Racial differences in nitric oxide-mediated vasodilator response to mental stress in the forearm circulation
Racial differences in nitric oxide-mediated vasodilator response to mental stress in the forearm circulation
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DOI：
10.1161/01.hyp.31.6.1235
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发表时间：
1998-06-01
期刊：
影响因子：
8.3
通讯作者：
Panza, JA
中科院分区：
文献类型：
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作者：
Cardillo, C;Kilcoyne, CM;Panza, JA
对应激刺激的异常血流动力学反应被认为是黑人高血压患病率较高的机制之一。鉴于一氧化氮(NO)在调节心血管内稳态中的重要作用，我们调查了精神应激期间血管NO活性的种族差异的可能性。为了验证这一假说，我们比较了14名白人和12名黑人健康受试者在动脉内注入生理盐水或NO合成抑制剂N-G-单甲基-L-精氨酸(L；4µmol/min)时前臂血流对精神应激的反应。我们还检测了两组血管对动脉内注射外源性NO供体硝普钠(0.8~3.2微克/分钟)的反应。在生理盐水输注过程中，白人因心理应激引起的FBF较基线的增加显著高于黑人(109+/-20%对58+/-8%；P=0.03)。在白人和黑人中，L-NMMA显著降低了应激引起的空腹血糖升高(从109.0%+/-20%到54%+/-11%；P=0.004)，但对黑人没有影响(从58%+/-8%到42+/-10%；P=0.24)；因此，在白人和黑人中，L-NMMA负荷测试的血管扩张效应相似(54+/-11%比42+/-10%；P=0.44)。黑人对硝普钠的血管扩张反应也低于白人(最大流量，6.9ml.min(-)1.dL(-1)，11.6+/-3.5mL.min(-)1.dL(-1)；P=0.001)，且两组均无明显改善作用。我们的发现表明，在精神压力期间，黑人的一氧化氮依赖性血管扩张剂活性减少。这种差异似乎与平滑肌对NO的血管扩张作用的敏感性降低有关，并可能在黑人高血压及其并发症的患病率增加中起一定作用。
An abnormal hemodynamic response to stressful stimuli has been proposed as a mechanism involved in the higher prevalence of hypertension in blacks. Given the important role of nitric oxide (NO) in the regulation of cardiovascular homeostasis, we investigated the possibility of racial differences in vascular NO activity during mental stress. To test this hypothesis, we compared the forearm blood flow (FBF) response to mental stress in 14 white and 12 black healthy subjects during intra-arterial infusion of either saline or NO synthesis inhibitor N-G-monomethyl-L-arginine (L-NMMA; 4 mu mol/min). We also examined vascular responses of the two groups to intra-arterial infusion of sodium nitroprusside (0.8 to 3.2 mu g/min), an exogenous NO donor. During saline infusion, the increase in FBF from baseline induced by mental stress was significantly higher in whites than in blacks (109+/-20% versus 58+/-8%; P=0.03). L-NMMA significantly reduced stress-induced increase in FBF in whites (from 109+/-20% to 54+/-11%; P=0.004) but not in blacks (from 58+/-8% to 42+/-10%; P=0.24); thus, the vasodilator effect of stress testing during L-NMMA was similar in whites and blacks (54+/-11% versus 42+/-10%; P=0.44). The vasodilator response to sodium nitroprusside was also lower in blacks than in whites (maximum flow, 6.9+/-2 versus 11.6+/-3.5 mL.min(-)1.dL(-1); P=0.001) and was not significantly modified by L-NMMA in either group. Our findings indicate that blacks have a reduced NO-dependent vasodilator activity during mental stress. This difference seems related to reduced sensitivity of smooth muscle to the vasodilator effect of NO and may play some role in the increased prevalence of hypertension and its complications in blacks.