• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.6
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• pp.485-491
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• 2015

This study was aimed to investigate the relaxation effects of Eucomiae Cortex (EC) extract in isolated rabbit corpus cavernosum smooth muscle and its mechanism. To evaluate the relaxation of EC extract in rabbit corpus cavernosum, EC extract was treated in corporal strips which were precontracted with phenylephrine(PE). To study its mechanism, Nω-nitro-L-arginine (L-NNA) was pretreated after infuse of EC extract and compared with non-treated. In calcium chloride (Ca²⁺) -free krebs solution, EC extract and Ca²⁺ 1 mM were infused by turns after Ca²⁺ 1 mM was treated into corporal strips contracted by PE. Cell ability, nitric oxide (NO) and epithelial nitric oxide synthase (eNOS) on human umbilical vein endothelial cell (HUVEC) were measured by MTT assay, Griess reagent system and histochemical, immunohistochemical methods. EC extract showed a significant relaxation effects on the corporal strips, this effects were inhibited by pretreatment of L-NNA. EC extract inhibited the increase of contraction by Ca²⁺ influx in Ca²⁺-free krebs solution, and eNOS positive reaction in corpus cavernosum, NO production in HUVEC increased by treatment of EC extract. These result suggest that the relaxation effects of EC extract in isolated corpus cavernosum smooth muscle are involved in increase of eNOS and NO production, blocking of extracellular Ca²⁺ influx.

• Biomolecules & Therapeutics
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• v.16 no.4
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• pp.328-335
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• 2008

This study was undertaken to investigate whether honokiol could enhance the pentobarbitalinduced sleeping behaviors through $\gamma$-aminobutyric acid (GABA) receptor $Cl^-$ channel activation. Thirty minutes after the oral administration of honokiol, mice were received sodium pentobarbital (42 mg/kg, i.p.). The time elapsed from pentobarbital injection to the loss of the righting reflex was taken as sleeping latency. The time elapsed between the loss and voluntary recovery of the righting reflex was considered as the total sleeping time. Western blot technique and $Cl^-$ sensitive fluorescence probe were used to detect the expression of $GABA_A$ receptor subunits and $Cl^-$ influx in the primary cultured cerebellar granule cells. Honokiol (0.1 and 0.2 mg/kg) prolonged the sleeping time induced by pentobarbital (42 mg/kg) in a dosage-dependent manner. Honokiol (20 and 50 ${\mu}M$) increased $Cl^-$ influx in primary cultured cerebellar granule cells, and selectively increased the $GABA_A$ receptor $\alpha$-subunit expression, but had no effect on the abundance of $\beta$ or $\gamma$-subunits. Chronic treatment with 20 ${\mu}M$ honokiol in primary cultured cerebellar neurons did not affect the abundance of GAD65/67. The results suggested that honokiol could potentiate pentobarbital-induced sleeping through $GABA_A$ receptor $Cl^-$ channel activation.

• Korean Journal of Veterinary Research
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• v.34 no.1
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• pp.25-36
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• 1994

The inward tail current after a short depolarizing pulse has been known as Na-Ca exchange current activated by intracellular calcium which forms late plateau of the action potential in rabbit atrial myocytes. Chloride conductance which is also dependent upon calcium concentration has been reported as a possible tail current in many other excitable tissues. Thus, in order to investigate the exsitance of the calcium activated chloride current and its contribution to tail current, whole cell voltage clamp measurement has been made in single atrial cells of the rabbit. The current was recorded during repolarization following a brief 2 ms depolarizing pulse to +40mV from a holding potential of -70mV. When voltage-sensitive transient outward current was blocked by 2 mM 4-aminopyridine or replacement potassium with cesium, the tail current were abolished by ryanodine$(1{\mu}M)$ or diltiazem$(10{\mu}M)$ and turned out to be calcium dependent. The magnitudes of the tail currents were increased when intracellular chloride concentration was increased to 131 mM from 21 mM. The current was decreased by extracellular sodium reduction when intracellular chloride concentration was low(21 mM), but it was little affected by extracellular sodium reduction when intracellual chloride concentration was high(131 mM). The current-voltage relationship of the difference current before and after extracellular sodium reduction, shows an exponential voltage dependence with the largest magnitude of the current occurring at negative potentials, with is similar to current-voltage relationship at negative potentials, which is similar to current-voltage relationship of Na-Ca exchange current. The current was also decreased by $10{\mu}M$ niflumic acid and 1 mM bumetanide, which is well known anion channel blockers. The reversal potentials shifted according to changes in chloride concentration. The current-voltage relationships of the niflumic acid-sensitive currents in high and low concentration of chloride were well fitted to those predicted as chloride current. From the above results, it is concluded that calcium activated chloride component exists in the tail current with Na-Ca exchange current and it shows the reversal of tail current. Therefore it is thought that in the physiologic condition it leads to rapid end of action potential which inhibits calcium influx and it contributes to maintain the low intracellular calcium concentration with Na-Ca exchange mechanism.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.4
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• pp.598-601
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• 2010

