Lowrie M B, More A F, Vrbová G
Department of Anatomy and Developmental Biology, University College, London, Great Britain.
Pflugers Arch. 1989 Nov;415(2):204-8. doi: 10.1007/BF00370593.
In newborn Wistar rats the load on the soleus muscle was reduced by removing the tibialis anterior (TA) and extensor digitorum longus (EDL) muscles. Eighteen days later the soleus muscles were removed from both the operated and control legs and examined physiologically and histologically. The time course of twitch contraction of the soleus on the operated side was not significantly different from that of control muscles, but the muscles developed less tension. The decreased tension was consistent with a smaller number of muscle fibres. Histochemical and immunocytochemical examination showed that in the operated muscle, fewer fibres reacted with an antibody against slow myosin, while the number of fibres that reacted for alkali-preincubated ATPase, indicative of neonatal or adult fast myosin, was increased. Some fibres expressed both types of myosin. These findings suggest that a reduced load delays the phenotypic expression of slow myosin isoform in the developing soleus muscle.
在新生Wistar大鼠中，通过切除胫骨前肌（TA）和趾长伸肌（EDL）来减轻比目鱼肌的负荷。18天后，从手术侧和对照侧腿部取出比目鱼肌，进行生理和组织学检查。手术侧比目鱼肌的抽搐收缩时间进程与对照肌肉无显著差异，但肌肉产生的张力较小。张力降低与肌纤维数量减少一致。组织化学和免疫细胞化学检查表明，在手术肌肉中，与抗慢肌球蛋白抗体反应的纤维较少，而与碱预孵育ATP酶反应的纤维数量增加，这表明存在新生或成年快肌球蛋白，一些纤维同时表达两种类型的肌球蛋白。这些发现表明，负荷降低会延迟发育中的比目鱼肌中慢肌球蛋白同工型的表型表达。
