• YAKHAK HOEJI
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• v.35 no.5
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• pp.416-426
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• 1991

The effects of an irreversible or a reversible $\alpha_1$-adrenoceptor antagonist (dibenamine or prazosin) on $\alpha_1$-adrenoceptor-mediated vasoconstrictions were studied in the endothelium-denuded rat aorta. In these experiments, the mobilization of intracelluier calcium and translocation of extracellular calcium were also studied. To exclude the modulation of endothelium releasing EDRF and EDCF, the endothelium was removed in all rat aortas. Contraction induced by phenylephrine (a full $\alpha_1$-adrenoceptor agonist) was separated into a fast phasic component of the response due to the release of intracellular calcium and a slow tonic one due to the influx of extracellular calcium. Pretreatments with increasing doses of reversible $\alpha_1$-adrenoceptor antagonist prazosin, as well as irreversible $\alpha_1$-adrenoceptor antagonist dibenamine, inhibited the phasic component of phenylephrine-induced contraction more effectively than the tonic one. Pretreatment of dibenamine (0.2 $\mu{M}$) or prazosin (10 nM) to the rat aorta abolished phasic response but remained tonic one about 41% and 51%, respectively. These results suggest that as the efficiency of phenylephrine was progressively reduced by pretreatments with increasing doses of an irreversible or a reversible $\alpha_1$-adrenoceptor antagonist (dibenamine or prazosin), the contraction induced by phenylephrine became progressively more dependent on the influx of extracellular calcium.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.88-88
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• 1995

Tetrahydroisoquinoline (THI) compounds have various pharmacological actions in the cardiovascular system. Recently, we have synthesized 1-${\alpha}$-naphthylmethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, YS 49. In the present study, we evaluated the effect of YS-49 on positive inotropic and chronotropic action using isolated rat heart and on blood pressure and heart rate using anesthesized rabbit. Vasodilating action was also assessed in isolated rat thoracic aorta. YS 49, concentration-dependently relaxed rat aorta precontracted with phenylephrine (PE, 0.3 ${\mu}$M) and high potassium (high K$\^$+/, 65.4 mM). The 50% inhibitory concentration (IC$\sub$50/) of YS 49 in PE-induced and high K$\^$+/-induded contraction was 5.36 ${\mu}$M and 2.52 ${\mu}$M, respectively. In isolated rat atria, YS 49 increased both heart rate and force, and in anesthesized rabbit it decreased blood pressure but increased heart rate. In addition, to know the mechanism of action of the compound, propranolol, nonselective ${\beta}$-antagonist, and phentolamine, ${\alpha}$-blocker, were used. Furthermore, a comparison with the effect of higenamine, trimetoquinol on the vasodilating action in rat thoracic aorta was also made. The action of YS 49 was inhibited by the presence of propranolo, not pentolamine. These results indicate that cardiotonic and vasodilatory action of YS 49 is attributable, at least in part, for ${\beta}$-receptor stimulation.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.5
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• pp.938-942
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• 2002

We have examined the relaxational response to the water extract of Rheum palmatum L.(ERP) and water extrc alcohol processed Rheum palmatum L.(ARP) in isolated thoracic aorta from sprague dawley (SD) rat. Rat thoracic aort investigated in vessel segments suspended for isometric tension recording by polygraph. Responses to ERP and ARP investigated in vessels precontracted with 5-hydroxytryptamine(5-HT). We found that the thoracic aorta segments respo to ERP and ARP with a dose-dependent vasorelaxation. We found that ; The thoracic aorta segments responded to I and ARP with a dose-dependent vasodilation. The 5-HT induced contraction at 10/sup -4/M were inhibited by 71.7% and a: after addition of the 0.01 g/mL water extract of ERP and ARP. The 5-HT induced contraction at 10/sup -4/M were inhibite 100% after 10/sup -3/M emodin. The concentration of emodin was 0.027% and 0.098% in ERP and ARP. In condusion, ERP ARP induced relaxation in the isolated rat thoracic aorta were composed of dose-dependent relaxation. and it has pi vasodilation.