This experiment was performed to investigate whether the combined-preparation of water extracts of germinated brown rice (WGR), water extracts of cultured mountain ginseng (WCG) and 70% ethanol extracts of Longanae Arillus (ELA) has hypnotic effects and/or enhances pentobarbital-induced sleep behaviors through the GABAergic system. The combined-preparation of WGR and WCG reduced sleep latency and prolonged sleep time induced by pentobarbital. ELA also reduced sleep latency and prolonged sleep time induced by pentobarbital. However, WGR or WCG itself did not induce sleep. The combined-preparation of WGR, WCG and ELA strongly reduced sleep latency and prolonged sleep time via chloride influx into primary cultured cerebellar granule cells. In conclusion, the combined-preparation of WGR, WCG and ELA augments pentobarbital-induced sleep behaviors through the modification of GABAergic system.

• Journal of Ginseng Research
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• v.44 no.5
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• pp.717-724
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• 2020

Background: Malignant arrhythmias require drug therapy. However, most of the currently available antiarrhythmic drugs have significant side effects. Ginsenoside Rg2 exhibits excellent cardioprotective effects and appears to be a promising candidate for cardiovascular drug development. So far, the oral toxicity and antiarrhythmic effects of Rg2 have not been evaluated. Methods: Acute oral toxicity of Rg2 was assessed by the Limit Test method in mice. Subchronic oral toxicity was determined by repeated dose 28-day toxicity study in rats. Antiarrhythmic activities of Rg2 were evaluated in calcium chloride-induced arrhythmic rats. Antiarrhythmic mechanism of Rg2 was investigated in arrhythmic rats and H9c2 cardiomyocytes. Results: The results of toxicity studies indicated that Rg2 exhibited no single-dose (10 g/kg) acute oral toxicity. And 28-day repeated dose treatment with Rg2 (1.75, 3.5 and 5 g/kg/d) demonstrated minimal, if any, subchronic toxicity. Serum biochemical examination showed that total cholesterol in the high-dose cohort was dramatically decreased, whereas prothrombin time was increased at Day 28, suggesting that Rg2 might regulate lipid metabolism and have a potential anticoagulant effect. Moreover, pretreatment with Rg2 showed antiarrhythmic effects on the rat model of calcium chloride induced arrhythmia, in terms of the reduced duration time, mortality, and incidence of malignant arrhythmias. The antiarrhythmic mechanism of Rg2 might be the inhibition of calcium influx through L-type calcium channels by suppressing the phosphorylation of Ca²⁺/calmodulin-dependent protein kinase II. Conclusion: Our findings support the development of Rg2 as a promising antiarrhythmic drug with fewer side effects for clinical use.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.5
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• pp.308-313
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• 2016

