oxidative stress.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.479-483
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• 2005

Antioxidative and protective effects of Ulmus davidiana var. japonica against oxidative damages induced by glutamate in PC 12 cells were investigated. Inhibitory activity against $FeSO_{4}-H_{2}O_{2}$-induced oxidative stress and DPPH radical-scavenging activity were detected in ethyl acetate and butanol fractions of ethanol extracts from stems and roots. Ethyl acetate and butanol fractions of ethanol extracts from roots significantly inhibited glutamate-induced cytotoxicity and reactive oxygen species in PC 12 cells. These results demonstrate ethyl acetate and butanol fractions of ethanol extracts of U. davidiana var. japonica have potent protective effect against glutamate-induced oxidative stress.