Figure 8

Direct effect of NO on wild-type SUR1/Kir6.2 and truncated Kir6.2ΔC36 channels expressed in COS-7cells. (A) Representative current traces of wild-type SUR1/Kir6.2 currents in inside-out patches at -60 mV holding potential. In the presence of 1 mM [ATP]i, bath application of SNAP (1 mM) activated wild-type SUR1/Kir6.2 channel. Activation was suppressed by the subsequent application of the thiol-reducing agent, DTT (5 mM). Arrows indicate closed channel state. (B) The concentration-dependent wild-type SUR1/Kir6.2 channel activity (NPo) on SNAP. Each point represents measurements from 7 patches (mean ± SD) *: indicate significant difference from baseline. (C) Representative traces of current via truncated Kir6.2ΔC36 channels in inside-out patches at -60 mV holding potential. In the presence of 1 mM [ATP]i, bath application of SNAP (1 mM) did not significantly activate truncated Kir6.2ΔC36 currents (in contrast to wild type SUR1/Kir6.2 currents shown in Figure 8A). Arrows indicate closed channel state. (D) Summary of SNAP effects on relative channel activity of wild-type SUR1/Kir6.2 currents and truncated Kir6.2ΔC36 channels, derived from experiments shown in Figure 8A and C. Each vertical bar represents measurements from 6–7 patches (mean ± SD).