Savard G, Strange S, Kiens B, Richter E A, Christensen N J, Saltin B
August Krogh Institute, University of Copenhagen, Denmark.
Acta Physiol Scand. 1987 Dec;131(4):507-15. doi: 10.1111/j.1748-1716.1987.tb08270.x.
Increases in plasma noradrenaline (NA) concentration occur during moderate to heavy exercise in man. This study was undertaken to examine the spillover of NA from both resting and contracting skeletal muscle during exercise. Six male subjects performed one-legged knee-extension so that all measurements could be made both in the exercising and in the resting leg. Subjects exercised for 10 min at each of 50% and 100% of the peak performance capacity of the leg. Leg blood flow was measured by thermodilution and blood samples were drawn for the determination of plasma NA and adrenaline, first in the resting leg and then in the exercising leg. To calculate NA spillover, the extraction of NA (NAe) or of adrenalin (Ae) is required: NAe was measured by repeating the experiment under constant [3H]NA infusion following a 40-min rest period. During exercise, NA spillover was significantly larger in the exercising leg than in the resting leg both during 50% and 100% leg exercise. These results suggest that contracting skeletal muscle may contribute to a larger extent than resting skeletal muscle to increasing the level of plasma NA during exercise. Contractile activity may influence the NA spillover from skeletal muscle by a presynaptic and/or postsynaptic influence on the sympathetic nervous activity to this tissue.
在人类进行中度至重度运动期间，血浆去甲肾上腺素（NA）浓度会升高。本研究旨在检测运动期间静息和收缩的骨骼肌中NA的溢出情况。六名男性受试者进行单腿膝关节伸展运动，以便在运动腿和静息腿上进行所有测量。受试者以腿部峰值运动能力的50%和100%分别运动10分钟。通过热稀释法测量腿部血流量，并采集血样以测定血浆NA和肾上腺素，先在静息腿上采集，然后在运动腿上采集。为了计算NA溢出量，需要测量NA（NAe）或肾上腺素（Ae）的提取率：在40分钟的休息期后，通过在恒定的[3H]NA输注下重复实验来测量NAe。在运动期间，无论是在50%还是100%的腿部运动中，运动腿的NA溢出量均显著大于静息腿。这些结果表明，在运动期间，收缩的骨骼肌对血浆NA水平升高的贡献可能比静息的骨骼肌更大。收缩活动可能通过对该组织交感神经活动的突触前和/或突触后影响来影响骨骼肌的NA溢出。
