Signal-averaged sympathetic transduction of blood pressure (BP) is inversely related to resting MSNA burst frequency in healthy cohorts. Whether this represents a physiological compensatory adaptation or a methodological limitation, remains unclear. The current analysis aimed to determine the contribution of methodological limitations by evaluating the dependency of MSNA transduction at different levels of absolute BP. Thirty-six healthy participants (27±7 years, 9 females) underwent resting measures of beat-to-beat heart rate, BP, and muscle sympathetic nerve activity (MSNA). Tertiles of mean arterial pressure (MAP) were computed for each participant to identify cardiac cycles occurring below, around, and above the MAP operating pressure (OP). Changes in hemodynamic variables were computed across 15 cardiac cycles within each MAP tertile to quantify sympathetic transduction. MAP increased irrespective of sympathetic activity when initiated below the OP, but with MSNA bursts provoking larger rises (3.0±0.9 vs. 2.1±0.7mmHg; P<0.01). MAP decreased irrespective of sympathetic activity when initiated above the OP, but with MSNA bursts attenuating the drop (-1.3±1.1 vs. -3.1±1.2mmHg; P<0.01). In participants with low vs. high resting MSNA (12±4 vs. 32±10 bursts/min), sympathetic transduction of MAP was not different when initiated by bursts below (3.2±1.0 vs. 2.8±0.9mmHg; P=0.26) and above the OP (-1.0±1.3 vs. -1.6±0.8mmHg; P=0.08), however, low resting MSNA was associated with a smaller proportion of MSNA bursts firing above the OP (15±5 vs. 22±5%; P<0.01). The present analyses demonstrate that the signal-averaging technique for calculating sympathetic transduction of BP is influenced by the timing of an MSNA burst relative to cyclic oscillations in BP.

中文翻译：

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血压振荡影响血压的信号平均交感神经转导：与静息交感神经流出相关的意义

血压 (BP) 的信号平均交感神经转导与健康队列中静息 MSNA 爆发频率呈负相关。这是否代表生理补偿性适应或方法学限制，仍不清楚。目前的分析旨在通过评估 MSNA 转导在不同绝对 BP 水平下的依赖性来确定方法学限制的贡献。36 名健康参与者（27±7 岁，9 名女性）接受了每搏心率、血压和肌肉交感神经活动 (MSNA) 的静息测量。计算每位参与者的平均动脉压 (MAP) 的三分位数，以识别发生在 MAP 操作压力 (OP) 以下、周围和以上的心动周期。计算每个 MAP 三分位数内 15 个心动周期的血流动力学变量的变化，以量化交感神经转导。当在 OP 以下开始时，MAP 增加，而与交感神经活动无关，但 MSNA 爆发引起更大的上升（3.0±0.9 对 2.1±0.7mmHg；P<0.01）。MAP 在 OP 以上开始时与交感神经活动无关，但随着 MSNA 爆发减弱了下降（-1.3±1.1 对 -3.1±1.2mmHg；P<0.01）。在静息 MSNA 低与高（12±4 与 32±10 次爆发/分钟）的参与者中，MAP 的交感神经转导在由低于以下爆发的爆发时没有差异（3.2±1.0 与 2.8±0.9mmHg；P=0.26）和高于 OP（-1.0±1.3 vs. -1.6±0.8mmHg；P=0.08），然而，低静息 MSNA 与较小比例的 MSNA 爆发在 OP 之上（15±5 vs. 22±5%）相关；P<0.01)。