Contribution of nitric oxide in the contraction-induced rapid vasodilation in young and older adults
Contribution of nitric oxide in the contraction-induced rapid vasodilation in young and older adults
复制标题
DOI：
10.1152/japplphysiol.00446.2013
复制
发表时间：
2013-08-01
影响因子：
3.3
通讯作者：
Joyner, Michael J.
中科院分区：
文献类型：
--
作者：
Casey, Darren P.;Walker, Branton G.;Joyner, Michael J.
我们测试了一氧化氮（NO）生物利用度降低有助于老年人单肌肉收缩后的衰减峰值和总血管舒张的假设。青年组（n = 10; 24 +/- 2岁）和老年人（n = 10; 67 +/- 2岁）在盐水输注（对照）和通过N-G-单甲基-L-精氨酸抑制NO合酶（NOS）期间，以最大值的10、20和40%进行单次前臂收缩。使用多普勒超声测量肱动脉直径和速度，并根据血流量（ml/min）和血压（mmHg）计算前臂血管传导性（FVC;单位为ml.min（-1. 100 mmHg（-1）。在所有强度下，老年人的峰值和总血管舒张反应[FVC较基线的变化（Delta）]均减弱（P < 0.05）。NOS抑制使Δ FVC峰值降低10%（88 +/- 12 vs. 52 +/- 9 ml.min（-1. 100 mmHg（-1）），20%（125 +/- 13 vs. 83 +/- 13 ml.min（-1. 100 mmHg（-1））和40%（年轻受试者为207 +/- 26 vs. 133 +/- 20 ml.min（-1. 100 mmHg（-1）），（所有患者P < 0.05），老年人为10%（59 +/- 5 vs. 47 +/- 7 ml.min（-1. 100 mmHg（-1），P < 0.05）和20%（88 +/- 9 vs. 68 +/- 9 ml.min（-1. 100 mmHg（-1），P < 0.05），但不是40%（128 +/- 12 vs. 105 +/- 11 ml.min（-1. 100 mmHg（-1），P = 0.11）。年轻人与老年人相比，NOS抑制导致的峰值Δ FVC相对降低（%）更大，分别为20%（-36 +/- 5 vs. -23 +/-5%，P < 0.05）和40%（-35 +/- 6 vs. -16 +/-7%，P < 0.05）。在所有强度下，年轻人与老年人相比，NOS抑制的总血管舒张反应（曲线下面积）的减少也更大。我们的数据表明，收缩引起的快速血管舒张部分是由NO介导的，并且在年轻人中NO的贡献更大。
We tested the hypothesis that reduced nitric oxide (NO) bioavailability contributes to the attenuated peak and total vasodilation following single-muscle contractions in older adults. Young (n = 10; 24 +/- 2 yr) and older (n = 10; 67 +/- 2 yr) adults performed single forearm contractions at 10, 20, and 40% of maximum during saline infusion (control) and NO synthase (NOS) inhibition via N-G-monomethyl-L-arginine. Brachial artery diameters and velocities were measured using Doppler ultrasound and forearm vascular conductance (FVC; in ml.min(-1).100 mmHg(-1)) was calculated from blood flow (ml/min) and blood pressure (mmHg). Peak and total vasodilator responses [change (Delta) in FVC from baseline] were attenuated in older adults at all intensities (P < 0.05). NOS inhibition reduced the peak Delta FVC at 10% (88 +/- 12 vs. 52 +/- 9 ml.min(-1).100 mmHg(-1)), 20% (125 +/- 13 vs. 83 +/- 13 ml.min(-1).100 mmHg(-1)), and 40% (207 +/- 26 vs. 133 +/- 20 ml.min(-1).100 mmHg(-1)) in young subjects, (P < 0.05 for all) and in older adults at 10% (59 +/- 5 vs. 47 +/- 7 ml.min(-1).100 mmHg(-1), P < 0.05) and 20% (88 +/- 9 vs. 68 +/- 9 ml.min(-1).100 mmHg(-1), P < 0.05), but not 40% (128 +/- 12 vs. 105 +/- 11 ml.min(-1).100 mmHg(-1), P = 0.11). The relative (%) reduction in peak Delta FVC due to NOS inhibition was greater in young vs. older adults at 20% (-36 +/- 5 vs. -23 +/- 5%, P < 0.05) and 40% (-35 +/- 6 vs. -16 +/- 7%, P < 0.05). The reduction in the total vasodilator response (area under the curve) with NOS inhibition was also greater in young vs. older adults at all intensities. Our data suggest that contraction-induced rapid vasodilation is mediated in part by NO, and that the contribution of NO is greater in young adults.