• Neonatal Medicine
• /
• 제18권1호
• /
• pp.59-69
• /
• 2011

목적: 6-cyano-7-nitroquinoxalin-2,3-dione (CNQX)는 저산소성허혈성뇌병증, 외상성뇌손상, 흥분독성과 같은 뇌 손상동물 모델에서 보호 효과가 있다고 발표되고 있지만 신생아기에 그 효과에 대해서는 아직 제한적이다. 저자들은 CNQX를 이용하여 저산소성허혈성뇌손상을 동반한 발달 과정에 있는 흰쥐 뇌에 산화질소합성효소 중재를 통한 뇌 보호 효과를 알아보고자 하였다. 방법: 생체내 실험으로 생후 7일된 신생 흰쥐의 좌측 총 경동맥을 결찰한 후 6개군(정상산소군, 수술없이 저산소군, sham수술 후 저산소군, 수술 후 저산소군, vehicle 투여 후 저산소군, CNQX 투여 후 저산소군)으로 나누었고, 저산소 손상은 특별히 제작한 통속에서 2시간 동안 8% $O_2$에 노출시켰다. CNQX은 뇌손상 전 30분에 체중 kg당 10 mg를 투여하였다. 생체외 실험으로 재태기간 18일된 태아 백서의 대뇌피질 세포를 배양하여 정상산소군은 5% $CO_2$ 배양기(95% air, 5% $CO_2$)에 두었고, 저산소군과 뇌손상 전 CNQX 투여군(10 ${\mu}g$/mL)은 1% $O_2$). 배양기(94% $N_2$, 5% $CO_2$)에서 16시간동안 뇌세포손상을 유도하였다. 생체내 외 실험 모두 산화질소합성효소와 관련된 iNOS, eNOS, nNOS 항체와 primer를 이용하여 western blotting과 실시간중합효소연쇄반응을 시행하였다. 결과: 산화질소합성효소와 관련된 생체외 내 실험에서 iNOS와 eNOS의 발현은 저산소군에서 정상산소군보다 감소하였으나 CNQX 투여군에서는 저산소군보다 증가하였다. nNOS의 발현은 반대로 표현되었다. 결론: 본 연구에서 CNQX는 산화질소합성효소 중재를 통하여 주산기 저산소성 허혈성 뇌손상에서 신경보호 역할을 하는 것을 알 수 있었다.

• The Korean Journal of Physiology and Pharmacology
• /
• 제9권3호
• /
• pp.179-186
• /
• 2005

Whole bee venom (WBV) and its major component, melittin, have been reported to induce long-lasting spontaneous flinchings and hyperalgesia. The current study was designed to elucidate the peripheral and spinal mechanisms of N-methyl-D-aspartate (NMDA) and non-NMDA receptors by which intraplantar (i.pl.) injection of WBV and melittin induced nociceptive responses. Changes in mechanical threshold and flinching behaviors were measured after the injection of WBV (0.04 mg or 0.1 mg/paw) and melittin (0.02 mg or 0.05 mg/paw) into the mid-plantar area of a rat hindpaw. MK-801 and CNQX (6-cyano-7-nitroquinoxaline-2,3-dione disodium) were administered intrathecally (i.t. $10{\mu}g$) or i.pl.($15{\mu}g$) 15 min before or i.t. 60 min after i.pl. WBV and melittin injection. Intrathecal pre- and postadministration of MK-801 and CNQX significantly attenuated the ability of high dose WBV and melittin to reduce paw withdrawal threshold (PWT). In the rat injected with low dose, but not high dose, of WBV and melittin, i.pl. injection of MK-801 effectively suppressed the decrease of PWTs only at the later time-points, but the inhibitory effect of CNQX (i.pl.) was significant at all time-point after the injection of low dose melittin. High dose WBV- and melittin-induced spontaneous flinchings were significantly suppressed by i.t. administration of MK-801 and CNQX, and low dose WBV- and melittin-induced flinchings were significantly reduced only by intraplantarly administered CNQX, but not by MK-801. These experimental flinchings suggest that spinal, and partial peripheral mechanisms of NMDA and non-NMDA receptors are involved in the development and maintenance of WBV- and melittin-induced nociceptive responses.

• Archives of Pharmacal Research
• /
• 제24권6호
• /
• pp.613-617
• /
• 2001

The present study examined the hypothesis that NMDA, AMPA/Kainate, and metabotropic (mGlu) glutamate receptors contribute to a behavioral stimulation induced by activation of dopamine receptors by comparing responses in apomorphine-induced cage climbing behaviors in mice. MK-801, CNQX, and MCPG were served as the NMDA receptor, AMPA/Kainate receptor, and mGlu receptor antagonist, respectively, to elucidate the glutamatergic modulation in apomorphine-induced eopaminergic activation in mice. Drugs were administered intracerebroventricularly (i.c.v.) into the mouse brain 15 min before the apomorphine treatment (2 mg/kg, s.c.). 1.c.v. injection of MK-801 inhibited the apomorphine-induced cage climbing behavior dose-dependently. However, treatments with CNQX and MCPG did not any significant change in apomorphine-induced cage climbing behavior in mice. These results suggest that stimulation of NMDA type of glutamate receptors could contribute to the dopaminergic sti mutation, but not AMPA/Kainate and mGlu type glutamate receptors.

