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首页> 外文期刊>Respiratory physiology & neurobiology >Systemic oxygen transport in rats artificially selected for running endurance.
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Systemic oxygen transport in rats artificially selected for running endurance.

机译：人工选择大鼠的全身氧气传输以提供耐力。

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The relative contribution of genetic and environmental influences to individual exercise capacity is difficult to determine. Accordingly, animal models in which these influences are carefully controlled are highly useful to understand the determinants of intrinsic exercise capacity. Studies of systemic O(2) transport during maximal treadmill exercise in two diverging lines of rats artificially selected for endurance capacity showed that, at generation 7, whole body maximal O(2) uptake ((.)V(O(2)(max)) was 12% higher in high capacity (HCR) than in low capacity runners (LCR) during normoxic exercise. The difference in (.)V(O(2)(max) between HCR and LCR was larger during hypoxic exercise. Analysis of the linked O(2) conductances of the O(2) transport system showed that the higher (.)V(O(2)(max) was not due to a higher ventilatory response, a more effective pulmonary gas exchange, or an increased rate of O(2) delivery to the tissue by blood. The main reason for the higher (.)V(O(2)(max) of HCR was an increased tissue O(2) extraction, due largely to a higher tissue diffusive O(2) conductance. The enhanced tissue O(2) diffusing capacity was paralleled by an increased capillary density of a representative locomotory skeletal muscle, the gastrocnemius, in HCR. Activities of skeletal muscle oxidative enzymes citrate synthase and beta-HAD were also higher in HCR than LCR. Thus, the functional characteristics observed during exercise are consistent with the structural and biochemical changes observed in skeletal muscle that imply an enhanced capacity for muscle O(2) uptake and utilization in HCR. The results indicate that the improved (.)V(O(2)(max) is solely due to enhanced muscle O(2) extraction and utilization. However, the question arises as to whether it is possible to maintain a continually expanding capacity for O(2) extraction at the tissue level with successive generations, without a parallel improvement in the capacity to deliver O(2) to the exercising muscles.
机译：遗传和环境影响对个人运动能力的相对贡献很难确定。因此，仔细控制这些影响的动物模型对于理解内在运动能力的决定因素非常有用。人工选择耐力的两条不同的大鼠最大跑步机运动期间全身O（2）转运的研究表明，在第7代时，全身最大O（2）摄入量（（。] V（O（2）（max ））在常氧运动中，高容量（HCR）的运动量比低运动量（LCR）高12％;在低氧运动过程中，HCR和LCR之间的（。）V（O（2）（max））差异更大。 O（2）传输系统的关联O（2）电导的结果显示，较高的（。）V（O（2）（max）并非由于较高的通气反应，更有效的肺气体交换或血液向组织中释放O（2）的速率增加。HCR较高（。）V（O（2）（max）的主要原因是组织O（2）提取增加，这主要是由于组织较高扩散的O（2）电导：增强的组织O（2）扩散能力与HCR中代表性的运动性骨骼肌腓肠肌的毛细血管密度增加并行。 HCR中骨骼肌氧化酶柠檬酸合酶和β-HAD的含量也高于LCR。因此，在运动过程中观察到的功能特征与骨骼肌中观察到的结构和生化变化一致，这暗示着HCR中肌肉O（2）的吸收和利用能力增强。结果表明，改善的（。）V（O（2）（max）完全是由于增强了肌肉O（2）的提取和利用，但是，是否有可能保持持续的扩张能力成为问题。 O（2）在组织水平上具有连续世代的提取，而在将O（2）传递到运动肌肉的能力上却没有得到平行提高。

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