Intracellular energetics and critical PO2 in resting ischemic human skeletal muscle in vivo.
Intracellular energetics and critical PO2 in resting ischemic human skeletal muscle in vivo.
复制标题
体内静息缺血人体骨骼肌的细胞内能量学和临界 PO2。
DOI：
10.1152/ajpregu.00225.2010
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Kent-Braun,JaneA
中科院分区：
文献类型：
--
作者：
Lanza,IanR;Tevald,MichaelA;Befroy,DouglasE;Kent-Braun,JaneA
During ischemia and some types of muscular contractions, oxygen tension (Po2) declines to the point that mitochondrial ATP synthesis becomes limited by oxygen availability. Although this critical Po2has been determined in animal tissue in vitro and in situ, there remains controversy concerning potential disparities between values measured in vivo and ex vivo. To address this issue, we used concurrent heteronuclear magnetic resonance spectroscopy (MRS) to determine the critical intracellular Po2in resting human skeletal muscle in vivo. We interleaved measurements of deoxymyoglobin using1H-MRS with measures of high-energy phosphates and pH using31P-MRS, during 15 min of ischemia in the tibialis anterior muscles of 6 young men. ATP production and intramyocellular Po2were quantified throughout ischemia. Critical Po2, determined as the Po2corresponding to the point where PCr begins to decline (PCrip) in resting muscle during ischemia, was 0.35 ± 0.20 Torr, means ± SD. This in vivo value is consistent with reported values ex vivo and does not support the notion that critical Po2in resting muscle is higher when measured in vivo. Furthermore, we observed a 4.5-fold range of critical Po2values among the individuals studied. Regression analyses revealed that time to PCripwas associated with critical Po2and the rate of myoglobin desaturation (r= 0.83,P= 0.04) but not the rate of ATP consumption during ischemia. The apparent dissociation between ATP demand and myoglobin deoxygenation during ischemia suggests that some degree of uncoupling between intracellular energetics and oxygenation is a potentially important factor that influences critical Po2in vivo.
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影响因子：
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作者：
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DOI：
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发表时间：
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影响因子：
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作者：
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