Thijssen Dick H J, Green Daniel J, Steendijk Sjoerd, Hopman Maria T E
Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Am J Physiol Heart Circ Physiol. 2009 Jan;296(1):H180-5. doi: 10.1152/ajpheart.00686.2008. Epub 2008 Nov 21.
During lower limb exercise, blood flow through the resting upper limbs exhibits a change characterized by increased anterograde flow during systole, but also large increases in retrograde diastolic flow. One explanation for the retrograde flow is that increased sympathetic nervous system (SNS) tone and concomitant increased peripheral resistance generate a rebound during diastole. To examine whether the SNS contributes to retrograde flow patterns, we measured femoral artery blood flow during arm-crank exercise in 10 healthy men (31 +/- 4 yr) and 10 spinal cord-injured (SCI) subjects who lack sympathetic innervation in the legs (33 +/- 5 yr). Before, and every 5 min during 25-min arm-crank exercise at 50% maximal capacity, femoral artery blood flow and peak anterograde and retrograde shear rate were assessed using echo Doppler sonography. Femoral artery baseline blood flow was significantly lower in SCI compared with controls. Exercise increased femoral artery blood flow in both groups (ANOVA, P < 0.05), whereas leg vascular conductance did not change during exercise in either group. Mean shear rate was lower in SCI than in controls (P < 0.05). Peak anterograde shear rate was higher in SCI than in controls (P < 0.05), whereas peak retrograde shear rate did not differ between groups. Arm-crank exercise induced an increase in peak anterograde and retrograde shear rate in the femoral artery in controls and SCI subjects (P < 0.05). This suggests that the SNS is not obligatory to change the flow pattern in inactive regions during exercise. Local mechanisms may play a role in the arm-crank exercise-induced changes in flow pattern in the femoral artery.
在下肢运动期间，流经静息上肢的血流呈现出一种变化，其特征为收缩期顺行血流增加，但舒张期逆行血流也大幅增加。逆行血流的一种解释是，交感神经系统（SNS）张力增加以及随之而来的外周阻力增加在舒张期产生了一种反弹。为了研究SNS是否促成了逆行血流模式，我们测量了10名健康男性（31±4岁）和10名脊髓损伤（SCI）受试者在手臂曲柄运动期间的股动脉血流，这些脊髓损伤受试者下肢缺乏交感神经支配（33±5岁）。在50%最大能力的25分钟手臂曲柄运动前及运动过程中每5分钟，使用超声多普勒超声评估股动脉血流以及顺行和逆行峰值剪切率。与对照组相比，SCI患者的股动脉基线血流显著更低。两组运动均增加了股动脉血流（方差分析，P<0.05），而两组运动期间腿部血管传导率均未改变。SCI患者的平均剪切率低于对照组（P<0.05）。SCI患者的顺行峰值剪切率高于对照组（P<0.05），而两组之间的逆行峰值剪切率无差异。手臂曲柄运动使对照组和SCI受试者的股动脉顺行和逆行峰值剪切率增加（P<0.05）。这表明，在运动期间改变非活动区域的血流模式并不一定需要SNS。局部机制可能在手臂曲柄运动引起的股动脉血流模式变化中起作用。
