• 대한약리학회지
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• 제32권2호
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• pp.127-138
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• 1996

The effects of adenosine analogues on the electrically-evoked acetylcholine(ACh) release and the influence of ischemia on the effects were studied in the rat hippocampus. Slices from the rat hippocampus were equilibrated with $0.1{\mu}M$ $[^3H]-choline$ and the release of the labelled product, $[^3H]-ACh$, was evoked by electrical stimulation(3 Hz, 2 ms, 5 $VCm^{-1}$ and rectangular pulses for 2 min), and the influence of various agents on the evoked tritiumoutflow was investigated. Ischemia(10 min with 95% $N_2$ + 5% $CO_2$) increased both the basal and evoked ACh release. These increases were abolished by glucose addition into the superfused medium, and they significantly inhibited either by 0.1 & $0.3{\mu}M$ TTX pretreatment or by removing $Ca^{++}$ in the medium. MK-801($1{\sim}10{\mu}M$), a specific NMDA receptor antagonist, and glibenclamide $(1{\mu}M)$, a $K^+-channel$ inhibitor, did not alter the evoked ACh release and nor did they affect the ischemia-induced increases In ACh release. However, polymyxin B(0.03 mg), a specific protein kinase C inhibitor, significantly inhibited the effects of ischemia on the evoked ACh release. Adenosine and $N^6-cyclopentyladenosine$ decreased the ACh release in a dose dependent manner in ischemic condition, though the magnitude of inhibition was far less than those in normal(normoxic) condition. However, the treatment with $5{\mu}M$ DPCPX, a potent $A_1-adenosine$ receptor antagonist, potentiated the ischemia-effect. These results indicate that the evoked-ACh release is potentiated by ischemia, and this process being most probably mediated by protein kinase C, and that the decreased effect of ACh release mediated by $A_1-adenosine$ receptor is significantly inhibited in ischemic state.

• 한국임상수의학회지
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• 제25권2호
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• pp.73-78
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• 2008

케타민은 N-methyl-D-aspartate (NMDA) 수용체의 비경쟁적인 길항제로 인의와 수의학에서 전신 마취제로 사용하는 약물이다. 본 연구진은 이전에 케타민이 개 말초혈액 백혈구의 순간산소과소비현상(oxidative burst activity)을 손상시킨다고 보고하였다. 현재 연구에서는 개 말초혈액 탐식세포의 탐식능(phagocytic capacity)에 대한 케타민의 효과를 검토하였다. 탐식능은 유세포 분석기로 분석하였다. 말초혈액 다형핵백혈구(peripheral blood polymorphonuclear cells; PMN)와 단구(monocytes)의 탐식능은 케타민의 직접 처리에 의해 감소하였으나 단핵구세포(peripheral blood mononuclear cells; PBMC) 분획에서의 탐식능은 케타민의 직접 처리에 의해 변화가 없었다. 말초혈액 다형핵백혈구와 단구의 탐식능은 케타민을 처리한 단핵구세포 배양상층액에 의해서도 감소하였다. 이상의 결과로부터 케타민은 호중구와 단구와 같은 개 말초혈액 탐식세포의 탐식능에 있어 직접적인 억제효과를 나타내며, 또한 케타민 처리 단핵구세포로부터 생산되는 가용성인자에 의해서도 탐식세포의 탐식능이 억제되는 것으로 사료되었다.

• The Korean Journal of Physiology and Pharmacology
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• 제20권1호
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• pp.101-109
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• 2016

