St-Pierre D M, Leonard D, Gardiner P F
Sciences de l'activité physique, Université de Montréal, Québec, Canada.
Exp Neurol. 1987 Dec;98(3):472-88. doi: 10.1016/0014-4886(87)90257-3.
The extent of recovery in rat gastrocnemius muscles which have undergone atrophic changes due to 4 weeks of inactivity caused by sciatic nerve superfusion of tetrodotoxin, was investigated. Control and tetrodotoxin-treated female Sprague-Dawley rats were subjected to either a daily program of grid-climbing or swim-training for 4 weeks, or benefited from cage activity only. In situ contractile properties of the gastrocnemius were then measured. Twenty-eight days of recovery was insufficient to allow a complete reversal of the changes produced by 28 days of inactivity. The gastrocnemius remained atrophied (25%) and tetanically weaker than normal in the recovered animals. The maximal rate of rise of the twitch was partially recovered whereas that developed during a maximal contraction was normal. Maximal rate of rise expressed relative to the tension output was elevated, however, for both twitch (%Pt/ms) and maximal contraction (%Po/ms). Swimming did not influence the recovery of muscle size or strength. Grid-climbing, on the other hand, produced heavier and stronger muscles and a faster recovery of %Pt/ms. This study clearly illustrates the importance of muscle load in regulating muscle size and strength.
研究了因坐骨神经灌注河豚毒素导致4周不活动而发生萎缩变化的大鼠腓肠肌的恢复程度。将对照和经河豚毒素处理的雌性斯普拉格-道利大鼠进行为期4周的每日爬格或游泳训练计划，或仅从笼内活动中受益。然后测量腓肠肌的原位收缩特性。28天的恢复不足以使28天不活动所产生的变化完全逆转。在恢复的动物中，腓肠肌仍然萎缩（25%），强直收缩比正常情况弱。抽搐的最大上升速率部分恢复，而在最大收缩期间发展的速率正常。然而，相对于张力输出表示的最大上升速率，对于抽搐（%Pt/ms）和最大收缩（%Po/ms）均升高。游泳不影响肌肉大小或力量的恢复。另一方面，爬格使肌肉更重、更强壮，并且%Pt/ms的恢复更快。这项研究清楚地说明了肌肉负荷在调节肌肉大小和力量方面的重要性。
