Figure 4.

Effect of intracellular iodide on WT and G230E. (A) Current responses in a cell expressing WT hClC-1 to a voltage step from 0 mV to −145 mV in standard extracellular solution. Current recordings from one cell perfused with standard intracellular solution (solid line) are superimposed by recordings from another cell with an intracellular solution containing (in mM): CsI (40), CsCl (90), MgCl₂ (2), EGTA (5), and Hepes (10), pH 7.4 (dashed line). Currents are normalized to the peak current amplitude. (B) Current recordings from a cell transfected with G230E using an identical protocol as described for A. (C and D) Voltage dependence of the instantaneous current amplitude for WT (C) and G230E (D) recorded in the absence (filled symbols) and presence (open symbols) of 40 mM intracellular CsI. Data are from experiments shown in A and B and are normalized to current values obtained at 75 mV.