In A, the ascending voltage ramp protocol employed in these experiments and three overlapping current traces obtained prior to and after switching perfusion channels to demonstrate the lack of its effect on NCXrev-mediated ion currents. 0.2% DMSO was used as a vehicle. In B-D, the effects of 5 mM Ni2+ (B), 0.5μM Ro 25-6981 (C), and 5μM ifenprodil (D) on NCXrev-mediated ion currents. The effects of inhibitors were calculated as percentage from the peak current without inhibitor taken as 100%. The time scale shown in panel D is applicable to all traces in B-D. For further details, see Materials and Methods.