Figure 5.

K_IR of human adrenal zona glomerulosa (AZG) cells. A: K⁺ selectivity. I-V relationships were obtained for the inwardly rectifying current of human AZG cells in external solutions containing 5 mM or 14 mM K⁺. Current traces in response to voltage steps of 300-ms duration applied at 30 s intervals from a holding potential of −60 mV to test potentials from +30 to −110 mV in 5 mM or 14 mM K⁺. B: current amplitudes recorded in 5 mM and 14 mM K⁺ are plotted against test potential for the traces in A. C: instantaneous and time-dependent components. K_IR current traces from five separate cells activated by test potentials to −110 mV from a holding potential of −60 mV. D: current-voltage relationship. Current amplitudes are plotted against test potential for traces in Fig. 1C at voltages from −140 to +30 mV. Number of independent experiments:  = 5 (A and B); n = 5 (C and D).