McDonagh J C, Callister R J, Favron M L, Stuart D G
Program in Physical Therapy, Arizona School of Health Sciences, A.T. Still University of Health Sciences, Mesa, AZ 85206, USA.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2004 Apr;190(4):321-9. doi: 10.1007/s00359-004-0501-z. Epub 2004 Feb 17.
The purpose of this study was to characterize the changes in a turtle hindlimb muscle (external gastrocnemius) after exposure to three conditions of disuse: immobilization, tenotomy, and spinalization. Histochemical analysis and measurement of muscle fiber cross-sectional area and weighted cross-sectional area were used to assess the potential conversion of muscle fiber types and changes in fiber size. It was found that unlike its counterpart in mammalian endotherms, the external gastrocnemius muscle of the adult turtle, Trachemys scripta elegans, was remarkably resistant to each model of reduced muscle function. It is suggested that such resistance to disuse is due to intrinsic mechanisms that enable heterothermic mammals and ectothermic vertebrates to tolerate an unfavorable climate and food and water shortages by using hypometabolic states.
本研究的目的是描述乌龟后肢肌肉（腓肠肌外侧头）在暴露于三种废用状态（固定、肌腱切断术和脊髓横断术）后的变化。采用组织化学分析以及肌肉纤维横截面积和加权横截面积的测量来评估肌肉纤维类型的潜在转变和纤维大小的变化。结果发现，与哺乳动物恒温动物的对应肌肉不同，成年秀丽锦龟的腓肠肌外侧头对每种肌肉功能减退模型都具有显著的抵抗力。有人提出，这种对废用的抵抗力归因于内在机制，这些机制使异温哺乳动物和变温脊椎动物能够通过利用低代谢状态来耐受不利的气候以及食物和水短缺。
