Department of Physiology, Radboud University Nijmegen Medical Centre, The Netherlands.
Med Sci Sports Exerc. 2009 Jun;41(6):1249-54. doi: 10.1249/MSS.0b013e318196c902.
INTRODUCTION/PURPOSE: During exercise, redistribution of blood takes place to enhance blood flow to exercising muscles. To examine the role of sympathetic control in blood redistribution, we assessed blood flow in inactive regions (leg-splanchnic area) during arm-crank exercise in controls and in subjects with spinal cord injury (SCI) who lack central sympathetic control.
SCI with a low lesion (< or = T7; SCI-L) have no leg sympathetic control and SCI with high lesion (> or = T6; SCI-H) lack sympathetic control in the legs and splanchnic area. This enables us to compare inactive regions between subjects with (controls, SCI-L; splanchnic) and without sympathetic innervation (SCI-L: leg, SCI-H: leg-splanchnic). Before and every 5 min during a 25-min arm-crank exercise bout at 50% of the individual maximal capacity, portal vein and femoral artery blood flow were measured.
Before exercise, portal vein blood flow was not different among groups. Arm-crank exercise induced a significant decrease in portal vein blood flow in subjects with splanchnic sympathetic control (able-bodied controls + SCI-L; ANOVA, P < 0.05), whereas SCI-H showed no change in portal vein blood flow. Baseline femoral artery blood was significantly lower in SCI compared with able-bodied controls. Exercise increased femoral artery blood flow in subjects with leg sympathetic control (controls; ANOVA, P < 0.05) but not in persons lacking sympathetic control in the leg (SCI). Leg vascular conductance did not change during exercise in both groups.
In summary, portal vein blood flow decreases in subjects with sympathetic control of the splanchnic area, whereas exercise-induced changes in femoral artery hemodynamics did not differ between groups. These observations primarily indicate the presence of regional differences regarding the magnitude of exercise-induced blood redistribution in vivo in humans.
简介/目的：在运动过程中，血液重新分布以增加流向运动肌肉的血流量。为了研究交感神经控制在血液重新分布中的作用，我们评估了对照组和缺乏中枢交感神经控制的脊髓损伤（SCI）患者在手臂转动运动中，非活动区域（腿部-内脏区域）的血流量。
低水平损伤的 SCI（<或= T7；SCI-L）没有腿部交感神经控制，高水平损伤的 SCI（>或= T6；SCI-H）缺乏腿部和内脏区的交感神经控制。这使我们能够比较有（对照组、SCI-L；内脏）和无交感神经支配（SCI-L：腿部，SCI-H：腿部-内脏）的受试者之间的非活动区域。在 25 分钟的手臂转动运动期间，在个体最大能力的 50%下，每 5 分钟测量门静脉和股动脉血流。
运动前，各组门静脉血流无差异。手臂转动运动导致有内脏交感神经控制的受试者门静脉血流明显下降（有能力的对照组+SCI-L；ANOVA，P < 0.05），而 SCI-H 门静脉血流无变化。与有能力的对照组相比，SCI 的基线股动脉血液明显较低。运动增加了有腿部交感神经控制的受试者的股动脉血流（对照组；ANOVA，P < 0.05），但缺乏腿部交感神经控制的人则没有。在两组中，运动期间腿部血管传导率均无变化。
总之，有内脏区交感神经控制的受试者门静脉血流下降，而股动脉血液动力学的运动诱导变化在两组之间没有差异。这些观察结果主要表明，在人体中，局部差异对运动诱导的血液重新分布的幅度存在差异。
