Leijendekker W J, Elzinga G
Laboratory for Physiology, Faculty of Medicine, Free University of Amsterdam, The Netherlands.
Pflugers Arch. 1990 Apr;416(1-2):22-7. doi: 10.1007/BF00370217.
Heat produced by a 1-s isometric tetanus of mouse extensor digitorum longus muscle (EDL; n = 6) and a 1.5-s isometric tetanus of soleus muscle (n = 7) was measured with thermopiles at 20 degrees C, and separated into initial heat (I) and recovery heat (R). In EDL the initial heat was 190 +/- 40 (SD) mJ g-1 and in soleus 52 +/- 9 (SD) mJ g-1. The recovery heat production rate immediately following the tetanus was almost zero in both muscles. It rose in 12 +/- 6 s (EDL) and in 30 +/- 3 s (soleus) to a maximum, to decrease thereafter monoexponentially with a time constant of 30.7 +/- 5.7 s (EDL) and 41.7 +/- 7.2 s (soleus). The measured recovery ratio (R/I) differed between EDL (0.95 +/- 0.14) and soleus (1.54 +/- 0.22). The value for soleus muscles was significantly different from the theoretical value of 1.13. EDL muscles were freeze-clamped at rest (n = 10) and during the recovery phase, 1 min after the onset of the tetanus (n = 10), to determine lactate and creatine phosphate. It was found that no significant amount of net lactate was produced. The amount of creatine phosphate reformed corresponded to the recovery heat produced. The results suggest that metabolic recovery after short tetani of EDL and soleus muscles occurs predominantly through oxidative phosphorylation, but knowledge of respiratory control in the living cell is insufficient to explain its slow onset immediately following contraction and the finding that EDL recovers faster than soleus.
在20摄氏度下，用热电堆测量了小鼠趾长伸肌（EDL；n = 6）1秒等长强直收缩和比目鱼肌（n = 7）1.5秒等长强直收缩产生的热量，并将其分为初始热（I）和恢复热（R）。在EDL中，初始热为190±40（标准差）mJ g-1，在比目鱼肌中为52±9（标准差）mJ g-1。强直收缩后立即的恢复产热率在两种肌肉中几乎为零。它在12±6秒（EDL）和30±3秒（比目鱼肌）内上升到最大值，此后以单指数形式下降，时间常数分别为30.7±5.7秒（EDL）和41.7±7.2秒（比目鱼肌）。测得的恢复率（R/I）在EDL（0.95±0.14）和比目鱼肌（1.54±0.22）之间有所不同。比目鱼肌的值与理论值1.13有显著差异。在静息状态（n = 10）和强直收缩开始1分钟后的恢复阶段（n = 10）对EDL肌肉进行冷冻钳夹，以测定乳酸和磷酸肌酸。发现没有产生大量的净乳酸。重新形成的磷酸肌酸量与产生的恢复热相对应。结果表明，EDL和比目鱼肌短时间强直收缩后的代谢恢复主要通过氧化磷酸化发生，但对活细胞呼吸控制的了解不足以解释其在收缩后立即缓慢开始以及EDL比比目鱼肌恢复更快的现象。
