• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2007년도 제48회 학술심포지움 및 추계국제학술대회
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• pp.24.2-24.2
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• 2007

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• The Korean Journal of Physiology and Pharmacology
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• 제12권2호
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• pp.43-49
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• 2008

Flavonoids have been shown to affect calcium signaling in neurons. However, there are no reports on the effect of apigenin on glutamate-induced calcium signaling in neurons. We investigated whether apigenin affects glutamate-induced increase of free intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) in cultured rat hippocampal neurons, using fura-2-based digital calcium imaging and microfluorimetry. The hippocampal neurons were used between 10 and 13 days in culture from embryonic day 18 rats. Pretreatment of the cells with apigenin ($1{\mu}M$ to $100{\mu}M$) for 5 min inhibited glutamate ($100{\mu}M$, 1 min) induced $[Ca^{2+}]_i$ increase, concentration-dependently. Pretreatment with apigenin ($30{\mu}M$) for 5 min significantly decreased the $[Ca^{2+}]_i$ responses induced by two ionotropic glutamate receptor agonists, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA, $10{\mu}M$, 1 min) and N-methyl-D-aspartate (NMDA, $100{\mu}M$, 1 min), and significantly inhibited the AMPA-induced peak currents. Treatment with apigenin also significantly inhibited the $[Ca^{2+}]_i$ response induced by 50 mM KCl solution, decreased the $[Ca^{2+}]_i$ responses induced by the metabotropic glutamate receptor agonist, (S)-3,5-dihydroxy-phenylglycine (DHPG, 100 $[Ca^{2+}]_i$, 90 s), and inhibited the caffeine (10 mM, 2 min)-induced $[Ca^{2+}]_i$ responses. Furthermore, treatment with apigenin ($30{\mu}M$) significantly inhibited the amplitude and frequency of 0.1 mM $[Mg^{2+}]_o$-induced $[Ca^{2+}]_i$ spikes. These data together suggest that apigenin inhibits glutamate-induced calcium signaling in cultured rat hippocampal neurons.

• Asian-Australasian Journal of Animal Sciences
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• 제30권8호
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• pp.1081-1085
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• 2017

Objective: Previously, we reported quantitative trait loci (QTLs) affecting backfat thickness (BFT) traits on pig chromosome 5 (SW1482-SW963) in an F2 intercross population between Landrace and Korean native pigs. The aim of this study was to evaluate glutamate receptor-interacting protein 1 (GRIP1) as a positional candidate gene underlying the QTL affecting BFT traits. Methods: Genotype and phenotype analyses were performed using the 1,105 $F_2$ progeny. A mixed-effect linear model was used to access association between these single nucleotide polymorphism (SNP) markers and the BFT traits in the $F_2$ intercross population. Results: Highly significant associations of two informative SNPs (c.2442 T>C, c.3316 C>G [R1106G]) in GRIP1 with BFT traits were detected. In addition, the two SNPs were used to construct haplotypes that were also highly associated with the BFT traits. Conclusion: The SNPs and haplotypes of the GRIP1 gene determined in this study can contribute to understand the genetic structure of BFT traits in pigs.

• Biomolecules & Therapeutics
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• 제30권3호
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• pp.232-237
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• 2022

Autism spectrum disorder (ASD) having core characteristics of social interaction problems and repetitive behaviors and interests affects individuals at varying degrees and comorbidities, making it difficult to determine the precise etiology underlying the symptoms. Given its heterogeneity, ASD is difficult to treat and the development of therapeutics is slow due to the scarcity of animal models that are easy to produce and screen with. Based on the theory of excitation/inhibition imbalance in the brain with ASD which involves glutamatergic and/or GABAergic neurotransmission, a pharmacologic agent to modulate these receptors might be a good starting point for modeling. N-methyl-D-aspartic acid (NMDA) is an amino acid derivative acting as a specific agonist at the NMDA receptor and therefore imitates the action of the neurotransmitter glutamate on that receptor. In contrast to glutamate, NMDA selectively binds to and regulates the NMDA receptor, but not other glutamate receptors such as AMPA and kainite receptors. Given this role, we aimed to determine whether NMDA administration could result in autistic-like behavior in adolescent mice. Both male and female mice were treated with saline or NMDA (50 and 75 mg/kg) and were tested on various behavior experiments. Interestingly, acute NMDA-treated mice showed social deficits and repetitive behavior similar to ASD phenotypes. These results support the excitation/inhibition imbalance theory of ASD and that NMDA injection can be used as a pharmacologic model of ASD-like behaviors.

