• 대한한의학회지
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• 제31권6호
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• pp.47-57
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• 2010

Objective: The present study investigated the effect of ethanol extract of Cynanchum wilfordii (ECW) on vascular relaxation and vascular inflammation in rat artery isolated from rats and anti-inflammatory activity in human aortic smooth muscle cells (HASMC). Methods: Vascular tone and guanosine 3',5'-cyclic monophosphate (cGMP) production were examined in rat artery isolated from Sprague Dawley rats, in the presence of ECW. HASMC were incubated with tumor necrosis factor-alpha (TNF-${\alpha}$) or Angiotensin II for 24 h. Matrix metalloproteinase (MMP)-2 and anti-oxidant activity of ECW was investigated by pretreatment with ECW in HASMC. Results: Cumulative treatment of ECW relaxed aortic smooth muscles of rats in a dose-dependent manner. ECW-induced vasorelaxation was significantly decreased by pretreatment of L-arginine methyl ester (L-NAME) or oxadiazolo-quinoxalinone (ODQ). Furthermore, ECW treatment of thoracic aorta significantly increased cGMP production. Incubation of ECW with ODQ or L-NAME markedly decreased ECW-induced cGMP production. ECW treatment dose-dependently suppressed TNF-${\alpha}$- or Angiotensin II-induced increase in matrix metalloproteinase-2 expression in HASMC. Also, ECW exhibited 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity in vitro and reduced TNF-${\alpha}$-induced increase in reactive oxygen species production in a dose-dependent manner. Conclusions: Taken together, the results suggest that ECW exerts vascular relaxation via NO/cGMP signaling pathway and decreases MMP-2 expression via anti-oxidant activity.

• 동의생리병리학회지
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• 제29권6호
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• pp.492-497
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• 2015

In the present study, vasorelaxant effect of the extract of seeds of Oenothera odorata (SOO) and its possible mechanism responsible for this effect were examined in vascular tissues isolated from rats. Changes in vascular tension, 3',5'-cyclic monophosphate (cGMP) levels were measured in thoracic aorta rings from rats. Methanol extract of seeds of Oenothera odorata relaxed endothelium-intact thoracic aorta in a dose-dependent manner. A dose-dependent vascular relaxation was also revealed by treatment of ethylacetate, n-butanol, and H₂O (aqua extract of seeds of Oenothera odorata , ASOO) extracts partitioned from methanol, but not by hexane extract. However, the vascular relaxation induced by ASOO were abolished by removal of endothelium of aortic tissues. Pretreatment of the endothelium-intact vascular tissues with N^G-nitro-L-arginine methyl ester (L-NAME) or ¹H-[1,2,4]-oxadiazole-[4,3-α]-quinoxalin-1- one (ODQ) significantly inhibited vascular relaxation induced by ASOO. Moreover, incubation of endothelium-intact aortic rings with ASOO increased the production of cGMP. However, ASOO-induced increases in cGMP production were blocked by pretreatment with L-NAME or ODQ. The vasorelaxant effect of ASOO was attenuated by tetraethylammonium (TEA), 4-aminopyridine, and glibenclamide attenuated. On the other hand, the ASOO-induced vasorelaxation was not blocked by verapamil, and diltiazem. Taken together, the present study demonstrates that ASOO dilate vascular smooth muscle via endothelium-dependent NO-cGMP signaling pathway, which may be closely related with the function of K⁺ channels.

