We tested the hypothesis that inducible NO synthase (iNOS) contributes to reduced NO-dependent vasodilation in non-Hispanic Blacks and prehypertensive non-Hispanic Whites. Twenty Black and 20 White participants (10 normotensive, 10 prehypertensive per group; n=40 total) participated in this study. Participants were instrumented with two microdialysis fibers and each site was randomized as control (lactated Ringer's) or iNOS inhibition (0.1 mM 1400W). Laser-Doppler flow probes and local heaters were used to measure skin blood flow and heat the skin to induce vasodilation, respectively. Each site was heated from 33°C to 39°C (rate: 0.1°C/sec). Once a plateau was established, 20 mM L-NAME, a non-specific NOS inhibitor, was infused at each site to quantify NO-dependent vasodilation. At control sites, %NO-dependent vasodilation was reduced in prehypertensive Whites (47 ± 10 %NO) and in both normotensive and prehypertensive Blacks (39 ± 9 and 28 ± 5 %NO, respectively) relative to normotensive Whites (73 ± 8 %NO; p < 0.0001 all comparisons). Compared to respective control sites, iNOS inhibition increased NO-dependent vasodilation in prehypertensive Whites (68 ± 8 %NO) and in both normotensive and prehypertensive Blacks (78 ± 8 and 55 ± 6 %NO, respectively; p < 0.0001 all comparisons). We failed to find an effect for normotensive Whites (77 ± 7 %NO). Following iNOS inhibition, %NO-dependent vasodilation was similar between normotensive Whites, prehypertensive Whites, and normotensive Blacks. Inhibition of iNOS increased NO-dependent vasodilation to a lesser extent in prehypertensive Blacks. These data suggest iNOS contributes to reduced NO-dependent vasodilation in prehypertension and in Black participants.

中文翻译：

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在高血压前期的非西班牙裔白人和非西班牙裔黑人中，iNOS 的抑制增强了皮肤内皮 NO 依赖性血管舒张

我们测试了诱导型 NO 合酶 (iNOS) 有助于减少非西班牙裔黑人和高血压前期的非西班牙裔白人的 NO 依赖性血管舒张的假设。20 名黑人和 20 名白人参与者（每组 10 名血压正常，10 名高血压前期患者；总共 n=40）参加了这项研究。参与者配备了两个微透析纤维，每个部位被随机分配为对照（乳酸林格氏）或 iNOS 抑制（0.1 mM 1400W）。激光多普勒血流探头和局部加热器分别用于测量皮肤血​​流和加热皮肤以引起血管舒张。每个部位从 33°C 加热到 39°C（速率：0.1°C/秒）。一旦建立平台，在每个部位注入 20 mM L-NAME，一种非特异性 NOS 抑制剂，以量化 NO 依赖性血管舒张。在控制点，相对于血压正常的白人 (73 ± 8 %NO；p < 0.0001 所有比较）。与各自的对照位点相比，iNOS 抑制增加了高血压前期白人 (68 ± 8 % NO) 和血压正常和高血压前期黑人 (分别为 78 ± 8 和 55 ± 6 %NO；p < 0.0001 所有比较) 的 NO 依赖性血管舒张。我们未能发现对血压正常的白人 (77 ± 7 %NO) 的影响。在 iNOS 抑制后，血压正常的白人、高血压前期的白人和血压正常的黑人之间的 %NO 依赖性血管舒张相似。在高血压前期的黑人中，iNOS 的抑制在较小程度上增加了 NO 依赖性血管舒张。