Direct effects of NO on K
channel activity in SS DRG neurons. (A) Representative current traces of KATP channel activity in inside-out patches at -60 mV holding potential excised from SS neurons. Bath application of SNAP (100 μM) activated KATP channel only in the presence of 1 mM, but not 10 μM [ATP]i. Arrows indicate closed channel state. (B) Concentration-response relationship between [ATP]i (0–1000 μM) and relative NPo in the presence or absence of SNAP in inside-out patches. The relative NPo values were calculated by dividing the channel activity (expressed as NPo) in the presence of various [ATP]i with the activity in the absence of ATP. Each point represents measurements from 5–6 patches (mean ± SD). *: indicate significant difference from control. (C) Current-voltage relations were plotted from inside-out recordings of single KATP currents in the presence or absence of SNAP (100 μM) at membrane potentials between -60 and +60 mV (n = 5 each). Application of SNAP to patches did not affect single channel conductance.