Group III and IV muscle afferents contribute to ventilatory and cardiovascular response to rhythmic exercise in humans
Group III and IV muscle afferents contribute to ventilatory and cardiovascular response to rhythmic exercise in humans
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DOI：
10.1152/japplphysiol.00462.2010
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发表时间：
2010-10-01
影响因子：
3.3
通讯作者：
Dempsey, Jerome A.
中科院分区：
文献类型：
--
作者：
Amann, Markus;Blain, Gregory M.;Dempsey, Jerome A.
我们调查了5名男性在有节奏运动中躯体感觉反馈对心脏舒张反应的作用。在一项双盲、安慰剂对照设计中，受试者在安慰剂条件下（棘突间盐水，L-3-L-4）进行相同的腿部自行车运动（50/100/150/325 +/-19 W，每次3 min），腰椎鞘内芬太尼损害脊髓阿片受体敏感性肌肉传入神经的中枢投射。芬太尼给药前后股四头肌强度相似。为了评估芬太尼的头向迁移是否影响脑干中的心脏运动控制中心，我们比较了每次注射后对高碳酸血症（HCVR）的静息运动反应和对手臂与腿部骑自行车运动的心脏运动反应。类似的HCVR和芬太尼对手臂运动的心脏舒张反应的轻微影响排除了芬太尼的直接延髓效应。通过股四头肌肌电图评估腿部运动时的中枢指令。在静息心率（HR）、通气量[每分钟通气量（V/dotE）]或平均动脉压（MAP）方面，未发现条件之间的差异。在四种稳态负荷下，两种条件下的四头肌肌电图、O-2消耗量（V/dotO（2））和血浆乳酸盐相似。与安慰剂相比，芬太尼运动期间的显著换气不足表现为呼吸频率降低导致的（V）/dotE/CO2产生（（V）/dotCO（2））降低8 - 17%，导致潮气末PCO2平均增加4 - 7 Torr（P <0.001）和在最重的工作负荷下（与dotO（2）的90%最大（V）相似）使用芬太尼时血红蛋白饱和度降低（-3 +/-1%; P <0.05）。芬太尼组与安慰剂组相比，心率降低2 - 8%，平均动脉压降低8 - 13%，感觉疲劳评分降低13%（P <0.05）。这些研究结果表明，肌肉传入反馈的基本贡献，在人类的运动节奏，心血管和知觉反应，即使在存在的其他主要输入的心脏运动控制不变的贡献。
We investigated the role of somatosensory feedback on cardioventilatory responses to rhythmic exercise in five men. In a double-blind, placebo-controlled design, subjects performed the same leg cycling exercise (50/100/150/325 +/- 19 W, 3 min each) under placebo conditions (interspinous saline, L-3-L-4) and with lumbar intrathecal fentanyl impairing central projection of spinal opioid receptor-sensitive muscle afferents. Quadriceps strength was similar before and after fentanyl administration. To evaluate whether a cephalad migration of fentanyl affected cardioventilatory control centers in the brain stem, we compared resting ventilatory responses to hypercapnia (HCVR) and cardioventilatory responses to arm vs. leg cycling exercise after each injection. Similar HCVR and minor effects of fentanyl on cardioventilatory responses to arm exercise excluded direct medullary effects of fentanyl. Central command during leg exercise was estimated via quadriceps electromyogram. No differences between conditions were found in resting heart rate (HR), ventilation [minute ventilation ((V) over dotE)], or mean arterial pressure (MAP). Quadriceps electromyogram, O-2 consumption ((V) over dotO(2)), and plasma lactate were similar in both conditions at the four steady-state workloads. Compared with placebo, a substantial hypoventilation during fentanyl exercise was indicated by the 8-17% reduction in (V) over dotE/CO2 production ((V) over dotCO(2)) secondary to a reduced breathing frequency, leading to average increases of 4-7 Torr in end-tidal PCO2 (P < 0.001) and a reduced hemoglobin saturation (-3 +/- 1%; P < 0.05) at the heaviest workload (similar to 90% maximal (V) over dotO(2)) with fentanyl. HR was reduced 2-8%, MAP 8-13%, and ratings of perceived exertion by 13% during fentanyl vs. placebo exercise (P < 0.05). These findings demonstrate the essential contribution of muscle afferent feedback to the ventilatory, cardiovascular, and perceptual responses to rhythmic exercise in humans, even in the presence of unaltered contributions from other major inputs to cardioventilatory control.