• Herbal Formula Science
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• v.11 no.2
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• pp.125-134
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• 2003

We have examined the relaxational response to the water extract of Angelica gigas $N_{AKAI}$ (AG), Gingko biloba $L_{INNE}$ (GB), Acanthopanax senticosus $H_{ARMS}.$ (AP) and Augumented-Four-Substance Decoction (AG-FSD, GB-FSD, AP-FSD) in isolated thoracic aorta from sprague dawley(SD) rat. Rat thoracic aorta was investigated in vessel segments suspended for isometric tension recording by polygraph. Responses to AG, GB, AP and AG-FSD, GB-FSD, AP-FSD were investigated in vessels precontracted with 5-hydroxytryptamine(5-HT) were compared in vasodilation effect. We found that the thoracic aorta segments responded to AG, GB, AP and AG-FSD, GB-FSD, AP-FSD with a dose-dependent vasodilation. The 5-hydroxytryptamine induced contraction at $10^{-4}M$ were inhibited by 26.3%, 75.8%, 87.5% and 6.9%, 22.6%, 30.8% after addition of the 0.1 g/mL water extract of AG, GB, AP and AG-FSD, GB-FSD, AP-FSD. In conclusion, AG, GB, AP and AG-FSD, GB-FSD, AP-FSD induced relaxation in the isolated rat thoracic aorta were composed of dose-dependent relaxation. AP-FSD has very potent vasodilation.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.2
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• pp.457-462
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• 2004

Bambusae Caulis in Liquamen has been used as a herbal medicine for the treatment of heat, paralysis of the hands or feet, or hemiplegia. In the present study, we investigated the effect of Bambusae Caulis in Liquamen to the phenylephrine (PE) induced contraction of isolated rat aorta Contractile force was measured with force displacement transducer under 1.5 g loading tension. Contractions evoked by PE 0.1 μM were significantly increased by low dosage of Bambusae Caulis in Liquamen, decreased by high dosage of Bambusae Caulis in Liquamen. L-NNA, ODQ and propranolol significantly altered the effect of Bambusae Caulis in Liquamen, but indomethacin did not change the relaxation of Bambusae Caulis in Liquamen. These results suggest that Bambusae Caulis in Liquamen can relax EP induced contraction of isolated rat aorta and that this decreasing contraction related to sympathetics.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.5
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• pp.1299-1304
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• 2003

This study is to determine the effect of Fructus Rubi to the phenylehrine (PE) induced contraction of isolated rat aorta. Contractile force was measured with force displacement transducer under 1.5g loading tension. Contractions evoked by PE 0.1 μM and KCI 65.4 mM were decreased significantly by Fructus Rubi. L-NNA, ODQ, indomethacin and atropine significantly altered the effect of Fructus Rubi, but propranolol did not change the relaxation of Fructus Rubi. These results indicate that Fructus Rubi can relax EP and KCI induced contraction of isolated rat aorta and that this decreasing contraction related to epithelium, nitric oxide, and parasympathetics.

• The Journal of Korean Medicine
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• v.25 no.1
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• pp.60-71
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• 2004

Objectives : We have examined the relaxational response to the water extract of genus Panax in rat thoracic aorta and mesenteric artery. Methods : Segments of thoracic aorta and mesenteric artery obtained from rats immediately after delivery were mounted in organ baths superfused on a polygraph. Results : We found that the thoracic aorta segments responded to the water extract of genus Panax with a dose-dependent vasorelaxation. At $10^{-5}m$ 5-hydroxytrptamine (5-HT), the maximal contraction force were 94.9% of the maximum KCl-response. At $10^{-5}m$ 5-HT - induced contraction, The contractile response of thoracic aortic rings were inhibited by 54.7%, 36.3% and 31.3% after addition of the high concentration (100 mg/ml) of water extract of Panax ginseng, Panax japonicus and Panax quinquefolium. The contractile response of mesenteric arteries were inhibited by 88.3%, 87.7%, and 70.3% after addition of the high concentration (100 mg/ml) of water extract of Panax ginseng, Panax japonicus and Panax quinquefolium. Conclusions : In conclusion, water extract of genus Panax - induced relaxation in the isolated rat thoracic aorta and mesenteric artery were composed of endothelium - independent relaxation and dose - dependent relaxation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.90-90
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• 1995

