title: Corneal epithelial Cl-dependent pump quantified.
abstract: Pairs of rabbit corneas were perfused and corneal thickness monitored. The epithelial side of the preparation, and after stabilization also the endothelial side, was covered with silicone oil. A constant thinning of the cornea was observed at a rate of 11.1 microns hr-1 (= 1.0 micron L h-1 cm-2) S.D. 2.1, n = 9. This thinning was also present after endothelial removal: 12.3 microns hr-1, S.D. 1.6 (n = 5). Epithelial abrasion virtually abolished the thinning (2.5 microns hr-1, S.D. 1.89, n = 4), as did cooling from 34 to 0 degrees C. When the preparation was perfused with a Cl-free solution (SO4(2-) instead of Cl-, corrected for osmolarity with sucrose) no significant thinning of the preparation was observed (2.4 microns hr-1, S.D. 2.49, n = 4) after covering both surfaces with silicone oil. This simple set of experiments quantified the epithelial pump mechanism. The epithelial pump rate of about 1.2 microns L hr-1 cm-2 has to be taken into account when endothelial pump rates are measured in the in vitro preparation with intact epithelium.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D002712:Chlorides / Q000378:metabolism*; D003080:Cold Temperature; D003315:Cornea / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D066298:In Vitro Techniques; D011817:Rabbits; D012827:Silicone Oils
chemical_list: D002712:Chlorides; D012827:Silicone Oils