Enables calcium:cation antiporter activity involved in regulation of postsynaptic cytosolic calcium ion concentration and calcium:sodium antiporter activity. Involved in cellular response to cAMP; metal ion transport; and telencephalon development. Acts upstream of or within cellular calcium ion homeostasis. Located in several cellular components, including dendritic spine; neuronal cell body; and sarcolemma. Is integral component of postsynaptic membrane. Biomarker of brain ischemia and status epilepticus. Orthologous to human SLC8A3 (solute carrier family 8 member A3). [provided by Alliance of Genome Resources, Apr 2022]