• The Korean Journal of Physiology and Pharmacology
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• 제13권4호
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• pp.265-271
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• 2009

Nitric oxide (NO) has both neuroprotective and neurotoxic effects depending on its concentration and the experimental model. We tested the effects of NG-nitro-L-arginine methyl ester (L-NAME), a nonselective nitric oxide synthase (NOS) inhibitor, and aminoguanidine, a selective inducible NOS (iNOS) inhibitor, on kainic acid (KA)-induced seizures and hippocampal CA3 neuronal death. L-NAME (50 mg/kg, i.p.) and/or aminoguanidine (200 mg/kg, i.p.) were administered 1 h prior to the intracerebroventricular (i.c.v.) injection of KA. Pretreatment with L-NAME significantly increased KA-induced CA3 neuronal death, iNOS expression, and activation of microglia. However, pretreatment with aminoguanidine significantly suppressed both the KA-induced and L-NAME-aggravated hippocampal CA3 neuronal death with concomitant decreases in iNOS expression and microglial activation. The protective effect of aminoguanidine was maintained for up to 2 weeks. Furthermore, iNOS knockout mice ($iNOS^{-1-}$) were resistant to KA-induced neuronal death. The present study demonstrates that aminoguanidine attenuates KA-induced neuronal death, whereas L-NAME aggravates neuronal death, in the CA3 region of the hippocampus, suggesting that NOS isoforms play different roles in KA-induced excitotoxicity.

• 대한수의학회지
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• 제51권3호
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• pp.185-191
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• 2011

Trimethyltin chloride (TMT) has been used as a neurotoxin for inducing brain dysfunction and neuronal death. Neuronal death in the hippocampus by TMT may generate excessive nitric oxide, but there are few studies about nitric oxide synthase enzyme involved in the synthesis of nitric oxide. The purpose of present study is to analyze the TMT toxicity in each region of rat hippocampus. To evaluate the involvement of nitric oxide, we analyzed the effects of aminoguanidine known as a selective inhibitor for inducible nitric oxide synthase on behavioral changes and the hippocampus of rat by TMT toxicity. 6-week-old male Sprague-Dawley rats were administered with a single dose of TMT (8 mg/kg b.w., i.p.) and the control group was similarly administered with distilled water. TMT + aminoguanidine-treated groups were administered with aminoguanidine (10 mg/kg or 100 mg/kg b.w., i.p.) for 3 days prior to TMT injection. The rats were sacrificed 2 days after TMT administration. In the TMT-treated group, a number of cell losses were seen in CA1, CA3 and the dentate gyrus. In the TMT + aminoguanidine-treated group, neuronal death was seen in CA1 and CA3, but reduced in the dentate gyrus compared to the TMT-treated group. Western blot analysis showed that cleaved caspase-3 expression was increased in the TMT-treated group compared to the control group. However, the expression significantly declined in the TMT + aminoguanidine-treated group. The present findings suggest that inducible nitric oxide synthase is involved in neuronal death induced by TMT.

• The Korean Journal of Physiology and Pharmacology
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• 제8권1호
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• pp.1-5
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• 2004

Transient forebrain ischemia results in the delayed neuronal death in the CA1 area of the hippo-campus. The present study was performed to determine effects of aminoguanidine, a selective iNOS inhibitor, on the generation of peroxynitrite and delayed neuronal death occurring in the hippocampus following transient forebrain ischemia. Transient forebrain ischemia was produced in the conscious rats by four-vessel occlusion for 10 min. Treatment with aminoguanidine (100 mg/kg or 200 mg/kg, i.p.) or saline (0.4 ml/100 g, i.p.) was started 30 min following ischemia-reperfusion and the animals were then injected twice daily until 12 h before sacrifice. Immunohistochemical method was used to detect 3-nitrotyrosine, a marker of peroxynitrite production. Posttreatment of aminoguanidine (200 mg/kg) significantly attenuated the neuronal death in the hippocampal CA1 area 3 days, but not 7 days, after ischemia-reperfusion. 3-Nitrotyrosine immunoreactivity was enhanced in the hippocampal CA1 area 3 days after reperfusion, which was prevented by the treatment of aminoguanidine (100 mg/kg and 200 mg/kg). Our findings showed that (1) the generation of peroxynitrite in the hippocampal CA1 area 3 days after ischemia-reperfusion was dependent on the iNOS activity; (2) the postischemic delayed neuronal death was attenuated in the early phase through the prevention of peroxynitrite generation by an iNOS inhibitor.

