Cannon R O
Cardiology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Clin Chem. 1998 Aug;44(8 Pt 2):1809-19.
Nitric oxide is a soluble gas continuously synthesized by the endothelium. This substance has a wide range of biological properties that maintain vascular homeostasis, including modulation of vascular dilator tone, regulation of local cell growth, and protection of the vessel from injurious consequences of platelets and cells circulating in blood. A growing list of conditions, including those commonly associated as risk factors for atherosclerosis such as hypertension and hypercholesterolemia, are associated with diminished release of nitric oxide into the arterial wall either because of impaired synthesis or excessive oxidative degradation. Diminished nitric oxide bioactivity may cause constriction of coronary arteries during exercise or during mental stress and contribute to provocation of myocardial ischemia in patients with coronary artery disease. Additionally, diminished nitric oxide bioactivity may facilitate vascular inflammation that could lead to oxidation of lipoproteins and foam cell formation, the precursor of the atherosclerotic plaque. Numerous therapies have been investigated to assess the possibility of reversing endothelial dysfunction by enhancing the release of nitric oxide from the endothelium, either through stimulation of nitric oxide synthesis or protection of nitric oxide from oxidative inactivation and conversion to toxic molecules such as peroxynitrite. Accordingly, causal relationships between improved endothelial function and reduction in myocardial ischemia and acute coronary events can now be investigated.
一氧化氮是一种由内皮持续合成的可溶性气体。这种物质具有广泛的生物学特性，可维持血管稳态，包括调节血管扩张张力、调节局部细胞生长以及保护血管免受血液中循环的血小板和细胞的有害影响。越来越多的病症，包括那些通常作为动脉粥样硬化危险因素的病症，如高血压和高胆固醇血症，都与一氧化氮向动脉壁的释放减少有关，这要么是由于合成受损，要么是由于过度氧化降解。一氧化氮生物活性降低可能会在运动或精神压力期间导致冠状动脉收缩，并促使冠心病患者发生心肌缺血。此外，一氧化氮生物活性降低可能会促进血管炎症，进而导致脂蛋白氧化和泡沫细胞形成，而泡沫细胞形成是动脉粥样硬化斑块的前身。已经研究了许多疗法，以评估通过增强内皮一氧化氮的释放来逆转内皮功能障碍的可能性，这可以通过刺激一氧化氮合成或保护一氧化氮免受氧化失活并转化为有毒分子（如过氧亚硝酸盐）来实现。因此，现在可以研究改善内皮功能与减少心肌缺血和急性冠状动脉事件之间的因果关系。