Reducing $[Mg^{2+}]_o$ to 0.1 mM can evoke repetitive $[Ca^{2+}]_i$ spikes and seizure activity, which induces neuronal cell death in a process called excitotoxicity. We examined the issue of whether cultured rat hippocampal neurons preconditioned by a brief exposure to 0.1 mM $[Mg^{2+}]_o$ are rendered resistant to excitotoxicity induced by a subsequent prolonged exposure and whether $Ca^{2+}$ spikes are involved in this process. Preconditioning by an exposure to 0.1 mM $[Mg^{2+}]_o$ for 5 min inhibited significantly subsequent 24 h exposure-induced cell death 24 h later (tolerance). Such tolerance was prevented by both the NMDA receptor antagonist D-AP5 and the L-type $Ca^{2+}$ channel antagonist nimodipine, which blocked 0.1 mM $[Mg^{2+}]_o$-induced $[Ca^{2+}]_i$ spikes. The AMPA receptor antagonist NBQX significantly inhibited both the tolerance and the $[Ca^{2+}]_i$ spikes. The intracellular $Ca^{2+}$ chelator BAPTA-AM significantly prevented the tolerance. The nonspecific PKC inhibitor staurosporin inhibited the tolerance without affecting the $[Ca^{2+}]_i$ spikes. While $G{\ddot{o}}6976$, a specific inhibitor of $PKC{\alpha}$ had no effect on the tolerance, both the $PKC{\varepsilon}$ translocation inhibitor and the $PKC{\zeta}$ pseudosubstrate inhibitor significantly inhibited the tolerance without affecting the $[Ca^{2+}]_i$ spikes. Furthermore, JAK-2 inhibitor AG490, MAPK kinase inhibitor PD98059, and CaMKII inhibitor KN-62 inhibited the tolerance, but PI-3 kinase inhibitor LY294,002 did not. The protein synthesis inhibitor cycloheximide significantly inhibited the tolerance. Collectively, these results suggest that low $[Mg^{2+}]_o$ preconditioning induced excitotoxic tolerance was directly or indirectly mediated through the $[Ca^{2+}]_i$ spike-induced activation of $PKC{\varepsilon}$ and $PKC{\xi}$, JAK-2, MAPK kinase, CaMKII and the de novo synthesis of proteins.

• The Korean Journal of Pain
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• 제12권1호
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• pp.123-127
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• 1999

Chronic pain is a frequent complication after spinal cord injury. Various medical and surgical approaches have been applied for management of spinal cord injury pain but none of them are definitive. The N-methyl-D-Aspartate (NMDA) receptor antagonist, ketamine has been reported to have a significant effect in the management of neuropathic pain. We used small divided doses of intravenous ketamine (30 mg divided by 6 equals 5 mg, 5 min interval) in spinal cord injury patients suffering from chronic pain, and accomplished significant pain relief without side effects.

• 한국한의학연구원논문집
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• 제4권1호통권4호
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• pp.99-114
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• 1998

The effect of herbal medicine on glutamate mediated neurotoxicity was studied in mouse neurons in primary culture. Immature cerebral cortex neurons (ED14) were maintained for up to 2 weeks in vitro, and we investigated the expression pattern of neuron differentiation and cytotoxicity of cell death, including LDH activity. Neuronal maturation initiated on day 7 and the susceptibility to glutamate-induced cell death was highly sensitive on Day 11 (Fig. 1). Thus, the exposure of the neurons to glutamate caused a dose$(0.1mM{\sim}1mM)$ and time$(4h{\sim}24h)$-dependent neurotoxicity(Fig. 4). Glutamate-induced neurodegeneration was prevented by Shipchondaebotang(SD), Yollyounggobondan(YG), Yugmijihwangwon(YJ) and the death of neurons exposed to glutamate was blocked by the NMDA receptor antagonist MK-801 (Fig. 5).

• Biomolecules & Therapeutics
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• 제25권3호
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• pp.249-258
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• 2017

To examine the effect of biflorin, a component of Syzygium aromaticum, on memory deficit, we introduced a scopolamine-induced cognitive deficit mouse model. A single administration of biflorin increased latency time in the passive avoidance task, ameliorated alternation behavior in the Y-maze, and increased exploration time in the Morris water maze task, indicating the improvement of cognitive behaviors against cholinergic dysfunction. The biflorin-induced reverse of latency in the scopolamine-treated group was attenuated by MK-801, an NMDA receptor antagonist. Biflorin also enhanced cognitive function in a naïve mouse model. To understand the mechanism of biflorin for memory amelioration, we performed Western blot. Biflorin increased the activation of protein kinase C-${\zeta}$ and its downstream signaling molecules in the hippocampus. These results suggest that biflorin ameliorates drug-induced memory impairment by modulation of protein kinase C-${\zeta}$ signaling in mice, implying that biflorin could function as a possible therapeutic agent for the treatment of cognitive problems.

