• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.481-487
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• 2014

Ischemic postconditioning (IPost) could decrease ischemia-reperfusion (IR) injury. It has not yet reported whether IPost is useful when ischemic heart disease is accompanied with co-morbidities like hyperthyroidism. The aim of this study was to examine the effect of IPost on myocardial IR injury in hyperthyroid male rats. Hyperthyroidism was induced with administration of thyroxine in drinking water (12 mg/L) over a period of 21 days. After thoracotomy, the hearts of control and hyperthyroid rats were perfused in the Langendorff apparatus and subjected to 30 minutes global ischemia, followed by 120 minutes reperfusion; IPost, intermittent early reperfusion, was induced instantly following ischemia. In control rats, IPost significantly improved the left ventricular developed pressure (LVDP) and ${\pm}dp/dt$ during reperfusion (p<0.05); however it had no effect in hyperthyroid rats. In addition, hyperthyroidism significantly increased basal $NO_x$ (nitrate+nitrite) content in serum ($125.5{\pm}5.4{\mu}mol/L$ vs. $102.8{\pm}3.7{\mu}mol/L$; p<0.05) and heart ($34.9{\pm}4.1{\mu}mol/L$ vs. $19.9{\pm}1.94{\mu}mol/L$; p<0.05). In hyperthyroid groups, heart $NO_x$ concentration significantly increased after IR and IPost, whereas in the control groups, heart $NO_x$ were significantly higher after IR and lower after IPost (p<0.05). IPost reduced infarct size (p<0.05) only in control groups. In hyperthyroid group subjected to IPost, aminoguanidine, an inducible nitric oxide (NO) inhibitor, significantly reduced both the infarct size and heart $NO_x$ concentrations. In conclusion, unlike normal rats, IPost cycles following reperfusion does not provide cardioprotection against IR injury in hyperthyroid rats; an effect that may be due to NO overproduction because it is restored by iNOS inhibition.

• Korean Journal of Veterinary Research
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• v.43 no.4
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• pp.597-606
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• 2003

Although the antidepressant effects of imipramine (IMI) have been well known in several studies, the effects on cardiovascular system, particularly the vasorelaxant effects, have not known clearly. We hypothesis that IMI-induced vasorelaxation involves NO (nitrie oxide), activation of guanylate cyclase (GC) and $Ca^{2+}$ channel. The possible roles of the endothelium and $Ca^{2+}$ in IMI-induced responses were investigated using isolated rings of rat thoracic aorta and anesthesized rats. In KCl-precontracted rings. IMI produces endothelium-dependent and endothelium-independent relaxations in intact (+E) as well as endothelium-denuded (-E) rat aorta in a concentration-dependent manner. In phenylephrine (PE)-precontracted rings, the IMI-induced relaxation was significantly greater in +E rings. The IMI-induced relaxations were suppressed by nitric oxide synthase (NOS) inhibitors, N(G)-nitro-L-arginine (L-NNA), N(omega)-nitro-L-arginine methyl ester (L-NAME) and aminoguanidine, a non-selective GC inhibitor, methylene blue, $Na^+$ channel blockers, lidocaine and procaine, or $Ca^{2+}$ channel blockers, nifedipine and verapamil, in PE-precontracted +E rings, but not in PE-precontracted -E rings. These relaxations were also suppressed by lidocaine or procaine in -E aortic rings. However, IMI-induced relaxations were not inhibited by a PLC inhibitor 2-nitro-4-carboxyphenyl-n,n-diphenylcarbamate (NCDC), an inositol monophosphatase inhibitor, lithium, indomethacin and dexamethasone in +E and -E rings. In vivo, infusion of IMI elicited significant decrease in arterial blood pressure. After intravenous injection of saponin, NOS inhibitors. MB and nifedipine, infusion of IMI inhibited the IMI-lowered blood pressure markedly. These findings suggest that the endothelium-dependent relaxation induced by IMI is mediated by activation of NO/cGMP signaling cascade or inhibition of $Ca^{2+}$ entry through voltage-gated channel, and this mechanism may contribute to the hypotensive effects of IMI in rats.

