• The Korean Journal of Physiology and Pharmacology
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• 제10권6호
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• pp.303-307
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• 2006

The effects of ethanol on corticostriatal synaptic transmission were examined, using extracellular recording and analysis of population spike amplitudes in rat brain slices, to study how acute ethanol intoxication impairs striatal function. Ethanol caused a decrease in population spike amplitudes in a dose dependent manner ($50{\sim}200mM$). Pretreatment with picrotoxin, a ${\gamma}-amino$ butyric acid $(GABA)_{A}$ receptor antagonist, increased the population spikes but ethanol (100 mM) was still effective in decreasing the population spikes under this condition. In the presence of $_{(DL)}-2-amino-5-phosphonovaleric$ acid (APV), N-methyl-D-aspartate (NMDA) receptor antagonist, the inhibitory action of ethanol on population spikes was not shown. These results suggest that ethanol inhibits the glutamatergic corticostriatal synaptic transmission through blockade of NMDA receptors.

• The Korean Journal of Physiology and Pharmacology
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• 제25권1호
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• pp.79-85
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• 2021

α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors are differentially regulated in the nucleus accumbens (NAcc) of the brain after cocaine exposure. However, these results are supported only by biochemical and electrophysiological methods, but have not been validated with immunohistochemistry. To overcome the restriction of antigen loss on the postsynaptic target molecules that occurs during perfusion-fixation, we adopted an immersion-fixation method that enabled us to immunohistochemically quantify the expression levels of the AMPA receptor GluA1 subunit in the NAcc. Interestingly, compared to saline exposure, cocaine significantly increased the immunofluorescence intensity of GluA1 in two sub-regions, the core and the shell, of the NAcc on withdrawal day 21 following cocaine exposure, which led to locomotor sensitization. Increases in GluA1 intensity were observed in both the extra-post synaptic density (PSD) and PSD areas in the two sub-regions of the NAcc. These results clearly indicate that AMPA receptor plasticity, as exemplified by GluA1, in the NAcc can be visually detected by immunohistochemistry and confocal imaging. These results expand our understanding of the molecular changes occurring in neuronal synapses by adding a new form of analysis to conventional biochemical and electrophysiological methods.

• Animal Bioscience
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• 제35권8호
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• pp.1235-1249
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• 2022

Objective: The purpose of this study was to evaluate the protection of glutamate (GLU) against the impairment in intestinal barrier function induced by lipopolysaccharide (LPS) stress in weaned pigs. Methods: Twenty-four weaned pigs were divided into four treatments containing: i) non-challenged control, ii) LPS-challenged control, iii) LPS+1.0% GLU, and iv) LPS+2.0% GLU. On day 28, pigs were treated with LPS or saline. Blood samples were collected at 0, 2, and 4 h post-injection. After blood samples collection at 4 h, all pigs were slaughtered, and spleen, mesenteric lymph nodes, liver and intestinal samples were obtained. Results: Dietary GLU supplementation inhibited the LPS-induced oxidative stress in pigs, as demonstrated by reduced malondialdehyde level and increased glutathione level in jejunum. Diets supplemented with GLU enhanced villus height, villus height/crypt depth and claudin-1 expression, attenuated intestinal histology and ultrastructure impairment induced by LPS. Moreover, GLU supplementation reversed intestinal intraepithelial lymphocyte number decrease and mast cell number increase induced by LPS stress. GLU reduced serum cortisol concentration at 4 h after LPS stress and downregulated the mRNA expression of intestinal corticotropin-releasing factor signal (corticotrophin-releasing factor [CRF], CRF receptor 1 [CRFR1], glucocorticoid receptor, tryptase, nerve growth factor, tyrosine kinase receptor A), and prevented mast cell activation. GLU upregulated the mRNA expression of intestinal transforming growth factor β. Conclusion: These findings indicate that GLU attenuates LPS-induced intestinal mucosal barrier injury, which is associated with modulating CRF signaling pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제13권6호
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• pp.455-460
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• 2009

Glutamate-induced cobalt uptake reveals that non-NMDA glutamate receptors (GluRs) are present in rat taste bud cells. Previous studies involving glutamate induced cobalt staining suggest this uptake mainly occurs via kainate type GluRs. It is not known which of the 4 types of taste bud cells express subunits of kainate GluR. Circumvallate and foliate papillae of Sprague-Dawley rats (45~60 days old) were used to search for the mRNAs of subunits of non-NMDA GluRs using RT-PCR with specific primers for GluR1-7, KA1 and KA2. We also performed RT-PCR for GluR5, KA1, $PLC\beta2$, and NCAM/SNAP 25 in isolated single cells from taste buds. Taste epithelium, including circumvallate or foliate papilla, express mRNAs of GluR5 and KA1. However, non-taste tongue epithelium expresses no subunits of non-NMDA GluRs. Isolated single cell RT-PCR reveals that the mRNAs of GluR5 and KA1 are preferentially expressed in Type II and Type III cells over Type I cells.

