CORNEAL ENDOTHELIUM BICARBONATE TRANSPORT AND EFFECT OF CARBONIC-ANHYDRASE INHIBITORS ON ENDOTHELIAL PERMEABILITY AND FLUXES AND CORNEAL THICKNESS

Abstract

Unidirectional fluxes of HCO3- across the [rabbit] corneal endothelium were determined. A net flux of HCO3- from the stromal to aqueous-facing surface was demonstrated. Under conditions of carbonic anhydrase inhibition the net HCO3- flux was reduced by 54%, and the passive water permeability of the endothelium was increased. Experiments with the specular microscope demonstrated an increased rate of corneal swelling under conditions of carbonic anhydrase inhibition. Attempts to identify H+ as the cation moving with the HCO3- to maintain electroneutrality were not successful because of the impossibility of sustaining a differential H+ concentration difference across the endothelium.