• Biomolecules & Therapeutics
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• 제13권3호
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• pp.190-197
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• 2005

Advanced glycation end products (AGE) have been implicated in the pathogenesis of diabetic complications including nephropathy. However, the role of AGE in the activation of mesangial cells cultured under high glucose has not been elucidated. The effects of aminoguanidine, which prevents formation of AGE and protein cross-linking, on the synthesis of $TGF-{\beta}1$ and fibronectin by rat mesangial cells cultured under high glucose for 2 weeks were examined and compared with the effects of $N^G$-nitro-L-arginine methyl ester (NAME), a selective nitric oxide synthase inhibitor, because aminoguanidine also inhibits the inducible nitric oxide synthase. Culture of mesangial cells in 30 mM (high) glucose for 2 weeks induced 1.5-fold (ELISA) and 1.9-fold (Western blot analysis) increase in AGE in the culture media compared to 5.6 mM (control) glucose. Northern blot analysis revealed 1.5-fold increase in $TGF-{\beta}1$ and 1.7-fold increase in fibronectin mRNA expression in cells cultured under high glucose compared to control glucose. Increases in mRNA expression were followed by increased protein synthesis. Mink lung epithelial cell growth inhibition assay revealed 1.4-fold increase in $TGF-{\beta}1$ protein in high glucose media compared to control. Fibronectin protein also increased 2.1-fold that of control glucose by Western blot analysis. Administration of aminoguanidine suppressed AGE formation in a dose dependent manner and at the same time suppressed $TGF-{\beta}1$ and fibronectin synthesis by mesangial cells cultured in both control and high glucose. In contrast, NAME did not affect high glucose-induced changes. These findings support a role for AGE in high glucose-induced upregulation of $TGF-{\beta}1$ and fibronectin synthesis by mesangial cells.

• 대한약리학회지
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• 제32권1호
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• pp.113-123
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• 1996

세포내 polyamine은 DNA 구조 뿐 아니라 전사과정, 세포의 성장, 분화, 및 증식 등에 간여하는 바, 배양 흉선세포의 apoptosis 을 억제한다고 한다. 따라서 dexamethasone에 의한 생쥐 흉선세포의 apoptosis 반응에 대한 polyamine의 억제작용을, polyamine 생성과 대사억제제들로 처치한 흉선세포의 일차배양실험에서 관찰하여, 그 결과를 A23187과 DHEA의 작용과 비교하였다. 1) 흉선세포 생존율이 dexamethasone, DHEA, A23187, DFMO, MGBG들에 의하여 직접 현저히 억제되며, aminoguanidine, putrescine, spermidine, 및 spermine들에 의해서는 영향을 받지 않았다. 2) 흉선세포 DNA의 분절화가 dexamethasone과 A2318T에 의하여 유의하게 증강되어 있으며 DHEA에 의하여도 다소 증가되었으나, DFMO, MGBG, aminoguanidine, putrescine, spermidine, 및 spermine들에 의하여는 크게 영향을 받지 않았다. 3) Dexamethasone에 의한 흉선세포의 apoptosis는 DHEA에 의하여 억제된 반면, DFMO, MGBG, 및 aminoguanidine에 의하여는 영향을 받지 않았다. Spermine은 dexamethasone과 A23187에 의한 세포생존율 감소를 유의하게 억제하였으며, A23187에 의한 세포생존율 감소는 putrescine과 spermidine에 의하여도 억제되는 경향을 보였다. 4) DFMO 및 MGBG에 의한 흉선세포 생존율 감소는 spermine에 의해 현저히 억제되었으나, putrescine과 spermidine에 의하여는 영향을 받지 않았다. 5) Dexamethasone을 DFMO 또는 MGBG와 병합처치하여 나타나는 흉선세포 생존율 감소는 각각 spermine과 putrescine에 의하여 유의하게 억제되었으나, aminoguanidine 또는 DHEA와 dexamethasone의 병합처치에 의한 생존율 감소는 polyamine 전처치에 의해 감소되지 않았다. 이상의 결과는 polyamine이 흉선세포의 apoptosis 반응을 억제할 수 있고, 이같은 억제효과의일부가 $[Ca^{2+}]_i$ 증가에 관련되는 신호전달과정과 연관될 뿐 아니라, 세포막의 polyamine transporter를 통한 polyamine 섭취가 이들의 생합성 또는 유리기능과 함께 세포내 polyamine 함량을 조정하므로, 흉선세포의 apoptosis에 억제적으로 작용할 수 있음을 시사하는 것으로 사료된다.

