Figure 3. The effect of NPPB on single channel currents through 4 pS amiloride-sensitive Na⁺ channels in inside-out patches.

A, actual traces of single channel currents before (a) and 20 min after (b) 200 μM NPPB applied to the cytosolic surface in an inside-out patch obtained from a cell 150 min after exposure to a hyposmotic solution. Even after application of NPPB to the bathing solution (cytosolic surface), the channel showed activity similar to that before its application. B, statistical results of the open probability (P_o) of the channel before () and 20 min after (▪) application of 200 μM NPPB. NPPB had no significant effect on the open probability of the channel. n = 6.