The role of afferent information from active muscle on hyperventilation during exercise

我们观察袖带闭塞时的通气限制了运动停止后活动肌肉的流量，以验证肌肉代谢受体和机械受体的传入信息增加运动时人体通气的假设。运动停止后袖带闭塞选择性地刺激肌肉中的代谢受体和代谢受体。第一年获得的结果是袖带闭塞与对照试验的通气无显著差异，而表明动脉CO2浓度的尾潮CO2分压在袖带闭塞期间低于对照组。这意味着颈动脉体二氧化碳传感器的刺激可能因袖带闭塞而减少，从而损害了肌肉受体传入信息的增加。在接下来的一系列实验中，我们控制激发CO2分压来振荡袖带闭塞期间的末潮CO2压力。6名受试者以最大自主收缩的30%进行2分钟等长腿部伸展运动。在实验试验停止运动后3分钟袖带闭塞期间和对照试验相应时期，吸入CO2保持在0、3.5和5%。将换气量与潮末CO2分压作对比，观察肌肉传入刺激对给定动脉CO2浓度的过度换气。6例受试者中有5例在潮末CO2分压38 ~ 42mmhg时通气量较高，且通气量增加幅度较小，提示运动时对代谢受体的刺激有增加通气量的作用，但作用量有限。我们用姿势的改变来研究机械感受器，但没有得到明确的结果。机械感受器在通气中的作用仍不清楚。

We observed the ventilation during cuff occlusion limiting the flow from and into the active muscle after exercise cessation, as to test the hypothesis that afferent information from muscle metaboreceptors and mechanoreceptors increase ventilation in humans during exercise. The cuff occlusion after the cessation of exercise selectively stimulates metaboreceptors and metaboreceptors in muscles. The results obtained in the first year were that there was no significant difference in ventilation between cuff occlusion and control trials, while the end-tidal CO2 partial pressure, which indicates the arterial CO2 concentration, was lower during cuff occlusion than in control. This implies the possibility that stimulus to the carotid body CO2 sensor decreased by cuff occlusion compromise the increment of afferent information from muscle receptors.In the next series of experiments, we controlled inspired CO2 partial pressure to oscillate the end-tidal CO2 pressure during cuff occlusion. Six subjects performed 2-min isometric leg extension exercise at 30% of maximal *oluntary contraction. During 3-min cuff occlusion after the cessation of exercise in the experimental trial and corresponding period in the control trial, inspired CO2 was maintained at 0, 3.5 and 5%. The ventilation was plotted against the end-tidal CO2 partial pressure to observe the hyperventilation to a given arterial CO2 concentration by muscle afferent stimulus. The ventilation was higher at 38-42mmHg of end-tidal CO2 partial pressure in five of six subjects, and the increase in ventilation was small, suggesting that the stimulus to metaboreceptors plays a role increasing ventilation during exercise but the amount of this role is limited. We applied change of posture to investigate the mechanoreceptors, but obtained no clear result. The role of mechanoreceptors on ventilation still remains unclear.