• Archives of Pharmacal Research
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• 제25권5호
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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.

• 대한약리학회지
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• 제28권2호
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• pp.115-128
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• 1992

Two-way shuttle box에서 active conditioned response (ACR)을 10일간 매일 30회 부하하여 10회 이상 반응한 웅성 Wistar 백서를 이용하여, 경련성 전기충격 (ECS: 50 mA, 100 Hz, 1.5 sec)에 의한 ACR-유지의 변동에 미치는 CDP-choline (250 mg/kg/day/CC), aminoguanidine (100 mg/kg/day: AG), ${\alpha}-difluoromethylornithine$ (250 mg/kg/day, DO), 및 spermine (10/mg/kg/day: SM) 각각의 10일간 복강내-주사의 영향을 검토하였다. 그 결과, 10일간 획득된 ACR은 그 다음 10일후에 더욱 증가되었으며, 이는 일일 간격의 5회 ECS (5-ECS) 또는 ACR-유지검사 3시간전 일회 ECS (ECS-3h)로 현저히 억제되나, ACR-유지검사 24시간전의 일회 ECS (ECS-24h)로는 별 영향을 받지 않았다. 아울러, ACR의 자연증가현상은 CC와 SM에 의하여 현저히 저하되었으나 AG와 DFMO에 의하여는 영향을 받지 않았다. 5-ECS에 의한 ACR-유지저해는 AG, SM, 및 CC에 의하여 유의하게 되었으며 DFMO에 의하여는 영향을 받지 않았다. ECS-3h 후의 ACR-유지저해는 SM와 AG에 의하여 다소 더 악화되었고 CC와 DFMO에 의하여는 별 영향을 받지 않았는데, 정상 백서에 비하여 큰 차를 보이지 않은 ECS-24h 후의 ACR은 CC, SM, DO, 및 AG에 의하여도 영향을 받지 않았다. 한편, ECS-3h와 ECS-24는 백서-대뇌 시상하부(HT), 해마(HC), 및 내후피질(EC)의 acetylcholine (ACh) 함량에 별 영향을 미치지 않았으나, $5{\times}ECS$는 다소 증가시켰으며 특히 EC의 ACh증가는 유의하였다. 아울러 CC과 SM도 대뇌-ACh 함량을 유의하게 증가시켰으나, DO와 AG는 별 영향을 미치지 않았다. ECS-3h와 ECS-24h는 대뇌 HT, HC, 및 EC의 polyamine 함량에 영향을 미치지 않았으나, $5{\times}ECS$는 HT와 HC의 putrescine (Pt) 함량과 HC의 spermine (Sm) 함량을 각각 유의하게 감소시켰다. CC는 PT함량에 영향을 미치지 않았으나 spermidine (Sd)와 Sm 함량은 현저히 증가시켰다. 그러나 이같은 CC의 작용을 ECS-3 시간후와 24시간후에는 전혀 볼 수 없었을 뿐 아니라, ECS-3 시간후의 HC의 Sd 함량은 정상치보다 유의한 감소로 역전되었다. 또한 CC는 $5{\times}ECS$에 의한 Pt와 Sm 함량-감소를 유의하게 억제하였다. SM은 전 부위의 Sd 함량과 EC의 Sm 함량을 유의하게 증가시켰고, 이같은 증가가 ECS-3 시간후에 더욱 상승되었으며, 이때 HC와 EC의 Pt함량도 유의하게 증가되었다. 또한 SM은 $5{\times}ECS$에 의해 Pt와 Sm 함량-감소를 유의하게 억제하였다. 그러나 DO는 HC의 Sd와 모든 부위의 Sm 함량을 유의하게 감소시켰고 또한 Pt와 Sm에 대한 $5{\times}ECS$의 감소작용을 더 상승시켰다. AG는 모든 부위의 Pt 함량을 현저히 증가시켰을 뿐 아니라 HT의 Sd와 모든 부위의 Sm도 유의하게 증가시켰고, $5{\times}ECS$에 의한 Pt와 Sm 함량-감소를 유의하게 억제하였다. 이상의 성적은 $5{\times}ECS$로 나타나는 ACR의 유지-저해에 대한 aminoguanidine의 보호작용의 일부가 polyamine 대사에 대한 그의 diamine oxidase 억제작용에 기인됨을 시사하는 것으로 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제1권6호
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• pp.665-672
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• 1997

