ULTRASTRUCTURE OF THE MYOCARDIAL SARCOLEMMA

这是对心肌肌膜的研究。 其方法是分析 用细胞化学方法观察了糖萼和双层的超微结构， 冷冻断裂技术 具体目标是确定，1）如果 糖萼和双层中的膜内颗粒（IMP）是 与膜渗透性有关，以及2）这些成分如何与膜渗透性有关，以及2）这些成分如何与膜渗透性有关。 膜是相互关联的。 方法是检查它们在扰动后的形态， 改变膜的渗透性或运输，在成熟的过程中， 肌膜，肌膜特化内和改变后 在双层内的阴离子磷脂中。 的结构性变化 IMP和细胞表面将与发病、程度和 防止细胞膜功能的改变 为此，将使用以下扰动：1）Ca耗尽， 饱食，2）缺血，3）洋地黄毒性，4）磷脂酶D治疗 和接触两亲物。 发展研究将比较 新生儿和成人心脏中肌膜成分的结构。 糖萼与IMP意志关系的探讨 涉及诱导IMP的聚集并确定是否存在 细胞表面细胞化学标记的平行分布。 反过来说， 细胞表面成分（阳离子化铁蛋白和Con A受体）将被 加盖并监测断裂肌膜的平行分布 IMP的。 传统的冷冻压裂技术加上改进， 超快速冷冻，旋转阴影将被用来描述和 量化IMP（数量、分布、大小、子结构）。 薄层 显微镜将使用胶体氢氧化铁，阳离子化铁蛋白，Con A 和单宁酸固定。 拟议的研究有两个方面 显著性：1）通过检测糖萼和IMP是否相关 对于膜的渗透性，它解决了一个基本的问题， 所有细胞的生物学，2）它侧重于结构-功能 关系（生理和病理生理）的“更大的” 膜，”在心脏中的信息很少，使用状态 艺术技术。

This is a study of the myocardial sarcolemma. Its approach is to analyze the ultrastructure of the glycocalyx and the bilayer with cytochemical and freeze-fracture techniques. The specific aims are to determine, 1) if the glycocalyx and the intramembrane particles (IMP's) in the bilayer are related to membrane permeability, and 2) how these components of the membrane are related to each other. The methodology is to examine their morphology after perturbations which alters membrane permeability or transport, during maturation of the sarcolemma, within specializations of the sarcolemma and after alterations in the anionic phospholipids within the bilayer. Structural changes in the IMP's and the cell surface will be related to the onset, to the degree and to the prevention of altered membrane function. To this end the following perturbations will be used: 1) Ca depletion and repletion, 2) ischemia, 3) digitalis toxicity, 4) phospholipase D treatment and exposure to amphiphiles. The developmental studies will compare the structure of the sarcolemmal components in the neonate and adult hearts. Investigation of the relationship between the glycocalyx and IMP's will involve induction of clustering of the IMP's and determining if there is a parallel distribution of cell surface cytochemical markers. In reverse, cell surface components (cationized ferritin and Con A receptors) will be capped and the fractured sarcolemma monitored for a parallel distribution of IMP's. Conventional freeze-fracturing techniques plus refinements such as ultra-rapid freezing, rotary shadowing will be used to describe and quantify IMP's (number, distribution, size, substructure). Thin-section microscopy will use colloidal iron hydroxide, cationized ferritin, Con A and tannic acid fixation. The proposed research has a two-fold significance: 1) by testing whether the glycocalyx and IMP's are related to permeability of the membrane it addresses a question fundamental to the biology of all cells, and 2) it focuses on the structure-function relationships (physiological and pathophysiological) of the "greater membrane," where in the heart there is little information, using state of the art techniques.