Figure 3. MGO affected single-channel properties of KATP channel.
A, In giant inside-out patch configuration, 3 mM MGO activated the Kir6.1/SUR2B currents in a manner similar to that seen in the whole cell configuration. This current could be further activated and inhibited by Pin and Glib, respectively. B, Summary of MGO treatment in inside-out patch study. C, Single-channel level currents were recorded in inside-out patches with a holding potential of -80 mV. The lower trace was an expansion from the upper trace between the arrows. The presence of two active channels was evident at baseline level. The NPo averaged 0.183 (n=4) in the baseline. D, With an exposure of the inside-out patch to 3 mM MGO, the single-channel activity was augmented, as a result of the appearance of one more active channel. The NPo averaged 0.444 with MGO treatment. E, F, Single-channel conductance was measured with a ramp protocol with voltage ranging from -100 mV to 100 mV. Three active channels were observed with both MGO alone (E) and Pin alone (F) treatments. The straight lines represented a slope conductance of 36 pS for all three channels.