Relationship between aging, muscle metabolisn and excercisp training by MRS

为了评估耐力训练后肌肉能量学的变化，我们在同一动物体内测量了训练前后大鼠肌肉的磷-31核磁共振（^<31>P NMR）谱。训练组进行3个月的耐力训练。^<31>的核磁共振波谱在休息、电刺激运动和恢复时依次获得。肌内磷酸肌酸（PCr）、无机磷酸盐（Pi）、ATP和pH由核磁共振光谱测定。训练3个月后，训练组与对照组在休息时的PCr/ (PCr+Pi)比值无显著差异。然而，在运动过程中，训练组的这一比例明显高于对照组。训练组在运动后恢复得更快。肌肉pH值在运动过程中略有下降，为0.1 pH单位，但两组间无显著差异。这些结果表明，3个月的耐力训练改善了肌肉中的ATP供应系统，但肌肉纤维类型没有明显变化。结果表明，^<31>P核磁共振是评价连续训练效果的有效方法。

To evaluate changes in muscle energetics following endurance training, we measured phosphorus -31 nuclear magnetic resonance ( ^<31>P NMR) spectra on rat muscle in vivo before and after training in the same animals. The endurance training was performed in the training group for 3 months. ^<31>P NMR spectra were obtained serially at rest, during exercise by electric stimulation, and during recovery. Intramuscular phosphocreatine (PCr), inorganic phosphate (Pi), ATP and pH were determined from the NMR spectra. The ratio of PCr/ (PCr+Pi) at rest showed no difference between the training and control group even after 3 months of training. During exercise, however, this ratio was significantly higher in the training group than in the control group. The ratio also recovered more rapidly after exercise in the training group. The muscular pH slightly decreased - 0.1 pH unit during exercise, but did not show significant difference in both groups. These results indicate that the endurance training of 3 months improves the ATP supply system in the muscle without significant change in the muscular fiber types. It is also demonstrated that ^<31>P NMR is a potent method to evaluate the training effects on the same individuals consecutively.