The properties of "active" Cl transport across the cornea of the toad Bufo marinus

1. 1. Active Cl transport occurs from the endothelial to epithelial side of the cornea of Bufo marinus. Na transport is much less and is in the opposite direction. 2. 2. The rate of Cl transport is not saturable and is linearly related to the Cl concentration on the endothelial side. 3. 3. Active efflux (endo to epi) of Cl is reduced (50%) by CN and abolished by IAA. Ouabain and Na-free solutions on the endothelial side also reduce Cl efflux. 4. 4. O₂ consumption or lactate production are also decreased by ouabain or Na-free solutions. However, metabolism was not inhibited by Cl-free solutions or a specific Cl blocking drug bumetanide. 5. 5. Cl transport exhibits some rather unusual characters and a model is proposed to account for them which involves an exchange of Cl for metabolically produced organic anions.