Stimulatory effect of angiotensin II on electrolyte transport in canine tracheal epithelium.

1. The present study examines the effect of angiotensin11 (A11) on Cl- and Na+ transport in canine tracheal epithelium. 2. A concentration-dependent increase in the potential difference and in short-circuit current of the trachea was found. 3. Frusemide reduced values of Cl- dependent electrical parameters; net Cl- flux from serosa to mucosa accounted for 72% of total short-circuit current. 4. Frusemide, indomethacin and chlorpromazine blocked the stimulatory effect of A11. 5. These reactions show that A11 stimulates ion transport across the canine tracheal epithelium and suggest that two mechanisms may be proposed to explain the action of A11 on Cl- flux: (1) Ca(2+)-dependent increase in intracellular cAMP and (2) increase in Na(+)-2Cl2-K+ Cotransport activity.