• International Journal of Oral Biology
• /
• 제32권2호
• /
• pp.59-65
• /
• 2007

It has been well known that excitatory amino acids, primarily glutamate, are involved in the transmission of nociception in pathological and physiological conditions in the spinal and brainstem level. Recently, peripheral glutamate also play a critical role in the peripheral nociceptive transmissions. The present study investigated the role of N-methyl-D-aspartic acid (NMDA) or non-NMDA ionotropic glutamate receptors in formalin-induced TMJ pain. Experiments were carried out on male Sprague-Dawley rats weighing 220-280 g. Intra-articular injection was performed under halothane anesthesia. Under anesthesia, AP-7 (10, $100\;{\mu}M$, $1\;mM/20\;{\mu}L$), a NMDA receptor antagonist, or CNQX disodium salt (0.5, 5, 50, $500\;{\mu}M/20\;{\mu}L$), a non-NMDA receptor antagonist, were administered intra-articularly 10 min prior to the application of 5% formalin. For each animal, the number of behavioral responses, such as rubbing and/or scratching the TMJ region, was recorded for nine successive 5-min intervals. Intra-articular pretreatment with 1 mM of AP-7 or $50\;{\mu}M$ CNQX significantly decreased the formalin-induced scratching behavioral responses during the second phase. Intra-articular pretreatment with $500\;{\mu}M$ of CNQX significantly decreased the formalin-induced scratching behavior during both the first and the second phase. These results indicate that the intra-articular administration of NMDA or non-NMDA receptor antagonists inhibit formalin-induced TMJ nociception, and peripheral ionotropic glutamate receptors may play an important role in the TMJ nociception.

• 동의생리학회지
• /
• 제14권2호통권20호
• /
• pp.55-66
• /
• 1999

The effects of Bogi, Boyang and Onri herbs on glutamate receptor using nystatin perforated patch clamp under voltage clamp were investigated and the following results was obtained. Ginseng radix and Astragali radix were chosen as Bogi herbs. Cervi cornu and Boshniakiae herba were used as Boyang herbs. Aconiti tuber and Zingiberis rhizoma were selected as Onri herbs. 1. $10^{-6}M$ of glycine brought about the increase of the ion currents by Astragali radix. Cervi cornu. Boshniakiae herba and Aconiti tuber to a minute extent that has no experimental meaning. 2. It was assumed that Bogi herb had no effect on glutamate receptor since the ion currents of Ginseng radix and Astragali radix that are Bogi herbs had not been inhibited to a great extent by D-AP5 and CNQX. 3. Boyang herbs were seem to have meaningful relationship with non-NMDA receptor since the ion currents by Cervi cornu and Boshniakiae that are Boyang herbs were inhibited by CNQX but not inhibited to a meaningful extent by D-AP5. 4. D-AP5 had not a significant effect on the ion currents activated by Onri herbs such as Aconiti tuber and Zingiberis rhizoma. CNQX had a significant effect on the ion currents of Aconiti tuber but no effect on the ion currents of Zingiberis rhizoma. Therefore, it seemed that Aconiti tuber had a relationship with non-NMDA receptor while Zingiberis rhizoma had no relationship with glutamate receptor. In summary, Bogi, Boyang and Onri herbs had different effects through different mechanisms on glutamate receptor. Hence it was believed that. through experiments on acetylcholine receptor new classification could be made.

• 대한약리학회지
• /
• 제29권2호
• /
• pp.189-193
• /
• 1993

흰쥐태 뇌간의 세포를 배양하여 glutamate에 6시간까지 노출시 glutamate의 농도 및 노출 시간에 의존적으로 세포내 5-HT 및 5-HIAA의 함량이 감소하였고, 배양액으로 LDH의 유출이 증가하였다. Tetrodotoxin은 glutamate의 작용을 차단하지 못하였다. NMDA 수용체 통로 봉쇄제인 MK-801에 의해 glutamate의 작용이 효과적으로 차단되었고, non-NMDA 길항제인 CNQX는 효과가 없었으므로, serotonin 신경세포에 대한 glutamate의 작용은 NMDA 수용체의 자극에 의한 것으로 사료된다.

