Electrogenic sodium-bicarbonate symport in cultured corneal endothelial cells.

Intracellular potential measurements on confluent monolayers of cultured bovine corneal endothelial cells were used to define passive ion transport processes in these cells. Previous studies [11, 12] have provided the experimental basis for a cellular model, is which bicarbonate entry across the basolateral membrane in indirectly driven by a Na+/H+-exchanger, which is inhibitable by amiloride (1 mmol/l). Na+ and HCO3- leave the cell via an electrogenic bicarbonate sodium cotransport, which is inhibitable by the disulfonic stilbene derivates SITS or DIDS.

Evidence for coupled transport of bicarbonate and sodium in cultured bovine corneal endothelial cells.

Using intracellular microelectrode technique, the response of the voltage V across the plasma membrane of cultured bovine corneal endothelial cells to changes in sodium and bicarbonate concentrations was investigated. (1) The electrical response to changes in [HCO3-]o (depolarization upon lowering and hyperpolarization upon raising [HCO3-]o) was dependent on sodium. Lithium could fairly well be substituted for sodium, whereas potassium or choline were much less effective.

Effect of bicarbonate, pH, methazolamide and stilbenes on the intracellular potentials of cultured bovine corneal endothelial cells.

Micropuncture of cultured bovine corneal endothelial cells led to registrations stable for hours. Intracellular potentials were mainly in the range of -40 to -55 mV, average 46.3 +/- 0.