Figure 2: Changes of the potential difference and short circuit current in cultured HCEC collagen sheets. (A) The average potential difference for HCEC sheets is 80-95 of that for human donor corneas denuded of epithelium. Addition of ouabain (a Na+-K+ ATPase inhibitor) causes the potential difference to become 0 mV in all samples tested. (B) The average short circuit current for HCEC sheets is 76-82 of that for human donor corneas denuded of epithelium. Addition of ouabain causes the short circuit current to become 0 μA in all samples tested. Closed circles, open circles, and squares indicate human donor corneas denuded of epithelium (n=4), HCEC sheets (n=4), and bare collagen sheets (n=4), respectively. Data are the mean±SD. *p<0.001, HCEC sheet vs. collagen sheet, †p<0.001, human donor cornea vs. collagen sheet.