Cellular distribution and function of ion channels involved in transport processes in rat tracheal epithelium.

Transport of water and electrolytes in airway epithelia involves chloride-selective ion channels, which are controlled either by cytosolic Ca or by cAMP The contributions of the two pathways to chloride transport differ among vertebrate species. Because rats are becoming more important as animal model for cystic fibrosis, we have examined how Ca- dependent and cAMP- dependent Cl secretion is organized in the rat tracheal epithelium. We examined the expression of the Ca-gated Cl channel anoctamin 1 (ANO1), the cystic fibrosis transmembrane conductance regulator (CFTR) Cl channel, the epithelial Na channel ENaC, and the water channel aquaporin 5 (AQP5) in rat tracheal epithelium.