Acetylcholinesterase activity in soleus muscle intrafusal and extrafusal fibres in tail suspended rats.
Objective. To explore the mechanisms involved in muscle atrophy and conversion of the fiber types induced by simulated weightlessness. Method. Weightlessness was simulated by tail suspension of female rats. Intrafusal and extrafusal fibers of soleus muscles in the rat were examined histochemically for their activity of acetylcholinesterase (AChE) and succinic dehydrogenase (SDH) in 7 d, 14 d, 21 d tail-suspended groups and control groups. Result. Staining for succinic dehydrogenase showed that simulated weightlessness caused obvious atrophy and change in fiber type composition in soleus muscle, with decrease of the proportion of type I fiber and increase of type II fiber. Acetylcholinesterase activities of intrafusal and extrafusal fibers were both decreased significantly after 21 d tail suspension. Conclusion. Simulated weightlessness could induce decrease of AChE activity in neuromuscular junctions, which might be linked with decrease in motor neuron activity.
Tang
Bin
B
Department of Physiology, Xi'an Jiaotong University.
Fan
Xiao-li
XL
Wu
Su-di
SD
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D005260:Female; D019417:Hindlimb Suspension; D006651:Histocytochemistry; D018656:Muscle Fibers, Fast-Twitch / Q000201:enzymology*; D018657:Muscle Fibers, Slow-Twitch / Q000201:enzymology*; D009470:Muscle Spindles / Q000201:enzymology / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000503:physiopathology; D009133:Muscular Atrophy / Q000201:enzymology / Q000209:etiology / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013385:Succinate Dehydrogenase / Q000378:metabolism*; D013997:Time Factors; D018474:Weightlessness Simulation / Q000009:adverse effects*
D013385:Succinate Dehydrogenase; D000110:Acetylcholinesterase