FILAMENTOUS AND MATRIX COMPONENTS OF SKELETAL-MUSCLE Z-DISKS
FILAMENTOUS AND MATRIX COMPONENTS OF SKELETAL-MUSCLE Z-DISKS
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DOI：
10.1002/ar.1091720403
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发表时间：
1972-01-01
影响因子：
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通讯作者：
CAHILL, MA
中科院分区：
文献类型：
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作者：
KELLY, DE;CAHILL, MA
脊椎动物骨骼“快”肌中Z盘晶格的精细结构外观取决于锇或戊二醛是否被用作主要固定剂。之前的研究者将这种差异归因于Z盘内肌动蛋白丝重叠程度的变化和/或Z盘细丝的重排。成年青蛙和幼蝾螈的“快”肌在不同程度的拉伸下进行了研究，使用几种不同的醛和锇固定程序，并在塑料切片消化技术后使用链霉蛋白酶或胃蛋白酶。Z盘的系列横截面与定向横截面和纵向截面相关。使用可力丁缓冲锇和醋酸弗罗醛缓冲戊二醛固定似乎提供了最大和最明显的对比差异。一个一致的安排相，丝状晶格，可以辨别后，任何固定。然而，第二阶段，称为“Z-盘基质”，似乎是可变的，可能是由于在初次锇固定手术期间的提取。戊二醛固定的青蛙肌肉Z盘显示丰富的基质，很少被锇固定完全耗尽。在幼蝾螈肌肉Z盘中，戊二醛固定后几乎没有基质存在，并且在初级锇后没有基质残留。在通过任一方法固定的Z盘中，保留的基质似乎以晶格状图案沉积。这表明，这些矩阵模式，或他们的损失，是在不同的固定条件下观察到的Z盘的不同图像的基础，丝状晶格是相对稳定的。链霉蛋白酶或胃蛋白酶消化Z盘比任何其他肌肉成分，包括肌动蛋白（它似乎明显不反应）更快地消失。快速消化效果仅限于假定包括基质相的区域。丝状和基质相的结构相互关系的模型进行了讨论，并与以前的Z盘模型进行了比较。
The fine structural appearance of Z‐disk lattices in vertebrate skeletal “fast” muscle varies depending upon whether osmium or glutaraldehyde has been employed as the primary fixative. Prior investigators have attributed the differences to change in the extent of actin filament overlap within the Z‐disk and/or to rearrangement of Z‐disk filaments.Adult frog and young newt “fast” muscle has been studied under various degrees of stretch, with several different aldehyde and osmium fixation procedures, and after plastic section digestion techniques utilizing Pronase or pepsin. Serial cross sections of Z‐disks were correlated with oriented cross and longitudinal sections. Fixation with collidine‐buffered osmium and veronal acetate‐buffered glutaraldehyde seems to provide the greatest and most distinctly contrasting differences. A consistently arranged phase, the filamentous lattice, can be discerned after either fixation. However, a second phase, termed “Z‐disk matrix,” appears variable, perhaps due to extraction during primary osmium fixation procedures. Glutaraldehyde‐fixed frog muscle Z‐disks display a copious matrix, one which is seldom totally depleted by osmium fixation. In young newt muscle Z‐disks, little matrix is present after glutaraldehyde fixation and none of it remains after primary osmium. In Z‐disks fixed by either method, matrix that is retained appears to be deposited in lattice‐like patterns. It is suggested that these matrix patterns, or their loss, are the basis for the varying images of Z‐disks observed under diferent fixation conditions and that the filamentous lattice is relatively stable. The Z‐disk is more rapidly obliterated by Pronase or pepsin digestion than is any other muscle component, including actin (which appears notably unreactive). The rapid digestion effect is limited to the region postulated to include the matrix phase. Models for the structural interrelationship of filamentous and matrix phases are discussed and compared to prior Z‐disk models.