Fig. 5.

Determination of the cation/anion relative permeability. A. Tail currents elicited with the protocol depicted in Fig. 4A in an FRT cell expressing the (abc) isoform. The traces show the effect of lowering the extracellular CsCl concentration from 150 mM to 30 mM. B. Current–voltage relationship from the same experiment. The graph reports the maximal value of the tail current at each membrane potential. C. Currents measured in an FRT cell expressing the (0) isoform with high and low CsCl in the extracellular solution. The voltage stimulation protocol was the same shown in Fig. 4C. D. Current–voltage relationship from the same experiment.