• 대한약리학회지
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• 제29권1호
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• pp.9-22
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• 1993

허혈성 뇌손상시 칼슘길항제, 항산화제와 산소라디칼 제거제 그리고 흥분성 아미노산 수용체 길항제의 보호효과를 검토하기 위해 본 연구에서는 랫트 뇌 해마조직 절편을 산소와 포도당을 제거한 반응액에 노출시켜 실험적 허혈상태를 유도하였다. 그리고 여러 약물을 처리한 상태에서 허혈시의 뇌세포 손상정도를 생화학적 지표들(절편내 ATP와 반응액내 lactate 및 malondialdehyde (MDA)유리량)을 측정하여 검토하였다. 60분까지 허혈상태를 유발시킨 경우 시간에 따라 절편내 ATP 함량이 감소하였고 lactate 유리량이 증가하였다. 그 후 산소와 포도당이 든 반응액으로 바꿔주니 이들 생화학적 변화들이 회복되는 양상을 보였다. 그러나 본 실험조건에서 허혈상태로부터 완전히 회복되지는 않았다. 동일한 허혈조건에서 verapamil과 비타민 E는 ATP 함량 감소와 절편으로부터의 lactate 유리량의 증가에 대해 보고효과를 보였다. 그리고 verapamil과 diltiazem은 반응액내로의 MDA유리를 감소시켰다. Superoxide dismutase (SOD), glutathione과 MK-801 (NMDA 수용체 길항제)은 20분 허혈조건에서 ATP 함량을 증가시켰으나 그외 다른 조건에서 보호효과를 보이지 않았다. 허혈 후 20분간 산소와 포도당을 재공급한 경우 verapamil은 ATP 함량과 lactate 유리에 보호효과를 보였다. 한편 비타민 E는 20분 허혈 조건에서의 lactate 유리와 60분 허혈시의 MDA 유리 증가에 대해 감소효과를 보였다. 이상의 결과는 칼슘길항제와 비타민 E가 랫트 뇌절편에서의 허혈성 생화학적 손상을 방지함으로 나타난 결과로 해석되며, 칼슘갈항제의 효과가 비타민 E보다 우수함으로 미루어 칼슘길항제는 허혈성 뇌손상에 예방 및 보고효과를 보일 것으로 믿어졌다.

• The Korean Journal of Physiology and Pharmacology
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• 제8권6호
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• pp.295-300
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• 2004

Serotonin (5-hydroxytroptamine, 5-HT) has been shown to affect the induction of long-term potentiation (LTP) in the cortex such as the hippocampus, the visual cortex and the prefrontal cortex. Fluoxetine, as a selective serotonin reuptake inhibitor, is used in the management of a wide variety of psychological diseases. To study the effect of fluoxetine on the induction of LTP, we recorded the field potential in layer II/III of the frontal cortex from 3-wk-old. LTP was induced in horizontal input by theta burst stimulation (TBS). TBS with two-folds intensity of the test stimulation induced LTP, which was blocked by application of D-AP5 $(50 {\mu}M)$, an NMDA receptor antagonist. Whereas bath application of 5-HT $(10 {\mu}M)$ inhibited the induction of LTP, treatment with the 5-HT depleting agent, para-chloroamphetamine $(PCA,\;10{\mu}M)$, for 2hr did not affect the induction of LTP. Bath application of fluoxetine (1, 3, and $10 {\mu}M)$ suppressed the induction of LTP in concentration-dependent manner, however, fluoxetine did not inhibit the induction of LTP in 5-HT-depleted slices. These results indicate that fluoxetine may inhibit the induction of LTP by modulating serotonergic mechanism in the rat frontal cortex.

• 한국임상수의학회지
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• 제23권4권
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• pp.393-399
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• 2006

전신마취제인 케타민은 흥분성 아미노산의 활성을 방해하는 N-methyl-D-aspartate (NMDA) 수용체의 비경쟁적인 길항제이다. 본 연구는 개 말초혈액 백혈구의 순간산소과소비현상(Oxidative burst activity; OBA)에 있어서 케타민의 효과를 검토하였다. 탐식세포의 OBA는 유세포 분석기로 분석하였다. 케타민을 말초혈액 다형핵백혈구(peripheral blood polymorphonuclear cells; PMN)와 monocyte-rich cells에 직접처리 하였을 때는 OBA가 감소하였으며, 또한 케타민을 처리한 말초혈액 단핵구세포(peripheral blood mononuclear cells; PBMC) 배양상층액에 의해서도 PMN과 monocyte-rich cells의 OBA가 감소하였다. 그러나 케타민을 처리한 PMN 배양상층액에 의해서는 탐식세포의 OBA에 있어서 아무런 변화가 없었다. 하지만 이러한 OBA의 감소는 latex beads를 넣어 탐식반응이 일어날 때만 측정되었다. 이상의 결과로부터 탐식반응이 일어나는 동안 케타민은 호중구와 단핵구와 같은 개 말초혈액 탐식구의 OBA에 있어 억제효과를 나타내었다.

• 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.