Integrative Cerebrovascular and Environmental Physiology SB Laboratory, Department of Human Health and Nutritional Sciences, College of Biological Science, University of Guelph, Guelph, Canada.
Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
J Cereb Blood Flow Metab. 2024 Oct;44(10):1840-1851. doi: 10.1177/0271678X241248228. Epub 2024 Apr 13.
The impact of physiological stressors on cerebral sympathetic nervous activity (SNA) remains controversial. We hypothesized that cerebral noradrenaline (NA) spillover, an index of cerebral SNA, would not change during both submaximal isometric handgrip (HG) exercise followed by a post-exercise circulatory occlusion (PECO), and supine dynamic cycling exercise. Twelve healthy participants (5 females) underwent simultaneous blood sampling from the right radial artery and right internal jugular vein. Right internal jugular vein blood flow was measured using Duplex ultrasound, and tritiated NA was infused through the participants' right superficial forearm vein. Heart rate was recorded via electrocardiogram and blood pressure was monitored using the right radial artery. Total NA spillover increased during HG (P = 0.049), PECO (P = 0.006), and moderate cycling exercise (P = 0.03) compared to rest. Cerebral NA spillover remained unchanged during isometric HG exercise (P = 0.36), PECO after the isometric HG exercise (P = 0.45), and during moderate cycling exercise (P = 0.94) compared to rest. These results indicate that transient increases in blood pressure during acute exercise involving both small and large muscle mass do not engage cerebral SNA in healthy humans. Our findings suggest that cerebral SNA may be non-obligatory for exercise-related cerebrovascular adjustments.
生理应激源对大脑交感神经活动（SNA）的影响仍存在争议。我们假设，大脑去甲肾上腺素（NA）溢出作为大脑 SNA 的指标，在最大等长握力（HG）运动后和运动后循环闭塞（PECO）以及仰卧位动态循环运动期间不会发生变化。12 名健康参与者（5 名女性）同时从右侧桡动脉和右侧颈内静脉取样。使用双功能超声测量右侧颈内静脉血流量，并通过参与者的右侧前臂浅静脉输注氚标记的 NA。通过心电图记录心率，通过右侧桡动脉监测血压。与休息相比，HG（P=0.049）、PECO（P=0.006）和中等强度的循环运动（P=0.03）期间总 NA 溢出增加。与休息相比，等长 HG 运动期间（P=0.36）、等长 HG 运动后的 PECO 期间（P=0.45）和中等强度的循环运动期间（P=0.94），大脑 NA 溢出保持不变。这些结果表明，涉及小肌肉群和大肌肉群的急性运动期间血压的短暂升高不会使健康人参与大脑 SNA。我们的研究结果表明，大脑 SNA 可能不是与运动相关的脑血管调节所必需的。
