Figure 2.

The Na⁺ _i dependence of outward Na⁺-Ca²⁺ exchange currents for CALX isoforms. Overlapping current traces for both CALX isoforms are shown. Outward currents were activated in the absence of regulatory Ca²⁺ _i by application of the indicated concentrations of Na⁺ _i, maintained until a steady state was attained, followed by switching back to a Li⁺ _i-based bath solution.