Figure 2.

Effects of H-7, U-73122, and GDPβS on M₁ receptor-mediated inhibition of the K_ATP current. The COS7 cells were cotransfected with cDNAs of Kir6.2, SUR2A, and the M₁ receptor. The K_ATP current was activated by the perfusion of 100 μM pinacidil (started at ↑). (A) The effect of H-7 on M₁ receptor-mediated inhibition. The applications of 1 μM ACh, 100 μM H-7, and 10 μM glibenclamide are indicated by the bars above the recording. (B) The effect of 1 μM U-73122. (C) A COS7 cell was dialyzed with the pipette solution containing 1 mM GDPβS. (D) Summary of the magnitudes of 1 μM ACh-induced maximal inhibition of the K_ATP current in control, H-7-, U-73122-, and GDPβS-treated cells. The numerals in parentheses indicate numbers of experiments. **, P < 0.01 vs. control.