The purpose of this study is to investigate the effects of Oja-Shingiwhan(OS) in contracted corpus cavernosum smooth muscle and its mechanism. To evaluate the relaxation of OS in contracted corpus cavernosum, OS was treated in strips which were precontracted with phenylephrine(PE). To examine its mechanism, OS was treated into corporal strips contracted by PE after pretreatment of Nω-nitro-L-arginine(L-NNA) and compared with non-pretreatment of _L-NNA. In calcium chloride(Ca²⁺)-free krebs solution, Ca²⁺ 1 mM was treated into corporal strips contracted by PE after pretreatment of OS and compared with non-pretreatment of OS. action were measured by histochemical, immunohistochemical methods. OS significantly affected on the relaxation of corporal strips, and the relaxation effects were inhibited by pretreatment of L-NNA. Contractions induced by Ca²⁺ influx were inhibited by pretreatment of OS in Ca²⁺-free krebs solution. OS increased eNOS positive reaction in corpus cavernosum, but decreased PDE-5 positive reaction. These result suggest that the effect of OS in contracted corpus cavernosum smooth muscle are shown by suppressing extracellular Ca²⁺ influx and increase of eNOS, NO production and decrease of PDE-5.

• Natural Product Sciences
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• v.23 no.1
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• pp.40-45
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• 2017

Epilepsy is a brain disorder that affects millions of people worldwide. It is characterized by recurrent and unpredictable seizures that are usually controlled with antiepileptic/anticonvulsive drugs. However, most antiepileptic drugs produce various side effects such as tolerance and sedation. Thus, there is a growing interest for alternative anticonvulsive drugs, preferably from natural or herbal sources. In this study, we evaluated the anticonvulsive effects of Rehmannia glutinosa (RG). The anticonvulsive effect of RG extract was evaluated using electroshock- and chemical-induced seizure tests in mice. To identify its probable mechanism of action, the effects of RG extract on $Cl^-$ influx was measured in vitro. We found that RG extract has anticonvulsive effects against electroshock-induced seizures, as indicated by an increased seizure threshold in mice. The RG extract also decreased the percentage of seizure responses induced by the GABAergic antagonist, pentylenetetrazole. These results suggest that the anticonvulsive effects of RG extract are mediated through a GABAergic mechanism. In support of this mechanism, our in vitro test showed that RG extract increases intracellular $Cl^-$ influx. Furthermore, RG extract did not show sedative and/or muscle relaxant effects in the open-field and rota-rod tests. Altogether, these results confirm that RG extract could be a herbal anticonvulsant and a potential alternative for clinical use.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.4
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• pp.400-408
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• 2013

This study aimed to investigate the relaxation effects and its underlying mechanisms of Rubus coreanus(RC) extract in contracted rabbit corpus cavernous tissues by phenylephrine(PE) $1{\mu}M$. In order to define the relaxation effects of RC, rabbit corpus cavernous tissues were prepared in $2{\times}2{\times}6mm$ sized strip. The dose-dependent relaxation responses of RC at 0.01-3.0 $mg/m{\ell}$ in contracted strips induced by PE were measured and also observed after endothelial denudation. To analyze the underlying mechanisms of RC-induced relaxation, indomethacin(IM), tetraethylammonium chloride(TEA), $N{\omega}$-nitro-L-arginine (L-NNA), methylene blue(MB) were treated before RC extract infused into precontracted strips induced by PE. To study the effect of RC extract on influx of extracellular $Ca^{2+}$ in corpus cavernous strips, calcium chloride(Ca) 1 mM infused into precontracted strips induced by PE after pretreatment of RC extract in $Ca^{2+}$-free krebs-ringer solution. To investigate cytotoxic activity and nitric oxide(NO) concentration of RC extract on human umbilical vein endothelial cell(HUVEC), cell viability on HUVEC was measured by MTT assay, and NO concentration was measured by Griess reagent system. The cavernous strips were significantly relaxed by RC extract at 1.0 $mg/m{\ell}$, 3.0 $mg/m{\ell}$ and the relaxation responses to RC were inhibited significantly by endothelial disruption. The pretreatment of IM, TEA didn't affect RC extract-induced endothelium-dependent relaxation, but the pretreatment of L-NNA, MB reduced RC extract-induced endothelium-dependent relaxation. When $Ca^{2+}$ was supplied the cavernous strips which were precontracted by PE in a $Ca^{2+}$-free krebs-ringer solution, contraction of strips was increased, but pretreatment of RC inhibited contractile response to $Ca^{2+}$. When RC extract was applicated on HUVEC, NO concentration was increased. Our findings show that RC extract exerts a relaxing effect on corpus cavernosum in part by suppressing influx of extracellular $Ca^{2+}$ through activating the NO-cGMP system.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.4
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• pp.198-206
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• 2019

