Calcium content and respiratory control index of skeletal muscle mitochondria during exercise and recovery
Calcium content and respiratory control index of skeletal muscle mitochondria during exercise and recovery
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DOI：
10.1152/ajpendo.1996.271.6.e1044
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发表时间：
1996-12-01
影响因子：
5.1
通讯作者：
Pedersen, PK
中科院分区：
文献类型：
--
作者：
Madsen, K;Ertbjerg, P;Pedersen, PK
本研究旨在评价75%最大氧耗量力竭运动前后线粒体线粒体钙离子浓度与呼吸控制指数(RCI；状态III/状态IV)的关系。12名中等训练男子在安静时、运动后即刻、运动后30或60分钟采集100~150 mg的肌肉活组织标本。力竭运动后线粒体Ca~(2+)含量显著高于运动前[分别为15.1(39.4)和11.6(6.5)nmol/mg蛋白；P<；0.05]，RCI由安静时的11.6(14.4)增加到力竭时的13.7(P<；0.05)。恢复60min后，线粒体Ca~(2+)含量仍较高[18.8(范围29.9)nmol/mg蛋白]，但由于状态IV值升高，RCI值明显降低，实际上低于运动前[8.6(范围5.1)；P<；0.05]。结果表明，在长时间力竭运动后，人体骨骼肌线粒体Ca~(2+)含量增加，RCI值升高，状态III略有增加，状态IV呼吸略有下降。线粒体Ca~(2+)水平升高的恢复是缓慢的，可能与状态IV呼吸增加有关，这共同表明在恢复过程中未耦合的Ca~(2+)呼吸。
The purpose of this study was to evaluate the relationship between mitochondrial Ca2+ concentration and the respiratory control index (RCI; state III/state IV) in isolated mitochondria before and after exhaustive exercise at 75% of maximal O-2 consumption. Muscle biopsies of 100-150 mg from 12 moderately trained men were sampled at rest, immediately after exercise, and 30 or 60 min after exercise. The mitochondrial Ca2+ content after exhaustive exercise was significantly higher than the preexercise level [15.1 (range 39.4) vs. 11.6 (range 6.5) nmol/mg protein, respectively; P < 0.05], and RCI increased from 11.6 (range 14.4) at rest to 13.7 (range 15.0) at exhaustion (P < 0.05). After 60 min of recovery, the mitochondrial Ca2+ content was still high [18.8 (range 29.9) nmol/mg protein], but the RCI value was significantly depressed because of the increased state IV value and, in fact, was lower than the preexercise value [8.6 (range 5.1); P < 0.05]. Our results show that the mitochondrial Ca2+ content is increased in human skeletal muscle after prolonged exhaustive exercise and that this is followed by an elevated RCI value, with slightly increased state III and decreased state IV respiration. The restoration of the elevated mitochondrial Ca2+ level is slow and could be related to an increased state IV respiration, which together indicate uncoupled Ca2+ respiration during recovery.