Influence of plasma osmolality on baroreflex control of sympathetic activity.
Influence of plasma osmolality on baroreflex control of sympathetic activity.
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血浆渗透压对交感神经活动的压力反射控制的影响。
DOI：
10.1152/ajpheart.01383.2006
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
Farquhar,WilliamB
中科院分区：
文献类型：
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作者：
Wenner,MeganM;Rose,WilliamC;Delaney,ErinP;Stillabower,MichaelE;Farquhar,WilliamB
本研究的目的是确定是否血浆渗透压改变压力反射控制的交感神经活动时，控制血管内容积的变化，我们假设，压力反射控制的交感神经活动将是更大的高渗刺激相比，等渗刺激时，血管内容积扩张相匹配。7名健康受试者（25 ± 2岁）完成了两次静脉输注：高渗盐水输注（HSI; 3% NaCl）和在单独情况下等渗盐水输注（ISO; 0.9% NaCl），速率均为0.15 ml·kg−1·min−1。为了分离渗透压摩尔浓度的影响，基于红细胞压积回顾性匹配HSI和ISO条件之间的比较;因此，在HSI 20 min和ISO 40 min时测定交感神经流出的压力反射控制。肌肉交感神经流出量（MSNA）直接测量使用腓神经显微神经造影技术，渗透压和血压（Finometer）进行了评估。通过计算控制呼吸期间MSNA与舒张压之间关系的斜率来估计交感神经流出的压力反射控制。HSI组血浆渗透压高于ISO组（HSI组：292 ± 0.9mosmol/kg，ISO组：289 ± 0.8mosmol/kg，P< 0.05）。血细胞比容匹配（HSI：39.1 ± 1%，ISO：39.1 ± 1%，P> 0.40）;因此，我们成功分离了渗透压。与ISO相比，HSI期间交感神经流出的压力反射控制更大（HSI：-8.3 ± 1.2任意单位·搏动-1·mmHg-1 vs. ISO：−4.0 ± 0.8任意单位·搏动−1·mmHg−1，P= 0.01）。总之，当控制血管内容量时，增加血浆渗透压可增强人交感神经活动的压力反射控制。
The purpose of this study was to determine if plasma osmolality alters baroreflex control of sympathetic activity when controlling for a change in intravascular volume; we hypothesized that baroreflex control of sympathetic activity would be greater during a hyperosmotic stimulus compared with an isoosmotic stimulus when intravascular volume expansion was matched. Seven healthy subjects (25 ± 2 yr) completed two intravenous infusions: a hypertonic saline infusion (HSI; 3% NaCl) and, on a separate occasion, an isotonic saline infusion (ISO; 0.9% NaCl), both at a rate of 0.15 ml·kg−1·min−1. To isolate the effect of osmolality, comparisons between HSI and ISO conditions were retrospectively matched based on hematocrit; therefore, baroreflex control of sympathetic outflow was determined at 20 min of a HSI and 40 min of an ISO. Muscle sympathetic outflow (MSNA) was directly measured using the technique of peroneal microneurography; osmolality and blood pressure (Finometer) were assessed. The baroreflex control of sympathetic outflow was estimated by calculating the slope of the relationship between MSNA and diastolic blood pressure during controlled breathing. Plasma osmolality was greater during the HSI compared with the ISO (HSI: 292 ± 0.9 mosmol/kg and ISO: 289 ± 0.8 mosmol/kg,P< 0.05). Hematocrits were matched (HSI: 39.1 ± 1% and ISO: 39.1 ± 1%,P> 0.40); thus, we were successful in isolating osmolality. The baroreflex control of sympathetic outflow was greater during the HSI compared with the ISO (HSI: −8.3 ± 1.2 arbitrary units·beat−1·mmHg−1vs. ISO: −4.0 ± 0.8 arbitrary units·beat−1·mmHg−1,P= 0.01). In conclusion, when controlling for intravascular volume, increased plasma osmolality enhances baroreflex control of sympathetic activity in humans.