[Ion transports across the respiratory epithelium]

The electrolytes and water transport across the respiratory epithelium have aroused particular interest for 20 years ago, with regard to the essential role they play in the regulation of the bronchial mucus composition and volume. The development of new in vitro and in vivo, techniques, allow better knowledge of these transport systems and their regulation. Transport involves two main ionic movements: chloride secretion and sodium absorption by the epithelial cells, associated with parallel water movements. In cystic fibrosis, the modification of bronchial mucus results from a defective protein-kinase dependent regulation of chloride secretion. This defect blocks water and chloride secretion by the respiratory epithelium causing dehydration of the mucus.