Effects of graded LBNP on MSNA and interstitial norepinephrine
Effects of graded LBNP on MSNA and interstitial norepinephrine
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DOI：
10.1152/ajpheart.00412.2001
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发表时间：
2002-11-01
影响因子：
4.8
通讯作者：
MacLean, DA
中科院分区：
文献类型：
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作者：
Khan, MH;Sinoway, LI;MacLean, DA
暴露于下体负压(LBNP)会导致交感神经系统(SNS)的激活和肌肉交感神经活动(MSNA)的增加。在这项研究中，我们研究了下体负压时MSNA和间质去甲肾上腺素(NEI)浓度的关系。研究对象为12名健康志愿者(26+/-6岁)。其中6名受试者同时收集了MSNA和微透析数据。分别在静息状态和递增下体负压(-10、-30、-50 mm Hg)状态下测量MSNA(微神经学)和NEI(股外侧微透析)。MSNA随下体负荷量的增加而升高(P<；0.001，n=12)。静息状态下血浆去甲肾上腺素浓度为0.9±0.1nmol/L(n=12)。6名受试者的内分泌指数从安静时的5.2+/-0.8nmol/L上升到-50毫米汞时的17.0+/-1.7nmol/L(P<；0.001)。值得注意的是，伴有下体负压的非负荷量的上升幅度远低于负荷率的变化(增量21+/-6%比增量197+/-52%，n=6，P<；0.015)。MSNA与NEI呈显著线性相关(r=0.721，P<；0.004)。激活SNS可增加MSNA和NEI水平。NEI增加的幅度远大于NEP，这表明NE进入循环的移动随着压力感受器负荷的减少而减少。
Exposure to lower body negative pressure (LBNP) leads to an increased activation of the sympathetic nervous system (SNS) and an increase in muscle sympathetic nerve activity (MSNA). In this study, we examined the relationship between MSNA and interstitial norepinephrine (NEi) concentrations during LBNP. Twelve healthy volunteers were studied (26 +/- 6 yr). Simultaneous MSNA and microdialysis data were collected in six of these subjects. Measurements of MSNA (microneurography) and NEi (microdialysis, vastus lateralis) were performed at rest and then during an incremental LBNP paradigm (-10, -30, and -50 mmHg). MSNA rose as a function of LBNP (P < 0.001, n = 12). The plasma norepinephrine (NEp) concentration was 0.9 +/- 0.1 nmol/l at rest (n = 12). NEi measured in six subjects rose from 5.2 +/- 0.8 nmol/l at rest to 17.0 +/- 1.7 nmol/l at -50 mmHg (P < 0.001). Of note, the rise in NEp with LBNP was considerably less compared with the changes in NEi (Delta21 +/- 6% vs. Delta197 +/- 52%, n = 6, P < 0.015). MSNA and NEi showed a significant linear relationship (r = 0.721, P < 0.004). Activation of the SNS increased MSNA and NEi levels. The magnitude of the NEi increase was far greater than that seen for NEp suggesting that NE movement into the circulation decreases with baroreceptor unloading.