Distinguishing the effects of convective and diffusive O₂ delivery on VO₂ on-kinetics in skeletal muscle contracting at moderate intensity.
Distinguishing the effects of convective and diffusive O₂ delivery on VO₂ on-kinetics in skeletal muscle contracting at moderate intensity.
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区分对流和扩散 O2 输送对中等强度骨骼肌收缩中 VO2 动力学的影响。
DOI：
10.1152/ajpregu.00136.2013
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Lai,Nicola
中科院分区：
文献类型：
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作者：
Spires,Jessica;Gladden,LBruce;Grassi,Bruno;Goodwin,MatthewL;Saidel,GeraldM;Lai,Nicola
目前的技术，实验测量本身不能表征的影响，氧血液组织扩散对肌肉摄氧（V ~ o2）动力学收缩骨骼肌。为了补充实验研究，一个计算模型被用来定量区分对流氧输送，扩散到细胞，和氧利用率的贡献，以V too 2动力学。使用先前发表的实验性V too 2动力学对犬肌肉中血流（Q）减慢时的动力学响应（τQ= 20 s、46 s和64 s）对模型进行了验证[Goodwin ML，Hernández A，Lai N，Cabrera ME，Gladden LB.J Appl Physiol. 112：9-19，2012]。研究了渗透率-比表面积或扩散电导（PS）和Q对V ~（o2）动力学的显著影响。模型模拟量化了PS和Q之间的关系，以及与PS和Q动态相关的扩散对V ~ o ~ 2的平均响应时间的影响。该模型表明，PS和Q是线性相关的，当对流输送受到较慢的Q动态的限制时，PS随Q增加更多。模拟预测，在正常自发条件下，在从休息到中等（次最大）能量需求的过渡期间，氧气对流或扩散输送都不会限制离体犬腓肠肌制备中的V ~ o2动力学，尽管两者都接近临界点。
With current techniques, experimental measurements alone cannot characterize the effects of oxygen blood-tissue diffusion on muscle oxygen uptake (V̇o2) kinetics in contracting skeletal muscle. To complement experimental studies, a computational model is used to quantitatively distinguish the contributions of convective oxygen delivery, diffusion into cells, and oxygen utilization to V̇o2kinetics. The model is validated using previously published experimental V̇o2kinetics in response to slowed blood flow (Q) on-kinetics in canine muscle (τQ= 20 s, 46 s, and 64 s) [Goodwin ML, Hernández A, Lai N, Cabrera ME, Gladden LB.J Appl Physiol. 112:9–19, 2012]. Distinctive effects of permeability-surface area or diffusive conductance (PS) and Q on V̇o2kinetics are investigated. Model simulations quantify the relationship betweenPSand Q, as well as the effects of diffusion associated withPSand Q dynamics on the mean response time of V̇o2. The model indicates thatPSand Q are linearly related and thatPSincreases more with Q when convective delivery is limited by slower Q dynamics. Simulations predict that neither oxygen convective nor diffusive delivery are limiting V̇o2kinetics in the isolated canine gastrocnemius preparation under normal spontaneous conditions during transitions from rest to moderate (submaximal) energy demand, although both operate close to the tipping point.