Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.
Baker Department of Cardiometabolic Health, The University of Melbourne, Melbourne, VIC, Australia.
Clin Auton Res. 2024 Feb;34(1):177-189. doi: 10.1007/s10286-024-01015-6. Epub 2024 Feb 3.
Sympathetic nerve activity towards muscle (MSNA) and skin (SSNA) regulates various physiological parameters. MSNA primarily functions in blood pressure and flow, while SSNA operates in thermoregulation. Physical and cognitive stressors have been shown to have effects on both types of sympathetic activity, but there are inconsistencies as to what these effects are. This article aims to address the discrepancies in the literature and compare MSNA and SSNA responses.
Microelectrode recordings were taken from the common peroneal nerve in 29 participants: MSNA (n = 21), SSNA (n = 16) and both MSNA and SSNA (n = 8). Participants were subjected to four different 2-min stressors: two physical (isometric handgrip task, cold pressor test) and two cognitive (mental arithmetic task, Stroop colour-word conflict test), the latter of which saw participants separated into responders and non-responders to the stressors. It was hypothesised that the physical stressors would have a greater effect on MSNA than SSNA, while the cognitive stressors would operate conversely.
Peristimulus time histogram (PSTH) analysis showed the mental arithmetic task to significantly increase both MSNA and SSNA; the isometric handgrip task and cold pressor test to increase MSNA, but not SSNA; and Stroop test to have no significant effects on changing MSNA or SSNA from baseline. Additionally, stress responses did not differ between MSNA and SSNA in participants who had both sets of data recorded.
This study has provided evidence to support the literature which claims cognitive stressors increase sympathetic activity, and provides much needed SSNA data in response to stressors.
肌肉（MSNA）和皮肤（SSNA）的交感神经活动调节各种生理参数。MSNA 主要作用于血压和血流量，而 SSNA 则作用于体温调节。已证实身体和认知应激源对这两种类型的交感神经活动都有影响，但这些影响是什么却存在不一致。本文旨在解决文献中的差异，并比较 MSNA 和 SSNA 的反应。
从 29 名参与者的腓总神经中记录微电极：MSNA（n=21）、SSNA（n=16）和 MSNA 和 SSNA 均有记录（n=8）。参与者接受了四种不同的 2 分钟应激源：两种身体应激源（等长握力任务、冷加压试验）和两种认知应激源（心算任务、Stroop 色词冲突试验），后者将参与者分为对应激源有反应和无反应的两组。假设身体应激源对 MSNA 的影响大于 SSNA，而认知应激源则相反。
刺激后时间直方图（PSTH）分析显示，心算任务显著增加了 MSNA 和 SSNA；等长握力任务和冷加压试验增加了 MSNA，但不增加 SSNA；Stroop 测试对从基线改变 MSNA 或 SSNA 没有显著影响。此外，在同时记录了这两组数据的参与者中，MSNA 和 SSNA 的应激反应没有差异。
本研究为声称认知应激源增加交感神经活动的文献提供了证据，并为应激反应提供了急需的 SSNA 数据。
