DIFFERENTIAL EFFECTS OF OSMOTIC COMPRESSION ON MYOFLIAMENT LATTICE STRUCTURES

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。所列机构为中心机构，不一定是研究者机构。带皮肌纤维已被广泛用于肌肉收缩的结构-功能。渗透压缩的方法已被用于使原本溶胀的结皮纤维恢复到体内尺寸（Kawai等人，1993; Chinn等人，2000年）。使问题复杂化的是，渗透剂可以不同地影响内部结构，从而混淆结构和动力学数据的解释。例如，右旋糖酐T500（用于大多数结皮纤维研究的试剂）不渗透肌丝晶格，而右旋糖酐T10或PEG 4000则渗透。前者压缩晶格，并且可能压缩其中的细丝，而后者确实渗透晶格，因此压缩细丝，但不压缩细丝晶格。所提出的实验的目的是了解的晶格和细丝水平的肌肉纤维的渗透压缩所产生的结构效应的范围。 我们还将确定作为压缩压力的函数的粗细丝之间的间距、直径和质量比的差异变化。实验结果将为解释过去和未来的功能研究渗透压缩对肌肉动力学特性的影响提供结构基础。（实验将于2006年3月完成）

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)