• Journal of Acupuncture Research
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• v.24 no.2
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• pp.63-71
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• 2007

목적 : 저주파에 해당하는 2Hz 전침 자극이 척수 N-methyl-D-aspartate receptor (NMDAR)의 NR-2B subunit의 발현 및 인산화에 미치는 영향을 조사하였다. 방법 : Sprague-Dawley계 흰쥐를 Storkson등의 방법에 의해 척수막의 지주막하강에 catheter를 삽입하는 수술을 행한 후 마비등의 척수 손상을 나타내지 않는 개체를 대상으로 하였다. N-methyl-D-aspartate (NMDA) antagonist인 D-2-amino-5- phosphonopentanoic acid (AP-5)를 투여한 후 족삼리와 삼음교에 해당하는 부위에 30분간 전침 자극하였다. 무통각 여부는 hot plate test를 시행하였으며 NMDAR NR-2 subunit 발현과 인산화 여부는 Western blot과 면역조직화학적으로 살펴보았다. 결과 : 전침 무통각은 전침 자극 후 180분 후까지 지속되었으며 NMDA antagonist인 AP-5를 투여하였을 때 전침 무통각이 저하되었으나 유의성은 나타내지 않았다. Western blot 분석으로 보아 NMDAR NR-2B 및 인산화 NR-2B의 발현은 전침자극에 의해 미약한 증가를 보이나 AP-5투여에 의해 현저한 저해를 보였다. 면역조직화학에 의한 척수배각 구역별 발현을 보면 NMDAR NR-2B 및 인산화 NR-2B는 전 배각에 걸쳐 관찰되나 경부(층판 V-VI)에서 약한 반응을 보였다. 전침 자극에 의한 각 군별 NR-2B 발현은 유의한 차이를 보여 주지 않았으나 인산화 NR-2B는 천층(층판I-II) 및 고유핵 층판(III-IV)에서 유의성 있는 증가를 보였다. 전침 자극시 AP-5 투여는 유의성은 보이지 않았으나 인산화 NR-2B 발현을 저해하였다. 결론: 저주파 2Hz 전침에 의한 무통각은 NMDA antagonist인 AP-5 투여에 의해 저해될 뿐 아니라 NMDAR NR-2B subunit의 인산화를 저해하는 것으로 보아 전침 무통각의 과정에 NMDAR 및 NMDAR NR-2B의 인산화가 관여함을 알 수 있다.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.697-703
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• 2002

We investigated that the role of nitric oxide (NO) on ischemic rats in brain and heart. Ischemia was induced by both common carotid arteries (CCA) occlusion for 24h following reperfusion. Then tissue samples were removed and measured NOx. In brain, NOx was increased by about 40% vs. normal and it was significantly inhibited by aminoguanidine, selective iNOS inhibitor. This result showed that NOx concentration was increased by iNOS. We investigated the role of $Ca^{2+}$ during ischemia. Nimodipine, L-type calcium channel blocker, didn't inhibit the increases of NOx concentration during ischemia. It suggested that increased NOx was due to calcium-independent NOS. MK-801, which N-methyl-D-aspartate (NMDA) receptor antagonist, didn't significantly prevent the increases of NOx. In heart, ischemia caused NOx decrease and it is inconsistent with NOx increase in brain. Aminoguanidine and nimodipine didnt affect on NOx decrease. But MK-801 more lowered NOx concentration than those of ischemia control group. It seemed that $Ca^{2+}$ influx in heart partially occurred via NMDA receptor and inhibited by NMDA receptor antagonist. The mean arterial pressure (MAP) in ischemic rats after 24h of CCA occlusion was decreased when compared to normal value, whereas the heart rates (HR) was not different between two groups. Aminoguanidine or MK801 had no effect on MAP or HR, but nimodipine reduced MAP. There was no difference the effects of aminoguanidine, nimodipine, or MK-801, on MAP and HR between normal rats and ischemic rats. In summary, ischemic model caused an increase of NOx concentration, suggesting that this may be produced via iNOS, which is calcium independent in brain. However in heart, ischemia decreased NOx concentration and NMDA receptor was partially involved. The basal MAP was decreased in ischemic rats but HR was not different from normal control, suggesting that increased NOx in brain of ischemic rat may result in the hypotension.

• Clinical and Experimental Pediatrics
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• v.52 no.5
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• pp.594-602
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• 2009

Purpose : Transforming growth factor (TGF)-${\beta}1$ reportedly increases neuronal survival by inhibiting the induction of inducible nitric oxide synthase (NOS) in astrocytes and protecting neurons after excitotoxic injury. However, the neuroprotective mechanism of $TGF-{\beta}1$ on hypoxic-ischemic (HI) brain injury in neonatal rats is not clear. The aim of this study was to determine whether $TGF-{\beta}1$ has neuroprotective effects via a NO-mediated mechanism and N-methyl-D-aspartate (NMDA) receptor modulation on perinatal HI brain injury. Methods : Cortical cells were cultured using 19-day-pregnant Sprague-Dawley (SD) rats treated with $TGF-{\beta}1$ (1, 5, or 10 ng/mL) and incubated in a 1% O2 incubator for hypoxia. Seven-day-old SD rat pups were subjected to left carotid occlusion followed by 2 h of hypoxic exposure (7.5% $O_2$). $TGF-{\beta}1$ (0.5 ng/kg) was administered intracerebrally to the rats 30 min before HI brain injury. The expressions of NOS and NMDA receptors were measured. Results : In the in vitro model, the expressions of endothelial NOS (eNOS) and neuronal NOS (nNOS) increased in the hypoxic group and decreased in the 1 ng/mL $TGF-{\beta}1-treated$ group. In the in vivo model, the expression of inducible NOS (iNOS) decreased in the hypoxia group and increased in the $TGF-{\beta}1$-treated group. The expressions of eNOS and nNOS were reversed compared with the expression of iNOS. The expressions of all NMDA receptor subunits decreased in hypoxia group and increased in the $TGF-{\beta}1$-treated group except NR2C. Conclusion : The administration of $TGF-{\beta}1$ could significantly protect against perinatal HI brain injury via some parts of the NO-mediated or excitotoxic 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.