FIGURE 7.

Block by external ions. (A) Example single channel currents for wild-type and T-338A-CFTR recorded from inside out patches at a membrane potential of +70 mV, under control conditions (left) and in the presence of 1 mM in the extracellular solution (right). (B) Mean unitary current-voltage relationships for wild-type and T-338A-CFTR, under control conditions (○) and in the presence of 1 mM in the extracellular solution (•). (C) Fractional unitary current remaining in the presence of 1 mM extracellular . Mean of data from 3–5 patches in each panel.