Figure 4.

Characterization of hfRPE cells. (A) Monolayer of pigmented hexagonal RPE cells grown on glass coverslips. (B) Papain digested individual figure-8–shaped cells seen with patch pipette on the left and membrane labeling on the right. (C) Representative current-voltage curve displaying whole-cell current measured in presence of 5 mM K⁺ (black trace) and 135 mM Rb⁺ (red trace). (D) Average increase in inward current in presence of external 135 mM Rb⁺ and 135 mM K⁺. (E) Current responses to step voltage pulses (+60, −60, and −100 mV) in presence of 5 mM K⁺, 135 mM Rb⁺, and 135 mM K⁺ in a representative cell.