Fig. 6.

Whole cell adenosine triphosphate–sensitive K⁺ (K_ATP) currents are not affected by specific openers of mito K-ATP channel openers. (A) Whole cell recording from HEK293 cell expressing Kir6.2 and SUR1. Plotted is the mean holding current at −20 mV every 15 s. The SUR1-specific K⁺ channel opener diazoxide (Dz) is applied as indicated by the solid bars and concentration-dependently potentiated the whole cell current. (B) Current–voltage relations demonstrating the lack of effect of the cardiac K⁺ channel opener pinacidil (Pin, 0.1 mm) on Kir6.2/SUR1 currents in HEK293 cells. (C) Mean effects of the various K⁺ channel openers on Kir6.2/SUR1 currents. (D) Diazoxide at 10 μm increases the plasma K_ATP current independently of its potential effect on mitochondrial K_ATP channels, as demonstrated by the lack of effect of the mitochondrial K_ATP channel inhibitor 5-hydroxy-decanoic acid (5-HD) on the diazoxide activation of the whole cell current. Numbers (n) are given above the bars. *P < 0.05.