Fig. 10.

Simplified model of ion transport across the corneal endothelium. A: Slc4a11 is expressed in the same membrane as the Na⁺-2HCO₃⁻ cotransporter (NBCe1) and H⁺-Lac⁻ cotransporter (MCT1). Although the actions of these two transporters are coupled, stromal [Lac⁻] can vary throughout the day. Imbalances in NBCe1/MCT1 action could disturb pH_i and transendothelial fluid movement. B and C: Slc4a11 action could respond to and compensate for such imbalances to maintain pH_i and endothelial function, preventing a rise in pH_i when stromal lactate is low and MCT1 action is suboptimal (B) and supporting MCT1 action when stromal lactate is elevated (C).