[Ion movement disorders in cystic fibrosis]

The most important of ion transport abnormalities is a reduced permeability to chlorine of certain epithelial cells, notably those of the sweat glands and bronchi. This abnormality is due to a defective regulation of the chlorine channels located in the apical membrane of these cells, and more precisely to the lack of activation of these channels by protein kinases A and C. Other epithelial ion transports are affected, but the mechanism of these disturbances is imperfectly known. In the airways, for instance, a decrease of chlorine secretion and an increase of sodium absorption concur to dehydrate the bronchial secretions and thus produce the respiratory manifestations of cystic fibrosis.