Murai Hisayoshi, Takamura Masayuki, Kaneko Shuichi
Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan.
Front Physiol. 2012 May 3;3:109. doi: 10.3389/fphys.2012.00109. eCollection 2012.
Elevated sympathetic activation is a characteristic feature of heart failure (HF). Excessive sympathetic activation under resting conditions has been shown to increase from the early stages of the disease, and is related to prognosis. Direct recording of multiunit efferent muscle sympathetic nerve activity (MSNA) by microneurography is the best method for quantifying sympathetic nerve activity in humans. To date, this technique has been used to evaluate the actual central sympathetic outflow to the periphery in HF patients at rest and during exercise; however, because the firing occurrence of sympathetic activation is mainly synchronized by pulse pressure, multiunit MSNA, expressed as burst frequency (bursts/min) and burst incidence (bursts/100 heartbeats), may have limitations for the quantification of sympathetic nerve activity. In HF, multiunit MSNA is near the maximum level, and cannot increase further than the heartbeat. Single-unit MSNA analysis in humans is technically demanding, but provides more detailed information regarding central sympathetic firing. Although a great deal is known about the response of multiunit MSNA to stress, little information is available regarding the responses of single-unit MSNA to physiological stress and disease. The purposes of this review are to describe the differences between multiunit and single-unit MSNA during stress and to discuss the advantages of single-unit MSNA recording in improving our understanding the pathology of increased sympathetic activity in HF.
交感神经激活增强是心力衰竭（HF）的一个特征性表现。在静息状态下，过度的交感神经激活在疾病早期就已出现增加，并与预后相关。通过微神经ography直接记录多单位传出肌肉交感神经活动（MSNA）是量化人体交感神经活动的最佳方法。迄今为止，该技术已被用于评估HF患者在静息和运动时外周实际的中枢交感神经输出；然而，由于交感神经激活的发放主要由脉压同步，以爆发频率（爆发次数/分钟）和爆发发生率（爆发次数/100次心跳）表示的多单位MSNA在交感神经活动量化方面可能存在局限性。在HF中，多单位MSNA接近最大水平，且不能超过心跳进一步增加。人体单单位MSNA分析技术要求较高，但能提供有关中枢交感神经发放的更详细信息。虽然关于多单位MSNA对应激的反应已有很多了解，但关于单单位MSNA对生理应激和疾病的反应的信息却很少。本综述的目的是描述应激期间多单位和单单位MSNA之间的差异，并讨论单单位MSNA记录在增进我们对HF中交感神经活动增加的病理学理解方面的优势。
