Detail from Fig. 6A showing the principal cell (PC) and an intercalated cell (IC) at higher magnification.

<p>The apical membrane of the intercalated cell has a highly complex organization that is formed of many microplicae and membrane furrows between these structures. Bar = 1 µm. (B) Higher magnification image of the elaborate intercalated cell apical membrane microplicae showing the deep infoldings of this membrane domain. Bar = 200 nm. (C) Apical membrane of a principal cell showing surface features that may represent exocytotic or endocytotic events. These depressions were frequently seen at the base of the short microvilli - a location in which clathrin mediated endocytosis often occurs. Bar = 200 nm.