amiloride administered on the luminal surface caused the transepithelial potential ( vt ) of normal ducts to depolarize to 0 mv , but in the absence of cl in the medium or in cf ducts , amiloride caused the vt to significantly reverse electrical polarity from lumen negative to lumen positive with respect to the serosal bath .
C0010674
cf
C0002502
amiloride