Effect of Ouabain on Active Transport of Sodium in the Cornea

Abstract

Introduction Ouabain (G-Strophanthin) inhibits the activity of Na-K activated adenosinetriphosphatase (ATPase) in in vitro and in vivo systems.^1-3 The active transport of Na and K across the membranes of frog skin and erythrocytes is also inhibited by ouabain.^4,5 Simon and Bonting⁶ have shown Na-K activated ATPase to be present in the ciliary body and to be inhibited by ouabain. Administration of ouabain resulted in a decrease in aqueous flow and a drop in intraocular pressure, presumably due to an inhibition of sodium transport across the ciliary epithelium.^6A The corneal epithelium actively transports sodium,⁷ but the enzyme Na-K activated ATPase has not yet been demonstrated in this tissue. It was the purpose of this investigation to study the effect of ouabain on the active transport of sodium across the corneal epithelium. Method A technique for maintaining rabbit corneas alive between two Lucite chambers so that the