• The Korean Journal of Physiology and Pharmacology
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• 제1권6호
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• pp.673-679
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• 1997

It has been generally accepted that glutamate mediates the ischemic brain damage, excitotoxicity, and induces release of neurotransmitters, including norepinephrine(NE), in ischemic milieu. In the present study, the role of nitric oxide(NO) in the ischemia-induced $[^3H]norepinephrine([^3H]NE)$ release from cortex slices of the rat was examined. Ischemia, deprivation of oxygen and glucose from $Mg^{2+}-free$ artificial cerebrospinal fluid, induced significant release of $[^3H]NE$ from cortex slices. This ischemia-induced $[^3H]NE$ release was significantly attenuated by glutamatergic neurotransmission modifiers. $N^G-nitro-L-arginine$ methyl ester(L-NAME), $N^G-monomethyl-L-arginine$ (L-NMMA) or 7-nitroindazole, nitric oxide synthase inhibitors attenuated the ischemia-evoked $[^3H]NE$ release. Hemoglobin, a NO chelator, and 5, 5- dimethyl-L-pyrroline-N-oxide(DMPO), an electron spin trap, inhibited $[^3H]NE$ release dose-dependently. Ischemia-evoked $[^3H]NE$ release was inhibited by methylene blue, a soluble guanylate cyclase inhibitor, and potentiated by 8-bromo-cGMP, a cell permeable cGMP analog, zaprinast, a cGMP phosphodiesterase inhibitor, and S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide generator. These results suggest that the ischemia-evoked $[^3H]NE$ release is mediated by NMDA receptors, and activation of NO system is involved.

• Archives of Pharmacal Research
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• 제24권6호
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• pp.607-612
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• 2001

Endogenous carbon monoxide (CO) shares with nitric oxide (NO) a role as a putative neural messenger in the brain. Both gases are believed to modulate CNS function via an increase in cytoplasmic cGMP concentrations secondary to the activation of soluble guanylate cyclase (sGC). Recently CO and NO were proposed as a possible mediator of febrile response in hypothalamus. NO has been reported to activate both the constitutive and inducible isoform of the cyclooxygenase (COX). Thus, we investigated whether CO arising from heme catabolism by heme oxygenate (HO) is involved in the febrile response via the activation of COX in the hypothalamus. $PGE_2$ which is a final mediator of febrile response released from primary cultured hypothalamic cells was taken as a marker of COX activity. $PGE_2$ concentration was measured with EIA kits. Exogenous CO (CO-saturated medium) and hemin (a substrate and potent inducer of HO) evoked an increase in $PGE_2$ release from hypothalamic cells, and these effects were blocked by methylene blue (an inhibitor of sGC). And membrane permeable cGMP analogue, dibutyryl-cGMP elicited significant increases in $PGE_2$release. These results suggest that there may be a functional link between HO and COX enzymatic activities. The gaseous product of hemin through the HO pathway, CO, might play a role through the modulation of the COX activity in the hypothalamus.

• 동의생리병리학회지
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• 제25권5호
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• pp.863-869
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• 2011

The aim of the present study is to investigate whether an ethanol extract of Acorus gramineus Soland (EAG) augments penile erection in vitro and in vivo experiment. Preconstructed with phenylephrine (PE) in isolated endothelium-intact rabbit corpus cavernosum, EAG relaxed penile smooth muscle in a dose-dependent manner, which was inhibited by pretreatment with NG-nitro-L-argininemethylester (L-NAME), a nitricoxide synthase inhibitor, and 1H-[1,2,4]-oxadiazole-[4,3-${\alpha}$]-quinoxalin-1-one (ODQ), a soluble guanylylcyclase (sGC) inhibitor, respectively. EAG-induced relaxation was significantly attenuated by pretreatment with tetraethylammonium (TEA), a nonselective $K^+$ channel blocker. EAG increased cGMP levels of the rabbit corpus cavernosum in a concentration-dependent manner without changes in cAMP levels. In addition, EAG caused increase of peak intracavernous pressure (ICP), ICP/MAP ratio and area under the carve (AUC) in SD rats. Taken together, these results suggest that EAG augments penile erection via NO-cGMP system and $K^+$ channels in corpus cavernosum.

