Figure 3.

Comparison of the properties of wild-type (WT) and mutant ROMK channels in Xenopus oocytes. Shown are families of whole-cell currents in oocytes injected with ROMK cRNA-encoding WT, mutant cRNA (S219R and L220F), or combinations of both to mimic heterozygosity and compound heterozygosity. Oocytes were held at −60 mV and clamped in 20 mV increments from −120 mV to +60 mV in 20 mV steps (5 mmol/L potassium).