Effects of amphotericin B on ion and fluid movement across dog tracheal epithelium

Abstract

Ion fluxes or fluid flow were measured across sheets of dog tracheal epithelium mounted in Ussing chambers or a special apparatus, respectively. Under short-circuit conditions, luminal amphotericin B (3 X 10(-5) M) caused an inhibition of net Cl secretion and an increase in net Na absorption across paired tissues. In paired tissues under resting open-circuit conditions, there was no significant net transepithelial flux of either Cl or Na. Amphotericin B induced significant net fluxes of both Cl and Na toward the serosal side. In separate tissues from the same animals, there was no significant transepithelial fluid movement under resting conditions. Amphotericin B caused a net absorption of fluid. The absorption of salt and fluid in amphotericin B-treated tissues was abolished by ouabain. We conclude that stimulation of active Na transport by amphotericin B leads to fluid absorption. In vivo, the movement of fluid across the dog tracheal epithelium may be dependent on a balance between active Cl secretion and active Na absorption.