• Molecules and Cells
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• v.39 no.3
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• pp.195-203
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• 2016

Copper is an essential element required for a variety of functions exerted by cuproproteins. An alteration of the copper level is associated with multiple pathological conditions including chronic ischemia, atherosclerosis and cancers. Therefore, copper homeostasis, maintained by a combination of two copper ions ($Cu^+$ and $Cu^{2+}$), is critical for health. However, less is known about which of the two copper ions is more toxic or functional in endothelial cells. Cubic-shaped $Cu_2O$ and CuO crystals were prepared to test the role of the two different ions, $Cu^+$ and $Cu^{2+}$, respectively. The $Cu_2O$ crystal was found to have an effect on cell death in endothelial cells whereas CuO had no effect. The $Cu_2O$ crystals appeared to induce p62 degradation, LC3 processing and an elevation of LC3 puncta, important processes for autophagy, but had no effect on apoptosis and necrosis. $Cu_2O$ crystals promote endothelial cell death via autophagy, elevate the level of reactive oxygen species such as superoxide and nitric oxide, and subsequently activate AMP-activated protein kinase (AMPK) through superoxide rather than nitric oxide. Consistently, the AMPK inhibitor Compound C was found to inhibit $Cu_2O$-induced AMPK activation, p62 degradation, and LC3 processing. This study provides insight on the pathophysiologic function of $Cu^+$ ions in the vascular system, where $Cu^+$ induces autophagy while $Cu^{2+}$ has no detected effect.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.743-748
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• 2005

This study was performed for the investigation of vasodilatory efficacy and its underlying mechanisms of Jagumhuan(JGH), a herbal remedy. JGH produced completely endothelium-dependent relaxation and relaxed phenylephrine(PE)-precontracted aorta in a concentration dependent manner. The magnitude of relaxation was greater in PE induced contraction than that of KCl, suggesting involvement of $K^+$ channel in the relaxant effect. Both glibenclamide$(10^{-5}M)$, a $K_{ATP}$ channel inhibitor and indometacin, a cyclooxygenase inhibitor, completely prevented this relaxation. The relaxation effects of JGH, involve in part the release of nitric oxide from the endothelium as pretreatment with L-NAME, an NOS inhibitor, and methylene blue, a cGMP inhibitor, attenuated the responses by 62% and 58%, respectively. In addition, nitrite was produced by JGH in human aortic smooth muscle cells and human umbilical vein endothelial cells. The relaxant effect of JGH was also inhibited by 55.41% by tetraethylammonium(TEA; 5mM), a $K_{Ca}$ channel inhibitor. In the absence of extracellular $Ca^{2+}$, pre-incubation of the aortic rings with JGH significantly reduced the contraction by PE, suggesting that the relaxant action of the JGH includes inhibition of $Ca^{2+}$ release from intracellular stores. These results indicate that in rat thoracic aorta, JGH may induce vasodilation through ATP sensitive $K^+$ channel activation by prostacyclin production. However, the relaxant effect of JGH may also mediated in part by NO pathways and $Ca^{2+}$ activated $K^+$ channel.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.4
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• pp.277-286
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• 2006

In the present study, I investigated the effects of N-methyl-D-aspartate (NMDA), arachidonic acid (AA), and Nitric Oxide Synthase Inhibitor (NOS-I), alone or in combination, on the viability of cultured primary normal human oral keratinocytes (NHOK). Specifically, we examined whether AA and NOS-I could protect primary NHOK from glutamate cytotoxicity. The purpose of this study was therefore the preliminary study for the examination of the interaction between these agents and NHOK in order to elucidate the mechanisms by which epithelial growth and regeneration are regulated. NHOK were obtained from gingival tissue of 20 individuals aged 20 to 29, and third passage (P3) cells were used for this study. Cell viability was measured by the MTT assay. NMDA and NNA, a calcium dependent NOS inhibitor, induced an initial increase in cell number, which subsequently decreased by the $7^{th}$ day. Low concentration of AA ($0.5\;{\mu}M$ & $1\;{\mu}M$) induced an increase in cell number while high concentrations of AA ($5\;{\mu}M$ & $10\;{\mu}M$) induced a decrease in cell number. The decrease in cell number induced by NMDA at the $7^{th}$ day was abolished by the addition of low concentrations of AA ($0.5\;{\mu}M$ & $1\;{\mu}M$) or NOS inhibitors. Low concentrations of AA ($0.5\;{\mu}M$ & $1\;{\mu}M$) or NOS inhibitors may protect the NHOK from NMDA induced cytotoxicity. These reactions might be related to the NMDA receptor in the cell and the change of the intracellular calcium ion concentration.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.6
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• pp.405-413
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• 2011

