• The Korean Journal of Physiology and Pharmacology
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• 제13권6호
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• pp.461-467
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• 2009

The auditory cortex (A1) encodes the acquired significance of sound for the perception and interpretation of sound. Nitric oxide (NO) is a gas molecule with free radical properties that functions as a transmitter molecule and can alter neural activity without direct synaptic connections. We used whole-cell recordings under voltage clamp to investigate the effect of NO on spontaneous GABAergic synaptic transmission in mechanically isolated rat auditory cortical neurons preserving functional presynaptic nerve terminals. GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs) in the A1 were completely blocked by bicuculline. The NO donor, S-nitroso-N-acetylpenicillamine (SNAP), reduced the GABAergic sIPSC frequency without affecting the mean current amplitude. The SNAP-induced inhibition of sIPSC frequency was mimicked by 8-bromoguanosine cyclic 3',5'-monophosphate, a membrane permeable cyclic-GMP analogue, and blocked by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, a specific NO scavenger. Blockade of presynaptic $K^+$ channels by 4-aminopyridine, a $K^+$ channel blocker, increased the frequencies of GABAergic sIPSCs, but did not affect the inhibitory effects of SNAP. However, blocking of presynaptic $Ca^{2+}$ channels by $Cd^{2+}$, a general voltage-dependent $Ca^{2+}$ channel blocker, decreased the frequencies of GABAergic sIPSCs, and blocked SNAP-induced reduction of sIPSC frequency. These findings suggest that NO inhibits spontaneous GABA release by activation of cGMP-dependent signaling and inhibition of presynaptic $Ca^{2+}$ channels in the presynaptic nerve terminals of A1 neurons.

• 대한의생명과학회지
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• 제20권2호
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• pp.70-76
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• 2014

In this study, we investigated the effect of DMSO, a highly dipolar organic liquid, in collagen ($5{\mu}g/ml$)-stimulated platelet aggregation. DMSO inhibited platelet aggregation at 0.5% by inhibiting production of thromboxane $A_2$ ($TXA_2$) which was associated with blocking cyclooxygenase (COX)-1 activity and $TXA_2$ synthase. In addition, DMSO significantly increased the formation of cyclic adenosine monophosphate (cAMP) from adenosine triphosphate (ATP) and cyclic guanosine monophosphate (cGMP) from guanosine triphosphate (GTP). On the other hand, DMSO (0.1~0.5% concentration) did not affect the LDH release which indicates the cytotoxicity. Based on these results, DMSO has anti-platelet effect by regulation of several platelet signaling pathways, therefore we suggest that DMSO could be a novel strategy on many thrombotic disorders.

• 대한한의학회지
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• 제18권2호
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• pp.15-32
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• 1997

This study was undertaken to define the mechanism of Siegesbeckiae Herba-induced relaxation in rabbit common carotid artery contracted by agonists. In order to investigate the effect of Siegesbeckiae Herba on contracted rabbit carotid arterial strips, transverse strips with intact or damaged endothelium were used for the experiment using organ bath. To analyze the mechanism of Siegesbeckiae Herba-induced relaxation, Siegesbeckiae Herba extract infused into contracted arterial strips induced by agonists after treatment of lanthanum chloride, indomethacin, atropine, $N\omega-nitro-{_L}-arginine$, cobalt chloride or methylene blue. The relaxation effect of Siegesbeckiae Herba was dependent on the presence of endothelium, showing that Siegesbeckiae Herba-induced relaxation was not observed in the strips without endothelium. The endothelium-dependent relaxation induced by Siegesbeckiae Herba was suppressed by the pretreatment of lanthanum chloride, $N\omega-nitro-{_L}-arginine$, cobalt chloride or methylene blue, but it was not observed in the strips pretreated with indomethacin or atropine. These results demonstrated that Siegesbeckiae Herba may inhibit agonist-induced contraction through an increase in the cyclic GMP by the production of nitric oxide in the vascular endothelial cells.

• 동아시아식생활학회지
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• 제15권5
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• pp.606-612
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• 2005

This study was performed to provide basic data that predict the application of Saengmaegsan(SMS) as medicinal food. SMS has been used in oriental medicine for many years as a therapeutic agent for cerebral disease. We examined the effects of SMS on physiological function in isolated abdominal aorta and femoral artery from rabbit and measured the changes of regional cerebral hood flow(rCBF), which was continually monitored by laser-doppler flowmeter and pressure transducer in anesthetized adult Spargue-Dawley rats through the data acquisition system composed of MacLab and Macintosh computer. The contraction forces by injection of norephinephrine in isolated abdominal aorta and femoral artery were significantly decreased in each concentration of SMS treatment compared with control. rCBF was increased by SMS in a dose-dependent manner. These results suggest that SMS causes a diverse response of rCBF and arterial diameter. These mechanism in rCBF increase may be mediated by prostaglandis, cyclic GMP and adrenergic $\beta-receptor$. Also mechanism in artery contraction decrease is also mediated by prostaglandis and cyclic GMP. These results indicate that SMS can be nsed as a safe and clinically applicable as a supplementation of diet therapy for cerebral cardiovascular disease patients.