• Molecules and Cells
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• 제21권3호
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• pp.337-342
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• 2006

Interstitial cells of Cajal (ICCs) are pacemaker cells that activate the periodic spontaneous depolarization (pacemaker potentials) responsible for the production of slow waves in gastrointestinal smooth muscle. The effects of vasoactive intestinal polypeptide (VIP) on the pacemaker potentials in cultured ICCs from murine small intestine were investigated by whole-cell patch-clamp techniques. Addition of VIP (50 nM-$1{\mu}M$) decreased the amplitude of pacemaker potentials and depolarized resting membrane potentials. To examine the type of receptors involved in ICC, we examined the effects of the $VIP_1$ agonist and found that it had no effect on pacemaker potentials. Pretreatment with $VIP_1$ antagonist ($1{\mu}M$) for 10 min also did not block the VIP (50 nM)-induced effects. On the other hand exposure to 1H-(1,2,4)oxadiazolo(4,3-A)quinoxalin-1-one (ODQ, $100{\mu}M$), an inhibitor of guanylate cyclase, prevented VIP inhibition of pacemaker potentials. Similarly KT-5823 ($1{\mu}M$) or RP-8-CPT-cGMPS ($10{\mu}M$), inhibitors of protein kinase G (PKG) blocked the effect of VIP (50 nM) on pacemaker potentials as did N-nitro-L-arginine (L-NA, $100{\mu}M$), a non-selective nitric oxide synthase (NOS) inhibitor. These results imply that the inhibition of pacemaker activity by VIP depends on the NO-cGMP-PKG pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제2권2호
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• pp.225-232
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• 1998

To investigate the possible involvement of outward potassium ($K^+$) currents in nitric oxide-induced relaxation in intestinal smooth muscle, we used whole-cell patch clamp technique in freshly dispersed guinea-pig ileum longitudinal smooth muscle cells. When cells were held at -60 mV and depolarized from -40 mV to -50 mV in 10 mV increments, sustained outward $K^+$ currents were evoked. The outward $K^+$ currents were markedly increased by the addition of 10 ${\mu}M$ sodium nitroprusside (SNP). 10 ${\mu}M$ S-nitroso-N-acetylpenicillamine (SNAP) and 1 mM 8-Bromo-cyclic GMP (8-Br-cGMP) also showed a similar effect to that of SNP. 1 mM tetraethylammonium (TEA) significantly reduced depolarization-activated outward $K^+$ currents. SNP-enhanced outward $K^+$ currents were blocked by the application of TEA. High EGTA containing pipette solution (10 mM) reduced the control currents and also inhibited the SNP-enhanced outward $K^+$ currents. 5 mM 4-aminopyridine (4-AP) significantly reduced the control currents but showed no effect on SNP-enhanced outward $K^+$ currents. 0.3 ${\mu}M$ apamin and 10 ${\mu}M$ glibenclamide showed no effect on SNP-enhanced outward $K^+$ currents. 10 ${\mu}M$ 1H-[1,2,4]oxadiazolo [4,3-a]quinoxaline-1-one (ODQ), a specific inhibitor of soluble guanylate cyclase, significantly blocked SNP-enhanced $K^+$ currents. We conclude that NO donors activate the $Ca^{2+}-activated$ $K^+$ channels in guinea-pig ileal smooth muscle via activation of guanylate cyclase.

• Clinical and Experimental Reproductive Medicine
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• 제26권2호
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• pp.203-211
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• 1999

