LOCATION OF PORE SYSTEMS IN CAPILLARY WALLS

小孔系统(血肽)探测分子的最新研究 导致了跨内皮细胞通道的发现，这些通道是由 肌毛细管壁融合的质膜小泡(大鼠 隔膜)。冷冻裂解制剂的可靠鉴定片段 微血管系统(小动脉、毛细血管、小静脉)显示 在细胞的组织中有特征的节段性变化 血管内皮细胞的连接处。这一发现和其他发现表明 渗透率的结构基础因区段而异。 在毛细血管和毛细血管后小静脉上对这一假设进行了验证。 鼠标横隔膜。在前者中，大分子示踪剂被输送 通过质膜小泡或通过跨内皮通道移动。在 后者，焦点开放的交汇点代表了一个额外的通道 小于70A的分子。阴离子中心在表面的分布 用阳离子铁蛋白研究质膜的腔面 作为一种追踪器。结果揭示了分化的存在。 与结构特征有关的“微域” 内皮细胞。酸性中心浓度最高的是 窗孔，其中它们主要由硫酸盐化贡献 糖胺多聚糖(硫酸乙酰肝素或肝素)。阴离子中心不是 可检测到质膜小泡、跨内皮通道及其 气孔孔。凝集素受体在管腔表面的分布 内皮细胞上有标记的糖蛋白和凝集素 甘露-吡喃糖基、N-乙酰氨基葡萄糖、D-半乳糖基、D-岩藻糖和 N-乙酰氨基半乳糖残基。分布是异质的：它 定义最小(隔窗)与最大的微域 结合(质膜囊泡的膜和隔膜)。它是 建议：-继续绘制地球表面活性部位的地图 内皮；-分离足够数量的微血管内皮细胞 细胞分级；-并研究囊泡运输中的调制 由血压、渗透压和身体的变化引起的 温度。

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.