This study was designed to elucidate high-$K^+$ induced response of circular and longitudinal smooth muscle from human gastric corpus using isometric contraction. Contraction from circular and longitudinal muscle stripes of gastric corpus greater curvature and lesser curvature were compared. Circular smooth muscle from corpus greater curvature showed high $K^+$ (50 mM)-induced tonic contraction. On the contrary, however, longitudinal smooth muscle strips showed high $K^+$ (50 mM)-induced sustained relaxation. To find out the reason for the discrepancy we tested several relaxation mechanisms. Protein kinase blockers like KT5720, PKA inhibitor, and KT5823, PKG inhibitor, did not affect high $K^+$-induced relaxation. $K^+$ channel blockers like tetraethylammonium (TEA), apamin (APA), glibenclamide (Glib) and barium ($Ba^{2+}$) also had no effect. However, N(G)-nitro-L-arginine (L-NNA) and 1H-(1,2,4) oxadiazolo (4,3-A) quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase (sGC) and 4-AP (4-aminopyridine), voltage-dependent $K^+$ channel (KV) blocker, inhibited high $K^+$ -induced relaxation, hence reversing to tonic contraction. High $K^+$-induced relaxation was observed in gastric corpus of human stomach, but only in the longitudinal muscles from greater curvature not lesser curvature. L-NNA, ODQ and KV channel blocker sensitive high $K^+$-induced relaxation in longitudinal muscle of higher portion of corpus was also observed. These results suggest that longitudinal smooth muscle from greater curvature of gastric corpus produced high $K^+$-induced relaxation which was activated by NO/sGC pathway and by $K_V$ channel dependent mechanism.

• Journal of Ginseng Research
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• v.39 no.2
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• pp.169-177
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• 2015

Background: Ginsenoside Rd (GSRd), one of the most abundant ingredients of Panax ginseng, protects the heart via multiple mechanisms including the inhibition of $Ca^{2+}$ influx.We intended to explore the effects of GSRd on L-type $Ca^{2+}$ current ($I_{Ca,L}$) and define the mechanism of the suppression of $I_{Ca,L}$ by GSRd. Methods: Perforated-patch recording and whole-cell voltage clamp techniques were applied in isolated rat ventricular myocytes. Results: (1) GSRd reduced $I_{Ca,L}$ peak amplitude in a concentration-dependent manner [half-maximal inhibitory concentration $(IC_{50})=32.4{\pm}7.1{\mu}mol/L$] and up-shifted the current-voltage (I-V) curve. (2) GSRd ($30{\mu}mol/L$) significantly changed the steady-state activation curve of $I_{Ca,L}$ ($V_{0.5}:-19.12{\pm}0.68$ vs. $-6.26{\pm}0.38mV$; n = 5, p < 0.05) and slowed down the recovery of $I_{Ca,L}$ from inactivation [the time content (${\zeta}$) from 91 ms to 136 ms, n = 5, p < 0.01]. (3) A more significant inhibitive effect of GSRd ($100{\mu}mol/L$) was identified in perforated-patch recording when compared with whole-cell recording [$65.7{\pm}3.2%$ (n = 10) vs. $31.4{\pm}5.2%$ (n = 5), p < 0.01]. (4) Pertussis toxin ($G_i$ protein inhibitor) completely abolished the $I_{Ca,L}$ inhibition induced by GSRd. There was a significant difference in inhibition potency between the two cyclic adenosine monophosphate elevating agents (isoprenaline and forskolin) prestimulation [$55{\pm}7.8%$ (n = 5) vs. $17.2{\pm}3.5%$ (n = 5), p < 0.01]. (5) 1H-[1,2,4]Oxadiazolo[4,3-a]-quinoxalin-1-one (a guanylate cyclase inhibitor) and N-acetyl-$\small{L}$-cysteine (a nitric oxide scavenger) partly recovered the $I_{Ca,L}$ inhibition induced by GSRd. (6) Phorbol-12-myristate-13-acetate (a protein kinase C activator) and GF109203X (a protein kinase C inhibitor) did not contribute to the inhibition of GSRd. Conclusion: These findings suggest that GSRd could inhibit $I_{Ca,L}$ through pertussis toxin-sensitive G protein ($G_i$) and a nitric oxide-cyclic guanosine monophosphate-dependent mechanism.

