The Journal of General Physiology, Vol 65, 503-514, Copyright © 1975 by The Rockefeller University Press
Action of ouabain on sodium transport in toad urinary bladder, Evidence for two pathways for sodium entry
AL Finn
The cardiac glycoside ouabain inhibits transepithelial sodium transport in
the toad urinary bladder. It is shown that this drug reduces the rate
coefficient for sodium exit at the serosal pump site. In addition, ouabain
inhibits entry across the mucosal border whenever the electrochemical
potential gradient for sodium is made less favorable. The data are
interpreted as indicating the existence of two separate pathways for sodium
entry, one of which is ouabain inhibitable.