The effects of ouabain on endothelial function in human and rabbit corneas

These experiments were undertaken to study the effects of ouabain on endothelial function in isolated perfused human and rabbit corneas. Both human and rabbit corneas swell at rates which are dose-dependent when perfused with ouabain (10(-8) to 10(-5) M). The human tissue, however, requires tenfold higher concentrations to achieve swelling rates comparable to rabbit. Dose-dependent ultrastructural changes are seen in ouabain-perfused endothelia progressing from moderate endothelial edema (7.5 X 10(-7) M) to marked edema with altered subcellular organelles and vacuolization (10(-5) M). Ouabain-perfused human corneas show marked endothelial edema even at the lowest concentrations of ouabain tested. Apical junctions remain intact, however, in both human and rabbit endothelia at all concentrations. These results suggest that endothelial Na/K ATPase is essential to pump function in both human and rabbit corneas.