cAMP activation of chloride and fluid secretion across the rabbit alveolar epithelium

The reabsorption of isotonic fluid instilled into the alveolar spaces of anesthesized rabbits has been studied. The role of sodium (Na+) and chlorine (Cl-) ions in this process has been examined by measuring normal saline in the presence or absence of amiloride and in chlorine ion-free solutions. The procedure is repeated after the intratracheal introduction of forskolin which increases cAMP in ATII cells. Results show the transcellular movements of Na+ and Cl- ions regulate the magnitude and direction of fluid fluxes across the alveolar epithelium after cAMP simulation.