목적: 일산화질소 (nitric oxide; NO)는 생식계를 비롯한 여러 생체내 기관에서 다양하고도 중요한 작용을 하는 것으로 알려져 있으며, 복강액은 난관내강과 연결되어 복강액 내의 세포 성분의 변화는 난관의 미세환경을 변화시켜 수정과 초기 배아 발생에 영향을 줄 수 있다. 본 연구는 배아 발생에 있어서 일산화질소의 역할을 이해하고 복강액 내의 NO농도 변화가 배아 발생에 미치는 역할을 조사하기 위해 수행되었다. 방법: 과배란시킨 1세대 잡종 암컷 생쥐 (C57BL${\times}$CBA/Ca)로부터 1세포기 배아를 얻어 10% synthetic serum substitute가 첨가된 modified human tubal fluid 배양액에서 4일 동안 체외배양하였다(대조군). 실험을 위해 이러한 배양조건에 sodium nitroprusside (SNP)를 $0{\sim}1mM$의 다양한 농도로 배양초기부터 첨가하거나, $200{\mu}M$ SNP를 2-, 4-, 8-세포기의 각기 다른 배아시기에 첨가하였으며, 복강경수술을 받는 42명의 여성으로부터 채취한 복강액을 SSS대신 단백질원으로 사용하여 포배아까지의 배아 발달율을 관찰하였으며, 복강액 내의 NO농도를 Griess방법에 의해 측정하였다. 배아의 apoptotic body는 H33342 염색법으로 조사하였으며 배아 발달율은 3회 이상 반복 실험한 결과의 mean${\pm}$SEM으로 나타내었다. 결과: SNP는 농도에 의존적으로 배발생을 억제하였으나 배아 단계에 대한 특이성은 관찰할 수 없었으며, 특히 $100{\mu}M$ 이상의 고농도의 SNP는 2-세포기 단계에서 배아 발생을 정지시켰다. 또한 단백질원으로 복강액 이용시 배 발생율은 복강액 내의 NO 농도에 따라 현저한 차이가 발견되었으며, $2.5{\mu}M$이상의 NO를 함유한 복강액에서 배양한 배아의 발생율은 현저하게 감소하였다. cGMP analogue인 8-bromo-cGMP를 배양액에 첨가시 배아 발생에는 변화가 없었으며, SNP에 의해 배발생이 정지된 2-세포기 배아에서 apoptotic body를 발견할 수 없었다. 결론: 이상의 결과로 보아 NO는 고농도에서 배아 발생을 저해하며, 복강액 내의 NO와 같은 성분의 변화는 배아 발생에 유해한 효과를 유발할 것으로 사료된다. 이러한 NO의 배아 발생 억제효과는 cGMP로 중재되는 경로나 apoptosis유발과는 관계가 없는 것 같다.

• Journal of Ginseng Research
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• 제22권1호
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• pp.22-31
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• 1998

Antiulcer effects of ginseng saponin, acidic polysaccharide and methanol extract of Panax ginseng in the patients and experimental animals were reported. Postulated action mechanisms of ginseng were histamine-Ht receptor blocking and increasing gastric blood flow In the present study, the effect of ginsenosides, the biologically active glycosides of ginseng, on gastric acid secretion was examined using gastric cells isolated from human and rabbit gastric mucosa. Ginseng saponin, ginsenoside $Rb_1$, $Rb_2$, $Rg_1$ and $Rh_2$ were tested in unstimulated as well as stimulated gastric cells. Histamine ($10^4$M) and 3-isobutyl-1-methylxanthine ($10^4$M) were used as secretagogues. To investigate the mechanism of ginsenosides on acid secretion, the levels of cAMP and cGMP were monitored in gastric cells. As a result, high concerltration(1mg/ml) of ginseng saponin showed 73-75% of stimulated acid secretion in control gastric cells. However, ginseng saponin had no effect on unstimulated acid secretion and the levels of cGMP and cAMP in gastric cells. Ginsenoside $Rb_1$, $Rb_2$ and $Rh_2$ significantly inhibited stimulated acid secretion. Gastric cGMP levels were increased by all ginsenosides tested while cAMP levels were increased by all ginsenosides in unstimulated state of gastric cells, but increased by ginsenosides ginsenoside $Rg_1$ and $Rh_2$in stimulated state of gastric cells. The results suggest that inhibition of ginseng saponin on gastric acid secretion represents a complex effect of individual ginsenosides, which produce a range of effect on acid secretion. The inhibition site of ginseng saponin on stimulated acid secretion is postulated as post cAMP levels in acid secretary pathway such as protein phosphorylation or proton pump. Nitric oxide may not be involved in the inhibitory effect of ginseng saponin on stimulated acid secretion.

• 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.