Farquhar William B, Wenner Megan M, Delaney Erin P, Prettyman Allen V, Stillabower Michael E
Department of Health, Nutrition, and Excercise Science, University of Delaware, USA.
Am J Physiol Heart Circ Physiol. 2006 Nov;291(5):H2181-6. doi: 10.1152/ajpheart.00191.2006. Epub 2006 Jun 9.
The purpose of this study was to examine the relationship between osmolality and efferent sympathetic outflow in humans. We hypothesized that increased plasma osmolality would be associated with increases in directly measured sympathetic outflow. Muscle sympathetic outflow was successfully recorded in eight healthy subjects during a 60-min intravenous hypertonic saline infusion (HSI; 3% NaCl) on one day and during a 60-min intravenous isotonic saline (ISO) infusion (0.9% NaCl) on a different day. The HSI provides an osmotic and volume stimulus, whereas the ISO infusion provides a volume-only stimulus. Muscle sympathetic nerve activity was quantified using the technique of peroneal microneurography. Plasma osmolality increased during the HSI but not during the ISO infusion (ANOVA, P < 0.05). Sympathetic outflow differed between the trials (ANOVA, P < 0.05); during the HSI burst, frequency initially increased from 14.6 +/- 2.5 to 18.1 +/- 1.9 bursts/min; during the ISO infusion, burst frequency initially declined from 14.7 +/- 2.5 to 12.0 +/- 2.1 bursts/min. Plasma norepinephrine concentration was greater at the end of the HSI compared with the end of the ISO infusion (HSI: 297 +/- 64 vs. ISO: 202 +/- 49 pg/ml; ANOVA, P < 0.05). We conclude that HSI-induced increases in plasma osmolality are associated with increases in sympathetic activity in humans.
本研究的目的是探讨人体渗透压与传出交感神经输出之间的关系。我们假设血浆渗透压升高会与直接测量的交感神经输出增加相关。在一天中，对8名健康受试者进行60分钟的静脉输注高渗盐水（HSI；3%氯化钠），并在另一天进行60分钟的静脉输注等渗盐水（ISO；0.9%氯化钠），期间成功记录肌肉交感神经输出。HSI提供渗透压和容量刺激，而ISO输注仅提供容量刺激。使用腓骨微神经图技术对肌肉交感神经活动进行量化。HSI期间血浆渗透压升高，而ISO输注期间未升高（方差分析，P<0.05）。两次试验之间交感神经输出不同（方差分析，P<0.05）；在HSI爆发期间，频率最初从14.6±2.5次/分钟增加到18.1±1.9次/分钟；在ISO输注期间，爆发频率最初从14.7±2.5次/分钟下降到12.0±2.1次/分钟。与ISO输注结束时相比，HSI结束时血浆去甲肾上腺素浓度更高（HSI：297±64 vs.ISO：202±49 pg/ml；方差分析，P<0.05）。我们得出结论，HSI诱导的血浆渗透压升高与人体交感神经活动增加相关。
