Human sympathetic and vagal baroreflex responses to sequential nitroprusside and phenylephrine
Human sympathetic and vagal baroreflex responses to sequential nitroprusside and phenylephrine
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DOI：
10.1152/ajpheart.1999.276.5.h1691
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发表时间：
1999-05-01
影响因子：
4.8
通讯作者：
Eckberg, DL
中科院分区：
文献类型：
--
作者：
Rudas, L;Crossman, AA;Eckberg, DL
我们对 18 名健康男性和女性的压力感受反射测试方法进行了评估，该方法包括顺序静脉推注硝普钠，然后去氧肾上腺素，去氧肾上腺素，然后硝普钠，并得出关于人类交感神经和迷走神经压力感受反射机制的推论。我们记录了心电图、光电体积描记手指动脉压和腓神经肌肉交感神经活动。然后，我们将来自降压药（硝普钠）和升压药（去氧肾上腺素）阶段的最小二乘线性回归斜率与 1）来自收缩动脉压和 R-R 间期自发波动的斜率，以及 2）来自收缩压和 R-R 间期交叉频谱分析的压力感受反射增益进行了对比。我们根据综合肌肉交感神经活动和舒张压计算了交感压力反射增益。我们发现，当动脉压下降时，迷走神经压力感受反射斜率比上升时要小，并且这种滞后现象存在于低于和高于基线水平的压力范围内。尽管药理学和自发迷走神经压力反射反应密切相关，但药理学压力反射斜率往往低于自发波动的斜率。当动脉压下降和上升时，交感压力反射斜率相似。然而，高于基线的小压力升高会使交感运动神经元沉默。迷走神经而非交感压力反射的增益与受试者的年龄及其基线动脉压成反比。交感神经和迷走神经压力反射增益之间没有相关性。我们建议重复连续使用硝普钠，然后服用去氧肾上腺素剂量，作为激发和表征人类迷走神经和交感压力反射反应的简单、有效的方法。
We evaluated a method of baroreflex testing involving sequential intravenous bolus injections of nitroprusside followed by phenylephrine and phenylephrine followed by nitroprusside in 18 healthy men and women, and we drew inferences regarding human sympathetic and vagal baroreflex mechanisms. We recorded the electrocardiogram, photoplethysmographic finger arterial pressure, and peroneal nerve muscle sympathetic activity. We then contrasted least squares linear regression slopes derived from the depressor (nitroprusside) and presser (phenylephrine) phases with 1) slopes derived from spontaneous fluctuations of systolic arterial pressures and R-R intervals, and 2) baroreflex gain derived from cross-spectral analyses of systolic pressures and R-R intervals. We calculated sympathetic baroreflex gain from integrated muscle sympathetic nerve activity and diastolic pressures. We found that vagal baroreflex slopes are less when arterial pressures are falling than when they are rising and that this hysteresis exists over pressure ranges both below and above baseline levels. Although pharmacological and spontaneous vagal baroreflex responses correlate closely, pharmacological baroreflex slopes tend to be lower than those derived from spontaneous fluctuations. Sympathetic baroreflex slopes are similar when arterial pressure is falling and rising; however, small pressure elevations above baseline silence sympathetic motoneurons. Vagal, but not sympathetic baroreflex gains vary inversely with subjects' ages and their baseline arterial pressures. There is no correlation between sympathetic and vagal baroreflex gains. We recommend repeated sequential nitroprusside followed by phenylephrine doses as a simple, efficient-means to provoke and characterize human vagal and sympathetic baroreflex responses.