NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil.
Human Cardiovascular Physiology Laboratory, Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
J Appl Physiol (1985). 2024 Apr 1;136(4):917-927. doi: 10.1152/japplphysiol.00009.2024. Epub 2024 Feb 22.
Microneurographic recordings of muscle sympathetic nerve activity (MSNA) and the succeeding changes in beat-to-beat blood pressure (i.e., sympathetic transduction) provide important insights into the neural control of the circulation in humans. Despite its widespread use, the reliability of this technique remains unknown. Herein, we assessed the intra- and interday test-retest reliability of signal-averaging sympathetic transduction to blood pressure. Data were analyzed from 15 (9 M/6 F) young, healthy participants who completed two baseline recordings of fibular nerve MSNA separated by 60 min (intraday). The interday reliability was obtained in a subset of participants ( = 13, 9 M/4 F) who completed a follow-up MSNA study. Signal-averaging sympathetic transduction was quantified as peak change in diastolic (DBP) and mean arterial pressure (MAP) following a burst of MSNA. Analyses were also computed considering different MSNA burst sizes (quartiles of normalized MSNA) and burst patterns (singlets, couplets, triplets, and quadruplets+), as well as nonburst responses. Intraclass-correlation coefficients (ICCs) were used as the main reliability measure. Peak changes in MAP [intraday: ICC = 0.76 (0.30-0.92), = 0.006; interday: ICC = 0.91 (0.63-0.97), < 0.001] demonstrated very good to excellent reliability. Sympathetic transduction of MSNA burst size displayed moderate to very good reliability, though the reliability of MSNA burst pattern was poor to very good. Nonburst responses revealed poor intraday [ICC = 0.37 (-1.05 to 0.80), = 0.21], but very good interday [ICC = 0.76 (0.18-0.93), = 0.01] reliability. Intraday reliability measures were consistently lower than interday reliability. Similar results were obtained using DBP. Collectively, these findings provide evidence that the burst-triggering signal-averaging technique is a reliable measure of sympathetic transduction to blood pressure in young, healthy adults. We found that signal-averaging sympathetic transduction to blood pressure displayed very good to excellent intra- and interday test-retest reliability in healthy, young adults. Reliability analyses according to muscle sympathetic burst size, burst pattern, and nonburst response were less consistent. Results were similar when using diastolic or mean arterial pressure in the transduction calculation. These findings suggest that the signal-averaging technique can be used with confidence to investigate sympathetic transduction to blood pressure in humans across time.
肌间神经丛运动神经活动（MSNA）的微神经记录和随后的逐搏血压变化（即交感神经传递）为理解人类循环的神经控制提供了重要的见解。尽管该技术应用广泛，但它的可靠性仍不清楚。在此，我们评估了信号平均交感神经传递至血压的日内和日间测试-再测试可靠性。对 15 名（9 名男性/6 名女性）年轻健康参与者的两项腓肠神经 MSNA 基线记录进行了数据分析，这两项记录相隔 60 分钟（日内）。对一组参与者（= 13，9 名男性/4 名女性）进行了后续 MSNA 研究，以获得日间可靠性。信号平均交感神经传递被量化为 MSNA 爆发后舒张压（DBP）和平均动脉压（MAP）的峰值变化。分析还考虑了不同的 MSNA 爆发大小（归一化 MSNA 的四分位数）和爆发模式（单发、双发、连发和四联发+）以及非爆发反应。使用组内相关系数（ICC）作为主要可靠性衡量标准。MAP 的峰值变化[日内：ICC = 0.76（0.30-0.92），= 0.006；日间：ICC = 0.91（0.63-0.97），<0.001]表现出极好到优秀的可靠性。MSNA 爆发大小的交感神经传递显示出中等至极好的可靠性，尽管 MSNA 爆发模式的可靠性较差到极好。非爆发反应显示出日内较差的可靠性[ICC = 0.37（-1.05 至 0.80），= 0.21]，但日间非常好的可靠性[ICC = 0.76（0.18-0.93），= 0.01]。日内可靠性指标始终低于日间可靠性。使用 DBP 也得到了类似的结果。综合这些发现，为年轻健康成年人的血压交感神经传递的爆发触发信号平均技术是一种可靠的测量方法提供了证据。我们发现，健康年轻成年人的血压信号平均交感神经传递具有极好到优秀的日内和日间测试-再测试可靠性。根据肌肉交感神经爆发大小、爆发模式和非爆发反应进行的可靠性分析不太一致。在传递计算中使用舒张压或平均动脉压时，结果相似。这些发现表明，信号平均技术可以有信心地用于研究人类血压的交感神经传递。
