앵엽(櫻葉) 에탄올 추출물의 혈관이완 효능 및 작용기전에 대한 연구

Abstract

Objectives : The purpose of present study was to investigate the vasorelaxant activities and mechanisms of action of the ethanol extract of P. yedoensis leaf (PYL) on isolated rat aortic rings. Methods : Dried P. yedoensis leaves were extracted 3 times with 100% ethanol for 3 h in a reflux apparatus. Isolated rat aortic rings were suspended in organ chambers containing 10 ml Krebs-Henseleit (K-H) solution. The rings were maintained at <TEX>$37^{\circ}C$</TEX> and aerated with a mixture of 95% <TEX>$O_2$</TEX> and 5% <TEX>$CO_2$</TEX>. Changes in their tension were recorded via isometric transducers connected to a data acquisition system. Results : PYL relaxed the contraction of aortic rings induced by phenylephrine (PE, 1 <TEX>${\mu}M$</TEX>) or KCl (60 mM) in a concentration dependent manner. However, the vasorelaxant effects of PYL on endothelium-denuded aortic rings were lower than endothelium-intact aortic rings. And the vasorelaxant effects of PYL on endothelium-intact aortic rings were reduced by pre-treatment with <TEX>$N{\omega}$</TEX>-Nitro-L-arginine methyl ester (10 <TEX>${\mu}M$</TEX>), methylene blue (10 <TEX>${\mu}M$</TEX>), 1-H-[1,2,4]-oxadiazolo-[4,3-<TEX>${\alpha}$</TEX>]-quinoxalin-1-one (10 <TEX>${\mu}M$</TEX>), tetraethylammonium (5 mM). In addition, PYL inhibited the contraction induced by extracellular <TEX>$Ca^{2+}$</TEX> in endothelium-denuded aortic rings pre-contracted by PE or KCl in <TEX>$Ca^{2+}$</TEX>-free K-H solution. Conclusions : These results suggest that PYL exerts its vasorelaxant effects via the activation of Nitric Oxide (NO) formation by means of L-arginine and NO-cGMP pathways and via the blockage of receptor operated calcium channels, voltage dependent calcium channels and calcium-activated potassium channels.