Figure 3.

VU573-dependent inhibition of Kir3.1/3.2, Kir2.3, and Kir7.1 channel activity expressed in HEK-293 cells. (A,D,G) Representative whole-cell Kir3.1/3.2, Kir2.3, and Kir7.1 current traces recorded from transfected HEK-293 cells. The cell was voltage ramped every 5 s between −120 and 120 mV for 200 ms from a holding potential of −75 mV. Normalized Kir3.1/3.2, Kir2.3, and Kir7.1 currents recorded before (black line) and after reaching steady-state inhibition by 30 μM VU573 (gray line) are shown. (B,E,H) Representative time course traces of VU573-dependent inhibition of Kir3.1/3.2, Kir2.3, and Kir7.1 by 30 μM VU573 using the protocol described above. After achieving whole-cell access, the current was allowed to stabilize before adding 30 μM VU573 and then 2 mM barium (Ba²⁺) to inhibit channel activity. (C,F,I) Mean ± SEM concentration–response curves for Kir3.1/3.2 (n = 4–7), Kir2.3 (n = 4–6), and Kir7.1 (n = 4–7), respectively.