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

• The Korean Journal of Pain
• /
• 제12권1호
• /
• pp.1-7
• /
• 1999

Background: To study the role of spinal alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors in pain behaviors caused by mild burn, we examined the effect of intrathecal administered ACEA 2085, which has been recently characterized as a high potency competitive AMPA receptor antagonist, on the thermal hyperalgesia state induced by mild burn. Methods: A thermal injury was induced by applying the left hind paw to a thermal surface ($52.5^{\circ}C$) for 45 sec. Thermal escape latency of the hind paw was determined using an underglass thermal stimulus. Thirty min after thermal injury, the paw withdrawal latency (PWL) in injured paw of all groups fell from 10~12 sec to 5~7 sec. At that time, ACEA 2085 (0.01~0.1 mcg) and 6-cyano-7-nitroquinoxalinedione (CNQX, 1~30 mcg) were injected through intrathecal heters in rats with mild burn injury on the right hindpaw. And then, PWL were measured in the both hindpaw every 30 minutes for about three hours. Results: The intrathecal injection of ACEA 2085 produced a dose dependent reversal of the hyperalgesia in the right hindpaw and more potent than CNQX, but had no effect upon the response latency of the normal left hind paw even at the largest doses. All effects were observed at doses that had no significant effect upon motor function. Conclusions: Intrathecal ACEA 2085, highly selective AMPA receptor antagonist produce a dose- dependent reversal of the thermal hyperalgesia evoked mild burn injury. These results suggested that spinal AMPA receptor play an important role in the hyperalgesia induced by mild burn injury.

• 대한의생명과학회지
• /
• 제11권3호
• /
• pp.319-326
• /
• 2005

It is well known that oxidative stress of reactive oxygen species (ROS) may be a causative factor in the pathenogenesis of bone disorder on osteoblast or osteoclast. The purpose of this study was to evaluate the cytotoxicity of oxidative stress, protective effect of glutamate receptor antagoinst against ROS-induced osteotoxicity, secretion of tumor necrosis factor $(TNF)-\alpha$ and the expression of c-fos gene in the cultured rat osteoblasts and osteoclasts. Cell viability by MTS assay or !NT assay, activity of glutathione peroxidase (GPx), lipid peroxidation (LPO) activity, protein synthesis by sulforhodamine B (SRB) assay, alkaline phosphatase (ALP) activity, lactate dehydrogenase (LDH) activity, MTS assay for NMDA (N-methyl-D-aspartate) receptor antagonist or AMPA/kainate receptor antagonist, measurement for $TNF-\alpha$, and c-fos gene expression were performed after these cells were treated with or without various cocentrations of xanthine oxidase (XO), hypoxanthine (HX), D-2-amino-5-phosphonovaleric acid (APV), 7-chlorokynurenic acid (CKA), 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and 6,7-dinitroquinoxaline-2,3-dione (DNQX), respectively. In this study, XO/HX showed decreased cell viability and glutathione peroxidase (GPx) activity, but it showed increased LPO activity, $TNF-\alpha$ secretion and c-fos expression. APV and CKA incresed protein sythesis and ALP activity. While, CNQX or DNQX did not show any protective effect in LDH activity or cell viability. From these results, XO/HX showed cytotoxic effect in cultured rat osteoblast or osteoclast, and also NMDA receptor antagonist such as APV or CKA was effective in blocking XO/HX-induced osteotoxicity in these cultures.

• Journal of Ginseng Research
• /
• 제36권1호
• /
• pp.47-54
• /
• 2012

Korean red ginseng (KRG) has been used worldwide as a traditional medicine for the treatment of various reproductive diseases. Gonadotropin releasing hormone (GnRH) neurons are the fundamental regulators of pulsatile release of gonadotropin required for fertility. In this study, an extract of KRG (KRGE) was applied to GnRH neurons to identify the receptors activated by KRGE. The brain slice patch clamp technique in whole cell and perforated patch was used to clarify the effect of KRGE on the membrane currents and membrane potentials of GnRH neurons. Application of KRGE (3 ${\mu}g$/${\mu}L$) under whole cell patch induced remarkable inward currents (56.17${\pm}$7.45 pA, n=25) and depolarization (12.91${\pm}$3.80 mV, n=4) in GnRH neurons under high $Cl^-$ pipette solution condition. These inward currents were not only reproducible, but also concentration dependent. In addition, inward currents and depolarization induced by KRGE persisted in the presence of the voltage gated $Na^+$ channel blocker tetrodotoxin (TTX), suggesting that the responses by KRGE were postsynaptic events. Application of KRGE under the gramicidin perforated patch induced depolarization in the presence of TTX suggesting its physiological significance on GnRH response. Further, the KRGE-induced inward currents were partially blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; non-NMDA glutamate receptor antagonist, 10 ${\mu}M$) or picrotoxin (PIC; $GABA_A$ receptor antagonist, 50 ${\mu}M$), and almost blocked by PIC and CNQX mixture. Taken together, these results suggest that KRGE contains ingredients with possible GABA and non-NMDA glutamate receptor mimetic activity, and may play an important role in the endocrine function of reproductive physiology, via activation of $GABA_A$ and non-NMDA glutamate receptors in GnRH neurons.