Recovery of microvascular PO2 during the exercise off-transient in muscles of different fiber type.
Recovery of microvascular PO2 during the exercise off-transient in muscles of different fiber type.
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不同纤维类型的肌肉运动过程中微血管 PO2 的恢复。
DOI：
10.1152/japplphysiol.00499.2003
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Poole,DavidC
中科院分区：
文献类型：
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作者：
McDonough,Paul;Behnke,BradJ;Musch,TimothyI;Poole,DavidC
运动后肌肉能量状态恢复的速度取决于氧化能力和血管氧分压。由于血管控制不同的肌肉组成的快与慢肌纤维，我们探讨的可能性，微血管O2压力（PmvO 2;成比例的O2输送-O2摄取比）将不同的恢复期间，在快肌腓（Per：86%的II型）与慢肌比目鱼肌（溶胶：84%的I型）。具体而言，我们假设，在Per中，PmvO 2在收缩后立即降低，并且与Sol相比，在收缩的关闭瞬态期间恢复得更慢。在停止电刺激（120 s; 1 Hz）后，研究了六只雌性Sprague-Dawley大鼠（体重= 0.220 g）的Per和Sol肌肉，以比较PmvO 2的恢复曲线。如假设，Per在整个恢复期的PmvO 2低于Sol（收缩末期：13.4 ± 2.2 vs. 20.2 ± 0.9 Torr;恢复末期：24.0 ± 2.4 vs. 27.4 ± 1.2 Torr，Per vs. Sol;P≤ 0.05）。此外，与Per相比，Sol的平均恢复响应时间显著更快（45.1 ± 5.3 vs. 66.3 ± 8.1 s，Sol vs. Per;P< 0.05）。尽管有这些发现，PmvO 2在两种肌肉中均逐渐升高，并且在任何时候都不会低于运动结束时的值。这些数据表明，在收缩恢复期间（在Per中延长），毛细血管O2驱动压力（即，PmvO 2）在快收缩肌中比慢收缩肌中减少。总之，本研究的结果可能部分解释了之前在1）快收缩与慢收缩肌肉和2）各种患者人群（如充血性心力衰竭和糖尿病患者）中发现的缓慢恢复动力学（磷酸肌酸和O2摄取）。
The speed with which muscle energetic status recovers after exercise is dependent on oxidative capacity and vascular O2pressures. Because vascular control differs between muscles composed of fast- vs. slow-twitch fibers, we explored the possibility that microvascular O2pressure (PmvO2; proportional to the O2delivery-to-O2uptake ratio) would differ during recovery in fast-twitch peroneal (Per: 86% type II) compared with slow-twitch soleus (Sol: 84% type I). Specifically, we hypothesized that, in Per, PmvO2would be reduced immediately after contractions and would recover more slowly during the off-transient from contractions compared with Sol. The Per and Sol muscles of six female Sprague-Dawley rats (weight = ∼220 g) were studied after the cessation of electrical stimulation (120 s; 1 Hz) to compare the recovery profiles of PmvO2. As hypothesized, PmvO2was lower throughout recovery in Per compared with Sol (end contraction: 13.4 ± 2.2 vs. 20.2 ± 0.9 Torr; end recovery: 24.0 ± 2.4 vs. 27.4 ± 1.2 Torr, Per vs. Sol;P≤ 0.05). In addition, the mean response time for recovery was significantly faster for Sol compared with Per (45.1 ± 5.3 vs. 66.3 ± 8.1 s, Sol vs. Per;P< 0.05). Despite these findings, PmvO2rose progressively in both muscles and at no time fell below end-exercise values. These data indicate that, during the recovery from contractions (which is prolonged in Per), capillary O2driving pressure (i.e., PmvO2) is reduced in fast-compared with slow-twitch muscle. In conclusion, the results of the present investigation may partially explain the slowed recovery kinetics (phosphocreatine and O2uptake) found previously in1) fast- vs. slow-twitch muscle and2) various patient populations, such as those with congestive heart failure and diabetes mellitus.