1) A beta agonist stimulated Na+ transport and decreased the intracellular Cl concentration ([Cl]c) associated with cell shrinkage via an increase in cytosolic cAMP level by activating adenylate cyclase in rat fetal distal lung epithelial (FDLE) cells. 2) Lowering [Cl-]c activated a 28-pS nonselective cation (NSC) channel by elongating the open time of the channel. 3) cAMP signals were converted to a protein tyrosine kinase (PTK)-mediated signal. 4) The PTK-mediated signal was involved in the cAMP-stimulated Na+ transport in rat FDLE cells.
Adrenergic beta-Agonists/pharmacology* ; Animal ; Biological Transport/physiology ; Biological Transport/drug effects ; Cell Size/physiology ; Chlorides/metabolism* ; Cyclic AMP/metabolism ; Cytosol/metabolism ; Enzyme Inhibitors/pharmacology ; Female ; Fetus/cytology ; Forskolin/pharmacology ; Nitrobenzoates/pharmacology ; Pregnancy ; Protein-Tyrosine Kinase/metabolism* ; Rats ; Rats, Wistar ; Respiratory Mucosa/enzymology* ; Respiratory Mucosa/embryology ; Respiratory Mucosa/cytology ; Sodium/metabolism* ; Tyrphostins/pharmacology