Notay Karambir, Incognito Anthony V, Millar Philip J
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and.
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and
Am J Physiol Heart Circ Physiol. 2017 Jul 1;313(1):H59-H65. doi: 10.1152/ajpheart.00163.2017. Epub 2017 May 5.
Acute dietary nitrate ([Formula: see text]) supplementation reduces resting blood pressure in healthy normotensives. This response has been attributed to increased nitric oxide bioavailability and peripheral vasodilation, although nitric oxide also tonically inhibits central sympathetic outflow. We hypothesized that acute dietary [Formula: see text] supplementation using beetroot (BR) juice would reduce blood pressure and muscle sympathetic nerve activity (MSNA) at rest and during exercise. Fourteen participants (7 men and 7 women, age: 25 ± 10 yr) underwent blood pressure and MSNA measurements before and after (165-180 min) ingestion of 70ml high-[Formula: see text] (~6.4 mmol [Formula: see text]) BR or [Formula: see text]-depleted BR placebo (PL; ~0.0055 mmol [Formula: see text]) in a double-blind, randomized, crossover design. Blood pressure and MSNA were also collected during 2 min of static handgrip (30% maximal voluntary contraction). The changes in resting MSNA burst frequency (-3 ± 5 vs. 3 ± 4 bursts/min, = 0.001) and burst incidence (-4 ± 7 vs. 4 ± 5 bursts/100 heart beats, = 0.002) were lower after BR versus PL, whereas systolic blood pressure (-1 ± 5 vs. 2 ± 5 mmHg, = 0.30) and diastolic blood pressure (4 ± 5 vs. 5 ± 7 mmHg, = 0.68) as well as spontaneous arterial sympathetic baroreflex sensitivity ( = 0.95) were not different. During static handgrip, the change in MSNA burst incidence (1 ± 8 vs. 8 ± 9 bursts/100 heart beats, = 0.04) was lower after BR versus PL, whereas MSNA burst frequency (6 ± 6 vs. 11 ± 10 bursts/min, = 0.11) as well as systolic blood pressure (11 ± 7 vs. 12 ± 8 mmHg, = 0.94) and diastolic blood pressure (11 ± 4 vs. 11 ± 4 mmHg, = 0.60) were not different. Collectively, these data provide proof of principle that acute BR supplementation can decrease central sympathetic outflow at rest and during exercise. Dietary [Formula: see text] supplementation may represent a novel intervention to target exaggerated sympathetic outflow in clinical populations. The hemodynamic benefits of dietary nitrate supplementation have been attributed to nitric oxide-mediated peripheral vasodilation. Here, we provide proof of concept that acute dietary nitrate supplementation using beetroot juice can decrease muscle sympathetic outflow at rest and during exercise in a normotensive population. These results have applications for targeting central sympathetic overactivation in disease.
急性补充膳食硝酸盐([化学式:见原文])可降低健康血压正常者的静息血压。这种反应归因于一氧化氮生物利用度的增加和外周血管舒张,尽管一氧化氮也会持续抑制中枢交感神经输出。我们假设,使用甜菜根(BR)汁急性补充膳食[化学式:见原文]会降低静息和运动期间的血压及肌肉交感神经活动(MSNA)。14名参与者(7名男性和7名女性,年龄:25±10岁)在双盲、随机、交叉设计中,于摄入70ml高[化学式:见原文](约6.4mmol[化学式:见原文])BR或[化学式:见原文]耗尽的BR安慰剂(PL;约0.0055mmol[化学式:见原文])之前和之后(165 - 180分钟)进行血压和MSNA测量。在静态握力(最大自主收缩的30%)的2分钟期间也收集血压和MSNA。与PL相比,BR后静息MSNA爆发频率(-3±5对3±4次/分钟,P = 0.001)和爆发发生率(-4±7对4±5次/100心跳,P = 0.002)的变化更低,而收缩压(-1±5对2±5mmHg,P = 0.30)、舒张压(4±5对5±7mmHg,P = 0.68)以及自发性动脉交感压力反射敏感性(P = 0.95)无差异。在静态握力期间,与PL相比,BR后MSNA爆发发生率的变化(1±8对8±9次/100心跳,P = 0.04)更低,而MSNA爆发频率(6±6对11±10次/分钟,P = 0.11)、收缩压(11±7对12±8mmHg,P = 0.94)和舒张压(11±4对11±4mmHg,P = 0.60)无差异。总体而言,这些数据提供了原理证明,即急性补充BR可在静息和运动期间减少中枢交感神经输出。膳食补充[化学式:见原文]可能代表一种针对临床人群过度交感神经输出的新型干预措施。膳食硝酸盐补充的血流动力学益处归因于一氧化氮介导的外周血管舒张。在此,我们提供概念证明,即使用甜菜根汁急性补充膳食硝酸盐可在血压正常人群的静息和运动期间减少肌肉交感神经输出。这些结果对于针对疾病中的中枢交感神经过度激活具有应用价值。