Figure 2.

The NO/cGMP/PKG pathway does not directly inhibit TRPM4. (A) Representative trace from a perforated patch-clamp experiment demonstrating that TICC activity is activated by the Ca²⁺ ionophore ionomycin (1 µM). (B) Summary data showing the increase in TICC activity in response to ionomycin (*P < .05; n = 8 cells from four animals). (C) Representative trace from a perforated patch-clamp experiment demonstrating that ionomycin (1 µM) reactivates SNAP (30 µM)-inhibited TICC activity. (D) Summary data showing reversal of the inhibitory effects of SNAP by ionomycin (*P < .05; n = 8 cells from four animals). (E) Time course of a representative conventional whole-cell patch-clamp recording showing that an outwardly rectifying cation current activated by applying voltage ramps from −100 to +100 mV during the first 100 s after breaking into the cell is abolished by the selective TRPM4 blocker 9-phenanthrol (30 µM). (F) I–V relationships for experiments shown in (E) in the presence and absence of 9-phenanthrol. Currents for I–V relationships were obtained 100 s after break-in (arrow). (G) Quantification of whole-cell TRPM4 currents at +100 mV (n = 6 cells from four animals). (H) Time course of a representative conventional whole-cell patch-clamp recording showing that whole-cell TRPM4 currents are unaffected by SNAP (100 µM) but are abolished by the selective TRPM4 blocker 9-phenanthrol (30 µM). (I) I–V relationships for experiments shown in (H) in the presence and absence of SNAP. Currents for I–V relationships were obtained 100 s after break-in (arrow). (J) Quantification of the effects of SNAP on whole-cell TRPM4 currents (n = 5 cells from three animals).