Role of central command on the visceral flow regulation during exercise

众所周知，中枢指令可以控制心脏和皮肤的交感神经活动，但在自愿锻炼期间对内脏循环的调节仍然不明确。本研究的重点是在自愿运动中，中枢指令是否对肾动脉和胃肠动脉的血流调节是必要的。我们首先测试了不同运动幅度和速度的主动(自愿)和被动(非自愿和机动驱动)屈肘练习。实验结果表明，屈肘以90度/秒的速度从40度到90度的屈肘运动在心血管变量上表现出被动运动和主动运动之间的明显差异。在第二个实验中，我们用超声方法研究了最大自主收缩(MVC)负荷为30%的静态握力运动时肾动脉(RA)的血流反应。本实验显示肾动脉血流量开始下降…。运动开始后即刻(10秒内)皱纹明显增多，提示中枢指令和/或肌肉机械反射可能是运动快速调整的原因。在第三个实验中，我们同样研究了30%MVC负荷下动态屈肘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，这表明中枢指令和/或机械反射对SMA的血流反应没有贡献。在第四个实验中，我们比较了被动运动和主动运动在RA和SMA中的心流反应，以确定中枢指令和机械反射中哪一个对运动的快速调节更重要。RA组和SMA组被动运动和主动运动的心流反应无明显差异。根据这些结果，我们得出结论，在自愿运动中，中枢指令在调节内脏区域的流动反应中没有发挥重要作用。较少

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