• Biomolecules & Therapeutics
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• 제30권4호
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• pp.320-327
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• 2022

Neurodevelopmental disorders are complex conditions that pose difficulty in the modulation of proper motor, sensory and cognitive function due to dysregulated neuronal development. Previous studies have reported that an imbalance in the excitation/inhibition (E/I) in the brain regulated by glutamatergic and/or GABAergic neurotransmission can cause neurodevelopmental and neuropsychiatric behavioral deficits such as autism spectrum disorder (ASD). NMDA acts as an agonist at the NMDA receptor and imitates the action of the glutamate on that receptor. NMDA however, unlike glutamate, only binds to and regulates the NMDA receptor subtypes and not the other glutamate receptors. This study seeks to determine whether NMDA administration in mice i.e., over-activation of the NMDA system would result in long-lasting behavioral deficits in the adolescent mice. Both gender mice were treated with NMDA or saline at early postnatal developmental period with significant synaptogenesis and synaptic maturation. On postnatal day 28, various behavioral experiments were conducted to assess and identify behavioral characteristics. NMDA-treated mice show social deficits, and repetitive behavior in both gender mice at adolescent periods. However, only the male mice but not female mice showed increased locomotor activity. This study implies that neonatal exposure to NMDA may illicit behavioral features similar to ASD. This study also confirms the validity of the E/I imbalance theory of ASD and that NMDA injection can be used as a pharmacologic model for ASD. Future studies may explore the mechanism behind the gender difference in locomotor activity as well as the human relevance and therapeutic significance of the present findings.

• The Korean Journal of Pain
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• 제14권1호
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• pp.1-6
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• 2001

Background: Subcutaneous injection of 5% formalin into the hind paw of the rat produces a biphasic nociceptive response. The second phase depends on changes in the dorsal horn cell function that occur shortly after an initial C-fiber discharge, spinal sensitization, or windup phenomenon. This study was performed to investigate the role of glutamate during spinal sensitization. Methods: Sprague-Dawley rats weighing 200 to 250 g were used for this study. Under light anesthesia (0.5% isoflurane) the rats were segregated in a specially designed cage and $50{\mu}l$ 0.5% formalin was injected subcutaneously in the foot dorsum of right hindlimb. Forty minutes after the formalin injection, the rat was quickly decapitated and spinal cord was removed. The spinal segments at the level of L3 (largest area) was collected and stored in a deep freezer ($-70^{\circ}C$). The mRNA gene expression of N-methyl-D-aspartate receptor (NMDAR) and the metabotropic glutamate receptor subtype 5 (mGluR5) were determined by the polymerase chain reaction. Results: The number of flinches was $19.8{\pm}2.3/min$. at one minute after formalin injection and decreased to zero after then. The second peak appeared at 35 and 40 minutes after formalin injection. The values were $17.8{\pm}2.2$ and $17.2{\pm}3.0/min$. The mRNA gene expressions of NMDAR and mGluR5 were increased by $459.0{\pm}46.8%$ (P < 0.01) and $111.1{\pm}4.8%$ (P > 0.05) respectively at 40 minutes after formalin injection. The increased rate of NMDAR was significantly higher than that of mGluR5 (P < 0.01). Conclusions: From these results it suggested that NMDAR partly contributed to the mechanism of central sensitization after the formalin test but mGluR5 did not.

