Mediates the electrogenic exchange of Ca(2+) against Na(+) ions across the cell membrane, and thereby contributes to the regulation of cytoplasmic Ca(2+) levels and Ca(2+)-dependent cellular processes (PubMed:12818181). Contributes to cellular Ca(2+) homeostasis in excitable cells (PubMed:12818181). Contributes to the rapid decrease of cytoplasmic Ca(2+) levels back to baseline after neuronal activation, and thereby contributes to modulate synaptic plasticity, learning and memory (PubMed:12818181). Plays a role in regulating urinary Ca(2+) and Na(+) excretion (PubMed:25498502). Ca(2+)(in) + 3 Na(+)(out) = Ca(2+)(out) + 3 Na(+)(in) Calcium transport is down-regulated by Na(+) and stimulated by Ca(2+). Detected in kidney cortex, in distal convoluted tubules and connecting segments (PubMed:25498502). Detected in brain and spinal cord (at protein level) (PubMed:12818181). Detected in brain, especially in hippocampus CA1, CA2 and CA3 fiels, dentate gyrus, cerebellum and brain cortex (PubMed:12818181). The cytoplasmic Calx-beta domains bind the regulatory Ca(2+). The first Calx-beta domain can bind up to four Ca(2+) ions. The second domain can bind another two Ca(2+) ions that are essential for calcium-regulated ion exchange. No obvious phenotype. In hippocampus pyramidal neurons, calcium exchange activity is reduced by about half, suggesting that other, additional calcium exchangers are active in these neurons. In these neurons, the neurotransmitter glutamate triggers a sharp increase in cellular Ca(2+) that does not depend on calcium exchanger activity. In contrast, the decrease to basal levels is mediated by calcium exchangers, and is considerably slower in mutant mice than in wild-type. Basal synaptic function is not impaired in mutant mice, but they display enhanced short-term plasticity and facilitated long-term potentiation, probably due to the slower decrease of Ca(2+) after an initial impulse. Mutant mice display an increased capacity for spatial learning and memory (PubMed:12818181). Heterozygous mutants show increased basal urine volume and increased urinary secretion of Ca(2+) and Na(+) (PubMed:25498502). Belongs to the Ca(2+):cation antiporter (CaCA) (TC 2.A.19) family. SLC8 subfamily.