• 作者： 顏茂雄; 吳錦楨; 邱文慧; 廖振宏
• 作者服務機構： 國防醫學院藥理學科; 國防醫學院生化學科
• 中文摘要： 本研究是以大白鼠主動脈為材料，探討hydralazine舒血管作用之可能機轉。實驗結果顯示hydralazine在0.1mM至0.5mM的範圍內，對完整的血管所引起之舒血管作用較去除內膜的血管來得大(其ID 分別為0.30±0.05 mM和0.51±0.07mM）。本實驗同時探討hydralazine的舒血管作用與guanosine cyclic 3',5'-monophosphate(cGMP)間的相關性，結果發現nitroglycerin產生舒血管作用時，伴隨著cGMP的增加﹔而hydralazine則不影響cGMP的濃度變化。此外，甲基藍（一種已知為guanylate cyclase的抑制劑）幾乎完全抑制nitroglycerin的舒血管作用，但並不影響hydralazine的作用。由以上結果，說明了hydralazine的舒血管作用不是經由增加細胞內cGMP來完成。另一方面，hydralazine顯著地抑制腎上腺素所引起之鈣離子自肌漿網膜釋放和從細胞外進入細胞內的現象，而且hydralazine抑制鈣離子自肌漿網膜釋放的作用大於抑制鈣離子內流的作用。結論，hydralazine的舒血管作用部分需透過內膜來完成。至於，其舒血管作用似乎與細胞內cGMP的變化無關，而其作用機轉可能是直接抑制細胞膜對鈣離子的通透性，進而使血管產生舒張反應。
• 英文摘要： The mechanism of the vasodilator effect of hydralazine on isolated rat aorta was studied. Resultsdemonstrated that the vasodilator effect of hydralazine was greater on intact aortas than on endothelium-denuded preparations, particularly at low concentrations of between 0.1 mM and 0.5 mM. In addition,hydralazine did not have any effect on cyclic GMP levels. We also found that methylene blue, an inhibitorof giranylate cyclase, completely abolished the vasorelaxant action of nitroglycerin but not that of hydral-azine. These results indicate that the vasodilator effect of hydralazine was not due to elevating the cyclicGMP levels. On the other hand, hydralazine significantly inhibited both the contractions induced bynorepinephrine and/or high-potassium. In conclusion, a part of the vasodilator effect of hydralazine seemsto depend on the integrity of the vascular endothelium. However, this vasodilator effect was not associatedwith any elevation in cyclic GMP level. Thus, the direct vasodilator action of hydralazine may be relatedto its interference with the movement and/or translocation of calcium across the cell membrane.
• 中文關鍵字： hydralazine; cGMP; rat aorta
• 英文關鍵字： --