LOCATION OF PORE SYSTEMS IN CAPILLARY WALLS

毛细管壁中孔隙系统的位置

• 批准号: 3335308
• 负责人: GEORGE E PALADE
• 金额: $ 24.44万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1977
• 资助国家: 美国
• 起止时间: 1977-03-01 至 1987-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3335308
• 关键词: angiotensin II; basement membrane; blood lipoprotein; blood osmolarity; blood pressure; body temperature; capillary; capillary bed; cell membrane; crosslink; electron microscopy; histochemistry /cytochemistry; intercellular connection; mucopolysaccharides; myocardium; radiotracer; vascular endothelium permeability; vascular smooth muscle

Recent work with probe molecules for the small pore system (hemepeptides) has led to the discovery of transendothelial channels formed by chains of fused plasmalemma vesicles in the wall of muscle capillaries (rat diaphragm). Freeze cleaved preparations of reliably identified segments of the microvasculature (arterioles, capillaries, venules) have shown that there are characteristic segmental variations in the organization of cell junctions in the vascular endothelium. This and other findings suggest that the structural basis of permeability varies from segment to segment. This assumption was checked on the capillaries and postcapillary venules of the mouse diaphragm. In the former, macromolecular tracers are transported by plasmalemmal vesicles or move through transendothelial channels. In the latter, focally open junctions represent an additional passageway for molecules smaller than 70A. The distribution of anionic sites on the luminal aspect of the plasmalemma was investigated with cationized ferritin as a tracer. The results revealed the existence of differentiated "microdomains" related to characteristic structural features of the endothelium. The highest concentration of acidic sites was found on fenestral apertures, where they were contributed primarily by sulfated glycosaminoglycans, (heparan sulfate or heparin). Anionic sites were not detectable on plasmalemmal vesicles, transendothlial channels and their stomatal apertures. Lectin receptor distribution - on the luminal surface of the endothelium with tagged lectins specific for gluco-and manno-pyranosyl, N-acetylglucosaminyl, D-galactosyl, D-fucosyl, and N-acetylgalactosaminyl residues. The distribution is heterogeneous: it defines microdomains of minimal (fenestral diaphragms) versus maximal binding (membranes and diaphragms of plasmalemmal vesicles). It is proposed to: - continue the mapping of active sites on the surface of the endothelium; - isolate microvascular endothelia in sufficient amount for cell fractionation; - and investigate modulation in vesicular transport induced by variations in blood pressure, osmotic pressure, and body temperature.

最近对小孔系统探针分子（血肽）的研究 导致发现了由蛋白质链形成的跨内皮通道， 毛细血管壁融合的质膜小泡（大鼠 隔膜）。 可靠鉴定的片段的冷冻切割制备物 微脉管系统（小动脉、毛细血管、小静脉）已经表明， 在细胞的组织中存在特征性的节段性变化 血管内皮中的连接。 这一发现和其他发现表明， 渗透率的结构基础因段而异。 这一假设在毛细血管和毛细血管后小静脉上得到了验证 老鼠的横膈膜 在前者中，大分子示踪剂被运输到 通过质膜囊泡或通过跨内皮通道移动。 在 后者，局灶性开放连接代表了一个额外的通道， 分子小于70A。 阴离子位点的分布 用阳离子化铁蛋白研究了质膜的管腔形态 作为一个追踪者。 结果显示，存在分化的 "微区"与微结构的特征性结构特征有关， 内皮细胞 酸性位点的最高浓度被发现在 窗孔，其中它们主要是由硫酸盐 糖胺聚糖（硫酸乙酰肝素或肝素）。 阴离子位点没有 在质膜囊泡、跨内皮通道及其 气孔开度 凝集素受体分布-管腔表面 用标记的凝集素特异性的葡萄糖和 甘露-吡喃糖基，N-乙酰葡糖胺基，D-半乳糖基，D-岩藻糖基，和 N-乙酰半乳糖胺残基。 分布是不均匀的：它 定义最小（窗隔）与最大的微域 结合（质膜囊泡的膜和隔膜）。 是 建议：-继续绘制地球表面的活动地点 - 分离足够量的微血管内皮细胞， 细胞分级;-并研究囊泡运输的调制 由血压、渗透压和身体的变化引起， 温度