The Influence of age on the endothelial modulation of angiotensin II (AII)-induced contractile response was investigated in isolated aortic rings of rats ranging in age from 0.7 to 20 months. Hemoglobin and L-NAME were used to examine whether age-related changes in the EDRF-releasing system were involved in endothelial modulation of All-induced contraction in rat aorta. In all five age groups (0.7, 1.5, 3, 6, 20 months), hemoglobin (10 ${\mu}$M) significantly enhanced All-induced contractile response only in aorta with endothelium intact. L-NAME (10 ${\mu}$M) Produced a significant enhancement in All responses in endothelium-intact aortas from rats aged 0.7 and 1.5 months, but it had no effect in aortas from older rats aged 6 and 20 months. Indomethacin (10 ${\mu}$M) did not affect All-induced contractile responses in both endothelium intact and removed aortas from rats at the age of 0.7 to 20 months. Hemoglobin (10 ${\mu}$M) abolished acetylcholine-induced relaxation response in aortas from young and old rats. L-NAME completely abolished the relaxation in aortas from young (0.7 and 1.5 months), but incompletely in aortas from older (6 and 20 months) rats. The sensitivity of endothelium-dependent relaxation to A23187 increased with age between ages of 0.7 and 6 months, with no further increase noted up to 20 months of age. These results suggest that endothelial modulation of AII-induced contraction in rat aorta might involve age-related alteration in EDRF-releasing system, probably via post-receptor mechanism.

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.515-522
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• 2004

The vasorelaxant effect of serotonin reuptake inhibitor fluoxetine was investigated in rat isolated thoracic aorta. Fluoxetine induced a concentration-dependent relaxation in aorta precontracted with phenylephrine (PE) and KCl. These relaxations were suppressed by removal of the endothelium (-E) or pretreatment of nitric oxide synthase inhibitors, N(G)-nitro-L-arginine (L-NNA) and N(omega)-nitro-Larginine methyl ester (L-NAME), guanylate cyclase inhibitors, methylene blue (MB) and 1H-[1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one (ODQ), and $Ca^{2+}$ channel blockers, nifedipine and verapamil, in PE-precontracted +E rings. However, fluoxetine-induced relaxations were not suppressed by pretreatment of $K^{+}$ channel blockers, tetrabutylammonium and glibenclamide, in PE-precontracted endothelium intact (+E) rings. The fluoxetine-induced relaxations were not suppressed by removal of the endothelium or pretreatment of LNNA and MB in KCl-precontracted +E rings. Also, fluoxetine inhibited PE-induced sustained contraction in +E rings. These inhibitory effects of fluoxetine on contractions could be reversed by removal of the endothelium or pretreatment of L-NNA, L-NAME, MB, ODQ, nifedipine and verapamil, but not by pretreatment of etrabutylammonium and glibenclamide. These findings suggest that the vasorelaxant effect of fluoxetine is modulated by intracellular $Ca^{2+}$ with an involvement of endothelial NO-cGMP pathway and also may be related to the inhibition of $Ca^{2+}$ entry through voltage-gated channel.

• The Korea Journal of Herbology
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• v.25 no.4
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• pp.69-75
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• 2010

Objectives : The root and rhizome of "Gangwhal" have been used as a traditional medicine for the treatment of cold, fever, headache, swelling, arthritis, rhinitis, and cardiovascular diseases in Korea and china. In china, Gangwhal is well known as a useful oriental medicinal plant that treats cardiovascular diseases such as stroke, headache and hypertension, but little research exists about the effect of O. koreanum on cardiovascular disease. Therefore we investigated the vasorelaxant effects of O. koreanum and compared the vasorelaxant effects of four species of Gangwhal. Methods : The vasorelaxant effects of the ethanol extracts of Ostericum koreanum (NK and BK), Notopterygium incisium (NI), and N. forbesii (NF) on phenyleprine ($1{\mu}M$) or KCl (60mM) pre-contracted rat thoracic aorta rings were compared. The vasorelaxant effects of the water extract and ethanol extract of NK on phenyleprine ($1{\mu}M$) or KCl (60mM) pre-contracted rat thoracic aorta rings were compared. And the vasorelaxant effects of chloroform, ethylacetate and water fraction of ethanol extract of NK on phenyleprine ($1{\mu}M$) or KCl (60mM) pre-contracted rat thoracic aorta rings were compared. Results : Ethanol extracts of NK, BK, NI and NF relaxed rat thoracic aorta rings with a concentration-dependent manner, and NK showed the greatest vasorelaxant effect. And ethanol extract of NK was much more effective than water extract of NK. Finally, chloroform, ethylacetate and water fraction of ethanol extract of NK also relaxed rat thoracic aorta rings, and chloroform fraction showed the greatest vasorelaxant effect.