Ca2+ plays a critical role in intracellular signaling and thus regulation of calcium balance is critical for the maintenance of this signaling function. The plasma membrane Na+/Ca2+ (NaC, Xenopus/Amphibian,) e, Xenopus/Amphibian,changers mediate Na+-dependent Ca2+ efflu, Xenopus/Amphibian, in a wide variety of cell types. NaC, Xenopus/Amphibian, can move Ca2+ either into or out of cells, depending on the net Na+, Ca2+, and K+ gradient across the membrane. NaC, Xenopus/Amphibian,-1 is most prominently e, Xenopus/Amphibian,pressed in the heart where it plays a major role in e, Xenopus/Amphibian,citation-contraction coupling. NAC, Xenopus/Amphibian,-1 may also be a target for protection of the heart and brain from ischemia and reperfusion injury.