Hamilton C A, McPhaden A R, Berg G, Pathi V, Dominiczak A F
Department of Medicine and Therapeutics, Western Infirmary, Glasgow G11 6NT, United Kingdom.
Am J Physiol Heart Circ Physiol. 2001 Jun;280(6):H2451-5. doi: 10.1152/ajpheart.2001.280.6.H2451.
In human radial arteries, a nitric oxide/prostanoid-independent mechanism that has the pharmacological characteristics of an EDHF contributes to endothelium-dependent relaxation. H2O2 can act as an EDHF in some vascular beds. We examined the hypothesis that endogenously produced H2O2 mediated the nitric oxide/prostanoid-independent relaxation to carbachol in radial arteries obtained from patients undergoing coronary artery bypass surgery. Superoxide levels, measured by chemiluminescence, were similar in radial and internal mammary arteries, but immunohistochemical staining for Cu/Zn superoxide dismutase (SOD) was lower in endothelium from radial arteries. In organ chamber studies, neither addition of catalase nor addition of SOD to the bathing fluid modified nitric oxide/prostanoid-independent relaxations to carbachol in radial arteries. However, nitric oxide-dependent vasorelaxation was enhanced in the presence of SOD. Thus the nitric oxide/prostanoid-independent relaxation to carbachol is not due to H2O2 and, unlike nitric oxide-mediated vasorelaxation, is not attenuated by superoxide. Blood vessels showing EDHF-mediated relaxations resistant to oxidative stress may provide favorable outcomes in revascularization surgery.
在人体桡动脉中，一种具有内皮依赖性超极化因子（EDHF）药理学特征的不依赖一氧化氮/前列腺素的机制有助于内皮依赖性舒张。过氧化氢（H2O2）在某些血管床中可作为一种EDHF发挥作用。我们检验了这样一种假说：内源性产生的H2O2介导了冠状动脉搭桥手术患者桡动脉对卡巴胆碱的不依赖一氧化氮/前列腺素的舒张反应。通过化学发光法测量的超氧化物水平在桡动脉和乳内动脉中相似，但桡动脉内皮中铜/锌超氧化物歧化酶（SOD）的免疫组织化学染色较低。在器官浴槽研究中，向浴液中添加过氧化氢酶或SOD均未改变桡动脉对卡巴胆碱的不依赖一氧化氮/前列腺素的舒张反应。然而，在有SOD存在的情况下，一氧化氮依赖性血管舒张增强。因此，对卡巴胆碱的不依赖一氧化氮/前列腺素的舒张反应并非由H2O2引起，并且与一氧化氮介导的血管舒张不同，它不会被超氧化物减弱。显示出对氧化应激有抗性的由EDHF介导的舒张反应的血管，可能在血管重建手术中带来良好的结果。