This study was conducted to evaluate the vasorelaxant effect of DangGuiSu-San and SamHwangSaSim-Tang extract on contracted rabbit carotid artery. To study the effect of DangGuiSu-San and SamHwangSaSim-Tang extract on contracted rabbit carotid arterial strips, arterial strips with intact or damaged endothelium were used for experiment using organ bath. The pre-contracted arterial strips with Phenylephrine(PE) was treated with various concentrations of DangGuiSu-San and SamHwangSaSim-Tang extract(0.01, 0.03, 0.1, 0.3 and $1.0mg/m{\ell}$). To determine the mechanisms of DangGuiSu-San and SamHwangSaSim-Tang-induced vasorelaxant, DangGuiSu-San and SamHwangSaSim-Tang extract were infused into contracted arterial rings which had been pretreated by indomethacin(IM), tetraethylammonium chloride(TEA), $N{\omega}$-nitro-L-arginine ($_L-NNA$), methylene blue(MB). And calcium chloride(Ca) 1 mM was infused into precontracted arterial ring induced by PE after treatment of DangGuiSu-San and SamHwangSaSim-Tang extract in $Ca^{2+}$-free krebs solution. DangGuiSu-San and SamHwangSaSim-Tang extract revealed significant relaxation on PE-induced arterial contraction. DangGuiSu-San and SamHwangSaSim-Tang extract also had an effective relaxation to the intact endothelium arterial ring. SamHwangSaSim-Tang extract on contracted rabbit carotid artery is related with NO-cGMP pathway. Pretreatment of DangGuiSu-San and SamHwangSaSim-Tang extract inhibited the contraction by influx of extracellular $Ca^{2+}$ in contracted arterial ring induced by NE. This study indicated that the relaxation effect of SamHwangSaSim-Tang extract on contracted rabbit carotid artery is related with NO-cGMP pathway. Pretreatment of DangGuiSu-San and SamHwangSaSim-Tang extract inhibited the contraction by influx of extracellular $Ca^{2+}$ in contracted arterial ring induced by NE.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.2
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• pp.180-188
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• 2015

This study was conducted to investigate the relaxation effects and its mechanisms of Nelumbinis Semen(NS) extract in isolated rabbit corpus cavernous tissues. In order to examine the relaxation effects and its mechanisms of NS, we treated the ethanol extract of NS(0.01-3.0 mg/ml) and indomethacin(IM), tetraethylammonium chloride(TEA), Nω -nitro-L-arginine (L-NNA), methylene blue(MB) were treated before NS extract to contracted strips induced by PE 1 μM. We also treated calcium chloride(Ca) 1 mM after pretreatment of NS extract in Ca²⁺-free krebs-ringer solution to contracted strips induced by PE. Cell viability and NO concentration on human umbilical vein endothelial cell(HUVEC) was measured by MTT assay, Griess reagent system. eNOS production was investigated by histochemical and immunohistochemical staining. NS extract was significantly affected on the relaxation of cavernous strips and NS extract-induced relaxation was not different by pretreatment of IM, TEA, MB, but inhibited by the pretreatment of L-NNA. And increase of contraction induced by Ca²⁺ addition, in a Ca²⁺-free solution, was decreased by pretreatment of NS. NO concentration on HUVEC was increased. When NS extract was applicated on corpus cavernosum of penis(CCP) in SHR, ratio of smooth muscles to collage fibers by PE was decreased and formation of eNOS around helicine artery was increased. These results suggest that CCP relaxation effects of NS extract are shown by suppressing influx of extracellular Ca²⁺ through the production of NO and eNOS.