Contribution of vasoactive prostanoids to vascular tone

内皮血管活性物质的血管活性缺陷在原发性高血压和高胆固醇血症中被观察到，并且被认为参与了这些疾病的血管异常特征。本研究旨在确定环氧化酶（COX）产物在维持血管张力和内皮介导的血管舒张中的作用，并探讨其在原发性高血压和高胆固醇血症患者内皮功能障碍中的作用。方法与结果。在24例正常、23例高血压和24例高胆固醇血症患者中，评估动脉内阿司匹林（ASA； 1、3和10 mg/min）对基础前臂血流量（FBF）（应变计体积描记仪）的影响以及对乙酰胆碱（Ach； 7.5、15和30 g/min）和硝基普钠（SNP; 0.8、1.6和3.2 g/min）的反应。3组间基本FBF差异无统计学意义（p=0.95）。ASA导致正常（p=0.003）、高血压（p=0.001）和高胆固醇血症（p=0.001）受试者的FBF较基线显著降低，三组间无差异（p=0.90）。ASA显著改善了正常组（p=0.008）、高血压组（p=0.008）和高胆固醇血症组（p=0.022）乙酰胆碱酯酶的作用，三组间差异无统计学意义（p= 0.46）。ASA在三组中均未显著改变SNP的血管舒张作用。结论。这些发现表明，在人类中，血管扩张剂前列腺素积极有助于维持基础血管张力，而COX活性的血管收缩产物限制了内皮依赖性血管舒张。COX产品似乎在高血压或高胆固醇血症患者的内皮功能障碍中不起主要作用。

A defective vascular activity of endothelial vasoactive substances is observed in essential hypertension and hypercholesterolemia, and is believed to participate in the vascular abnormalities characteristic of these conditions. The present study aimed to determine the role of cyclooxygenase (COX) products in the maintenance of vascular tone and in the endothelium-mediated vasodilation of healthy subjects, and to investigate their contribution to the endothelial dysfunction of essential hypertensive and hypercholesterolemic patients. Methods and Results. The effects of intraarterial aspirin (ASA; 1, 3 and 10 mg/min), were assessed on basal forearm blood flow (FBF) (strain gauge plethysmography) and on the responses to acetylcholine (Ach; 7.5, 15 and 30 g/min) and sodium nitroprusside (SNP; 0.8, 1.6 and 3.2 g/min) in 24 normal, 23 hypertensive and 24 hypercholesterolemic subjects. Basal FBF was not different among the 3 groups (p=0.95). ASA resulted in a significant reduction of FBF from baseline in normal (p=0.003), hypertensive (p=0.001), and hypercholesterolemic subjects (p=0.001), without any difference among the 3 groups (p=0.90). ASA significantly improved the effect of Ach in normal (p=0.008), hypertensive (p=0.008), and hypercholesterolemic subjects (p=0.022), without significant difference among the 3 groups (P=0.46). ASA did not significantly modify the vasodilator effect of SNP in any of the 3 groups. Conclusions. These findings suggest that, in humans, vasodilator prostanoids actively contribute to the maintenance of basal vascular tone, while vasoconstrictor products of COX activity limit endothelium-dependent vasodilation. COX products do not appear to play a major role in the endothelial dysfunction of hypertensive or hypercholesterolemic patients.