Naphthoquinone類衍生物,Naphthazarin與Methylnaphthazarin調控血管張力與抑制內皮細胞一氧化氮生成機制之探討 本篇論文主要目的在於探討naphthaoquinone類衍生物，Methylnaphthazarin及Naphthazarin對血管張力的影響，及其參與的調控機制。我們利用離體的大鼠胸主動脈環張力實驗，發現在低濃度下，Methylnaphthazarin (0.1-10 mM) 及Naphthazarin (0.01-0.1 mM) 具有濃度關係的增加Phenylephrine (PE)所導致的血管收縮作用，且此作用必須在內皮細胞存在下才能發生，同時也發現Methylnaphthazarin及Naphthazarin具有濃度關係的抑制了Acetylcholine造成的血管放鬆作用，顯示兩者可能透過抑制NO-cGMP pathway的路徑而影響了血管的正常功能，並由以上結果推測內皮細胞在此扮演重要角色。 因此我們利用分離自人類臍靜脈的血管內皮細胞 (HUVECs)來探討抑制ACh造成血管放鬆的機制，發現Methylnaphthazarin及Naphthazarin具有濃度關係的抑制一氧化氮 (Nitric Oxide)的生成及一氧化氮合成酶 (Nitric Oxide Synthase, NOS)的活性，但並不影響eNOS蛋白質的表現。證實Naphthazarin及Methylnaphthazarin可能透過抑制一氧化氮的生成而導致對ACh引發的血管舒張反應的抑制。此外，我們亦初步發現Naphthazarin及Methylnaphthazarin可能會誘發Superoxide anion (O2-.)的生成。 綜合以上的結果，我們認為Methylnaphthazarin及Naphthazarin這兩種Naphthoquinone類衍生物可能透過抑制血管內皮細胞一氧化氮之活性，導致對於血管張力的增強及血管鬆弛的抑制。至於確實的作用機制與O2-.在此所扮演的角色可能需要更進一步的探討。

Mechanism of Naphthoquinone Derivatives, Naphthazarin and Methylnaphthazarin Regulate Vessel Tension and Inhibit Endothelial Nitric Oxide Formation in Human Umbilical Vein Endothelial Cells The purpose of this experiment is to investigate the effect of naphthoquinone derivatives, methylnaphthazarin and naphthazarin in rat thoracic aortic rings isolated from rats and the pathway involved. After incubated with rat thoracic aortic rings, we found methylnaphthazarin and naphthazarin concentration-dependently potentiated phenylephrine induced vasocontraction and inhibited acetylcholine induced vasorelaxation in endothelium dependent manner. These data suggested that endothelium might be involved in this pathway. Human Umbilical Endothelium Vein Cells (HUVECs) were used to investigate the effect of naphthazarin and methylnaphthazarin on endothelium. We found methylnaphthazarin and naphthazarin concentration-dependently inhibited nitric oxide production and eNOS activity, with no effect on eNOS protein expression. These data suggested that the inhibitory effect of methylnaphthazarin and naphthazarin on vasorelaxation induced by acetylcholine might due to the inhibition of NO production and eNOS activity. We further detected the increasing of superoxide anion formation induced by naphthazarin and methylnaphthazarin. Finally, we concluded methylnaphthazarin and naphthazarin might inhibit endothelium nitric oxide activity resulted in the potentiated vasocontraction and inhibited vasodilation.