• 대한불안의학회지
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• 제2권2호
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• pp.79-85
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• 2006

Anxiety and anxiety disorders are related to many neurotransmitters, such as norepinephrine, serotonine, dopamine, glutamate, and Gamma-aminobutyric acid (GABA). GABA, the main inhibitory neurotransmitter of the CNS, is known to counterbalance the action of the excitatory neurotransmitters and control anxiety. GABA acts on 3 GABA receptor subtypes, $GABA_A$, $GABA_B$, and $GABA_C$. $GABA_A$ and $GABA_c$ receptors are oligomeric transmembrane glycoproteins composed of 5 subunits that are arranged around a central chloride channel. $GABA_B$ receptor comprises two 7-transmembraneis-spanning proteins that are coupled to either calcium or potassium channel via G proteins. This article highlights neurobiological interactions between anxiety and GABA system.

• The Korean Journal of Physiology and Pharmacology
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• 제2권3호
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• pp.279-286
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• 1998

It has been well documented that transient forebrain global ischemia causes selective neuronal degeneration in hippocampal CA1 pyramidal neurons with a delay of a few days. The mechanism of this delayed hippocampal CA1 pyramidal neuronal death (DND) is still controversial. To delineate the mechanisms of the DND, the effects of treatment with MK-801, an NMDA receptor antagonist, kynurenic acid, a NMDA/non-NMDA receptor antagonist, and/or cycloheximide, a protein synthesis inhibitor, on the DND were investigated in male Wistar rats. To examine the participation of apoptotic neuronal death in the DND, TUNEL staining was performed in ischemic brain section. Global ischemia was induced by 4-vessel occlusion for 20 min. All animals in this study showed the DND 3 and 7 days after the ischemic insult. The DND that occured 3 days and 7 days after the ischemia were not affected by pretreatment with MK-801 (1 mg/kg), but markedly attenuated by the pretreatment with kynurenic acid (500 mg/kg). Treatment with cycloheximide (1 mg/kg) also markedly inhibited the DND. The magnitudes of attenuation by the two drugs were similar. The magnitude of attenuation by co-treatments with kynurenic acid and cycloheximide was not greater than that with any single treatment. TUNEL staining was negative in the sections obtained 1 or 2 days after the ischemic insults, but it was positive at hippocampal CA1 pyramidal cells in sections collected 3 days after the ischemia. These results suggested that the DND should be mediated by the activation of non-NMDA receptor, not by the activation of NMDA receptor and that the activation of AMPA receptor should induce the apoptotic process in the DND.

• 동의신경정신과학회지
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• 제24권3호
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• pp.281-292
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• 2013

Objectives : A growing body of evidence has suggested that the dysfunction of glutamatergic systems plays a pivotal role in major depressive disorder (MDD). This study was performed to investigate the antidepressant-like effects of the ethanolic extract of Gastrodia elata Bl (GE) in mouse models and to investigate the role of ${\alpha}$-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors in producing these antidepressant-like effects. Methods : The forced swim test (FST) and tail suspension test (TST) were used to investigate GE's behavioral effects in mice. Additional biochemical and behavioral experiments with NBQX, an AMPA receptor antagonist, were undertaken to determine whether the antidepressant-like properties of GE are involved in AMPA receptor throughput. Results : Oral administration of GE extract (1,600 mg/kg) 1h prior to testing significantly reduced the immobility times in the FST and TST. These antidepressant-like effects of GE extract were increased dose-dependently. Pre-treatment with NBQX significantly attenuated the reduction in immobility time induced by the GE extract in the FST and TST. Conclusions : The ethanolic extract of GE may exert antidepressant-like effects with involvement of AMPA receptor.

