8. A–C; Representative traces of A/M2 channel activity inhibited by either BL-1743 (1000 μM, A), amantadine (100 μM, B), or spiran amine 8 (100 μM, C). A/M2 channel activity was induced by application of the activating solution (pH 5.5, red horizontal bar above the trace). The currents were inhibited by the application of the activating solution containing either BL-1743 (green horizontal bar, A), amantadine (yellow horizontal bar, B), or spiran amine 8 (orange horizontal bar, C) for 60–90 sec. After the maximal inhibition was achieved, oocytes were superfused with the non-activating solution (pH 8.5, second blue horizontal bar) for 5 min to allow current recovery and the channel activity was assayed again by the application of the activating solution (second red horizontal bar). Note that recovery was complete only for BL-1743.