The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark.
Am J Physiol Regul Integr Comp Physiol. 2010 Mar;298(3):R843-8. doi: 10.1152/ajpregu.00730.2009. Epub 2010 Jan 20.
The effect of low blood flow at onset of moderate-intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5-min one-legged knee-extensor exercise bout (24 +/- 1 W, mean +/- SD) without (Con) and with (double blockade; DB) arterial infusion of inhibitors of nitric oxide synthase (N(G)-monomethyl-l-arginine) and cyclooxygenase (indomethacin) to inhibit the synthesis of nitric oxide and prostanoids, respectively. Leg blood flow and leg oxygen delivery throughout exercise was 25-50% lower (P < 0.05) in DB compared with Con. Leg oxygen extraction (arteriovenous O(2) difference) was higher (P < 0.05) in DB than in Con (5 s: 127 +/- 3 vs. 56 +/- 4 ml/l), and leg oxygen uptake was not different between Con and DB during exercise. The difference between leg oxygen delivery and leg oxygen uptake was smaller (P < 0.05) during exercise in DB than in Con (5 s: 59 +/- 12 vs. 262 +/- 39 ml/min). The present data demonstrate that muscle blood flow and oxygen delivery can be markedly reduced without affecting muscle oxygen uptake in the initial phase of moderate-intensity exercise, suggesting that blood flow does not limit muscle oxygen uptake at the onset of exercise. Additionally, prostanoids and/or nitric oxide appear to play important roles in elevating skeletal muscle blood flow in the initial phase of exercise.
研究了中等强度运动起始时低血流量对肌肉氧摄取率上升速度的影响。7 名男性受试者进行了 3.5 分钟的单腿伸膝运动（24 ± 1 W，平均值 ± SD），其中无（Con）和有（双重阻断；DB）动脉输注一氧化氮合酶抑制剂（N（G）-单甲基-l-精氨酸）和环氧化酶抑制剂（吲哚美辛），分别抑制一氧化氮和前列腺素的合成。与 Con 相比，DB 期间腿部血流量和腿部氧输送在整个运动过程中降低了 25-50%（P < 0.05）。DB 中的腿部氧提取（动静脉 O2 差）高于 Con（5 s：127 ± 3 对 56 ± 4 ml/l），并且在运动期间，Con 和 DB 之间的腿部氧摄取没有差异。与 Con 相比，DB 期间运动时腿部氧输送与腿部氧摄取之间的差异较小（5 s：59 ± 12 对 262 ± 39 ml/min）。本研究数据表明，肌肉血流量和氧输送可以明显减少，而在中等强度运动的初始阶段不会影响肌肉氧摄取，这表明在运动起始时血流量不会限制肌肉氧摄取。此外，前列腺素和/或一氧化氮似乎在运动初始阶段增加骨骼肌血流量方面发挥重要作用。
