Baroreflex control of sinus node during dynamic exercise in humans: Effects of central command and muscle reflexes
Baroreflex control of sinus node during dynamic exercise in humans: Effects of central command and muscle reflexes
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DOI：
10.1152/ajpheart.1997.272.3.h1157
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发表时间：
1997-03-01
影响因子：
4.8
通讯作者：
Peruzzi, G
中科院分区：
文献类型：
--
作者：
Iellamo, F;Legramante, JM;Peruzzi, G
本研究评估了动态运动中中枢指令和肌肉传入刺激（机械和化学）对窦结综合动脉压力反射控制的影响。22名健康男性在自由流动和停止流动条件下进行了自愿膝关节伸展和电诱导动态膝关节伸展（n = 18）。连续无创测量收缩压（SAP）和脉搏间隔（PI）。动脉压力反射通过分析以下一个心跳的SAP和PI为特征的三个或更多连续心跳序列的斜率来评估；线性的以线性方式增加或减少的与休息相比，在血流停止的情况下，自愿运动和电诱导运动都能维持压力反射敏感性（BRS分别为11.7 +/- 1.2 vs. 9.6 +/- 0.7和11.3 +/- 1.4 vs. 9.8 +/- 1.5 ms/mmHg；无统计学意义），SAP与PI相关的回归线明显向右移动。自由血流条件下的电诱导运动导致BRS显著降低（12.1 +/- 1.4 vs. 8.8 +/- 0.8 ms/mmHg; P < 0.05）。这些数据表明，中枢指令和肌肉化学反射起到保护BRS的作用，可能“重置”压力感受器-心脏反应关系，而机械敏感受体的刺激似乎能够改变人类窦结功能的综合压力反射控制。然而，前两种机制似乎压倒了后一种机制来维持BRS，从而允许伴随的动脉压和心率的增加。
This study evaluated the influence of central command and muscle afferent stimulation (mechanical and chemical) on the integrated arterial baroreflex control of the sinus node during dynamic exercise. Twenty-two healthy men performed voluntary knee extension and electrically induced dynamic knee extension under free-flow and arrested-flow (n = 18) conditions. Systolic arterial pressure (SAP) and pulse interval (PI) were measured continuously and noninvasively. The arterial baroreflex was evaluated by analyzing the slopes of sequences of three or more consecutive beats characterized by the SAP and PI of the following beat; both increased or decreased in a linear fashion. Compared with rest, both voluntary exercise and electrically induced exercise under arrested-flow conditions resulted in a maintained baroreflex sensitivity (BRS; 11.7 +/- 1.2 vs. 9.6 +/- 0.7 and 11.3 +/- 1.4 vs. 9.8 +/- 1.5 ms/mmHg, respectively; not significant), with an apparent rightward shift in the regression line relating SAP to PI. Electrically induced exercise under free-flow conditions resulted in a significant decrease in BRS (12.1 +/- 1.4 vs. 8.8 +/- 0.8 ms/mmHg; P < 0.05). These data suggest that the central command and muscle chemoreflex act to preserve the BRS, possibly ''resetting'' the baroreceptor-cardiac response relationship, whereas stimulation of mechanosensitive receptors appears capable of modifying the integrated baroreflex control of sinus node function in humans. The first two mechanisms seem, however, to overwhelm the latter to maintain BRS, thus permitting a concomitant increase in arterial pressure and heart rate.