Systems physiology of the baroreflex during orthostatic stress: from animals to humans
Systems physiology of the baroreflex during orthostatic stress: from animals to humans
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DOI：
10.3389/fphys.2014.00256
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发表时间：
2014-07-08
影响因子：
4
通讯作者：
Sugimachi, Masaru
中科院分区：
文献类型：
--
作者：
Kamiya, Atsunori;Kawada, Toru;Sugimachi, Masaru
压力感受器反射是人体立位时控制动脉压(AP)的关键机制。然而，压力感受器反射是一个从压力感受器压力输入到全身AP的闭环反馈系统，因此需要开环实验来确定其系统特性。这一要求限制了我们识别人体压力反射系统特征的能力。在动物身上的开环研究揭示了压力感受器反射的两个子系统：神经和外周弧的动态和静态特征。从压力感受器压力输入到交感神经活动(SNA)的神经弧具有高通动力学特征，表明输入AP变化越快，SNA反应越大。相反，从SNA输入到全身AP的周边弧具有低通特性。正位法增加了神经弧的增益，从而补偿了外周弧较低的传递增益，进而维持了总的压力反射功能。在这里，我讨论了在动物身上发现的压力感受器反射子系统特征可以应用于人类对立位的交感反应的可能性，重点是立位交感神经激活的负荷速度依赖性。
The baroreflex is a key mechanism involved in the control of arterial pressure (AP) during orthostasis in humans. However, the baroreflex is a closed-loop feedback system, from baroreceptor pressure input to systemic AP and therefore requires open-loop experiments to identify its system characteristics. The requirement limits our ability to identify baroreflex system characteristics in humans. Open-loop research in animals has revealed dynamic and static characteristics of the two baroreflex subsystems: the neural and peripheral arcs. The neural arc, from baroreceptor pressure input to sympathetic nerve activity (SNA), has high-pass dynamic characteristics, indicating that more rapid change in input AP causes greater response in SNA. In contrast, the peripheral arc, from SNA input to systemic AP has low-pass characteristics. Orthostasis increases the gain of the neural arc, which compensates for the lower transfer gain of the peripheral arc and in turn maintains total baroreflex function. Here, I discuss the possibility that baroreflex subsystem characteristics identified in animals can be applicable to the human sympathetic response to orthostasis, with a focus on loading speed-dependence of orthostatic sympathetic activation.