• Archives of Pharmacal Research
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• v.29 no.7
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• pp.591-597
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• 2006

Aerial parts of Artemisia asiatica (Compositae) have been traditionally used as an oriental medicine for the treatment of inflammatory and ulcerogenic diseases. In the present study, artemisolide was isolated as a nuclear factor $(NF)-{\kappa}B$ inhibitor from A. asiatica by activity-guided fractionation. Artemisolide inhibited $NF-{\kappa}B$ transcriptional activity in lipopolysaccharide (LPS)-stimulated macrophages RAW 264.7 with an $IC_{50}$ value of $5.8\;{\mu}M$. The compound was also effective in blocking $NF-{\kappa}B$ transcriptional activities elicited by the expression vector encoding the $NF-{\kappa}B$ p65 or p50 subunits bypassing the inhibitory kB degradation signaling $NF-{\kappa}B$ activation. The macrophages markedly increased their $PGE_2$ and NO production upon exposure to LPS alone. Artemisolide inhibited LPS-induced $PGE_2$ and NO production with $IC_{50}$ values of $8.7\;{\mu}M$ and $6.4\;{\mu}M$, respectively, but also suppressed LPS-induced synthesis of cyclooxygenase (COX)-2 or inducible NO synthase (iNOS). Taken together, artemisolide is a $NF-{\kappa}B$ inhibitor that attenuates LPS-induced production of $PGE_2$ or NO via down-regulation of COX-2 or iNOS expression in macrophages RAW 264.7. Therefore, artemisolide could represent and provide the anti-inflammatory principle associated with the traditional medicine, A. asiatica.

• Journal of Life Science
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• v.29 no.4
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• pp.402-409
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• 2019

Korean red ginseng made from steaming and drying fresh ginseng has long been used as a traditional herbal medicine due to its effects on the immune, endocrine, and central nerve systems and its anti-inflammatory activity. In this study, we investigated the molecular mechanism responsible for the anti-inflammatory effects of a formulated Korean red ginseng extract (RGE) in response to lipoteichoic acid (LTA), a cell wall component of gram-positive bacteria. RGE inhibited LTA-induced nitric oxide (NO) secretion and inducible nitric oxide synthase (iNOS) expression in BV-2 microglial cells, without affecting cell viability. RGE also inhibited nuclear translocation of nuclear factor kappa B ($NF-{\kappa}B$) p65 and degradation of $I{\kappa}B-{\alpha}$. In addition, RGE increased the expression of heme oxygenase-1 (HO-1) in a dose-dependent manner, and the inhibitory effect of RGE on iNOS expression was abrogated by small interfering RNA-mediated knockdown of HO-1. Moreover, RGE induced nuclear translocation of nuclear factor E2-related factor 2 (Nrf2), a transcription factor that regulates HO-1 expression. Furthermore, the phosphoinositide-3-kinase (PI-3K) inhibitor and mitogen-activated protein kinase (MAPK) inhibitors suppressed RGE-mediated expression of HO-1, and RGE enhanced the phosphorylation of Akt, extracellular signal-regulated kinases (ERKs), p38, and c-JUN N-terminal kinases (JNKs). These results suggested that RGE suppressed the production of NO, a proinflammatory mediator, by inducing HO-1 expression via PI-3K/Akt- and MAPK-dependent signaling in LTA-stimulated microglia. The findings indicate that RGE could be used for the treatment of neuroinflammation induced by grampositive bacteria and that it may have therapeutic potential for various neuroinflammation-associated disorders.

• Journal of Korean Neurosurgical Society
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• v.50 no.5
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• pp.403-408
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• 2011

Objective : Contrary to some clinical belief, there were quite a few studies regarding animal models of intracerebral hemorrhage (ICH) $in$ $vivo$ suggesting that prior use of statins may improve outcome after ICH. This study reports the effect of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG CoA) reductase inhibitor, simvastatin given before experimental ICH. Methods : Fifty-one rats were subjected to collagenase-induced ICH, subdivided in 3 groups according to simvastatin treatment modality, and behavioral tests were done. Hematoma volume, brain water content and hemispheric atrophy were analyzed. Immunohistochemical staining for microglia (OX-42) and endothelial nitric oxide synthase (eNOS) was performed and caspase-3 activity was also measured. Results : Pre-simvastatin therapy decreased inflammatory reaction and perihematomal cell death, but resulted in no significant reduction of brain edema and no eNOS expression in the perihematomal region. Finally, prior use of simvastatin showed less significant improvement of neurological outcome after experimental ICH when compared to post-simvastatin therapy. Conclusion : The present study suggests that statins therapy after ICH improves neurological outcome, but prior use of statins before ICH might provide only histological improvement, providing no significant impact on neurological outcome against ICH.