SEPARATE MEASURES OF ATP UTILIZATION AND RECOVERY IN HUMAN SKELETAL-MUSCLE
SEPARATE MEASURES OF ATP UTILIZATION AND RECOVERY IN HUMAN SKELETAL-MUSCLE
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DOI：
10.1113/jphysiol.1993.sp019673
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发表时间：
1993-06-01
影响因子：
5.5
通讯作者：
KUSHMERICK, MJ
中科院分区：
文献类型：
--
作者：
BLEI, ML;CONLEY, KE;KUSHMERICK, MJ
1.使用P-31核磁共振（NMR）光谱法将正常人受试者前臂屈肌组织收缩活动期间的化学变化与恢复代谢分离。经皮，超大抽搐刺激正中神经和尺神经与暂时性缺血的前臂，以表征总的ATP酶活性。血流恢复后的恢复提供了氧化ATP合成活性的量度。这些过程是基于磷酸肌酸（PCr）含量的动态测量的.如250 +/-33秒后PCr分解所示，在无刺激的情况下使用局部缺血耗尽肌肉氧储存（平均值+/- S.D.; n = 5），其提供基础代谢率的量度（0.008 +/-0.002mM s-1，n = 5）。缺氧肌肉的抽搐刺激期间的PCr分解速率恒定在1 Hz，每秒或每次抽搐0.15 +/- 0.03 mm PCr（n = 8）。从0.5到2 Hz刺激发现每次抽搐的恒定成本（每次抽搐的PCr消耗=每次抽搐0.15 mm）。在刺激后2分钟的缺血期间没有发现PCr的净无氧恢复。血流恢复后，PCr恢复遵循指数时间过程，时间常数为63 +/- 14 s（n = 8）。从这些回收率，氧化磷酸化的能力估计为0.4 mm s-1.6。该实验方法定义了人体肌肉ATP酶速率和ATP合成酶速率的非侵入性和定量测量。
1. The chemical changes during contractile activity were separated from recovery metabolism in the forearm flexor musculature in normal human subjects using P-31 nuclear magnetic resonance (NMR) spectroscopy. Percutaneous, supramaximal twitch stimulation of the median and ulnar nerves was used in combination with temporary ischaemia of the forearm to characterize the summed ATPase activity. The recovery following restoration of blood flow provided a measure of oxidative ATP synthesis activity. These processes were measured based on the dynamics of creatine phosphate (PCr) content.2. Muscle oxygen stores were depleted using ischaemia without stimulation as indicated by PCr breakdown after 250 +/- 33 s (mean +/- S.D.; n = 5), which provided a measure of the basal metabolic rate (0.008 +/- 0.002 mM s-1, n = 5).3. The PCr breakdown rate during twitch stimulation of the oxygen-depleted muscle was constant at 1 Hz at 0.15 +/- 0.03 mm PCr per second or per twitch (n = 8). A constant cost per twitch was found from 0.5 to 2 Hz stimulation (depletion of PCr per twitch = 0.15 mm per twitch).4. No net anaerobic recovery of PCr was found during a 2 min post-stimulation ischaemia.5. Upon restoration of blood flow, PCr recovery followed an exponential time course with a time constant of 63 +/- 14 s (n = 8). From these recovery rates, the capacity for oxidative phosphorylation was estimated to be 0.4 mm s-1.6. This experimental approach defines a non-invasive and quantitative measure of human muscle ATPase rate and ATP synthetase rate.