Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
School of Health Sciences, Western Sydney University, Sydney, New South Wales, Australia.
Am J Physiol Heart Circ Physiol. 2024 Mar 1;326(3):H612-H622. doi: 10.1152/ajpheart.00497.2023. Epub 2024 Jan 12.
Discharge of postganglionic muscle sympathetic nerve activity (MSNA) is related poorly to blood pressure (BP) in adults. Whether neural measurements beyond the prevailing level of MSNA can account for interindividual differences in BP remains unclear. The current study sought to evaluate the relative contributions of sympathetic-BP transduction and sympathetic baroreflex gain on resting BP in young adults. Data were analyzed from 191 (77 females) young adults (18-39 years) who underwent continuous measurement of beat-to-beat BP (finger photoplethysmography), heart rate (electrocardiography), and fibular nerve MSNA (microneurography). Linear regression analyses were computed to determine associations between sympathetic-BP transduction (signal-averaging) or sympathetic baroreflex gain (threshold technique) and resting BP, before and after controlling for age, body mass index, and MSNA burst frequency. K-mean clustering was used to explore sympathetic phenotypes of BP control and consequential influence on resting BP. Sympathetic-BP transduction was unrelated to BP in males or females (both < 0.01; > 0.67). Sympathetic baroreflex gain was positively associated with BP in males ( = 0.09, < 0.01), but not in females ( < 0.01; = 0.80), before and after controlling for age, body mass index, and MSNA burst frequency. K-means clustering identified a subset of participants with average resting MSNA, yet lower sympathetic-BP transduction and lower sympathetic baroreflex gain. This distinct subgroup presented with elevated BP in males ( < 0.02), but not in females ( = 0.10). Sympathetic-BP transduction is unrelated to resting BP, while the association between sympathetic baroreflex gain and resting BP in males reveals important sex differences in the sympathetic determination of resting BP. In a sample of 191 normotensive young adults, we confirm that resting muscle sympathetic nerve activity is a poor predictor of resting blood pressure and now demonstrate that sympathetic baroreflex gain is associated with resting blood pressure in males but not females. In contrast, signal-averaged measures of sympathetic-blood pressure transduction are unrelated to resting blood pressure. These findings highlight sex differences in the neural regulation of blood pressure.
节后交感神经肌肉活动（MSNA）的放电与成人血压（BP）的相关性较差。神经测量值是否超出 MSNA 的普遍水平可以解释 BP 的个体差异尚不清楚。本研究旨在评估交感神经-BP 转导和交感神经压力反射增益对年轻成年人静息血压的相对贡献。对 191 名（77 名女性）年轻成年人（18-39 岁）进行了连续的逐搏血压（手指光体积描记法）、心率（心电图）和腓肠神经 MSNA（微神经记录）测量，分析了这些数据。计算线性回归分析以确定交感神经-BP 转导（信号平均）或交感神经压力反射增益（阈值技术）与静息血压之间的关联，在控制年龄、体重指数和 MSNA 爆发频率之前和之后进行。K-均值聚类用于探索 BP 控制的交感神经表型及其对静息血压的后续影响。在男性或女性中，交感神经-BP 转导与 BP 均无关（均<0.01；>0.67）。在控制年龄、体重指数和 MSNA 爆发频率之前和之后，交感神经压力反射增益与男性的 BP 呈正相关（=0.09，<0.01），但与女性的 BP 无关（<0.01；=0.80）。K-均值聚类确定了一组具有平均静息 MSNA 的参与者，但交感神经-BP 转导和交感神经压力反射增益较低。在男性中，这个独特的亚组的 BP 升高（<0.02），但在女性中则没有（=0.10）。交感神经-BP 转导与静息血压无关，而男性交感神经压力反射增益与静息血压之间的关联揭示了静息血压中交感神经决定因素的重要性别差异。在 191 名血压正常的年轻成年人样本中，我们证实静息肌肉交感神经活动是静息血压的一个较差预测指标，现在证明交感神经压力反射增益与男性静息血压相关，但与女性无关。相比之下，交感神经-血压转导的信号平均测量与静息血压无关。这些发现强调了血压神经调节中的性别差异。
