Abstract：
OBJECTIVE: The nadir pressure responses to cardiac cycles absent of muscle sympathetic nerve activity (MSNA) bursts (or non-bursts) are typically reported in studies quantifying sympathetic transduction, but the information gained by studying non-bursts is unclear. We tested the hypothesis that longer sequences of non-bursts (≥8 cardiac cycles) would be associated with a greater nadir diastolic blood pressure (DBP) and that better popliteal artery function would be associated with an augmented reduction in DBP.
METHODS: Resting beat-by-beat DBP (via finger photoplethysmography) and common peroneal nerve MSNA (via microneurography) were recorded in 39 healthy, adults (age 23.4 ± 5.3 years; 19 females). For each cardiac cycle absent of MSNA bursts, the mean nadir DBP (ΔDBP) during the 12 cardiac cycles following were determined, and separate analyses were conducted for ≥8 or < 8 cardiac cycle sequences. Popliteal artery endothelial-dependent (via flow-mediated dilation; FMD) and endothelial-independent vasodilation (via nitroglycerin-mediated dilation; NMD) were determined.
RESULTS: The nadir DBP responses to sequences ≥8 cardiac cycles were larger (-1.40 ± 1.27 mmHg) than sequences <8 (-0.38 ± 0.46 mmHg; p < 0.001). In adjusting for sex and burst frequency (14 ± 8 bursts/min), larger absolute or relative FMD (p < 0.01), but not NMD (p > 0.53) was associated with an augmented nadir DBP. This overall DBP-FMD relationship was similar in sequences ≥8 (p = 0.04-0.05), but not <8 (p > 0.72).
CONCLUSIONS: The DBP responses to non-bursts, particularly longer sequences, were inversely associated with popliteal endothelial function, but not vascular smooth muscle sensitivity. This study provides insight into the information gained by quantifying the DBP responses to cardiac cycles absent of MSNA.
METHODS: Resting beat-by-beat DBP (via finger photoplethysmography) and common peroneal nerve MSNA (via microneurography) were recorded in 39 healthy, adults (age 23.4 ± 5.3 years; 19 females). For each cardiac cycle absent of MSNA bursts, the mean nadir DBP (ΔDBP) during the 12 cardiac cycles following were determined, and separate analyses were conducted for ≥8 or < 8 cardiac cycle sequences. Popliteal artery endothelial-dependent (via flow-mediated dilation; FMD) and endothelial-independent vasodilation (via nitroglycerin-mediated dilation; NMD) were determined.
RESULTS: The nadir DBP responses to sequences ≥8 cardiac cycles were larger (-1.40 ± 1.27 mmHg) than sequences <8 (-0.38 ± 0.46 mmHg; p < 0.001). In adjusting for sex and burst frequency (14 ± 8 bursts/min), larger absolute or relative FMD (p < 0.01), but not NMD (p > 0.53) was associated with an augmented nadir DBP. This overall DBP-FMD relationship was similar in sequences ≥8 (p = 0.04-0.05), but not <8 (p > 0.72).
CONCLUSIONS: The DBP responses to non-bursts, particularly longer sequences, were inversely associated with popliteal endothelial function, but not vascular smooth muscle sensitivity. This study provides insight into the information gained by quantifying the DBP responses to cardiac cycles absent of MSNA.
摘要：
目的：在定量交感神经传导的研究中，通常报道了对缺乏肌肉交感神经活动（MSNA）爆发（或非爆发）的心动周期的最低点压力反应。但是通过研究非突发获得的信息尚不清楚。我们测试了以下假设：较长的非爆发序列（≥8个心动周期）将与较高的最低点舒张压（DBP）有关，而更好的the动脉功能将与DBP的降低增加有关。
方法：记录39例健康人的静息逐次搏动DBP（通过手指光体积描记术）和腓总神经MSNA（通过显微神经描记术）。成人（年龄23.4±5.3岁；19名女性）。对于没有MSNA爆发的每个心动周期，测定12个心动周期的平均最低点DBP(ΔDBP),并对≥8个或<8个心动周期序列进行单独分析.确定了p动脉内皮依赖性（通过流量介导的扩张；FMD）和内皮非依赖性血管舒张（通过硝酸甘油介导的扩张；NMD）。
结果：序列≥8个心动周期的最低点DBP反应（-1.40±1.27mmHg）大于序列<8（-0.38±0.46mmHg；p<0.001）。在调整性别和爆发频率(14±8爆发/分钟)时，较大的绝对或相对口蹄疫（p<0.01），但NMD(p>0.53)与最低点DBP增加相关。这种总体DBP-FMD关系在序列≥8中相似（p=0.04-0.05），但不是<8（p>0.72）。
结论：DBP对非突发的反应，特别是更长的序列，与pop血管内皮功能呈负相关，但不是血管平滑肌的敏感性.这项研究提供了对通过量化对缺乏MSNA的心动周期的DBP反应而获得的信息的见解。
方法：记录39例健康人的静息逐次搏动DBP（通过手指光体积描记术）和腓总神经MSNA（通过显微神经描记术）。成人（年龄23.4±5.3岁；19名女性）。对于没有MSNA爆发的每个心动周期，测定12个心动周期的平均最低点DBP(ΔDBP),并对≥8个或<8个心动周期序列进行单独分析.确定了p动脉内皮依赖性（通过流量介导的扩张；FMD）和内皮非依赖性血管舒张（通过硝酸甘油介导的扩张；NMD）。
结果：序列≥8个心动周期的最低点DBP反应（-1.40±1.27mmHg）大于序列<8（-0.38±0.46mmHg；p<0.001）。在调整性别和爆发频率(14±8爆发/分钟)时，较大的绝对或相对口蹄疫（p<0.01），但NMD(p>0.53)与最低点DBP增加相关。这种总体DBP-FMD关系在序列≥8中相似（p=0.04-0.05），但不是<8（p>0.72）。
结论：DBP对非突发的反应，特别是更长的序列，与pop血管内皮功能呈负相关，但不是血管平滑肌的敏感性.这项研究提供了对通过量化对缺乏MSNA的心动周期的DBP反应而获得的信息的见解。
