Brown D, Sorscher E J, Ausiello D A, Benos D J
Renal Unit, Massachusetts General Hospital, Boston.
Am J Physiol. 1989 Feb;256(2 Pt 2):F366-9. doi: 10.1152/ajprenal.1989.256.2.F366.
Amiloride-sensitive Na+ channels were localized in semithin frozen sections of rat renal medullary collecting ducts, using polyclonal antibodies directed against purified bovine kidney Na+ channel protein. The apical plasma membrane of collecting duct principal cells was heavily stained by indirect immunofluorescence, whereas intercalated cells were negative. Basolateral plasma membranes of both cell types were unstained, as were subapical vesicles in the cytoplasm of these cells. In the thick ascending limb of Henle, some scattered granular fluorescence was seen in the cytoplasm and close to the apical pole of epithelial cells, suggesting the presence of antigenic sites associated with some membrane domains in these cells. No staining was detected in thin limbs of Henle, or in proximal tubules in the outer medulla. These results show that amiloride-sensitive sodium channels are located predominantly on the apical plasma membrane of medullary collecting duct principal cells, the cells that are involved in Na+ homeostasis in this region of the kidney.
使用针对纯化的牛肾钠通道蛋白的多克隆抗体，将氨氯地平敏感的钠通道定位在大鼠肾髓质集合管的半薄冰冻切片中。集合管主细胞的顶端质膜通过间接免疫荧光被强烈染色，而闰细胞呈阴性。两种细胞类型的基底外侧质膜均未染色，这些细胞胞质中的顶端下小泡也是如此。在髓袢升支粗段，在细胞质中以及靠近上皮细胞的顶端极处可见一些散在的颗粒状荧光，提示这些细胞中与某些膜结构域相关的抗原位点的存在。在髓袢细段或外髓质的近端小管中未检测到染色。这些结果表明，氨氯地平敏感的钠通道主要位于髓质集合管主细胞的顶端质膜上，这些细胞参与了肾脏该区域的钠稳态。
