Role of central command on the visceral flow regulation during exercise

众所周知，中央指挥可以控制心脏和皮肤交感神经活动，但在自主运动中，对内脏循环调节的作用仍不明确。本研究的重点是在自主运动时，中央指挥是否对肾脏和胃肠道动脉的血流调节至关重要。我们首先测试了不同幅度和运动速度的主动（自愿）和被动（非自愿和运动驱动）肘关节屈曲练习。本实验表明，以90度/秒的速度从40度移动到90度的肘关节屈曲与被动运动和主动运动在心血管变量上的明显差异最为相关。在第二个实验中，我们用超声方法研究了在30%最大自愿收缩（MVC）负荷的静态握力运动中肾动脉（RA）的血流反应。本实验表明，在运动开始后（10秒内），肾动脉血流量开始明显减少，提示中枢指令和/或肌肉机械反射可能是快速适应运动的原因。在第三个实验中，同样研究了30% MVC负荷下动态肘关节屈曲开始时肠系膜上动脉（SMA）的血流反应。与RA反应相反，SMA的血流在运动开始时没有改变，这表明中央指令和/或机械反射对SMA的血流反应没有贡献。在第四项实验中，我们比较了RA和SMA被动和主动运动时的血流反应，以确定在快速调整运动时，中枢指令和机械反射哪个更重要。在RA和SMA的被动和主动运动中，血流反应没有差异。从这些结果中，我们得出结论，中央指挥在自主运动中调节内脏区域的血流反应中不起重要作用。少

Central command is well known to control cardiac and skin sympathetic nervous activities but still equivocal for visceral circulatory adjustments during voluntary exercise. The present study focused on whether central command is essential for the blood flow regulation in renal and gastrointestinal arteries during voluntary exercise. We firstly tested active (voluntary) and passive (non-voluntary and motor-driven) elbow-flexion exercises with various amplitudes and velocities of movements. This experiment provided that the elbow-flexion moving from 40 to 90 degree with a speed of 90 degree/sec was the most relevant to manifest a clear difference between passive and active exercises in the cardiovascular variables. In the second experiments, we investigated the blood flow responses in renal artery (RA) during static handgrip exercise with a load of 30 % of maximum voluntary contraction (MVC) by using ultrasound method. This experiment showed that the renal arterial blood flow began to de … More crease significantly immediately after the onset of exercise (within 10 sec), suggesting that central command and/or muscle mechanoreflex were probably responsible for the rapid adjustment to exercise. In the third experiments, the blood flow responses in the superior mesenteric artery (SMA) were similarly studied at the onset of dynamic elbow flexion with a load of 30 % MVC. In contrast to the RA responses, the blood flow in SMA did not change at the onset of exercise suggesting no contribution of central command and/or mechanoreflex to the flow responses in SMA. In fourth experiments, we compared the flow responses between passive and active exercises in RA and SMA to determine which is more important between central command or mechanoreflex for the rapid adjustment to exercise. There was no difference in flow responses between passive and active exercises in both RA and SMA. From these results, we concluded that central command does not play an important role in regulating flow responses in visceral regions during voluntary exercise. Less