Fig. 4.

Effect of extracellular Cl⁻ replacement with gluconate. A. Scheme of the voltage stimulation protocol and representative traces from an experiment on an FRT cell expressing TMEM16A(abc). B. Current–voltage relationship from the same experiment. The graph reports the maximal value of the tail current elicited at different membrane potentials after the pre-activating stimulus at + 80 mV. C. Scheme of the voltage stimulation protocol and representative traces from an experiment on an FRT cell expressing TMEM16A(0). D. Current–voltage relationship from the same experiment. In these experiments, as well as in those shown in Figs. 5 and 6, the free Ca²⁺ concentration in the pipette solution was 305 nM (total Cl⁻ concentration: 148 mM).