Effects of an external charged layer on transepithelial ion movement in frog skin

Summary The importance of a mucus layer in the transepithelial movement of ions was examined in frogs by altering the surface charge density while measuring²²Na and³⁶Cl fluxes. Cationic dyes such as Alcian Blue and Ruthenium Red titrate surface mucus but did not affect²²Na or³⁶Cl influx or efflux. Other agents such as lanthanum, Azure II, calcium and arginine titrate the subcorni-fied space mucus yet did not affect²²Na movement through this action. Thus, the mucus layer does not play a role in epithelial sodium or chloride movement across frog skin.