ULTRASTRUCTURE OF THE MYOCARDIAL SARCOLEMMA

心肌肌膜的超微结构

• 批准号: 3340080
• 负责人: JOY S FRANK
• 金额: $ 18.28万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 1982
• 资助国家: 美国
• 起止时间: 1982-05-01 至 1990-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3340080
• 关键词: anesthetics; calcium transporting ATPase; cell membrane; digitalis; electron microscopy; freeze etching; glycolipids; glycoproteins; heart pharmacology; histochemistry /cytochemistry; laboratory rabbit; laboratory rat; membrane activity; membrane permeability; myocardial ischemia /hypoxia; myocardium; phospholipase D; sarcolemma; verapamil

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.

这是对心肌肌膜的研究。 其方法是分析 糖萼和双层的超微结构与细胞化学和 冷冻断裂技术。 具体目标是确定，1) 是否 双层中的糖萼和膜内颗粒（IMP）是 与膜渗透性有关，以及2）这些成分如何 膜是相互关联的。 该方法是在扰动后检查它们的形态， 在成熟过程中改变膜渗透性或运输 肌膜，在肌膜的专门化范围内和改变后 在双层内的阴离子磷脂中。 结构性变化 IMP 与细胞表面的发生、程度和程度有关 以防止膜功能改变。 为此，将使用以下扰动：1）Ca 消耗和 补充，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 新生儿和成人心脏肌膜成分的结构。 糖萼与IMP意志之间关系的调查 涉及诱导 IMP 的聚类并确定是否存在 细胞表面细胞化学标记物平行分布。 相反， 细胞表面成分（阳离子化铁蛋白和 Con A 受体）将 监测封盖和骨折肌膜的平行分布 IMP 的。 传统的冷冻压裂技术加上改进，例如 超快速冷冻、旋转阴影将用于描述和 量化 IMP（数量、分布、大小、子结构）。 薄片 显微镜检查将使用胶体氢氧化铁、阳离子铁蛋白、Con A 和单宁酸固定。 拟议的研究有两个方面 意义：1）通过测试糖萼和IMP是否相关 它解决了膜的渗透性的一个基本问题 所有细胞的生物学，2）它侧重于结构功能 “更大的关系”（生理学和病理生理学） 膜”，在心脏中几乎没有信息，使用状态 艺术技巧。