Fig. 4.

HK-induced stimulation of ROMK in late distal convoluted tubule (DCT2)/connecting tubule (CNT) is preserved in kidney-specific-with-no-lysine kinase-null (WNK4^−/−) mice. A: whole cell recording shows tertiapin-Q (TPNQ)-sensitive K⁺ currents at −40 mV in of WNK4^−/− mice on normal potassium (NK) and high potassium (HK). Arrows indicate the addition of 400 nM TPNQ to the bath. B: scatterplot summarizes the experiments in which TPNQ-sensitive K⁺ currents were measured at −40 mV with whole cell recording. Results were obtained from six experiments (tubules). C: line graph shows the effect of dietary K⁺ intake on TPNQ-sensitive K⁺ currents in the DCT of wild-type (WT) and WNK4^−/− mice. The # symbol indicates the difference between WT and WNK4^−/− mice is significant using two-way ANOVA. D: table shows plasma K⁺ concentrations of WNK4^−/− mice on NK and HK diets for 7 days (n = 5 mice).