• 대한의생명과학회지
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• 제29권1호
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• pp.41-47
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• 2023

Discovery of new substance that can regulate platelet aggregation or suppress aggregation will aid in the prevention and treatment of cardiovascular diseases. Artesunate is a compound from plant roots of Artemisia or Scopolia, and its effects have shown to be promising in areas of anticancer and Alzheimer's disease. However, the role and mechanisms by which artesunate affects the aggregation of platelets, and the formation of a thrombus are currently not understood. This study examined the ways artesunate affects platelets activation and thrombus formation induced by collagen. As a result, cAMP and cGMP production were increased significantly by artesunate relative to the doses, as well as phosphorylated VASP and IP₃R, substrates to cAMP-dependent kinase and cGMP-dependent kinase, in a significant manner. The Ca²⁺ normally mobilized from the dense tubular system was inhibited due to IP₃R, phosphorylation from artesunate, and phosphorylated VASP aided in inhibiting platelet activity via αIIb/β₃ platelet membrane inactivation and inhibiting fibrinogen binding. Finally, artesunate inhibited thrombin-induced thrombus formation. Therefore, we suggest that artesunate has importance with cardiovascular diseases stemming from the abnormal platelets activation and thrombus formation by acting as an effective prophylactic and therapeutic agent.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.158-158
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• 2015

Myoblast are myogenic precursors that proliferate, activate, and differentiate on muscle injury to sustain the regenerative capacity of skeletal muscle; The neuronal isoform of nitric oxide synthase (nNOS, termed also NOS-I) is expressed in normal adult skeletal muscle, suggesting important functions for Nitric oxide (NO) in muscle biology1,2,3. However, the expression and subcellular localization of NO in muscle development and myoblast differentiation are largely unknown. In this study, we examined effects of the nitric oxide generated by a microwave plasma torch, on proliferation/differentiation of rat myoblastic L6 cells. Experimental data pertaining to nitric oxide production are presented in terms of the oxygen input in units of cubic centimetres per minute. The various levels of nitric oxide are observed depending on the flow rate of nitrogen gas, the ratio of oxygen gas, and the microwave power4. In order to evaluate the potential of nitric oxide as an activator of cell differentiation, we applied nitric oxide generated from the microwave plasma torch to L6 skeletal muscles. Differentiation of L6 cells into myotubes was significantly enhanced the differentiation after nitric oxide treatment. Nitric oxide treatment also increase the expression of myogenesis marker proteins and mRNA level, such as myogenin and myosin heavy chain (MHC), as well as cyclic guanosine monophosphate (cGMP), However during the myotube differentiation we found that NO activate oxidative stress signaling erks expression. Therefore, these results establish a role of NO and cGMP in regulating myoblast differentiation and elucidate their mechanism of action, providing a direct link with oxidative stress signalling, which is a key player in myogenesis. Based on these findings, nitric oxide generated by plasma can be used as a possible activator of cell differentiation and tissue regeneration.

• Biomolecules & Therapeutics
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• 제19권2호
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• pp.218-223
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• 2011

In this study, we investigated the effect of spinach saponin-enriched fraction (SSEF) on collagen (10 ${\mu}g/ml$)-stimulated platelet aggregation. SSEF inhibited collagen-induced platelet aggregation, and which was involved in the inhibition of thromboxane $A_2$ ($TXA_2$) production, an intracellular $Ca^{2+}$-agonist as an aggregation-inducing autacoidal molecule. In addition, SSEF significantly increased the formation of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), intracellular $Ca^{2+}$-antagonists as aggregation-inhibiting molecules, in collagen-stimulated platelets. These results suggest that SSEF might inhibit $Ca^{2+}$-elevation and $TXA_2$ formation by increasing the production of $Ca^{2+}$-antagonistic molecules cAMP and cGMP. These mean that SSEF is a potent inhibitor of collagen-stimulated platelet aggregation. On the other hand, prothrombin time (PT) and activated partial thromboplastin time (APTT) were potently prolonged by SSEF. These findings suggest that SSEF prolongs the internal time between the conversion of fibrinogen to fibrin. Accordingly, our data demonstrate that SSEF may be a crucial tool for a negative regulator during platelet activation and blood coagulation on thrombotic diseases.