• The Korean Journal of Physiology and Pharmacology
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• 제4권5호
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• pp.347-353
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• 2000

It has been well documented that a massive release of not only glutamate but also other neurotransmitters may modulate the final responses of nerve cells to the ischemic neuronal injury. But there is no information regarding whether the release of monoamines is directly associated with synaptic vesicular proteins under ischemia. In the present study, it was investigated whether synapsin 1, syntaxin and SNAP-25 are involved in the release of 5-hydroxytryptamine $([^3H]5-HT)$ in glucose/oxygen deprived (GOD) rat hippocampal slices. And, the effect of NMDA receptor using DL-2-amino-5-phosphonovaleric acid (APV) on ischemia- induced release of 5-HT and the changes of the above proteins were also investigated. GOD for 20 minutes enhanced release of $[^3H]5-HT,$ which was in part blocked by the NMDA receptor antagonist, APV. The augmented expression of synapsin 1 during GOD for 20 minutes, which was also in part prevented by APV. In contrast, the expression of syntaxin and SNAP-25 were not altered during GOD. These results suggest that ischemic insult induces release of $[^3H]5-HT$ associated with synapsin 1, synaptic vesicular protein, via activation of NMDA receptor in part.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.46-53
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• 2017

알츠하이머병은 치매를 유발하는 가장 주된 원인 질환으로 환자들은 인지장애를 겪게 된다. 현재 치료약으로 사용되는 약으로는 acetylcholinesterase 저해재가 있지만 이 약들의 효과는 미비하다. 그래서 인지기능에 영향을 미친다고 알려진 신경전달물질인 GABA, Glutamate, acetylcholine의 수치를 조절 할 수 있는 $5-HT_6$ receptor antagonist가 현재 개발되고 있다. 현재 여러 antagonist들이 임상실험 되었고, 인지 능력향상에 효과를 보이고 있다. 그러나, $5-HT_6$ receptor의 구조가 밝혀지지 않아 아직 원자적 수준의 결합 분석이 이루어지지 않았으므로 이 부분에 대한 연구가 필요하다. 따라서 본 연구에서는 Homology modeling을 통해 receptor의 구조를 예측하고, 현재 임상실험 중인 antagonist들 중 7개를 docking을 통해 단백질과 리간드의 결합을 예측하였다. Edison에서 Galaxy TBM과 Galaxy Refine을 사용하여 Homology modeling 한 결과 GPCR의 전형적인 모델에 특징적으로 긴 cterminal을 가졌다는 것을 확인 할 수 있었다. 생성된 구조를 가지고 Edison의 Dock 프로그램으로 7개의 antagonist가 어떠한 결합을 하는지 분석하였다. 그 결과, binding pose에 공통적으로 Trp102, Asp106, Val107, Pro177, Phe188, Val189, Ala192, Phe284, Phe285, Asn288, Thr306, Tyr310이 관여하는 것을 docking을 통해 알 수 있었다. 특히, Phe285는 7개의 antagonist 중에 4개와의 interaction을 하고 있는 것을 관찰하였다. 이 연구를 통하여 $5-HT_6$에 효과적으로 결합하여 치료효과를 낼 수 있는 신약을 개발할 수 있다.

• Journal of Ginseng Research
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• 제24권4호
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• pp.196-201
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• 2000

흰쥐 소뇌로부터 과립신경세포를 배양하여 NaCN으로 유도되는 신경세포손상에 대한 ginsenosides의 보호효과를 검토하였다. NaCN(I~10 M)을 배양된 세포에 1시간 동안 처리하면 농도 의존적으로 신경세포사를 일으켰다. Ginsenosides(Rb$_1$, Rc, Re, Ri, Rg$_1$)(0.5, 5 $\mu\textrm{g}$/ml를 세포에 전처치하면 10 mM NaCN으로 유도되는 세포사가 현저히 감소되었다. Rb$_1$과 Rc(5$\mu\textrm{g}$/ml)는 5 mM NaCN에 의하여 배양액 중으로 유리되는 glutamate의 증가를 현저히 억제하였으며, 1 mM N3CN에 의하여 유발되는 세포내 $Ca^{2+}$농도의 증가를 억제하였다. NaCN으로 유발되는 세포독성은 또한 MK-801, verapamil, NAME에 의하여도 억제되었다. 따라서, NaCN으로 유도되는 신경세포사는 glutamate release를 통한 NMDA수용체의 활성화와 그에 따른 $Ca^{2+}$의 세포내유입에 의한 것임을 알수 있고, ginsenosides, 특히 Rb$_1$과 Rc는 $Ca^{2+}$의 유입을 억제하므로서 NaCN에 의한 신경세포사를 억제하는 것으로 생각된다.