Increase in epinephrine-induced responsiveness during microgravity simulated by head-down bed rest in humans
Increase in epinephrine-induced responsiveness during microgravity simulated by head-down bed rest in humans
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DOI：
10.1152/jappl.1999.87.5.1614
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发表时间：
1999-11-01
影响因子：
3.3
通讯作者：
Berlan, M
中科院分区：
文献类型：
--
作者：
Barbe, P;Galitzky, J;Berlan, M
在通过模拟微重力降低交感神经系统活动之前和期间，研究了肾上腺素对交感神经系统和代谢功能的影响。在头低位卧床休息（HDBR）前和第5天，以3种分级速率（0.01、0.02和0.03 μ g.kg（-1）.min（-1），各40 min）输注Epi。评价了Epi对SNS（通过血浆去甲肾上腺素水平和收缩压和心率变异性的频谱分析评估）、对甘油、非酯化脂肪酸（NEFA）、葡萄糖和胰岛素的血浆水平以及对能量消耗的影响。HDBR降低了尿去甲肾上腺素排泄（28.1 ± 4.2 vs. 51.5 ± 9.1 μ g/24 h）和中频范围内收缩压的频谱变异性（16.3 ± 1.9 vs. 24.5 ± 0.9标准化单位）。Epi在HDBR期间增加血浆去甲肾上腺素水平（P < 0.01）和收缩压频谱变异性（P < 0.009），但在HDBR之前不增加。在HDBR期间未观察到Epi诱导的心率和收缩压和舒张压变化的改变。肾上腺素增加血浆葡萄糖，胰岛素和NEFA水平之前和期间HDBR。在HDBR期间，Epi诱导的血浆甘油和乳酸水平的升高比HDBR前更明显（分别为P < 0.005和P < 0.001）。Epi诱导的能量消耗在HDBR期间高于HDBR（P < 0.02）。我们的数据表明，在模拟微重力过程中，肾上腺素的影响增加可能与肾上腺素输注引起的SNS反应增加和/或与终末器官，特别是脂肪组织和骨骼肌的β-肾上腺素能受体敏化有关。
The epinephrine (Epi)-induced effects on the sympathetic nervous system (SNS) and metabolic functions were studied in men before and during a decrease in SNS activity achieved through simulated microgravity. Epi was infused at 3 graded rates (0.01, 0.02, and 0.03 mu g.kg(-1).min(-1) for 40 min each) before and on the fifth day of head-down bed rest (HDBR). The effects of Epi on the SNS (assessed by plasma norepinephrine levels and spectral analysis of systolic blood pressure and heart rate variability), on plasma levels of glycerol, nonesterified fatty acids (NEFA), glucose and insulin, and on energy expenditure were evaluated. HDBR decreased urinary norepinephrine excretion (28.1 +/- 4.2 vs. 51.5 +/- 9.1 mu g/24 h) and spectral variability of systolic blood pressure in the midfrequency range (16.3 +/- 1.9 vs. 24.5 +/- 0.9 normalized units). Epi increased norepinephrine plasma levels (P < 0.01) and spectral variability of systolic blood pressure (P < 0.009) during, but not before, HDBR. No modification of Epi-induced changes in heart rate and systolic and diastolic blood pressures were observed during HDBR. Epi increased plasma glucose, insulin, and NEFA levels before and during HDBR. During HDBR, the Epi-induced increase in plasma glycerol and lactate levels was more pronounced than before HDBR (P < 0.005 and P < 0.001, respectively). Epi-induced energy expenditure was higher during HDBR (P < 0.02). Our data suggest that the increased effects of Epi during simulated microgravity could be related to both the increased SNS response to Epi infusion and/or to the beta-adrenergic receptor sensitization of end organs, particularly in adipose tissue and skeletal muscle.