Frischknecht R, Belverstone D, Vrbová G
Department of Anatomy and Developmental Biology, University College London, UK.
Pflugers Arch. 1995 Dec;431(2):204-11. doi: 10.1007/BF00410192.
The effect of overload on the rat plantaris muscle was studied in animals of different ages. Overload was induced by removal of gastrocnemius and soleus muscles. As expected, when the operation was carried out in adults, the plantaris muscle became heavier and stronger. These changes occured within 30 days after the operation. In animals in which the operation was carried out 1-12 days after birth and the muscle examined 6-20 weeks later, different results were obtained. In the group operated at 1-9 days of age, the muscles developed a lower maximal twitch and tetanic tension than the contralateral plantaris muscle. There was no difference in the time to peak or muscle weight between the overloaded and the contralateral muscles. Similar changes were observed in animals where the overload was induced at 11 or 12 days of age except for the weight which was significantly higher than that of the control plantaris muscles. The number of slow fibers increased in animals where overload was induced 11-12 days postnatally or in adults, but not when muscles were overloaded at 9 days of age. The possible reasons for the different response of adult and neonatal muscles to overload are discussed.
在不同年龄的动物中研究了超负荷对大鼠跖肌的影响。通过切除腓肠肌和比目鱼肌诱导超负荷。正如预期的那样，在成年动物中进行手术后，跖肌变得更重更强壮。这些变化在手术后30天内发生。在出生后1 - 12天进行手术并在6 - 20周后检查肌肉的动物中，获得了不同的结果。在1 - 9日龄进行手术的组中，与对侧跖肌相比，这些肌肉产生的最大抽搐和强直张力较低。超负荷肌肉和对侧肌肉在达到峰值的时间或肌肉重量方面没有差异。在11或12日龄诱导超负荷的动物中观察到了类似的变化，只是重量显著高于对照跖肌。出生后11 - 12天或成年后诱导超负荷的动物中慢肌纤维数量增加，但在9日龄肌肉超负荷时则没有增加。讨论了成年和新生肌肉对超负荷反应不同的可能原因。
