Figure 6.

NAGly suppresses NCX currents independently of G-proteins. (A) Representative time course of changes in NCX current amplitudes at −100 and +85 mV during voltage ramps before and during application of 10 μM O-1918. (B) O-1918 (10 μM) suppresses NCX_pm current pre-stimulated with a decrease in bath Na⁺ to 20 mM. The time course of the response. (C) Corresponding current traces elicited by voltage ramps at time points indicated in (B). (D) Representative time course of changes in the NCX_pm current amplitudes to voltage ramps at voltages indicated in the presence of GDPβS in the patch pipette under control conditions (1), in the presence of 20 mM Na⁺ in the bath (2) and in the presence of either 3 μM (3) or 10 μM (4) of bath NAGly in low Na⁺ solution. (E) Corresponding current traces at time points shown in (D). (F) Representative time course of changes in current amplitudes at −100 and +85 mV during voltage ramps before and during application of 10 μM NAGly in the continued presence of URB597. Pipette solution was supplemented with 0.5 mM GDPβS. (G) Corresponding I-V relationship. (H) Representative time course of the changes in current amplitude during intracellular dialysis of EA.hy926 cell with 10 μM NAGly before and after a decrease in bath Na⁺, (I) corresponding I-V relationship at time points indicated in (A). (J) Mean fractional inhibition of I_NCX at +85 mV by extracellular and intracellular NAGly (10 μM). Fractional inhibition was obtained using the function: fractional inhibition = (I_control − I_NAGly)/I_control × 100.