The effect of bicarbonate ion concentration on trans-endothelial short circuit current in ox corneas.

Experiments were performed in vitro, to determine the effect of bicarbonate ion concentration on bovine cornea endothelial potential difference, short circuit current and resistance. Corneas were perfused with Ringer solutions containing 36, 12, 6, 3, 0 mM NaHCO3. Endothelial potential difference, short circuit current and resistance were measured at each concentration. Decreasing the bicarbonate concentration resulted in a reversible and parallel fall in potential difference and short circuit current, whereas resistance remained unchanged. The results demonstrate that bicarbonate is a necessary component of the mechanisms that generate trans-endothelial short circuit current.