The effects of amiloride, ouabain and osmolality on sodium transport across bovine cornea.

Electrical parameters across different parts of bovine cornea were measured after varying osmolality, temperature, pH and sodium concentration of bathing solutions, with and without amiloride or ouabain. It is concluded, that the transcorneal potential difference represents the sum of the transendothelial and transepithelial potential differences. Amiloride completely and reversibly inhibited the potential difference and the short circuit current originating in the epithelium (Ki = 2 X 10(-6) mol/l). Furthermore, the transcorneal electrical resistance increased by 28 +/- 8%. The results were used to calculate the cellular and paracellular pathway resistances in the corneal epithelium. An equivalent electrical circuit for sodium transport across the bovine cornea is proposed, which simulates the results obtained.