This study aimed to investigate the mechanism of cerebroprotection of platelet-activating factor(PAF) antagonists in transient cerebral ischemia of rat. Right middle cerebral artery(MCA) of Sprague-Dawley rat was occluded for 2 hours using an intraluminal filament technique. After 22 hours of reperfusion, morphometrically detectable infarct was developed in the cortex and striatum identical to the territory of MCA. The infarct size was significantly reduced by PAF antagonists, BN 52021 and CV-6209, as well as an inducible nitric oxide synthase(iNOS) inhibitor aminoguanidine(1 mg/kg, i.p., respectively) administered 5 min after MCA occlusion. PAF antagonists significantly inhibited the enzymatic activities of both myeloperoxidase and iNOS in the cerebral hemisphere ipsilateral to ischemia, whereas aminoguanidine did not inhibit myeloperoxidase activity but significantly inhibited the iNOS activity. These results suggest that PAF antagonists exert a cerebroprotective effect against ischemic brain damage through inhibition of leukocyte infiltration and iNOS activity in the postischemic brain.

• 생약학회지
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• 제40권4호
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• pp.388-393
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• 2009

Advanced glycation end products (AGEs) have been implicated in the development of diabetic complications. The AGEs inhibitors or cross-link breakers attenuate various functional and structural manifestations of diabetic complications. In this study, 64 herbal medicines from China and Vietnam have been investigated with an in vitro evaluation system using AGEs inhibitory activity. Of these, eight herbal medicines ($IC_{50}$<50 ${\mu}g$/ml) were found to have strong AGEs inhibitory activity compared with aminoguanidine (14 days, $IC_{50}$=75.98 ${\mu}g$/ml; 28 days, $IC_{50}$=88.27 ${\mu}g$/ml). Particularly, four herbal medicines, Buddleja officinalis (whole plant), Syzygium cuminii (leaf), Eugenia caryophyllate (seed), and Paeonia suffruticosa (root) showed more potent inhibitory activity (approximately 5-6 fold) than the positive control aminoguanidine.

• 생약학회지
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• 제33권4호통권131호
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• pp.308-311
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• 2002

Advanced glycation end products(AGEs) are largly involved in the pathogenesis of diabetic nephropathy. It is obvious that inhibition of AGEs formation is important in preventing the occurrence and progression of diabetic nephropathy. In diabetes, this reaction is greatly accerated and is important in the pathogenesis of diabetic complications, especially diabetic nephropathy. Therefore, to seek possible AGEs inhibitors in herbal medicines, unprocessed - and processed Magnolia Bark were examined in vitro as basic data for aniaml experiment. The content of magnolol in unprocessed Magnolia Bark was $0.796{\pm}0.072%$, and after processing was decreased to $0.586{\pm}0.101%(p<0.01)$. The content of AGEs was measured by their intrinsic fluorescence. The $IC_{50}({\mu}g/ml)$ values of aminoguanidine, unprocessed- and procesled Magnolia Bark are $38.845{\pm}8.36{\mu}g/ml$, $54.264{\pm}3.153{\mu}g/ml$ and $27.882{\pm}1.836{\mu}g/ml$, respectively. This result means that prcessed Magnolia Bark was more effective than aminoguanidine, as positive control.