Saito M, Mano T
Department of Work Physiology, Toyota Technological Institute, Nagoya, Japan.
Jpn J Physiol. 1991;41(1):143-51. doi: 10.2170/jjphysiol.41.143.
To compare the responses of remote sympathetic nerves to dynamic and static leg exercises, we recorded sympathetic nerve activity leading to skeletal muscle (MSNA) using a tungsten microelectrode during one-leg cycling at loads of 0, 25, and 50 W and during static leg extension (SLE) at 20% of maximal voluntary contraction. Oxygen uptake (Douglas bag method) and local fatigue sensation (LFS) of the working muscle were measured during cycling and SLE. MSNA decreased from the control value, respectively, by 25, 21, and 12% during cycling at loads of 0, 25, and 50 W. The differences from the control value were significant except during cycling at 50 W. On the contrary, MSNA increased from the control value by 83% during SLE. Oxygen uptake during 25 and 50 W leg cycling was greater than during SLE, whereas LFS was higher during SLE than during leg cycling at any load. The results indicate that the response of muscle sympathetic nerves to exercise does not exclusively reflect whole body metabolism, but is instead related to the local metabolic changes.
为比较远端交感神经对动态和静态腿部运动的反应，我们在单腿骑行负荷为0、25和50瓦以及静态腿部伸展（SLE）时，以最大自主收缩的20%强度，使用钨微电极记录通向骨骼肌的交感神经活动（MSNA）。在骑行和SLE过程中测量工作肌肉的摄氧量（道格拉斯袋法）和局部疲劳感（LFS）。在负荷为0、25和50瓦的骑行过程中，MSNA分别比对照值降低了25%、21%和12%。除了在50瓦骑行时，与对照值的差异具有显著性。相反，在SLE期间，MSNA比对照值增加了83%。25瓦和50瓦腿部骑行时的摄氧量大于SLE时，而在任何负荷下，SLE期间的LFS都高于腿部骑行时。结果表明，肌肉交感神经对运动的反应并非完全反映全身代谢，而是与局部代谢变化有关。
