The effect of amiloride on Na, K and water in bovine corneal epithelium.

The Na and K concentrations of bovine corneal epithelium and stroma were determined by chemical analysis. The effect of ambient Na concentration on these concentrations was evaluated. In the epithelium, approx. 10 mmol Na kg-1 H2O entered the cells from the tear side of the cornea. An inhibition of Na entry at the apical membrane by 5 x 10(-5) mol l-1 amiloride resulted in a loss of this amount of Na from the cells, accompanied by a loss of water. A linear relationship between the Na concentration in the stromal tissue and Na concentration on the on the aqueous side of the cornea was observed.