• Journal of Ginseng Research
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• 제47권5호
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• pp.638-644
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• 2023

Background: The anti-platelet activity of the saponin fraction of Korean Red Ginseng has been widely studied. The saponin fraction consists of the panaxadiol fraction (PDF) and panaxatriol fraction (PTF); however, their anti-platelet activity is yet to be compared. Our study aimed to investigate the potency of anti-platelet activity of PDF and PTF and to elucidate how well they retain their anti-platelet activity via different administration routes. Methods: For ex vivo studies, Sprague-Dawley rats were orally administered 250 mg/kg PDF and PTF for 7 consecutive days before blood collection via cardiac puncture. Platelet aggregation was conducted after isolation of the washed platelets. For in vitro studies, washed platelets were obtained from Sprague-Dawley rats. Collagen and adenosine diphosphate (ADP) were used to induce platelet aggregation. Collagen was used as an agonist for assaying adenosine triphosphate release, thromboxane B2, serotonin, cyclic adenosine monophosphate, and cyclic guanosine monophosphate (cGMP) release. Results: When treated ex vivo, PDF not only inhibited ADP and collagen-induced platelet aggregation, but also upregulated cGMP levels and reduced platelet adhesion to fibronectin. Furthermore, it also inhibited Akt phosphorylation induced by collagen treatment. Panaxadiol fraction did not exert any antiplatelet activity in vitro, whereas PTF exhibited potent anti-platelet activity, inhibiting ADP, collagen, and thrombin-induced platelet aggregation, but significantly elevated levels of cGMP. Conclusion: Our study showed that in vitro and ex vivo PDF and PTF treatments exhibited different potency levels, indicating possible metabolic conversions of ginsenosides, which altered the content of ginsenosides capable of preventing platelet aggregation.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1993년도 학술대회지
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• pp.40-48
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• 1993

Intravenous administration of saponin extracted from the root of Panax ginseng lowered the blood pressure dose-dependently (10-200 mg/kg, B.W) in anesthetized rats. Therefore, experiments were designed to study the hypothesis that the lowering of blood pressure is associated with the release of endothelium-derived relaxing factor and the accumulation of guanosine 3, 5-cyclic monophosphate (cGMP). Rings of thoracic aorta with and without endothelium were suspended for the measurement of isometric tension in organ chamber and the tissue content of cGMP was measured by radioimmunoassay. All experiments were performed in the presence of $indomethacin(10^{-5}M).$ Ginseng saponin $(10^{-5}-3{\times}10^{-6}g/ml)$ relaxed contractions induced by phenylephrine $10^{-6}M)$ in the aorta with endothelium but not in that without endothelium. Treatment of aortic rings with $N^G$ monomethyl-L-arginine (L-NMMA, $10^{-4}M$ for 30 min), a competitive inhibitor of nitric oxide synthase, and methylene blue $(MB,\;3{\times}10^{-7}M$ for 30 min). an inhibitor of soluble guanylate cyclase, diminished the relaxation induced by Ginseng saponin. Ginseng saponin $10^{-4}g/ml$ for 2 min) increased the accumulation of cGMP in rings with endothelium. L-NMMA and MB inhibited the accumulation of cGMP induced by Ginseng saponin. These data suggest that vascular relaxations induced by Ginseng saponin are mediated by release of endothelium-derived relaxing factor and the accumulation of cGMP. The effect of Ginseng saponin on endothelial function in hypercholesterolemic rabbits was examined. In hypercholesterolemic rabbits fed with $2\%$ cholesterol for 8 weeks, relaxation of aortic rings to acetylcholine was impaired. The impaired relaxations of aortic rings in hypercholesterolemic rabbits were improved by dietary supplementation of Ginseng saponin, probably because of an improved release of endothelium - derived relaxing factor.

• Journal of Ginseng Research
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• 제37권2호
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• pp.176-186
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• 2013

In this study, we have investigated the effects of total saponin from Korean red ginseng (TSKRG) on thrombin-induced platelet aggregation. TSKRG dose-dependently inhibited thrombin-induced platelet aggregation with $IC_{50}$ value of about 81.1 ${\mu}g/mL$. In addition, TSKRG dose-dependently decreased thrombin-elevated the level of cytosolic-free $Ca^{2+}$ ($[Ca^{2+}]_i$), one of aggregation-inducing molecules. Of two $Ca^{2+}$-antagonistic cyclic nucleotides as aggregation-inhibiting molecules, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), TSKRG significantly dose-dependently elevated intracellular level of cAMP, but not cGMP. In addition, TSKRG dose-dependently inhibited thrombin-elevated adenosine triphosphate (ATP) release from platelets. These results suggest that the suppression of $[Ca^{2+}]_i$ elevation, and of ATP release by TSKRG are associated with upregulation of cAMP. TSKRG elevated the phosphorylation of vasodilator-stimulated phosphoprotein (VASP)-$Ser^{157}$, a cAMP-dependent protein kinase (A-kinase) substrate, but not the phosphorylation of VASP-$Ser^{239}$, a cGMP-dependent protein kinase substrate, in thrombin-activated platelets. We demonstrate that TSKRG involves in increase of cAMP level and subsequent elevation of VASP-$Ser^{157}$ phosphorylation through A-kinase activation to inhibit $[Ca^{2+}]_i$ mobilization and ATP release in thrombin-induced platelet aggregation. These results strongly indicate that TSKRG is a beneficial herbal substance elevating cAMP level in thrombin-platelet interaction, which may result in preventing of platelet aggregation-mediated thrombotic diseases.