Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Canada.
Am J Physiol Regul Integr Comp Physiol. 2012 Aug 1;303(3):R332-9. doi: 10.1152/ajpregu.00053.2012. Epub 2012 Jun 13.
We tested the hypotheses that 4 wk of exercise training would diminish the magnitude of vasoconstriction in response to sympathetic nerve stimulation and augment endothelium-dependent vasodilation (EDD) in resting skeletal muscle in a training intensity-dependent manner. Sprague-Dawley rats were randomly assigned to sedentary time-control (S), mild- (M; 20 m/min, 5% grade), or heavy-intensity (H; 40 m/min, 5% grade) treadmill exercise groups. Animals trained 5 days/wk for 4 wk with training volume matched between groups. Rats were anesthetized and instrumented for study 24 h after the last training session. Arterial pressure and femoral artery blood flow were measured, and femoral vascular conductance (FVC) was calculated. Lumbar sympathetic chain stimulation was delivered continuously at 2 Hz and in patterns at 20 and 40 Hz. EDD was assessed by the vascular response to intra-arterial bolus injections of ACh. The response (% change FVC) to sympathetic stimulation increased (P < 0.05) in a training intensity-dependent manner at 2 Hz (S: -20.2 ± 9.8%, M: -34.0 ± 6.7%, and H: -44.9 ± 2.0%), 20 Hz (S: -22.0 ± 10.6%, M: -31.2 ± 8.4%, and H: -42.8 ± 5.9%), and 40 Hz (S: H -24.5 ± 8.5%, M: -35.1 ± 8.9%, H: -44.9 ± 6.5%). The magnitude of EDD also increased in a training intensity-dependent manner (P < 0.05). These data demonstrate that short-term exercise training augments the magnitude of vasoconstriction in response to sympathetic stimulation and EDD in resting skeletal muscle in a training intensity-dependent manner.
4 周的运动训练将以训练强度依赖的方式减少对交感神经刺激的血管收缩幅度，并增强静息骨骼肌中的内皮依赖性血管舒张（EDD）。Sprague-Dawley 大鼠被随机分配到久坐不动的时间对照组（S）、轻度（M；20 m/min，5%坡度）或高强度（H；40 m/min，5%坡度）跑步机运动组。动物每周训练 5 天，4 周内组间训练量匹配。大鼠在最后一次训练结束后 24 小时进行麻醉和仪器测量。动脉压和股动脉血流均被测量，股血管传导率（FVC）被计算。连续以 2 Hz 的频率和 20 Hz 和 40 Hz 的模式输送腰椎交感神经链刺激。通过动脉内注射 ACh 来评估 EDD。2 Hz（S：-20.2±9.8%，M：-34.0±6.7%，H：-44.9±2.0%）、20 Hz（S：-22.0±10.6%，M：-31.2±8.4%，H：-42.8±5.9%）和 40 Hz（S：-24.5±8.5%，M：-35.1±8.9%，H：-44.9±6.5%）的交感刺激反应（FVC 变化百分比）呈训练强度依赖性增加。EDD 的幅度也呈训练强度依赖性增加（P<0.05）。这些数据表明，短期运动训练增强了静息骨骼肌对交感刺激的血管收缩幅度和 EDD，以训练强度依赖的方式。
