DIFFERENTIAL EFFECTS OF OSMOTIC COMPRESSION ON MYOFLIAMENT LATTICE STRUCTURES

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。带皮肌肉纤维被广泛用于肌肉收缩的结构和功能。渗透压的方法已经被用来将原本膨胀的皮肤纤维恢复到活体大小(Kawai等人，1993；Chinn等人，2000)。使问题复杂化的是，渗透剂可能以不同的方式影响内部结构，从而混淆了对结构和动力学数据的解释。例如，葡聚糖T500(大多数蒙皮纤维研究中使用的试剂)不会渗透到肌丝晶格中，而葡聚糖T10或PEG4000会渗透到肌丝晶格中。前者压缩晶格，也可能压缩晶格内的细丝，而后者确实渗透到晶格中，因此压缩细丝，但不压缩细丝晶格。拟议实验的目的是了解肌肉纤维渗透压缩在晶格和细丝水平上产生的结构效应的范围。我们还将确定粗丝和细丝之间的间距、直径和质量比随压缩压力的不同变化。这些实验结果将为解释过去和未来研究渗透压对肌肉运动特性影响的功能研究提供结构基础。(实验将于2006年3月进行)

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Skinned muscle fibers have been used extensively for structure-function of muscle contraction. Methods of osmotic compression have been used to return the otherwise swollen skinned fibers to in vivo size (Kawai et al., 1993; Chinn et al., 2000). Complicating the issue, osmotic agents can affect internal structures differentially, thereby confounding the interpretation of structural and kinetic data. Dextran T500 (the agent used in most skinned fiber studies), for example, does not permeate the myofilament lattice, while Dextran T10 or PEG 4000 does. The former compresses the lattice and, presumably, the filaments within, whereas the latter do permeate the lattice and therefore compress the filaments but not the filament lattice. The objectives of the proposed experiments are to understand the range of structural effects at the lattice and filament levels resulting from osmotic compression of muscle fibers. We will also determine the differential changes in spacing, diameter, and mass ratio between thick and thin filaments as a function of compressive pressure. The results of the experiments will provide a structural basis for interpreting past and future functional studies investigating effects of osmotic compression on kinetic properties of muscle. (Experiments will be done March 2006)