• The Korean Journal of Physiology and Pharmacology
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• 제6권3호
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• pp.149-154
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• 2002

The blood pressure (BP) is regulated by the nervous system and humoral factors, such as renin- angiotensin system, vasopressin and others. In the present study, we examined the central effects of glutamate and GABA on the cardiovascular regulation by injection of these substances into the lateral ventricle and also investigated the relationship between these central effects and the action of angiotensin II (Ang). Male Sprague Dawley rats, $350{\sim}400$ g, were anesthetized with urethane and instrumented with an arterial catheter for direct measurement of BP and heart rate (HR), and an guide cannula in the lateral ventricle for drug injection. A glass microelectode was inserted into the rostral ventrolateral medulla (RVLM) for recording single unit spikes. Barosensitive neurons were identified by changes of single unit spikes in RVLM following intravenous injection of nitroprusside and phenylephrine. The effects of GABA and glutamate injected into the lateral ventricle were studied in single neuronal activity of the RVLM in addition to changes in BP and heart rate, and compared the results before and after treatment with intravenous losartan, nonpeptide Ang II-type 1 receptor antagonist (1 mg/100 g BW). Intracerebroventricular administration of GABA decreased systolic blood pressure (SBP) and HR, but increased the firing rates in the RVLM. However, intracerebroventricular glutamate injection produced effects opposite to GABA. After pretreatment of intravenous losartan, the central effects of GABA on BP and firing rate in the RVLM were significantly attenuated and that of glutamate showed a tendency of attenuation. These results suggested that central GABA and glutamate regulated BP and firing rates in RVLM were inversely related to BP change. The central effects of GABA or glutamate on the autonomic nervous function were modulated by humoral factor, Ang II, by maintaining BP.

• The Korean Journal of Pain
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• 제19권1호
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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.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2005년도 제45회 학술심포지움 및 추계학술대회
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• pp.129-129
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• 2005

• Journal of Korean Neurosurgical Society
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• 제29권8호
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• pp.1008-1018
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• 2000

Objective : Glutamate induced excitotoxicity is one of the leading causes of cell death under pathologic condition. However, there is controversy whether excitotoxicity may also participate in the neuronal death under low intensity insult such as simple hypoxia or hypoglycemia. To investigate the role of NMDA receptor in low intensity insult, we chose anoxia as the method of injury and used organotypically cultured hippocampal slice as the material of experiment. Materials & Methods : The hippocampal slices cultured for 2-3 weeks were exposed to 60 minutes of complete oxygen deprivation(anoxia). Neuronal death was assessed with Sytox stain. Corrected optical density of fluorescence in gray scale, used as cellular death indicator, was obtained from pictures taken at 24 and 48 hours following the insult. The well-known in vivo phenomenon of regional difference in susceptibility of hippocampal sub-fields to ischemic insult was reproduced in HOSC(hippocampal organotypic slice culture) by complete oxygen deprivation injury. Results : $CA_1$ was the most vulnerable to complete oxygen deprivation in hippocampus while $CA_3$ was resistant. Oxygen deprivation for 10 and 20 minutes with glucose(6.5g/l) present was insufficient to induce neuronal death in the cultured hippocampal slice. However, after 30 minutes exposure under anoxic condition, neuronal death was able to be detected in the center of $CA_1$ area. The intensity and area of fluorescence indicating cell death correlated with the duration of oxygen deprivation. NMDA receptor and non-NMDA receptor blocking with MK-801(30 & $60{\mu}M$) and CNQX($100{\mu}M$) did not provide cellular protection to HOSC against damage induced by oxygen deprivation, but increased intracellular calcium buffering capacity with BAPTA-AM($10{\mu}M$) was effective in preventing neuronal death (p=0.01, Student's t-test). Cycloheximide($1{\mu}g/ml$, $10{\mu}g/ml$) provided no protection to HOSC against insult of complete oxygen deprivation for 60 minutes and combined therapy of MK-801(30 & $60{\mu}M$) and cycloheximide(1 & $10{\mu}g/ml$) was also ineffective in preventing neuronal death. Conclusion : The results of this study show that the another mechanism not associated with glutamate receptor(NMDA & non NMDA) may play major role in cell death mechanisms induced by complete oxygen deprivation and increased intracellular calcium during anoxia may participate in the neuronal death mechanism of oxygen deprivation. Further investigation of the calcium entry channel activated during oxygen deprivation is necessary to understand the neuronal death of anoxia.