由于硝酸甘油具有多种心血管作用,故其改善缺血的真正机理尚不清楚。最近应用其他扩血管药的经验提示,不同的血管床对不同药物或剂量有不同的反应,说明可能有多种血管受体部位存在。例如,口服肼苯哒嗪的主要效应是扩张体循环小动脉,而哌唑嗪和硝普钠则对动脉与静脉具有相同效应。不同剂量对血管的不同影响虽尚未完全阐明,但晚近的工作提示,小剂量药物对某些受体的作用比大 Since nitroglycerin has a variety of cardiovascular effects, its true mechanism of improving ischemia is unclear. Recent experience with other vasodilators has suggested that different vascular beds respond differently to different drugs or doses, indicating the possible presence of multiple vascular receptors. For example, the main effect of oral hydralazine is the dilatation of the systemic arterioles, whereas prazosin and sodium nitroprusside have the same effect on arteries and veins. The different effects of different doses on blood vessels have not yet been fully elucidated, but recent work suggests that the effect of small doses on certain receptors is greater