Nellis S H, Flaim S F, McCauley K M, Zelis R
Am J Physiol. 1980 Mar;238(3):H331-9. doi: 10.1152/ajpheart.1980.238.3.H331.
Oxygen consumption (VO2) in an isolated, autoperfused, statically exercising canine gracilis muscle (2.5% P0) was studied in low blood flow (Q) states induced by constant norepinephrine (NE) infusion and by mechanical occlusion (MO). Q and VO2 were evaluated at rest (Qc and VO2c), after 5 min of exercise (Qe and VO2e) and after 5 more min of exercise with either NE or MO (Qt and VO2t). Data were normalized and plotted as the VO2e-VO2t)/(VO2c-VO2e) vs. (Qe-Qt)/(Qc-Qe) and equations of the lines for NE (y = 0.090x + 0.048) and for MO (y = 0.488x + 0.070) were determined. The slopes of the lines, tested by analysis of covariance, were significantly different (P less than 0.005). These data indicate that when NE reduced Q during exercise, the exercise induced in VO2 was protected to a greater degree than when MO reduced Q under similar conditions. To determine if the effect of NE on VO2 was secondary to a beta-adrenergic-receptor-mediated of skeletal muscle metabolic processes, the experiments were repeated in the presence of beta-blockade with propranolol. In the presence of beta-blockade, the effects of NE on skeletal muscle VO2 were unchanged. It is therefore hypothesized that the mechanism of this effect of NE may be an increase in the efficiency of oxygen extraction resulting from a redistribution of blood flow to more active muscle fiber regions.
在由持续输注去甲肾上腺素（NE）和机械阻塞（MO）诱导的低血流（Q）状态下，研究了分离的、自身灌注的、静态运动的犬股薄肌（2.5% P0）的氧耗量（VO2）。在静息状态（Qc和VO2c）、运动5分钟后（Qe和VO2e）以及在使用NE或MO再运动5分钟后（Qt和VO2t）评估Q和VO2。数据进行归一化处理，并绘制为（VO2e - VO2t）/（VO2c - VO2e）对（Qe - Qt）/（Qc - Qe）的关系图，并确定了NE组（y = 0.090x + 0.048）和MO组（y = 0.488x + 0.070）的直线方程。通过协方差分析测试的直线斜率有显著差异（P < 0.005）。这些数据表明，在运动过程中当NE降低Q时，与在类似条件下MO降低Q相比，运动诱导的VO2受到的保护程度更大。为了确定NE对VO2的影响是否继发于β - 肾上腺素能受体介导的骨骼肌代谢过程，在普萘洛尔β受体阻滞存在的情况下重复了实验。在β受体阻滞存在时，NE对骨骼肌VO2的影响未改变。因此推测，NE这种作用的机制可能是由于血流重新分布到更活跃的肌纤维区域导致氧摄取效率增加。
