LOCATION OF PORE SYSTEMS IN CAPILLARY WALLS

连续和有孔微血管的管腔质膜 内皮细胞（从牛和大鼠获得）将在 通过选择有希望的抗原（糖蛋白和 蛋白聚糖）用于产生单克隆或 多克隆抗体。 后者将被用来本地化同源 特异性分化质膜微区的抗原，例如， 质膜小泡、跨内皮通道、有孔窗和 细胞间连接 免疫细胞化学检测将在 完整的动物（大鼠），以确定抗原分布是否是 与在培养中相同。 因为我们有证据表明白蛋白 通过受体介导的胞吞转运穿过内皮， 我们将尝试识别和描述这种受体，并扩展 对其他血浆蛋白质转胞吞作用的研究。 抗体与 将测试假定的受体，以确定它们是否阻断配体 捆绑和运输。 实验将在肠系膜微血管上进行， 青蛙试图定位出口网站（小孔）的白蛋白 和其它较小的蛋白质（例如，过氧化物酶）。 白蛋白（或过氧化物酶） 与光活化基团缀合的化合物将灌注在个体中， 毛细管，与周围结构交联（通过光暴露） 在灌注开始后10秒，并且定位于其出口附近 通过免疫细胞化学，使用标记的抗体（或过氧化物酶） 反应）。 肠系膜微血管也将用于研究 周细胞控制局部血流的能力。 工作 周细胞的收缩相关蛋白将被扩展到新的 抗原，特别是血管平滑肌特异性α-肌动蛋白， 这些细胞与正常血管平滑肌的距离有多近。 内皮细胞表面精细结构的TEM和SEM研究将继续进行 并通过标记的（或未标记的）抗体扩展到抗原定位。

The luminal plasmalemma of continuous and fenestrated microvascular endothelia (obtained from bovines and rats) will be mapped at the macromolecular level by selecting promising antigens (glycoproteins and proteoglycans) from cultured cells for the generation of monoclonal or polyclonal antibodies. The latter will be used to localize the cognate antigens to specific differentiated plasmalemmal microdomains, e.g., plasmalemmal vesicles, transendothelial channels, apertured fenestrae and intercellular junctions. Immunocytochemical tests will be carried out in the intact animal (rat) to find out whether the antigen distribution is the same in situ as in culture. Since we have evidence suggesting that albumin is transported across the endothelium by receptor-mediated transcytosis, we'll attempt to identify and characterize this receptor, and to extend the inquiry to the transcytosis of other plasma proteins. Antibodies to the putative receptor will be tested to find out whether they block ligand binding and transport. Experiments will be carried out on the mesenteric microvasculature of the frog in an attempt to localize the sites of exit (small pores) for albumin and other smaller proteins (e.g., peroxidases). Albumin (or peroxidases) conjugated to photoactivatable groups will be perfused in individual capillaries, crosslinked to surrounding structures (by light exposure) seconds after the beginning of perfusion, and localized close to its exit sites by immunocytochemistry, using a tagged antibody (or a peroxidatic reaction). The mesenteric microvasculature will also be used to investigate the ability of pericytes to control local blood flow. Work on the contraction-associated proteins of pericytes will be expanded to new antigens, especially vascular smooth muscle-specific Alpha-actin, to find out how close these cells come to regular vascular smooth muscle. TEM and SEM work on endothelial surface fine structure will be continued and extended to antigen localization via tagged (or untagged) antibodies.