尾部悬吊对大鼠比目鱼肌mATP酶活性的影响

目的　研究尾部悬吊对大鼠比目鱼肌梭内、外肌纤维的mATP酶活性的影响 ,旨在探讨失重条件下梭内、外肌代谢的改变。方法　采用尾部悬吊法建立模拟失重模型 ,以钙增强的mATPase法检测模拟失重不同时期大鼠比目鱼肌梭内、外肌的mATP酶活性。结果　尾部悬吊可使梭外肌Ⅰ型肌纤维的构成比减少 ,Ⅱ型肌纤维的构成比增加 ,梭内肌纤维mATP酶活性增强 ,核袋 1纤维mATP酶染色不变或由阴性转变为弱阳性 ,核袋 2纤维和核链纤维由阳性转变为强阳性。结论　模拟失重导致梭内、外肌代谢发生改变 ,梭外肌纤维类型发生转化。

Changes in activities of myosin adenosine triphosphatase of intrafusal and extrafusal fibres in rat soleus muscle after tail suspension

ObjectiveTo study whether simulated weightl es sness could induce changes of myosin ATPase activities of intrafusal and extrafu sal fibres in soleus muscle.Methods~{**!~!<~}WTBZ~{!=!<~}KG(*9~{!=~}The activit ies of myosin ATPase of intrafusal and extrafusal fibres in soleus muscle were d etected in~{!<~}KG)~{!=~} 4 ?d,7?d,14?d tailsuspended respectively and in 14?d recovered rats and t hen compared with control.ResultsThe constituent ratios of typ e ~{"q~} fiber decrease while that of type ~{"r~} fiber increase.The activities of myosi n ATPase of intrafusal fibres become higher after tailsuspension.Bag 1 intrafu sal fibers show medium activity instead of negative,while bag 2 intrafusal fiber s and chain fibers show higher activity as compared with control.Conclusi o nSimulated weightlessness can induce changes in activities of myosin A TPase of intrafusal and extrafusal fibres in soleus muscle,which may contribute to muscle atrophy and transformation of type ~{"q~} to type ~{"r~} fibers.