title: Forefront of Na+/Ca2+ exchanger studies: stoichiometry of cardiac Na+/Ca2+ exchanger; 3:1 or 4:1?
abstract: The stoichiometry of the Na+/Ca2+ exchanger (NCX) had been generally accepted as 3 Na+:1 Ca2+. However, recently a challenging stoichiometry of 4:1 was proposed. Therefore, using guinea pig ventricular cells, we re-examined the stoichiometry by measuring the reversal potential of the NCX current and intracellular Ca2+ concentrations under the whole-cell voltage clamp. We confirmed that the stoichiometry of NCX is 3:1 not 4:1. In addition, we explored the possible reasons for obtaining erroneous results of a 4:1 stoichiometry.
authors.affiliation: Department of Pharmacology, School of Medicine, Fukushima Medical University, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Hinata
authors.forename: Junko
authors.initials: J
authors.lastname: Kimura
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D006801:Humans; D009206:Myocardium / Q000378:metabolism*; D019831:Sodium-Calcium Exchanger / Q000378:metabolism*
chemical_list: D019831:Sodium-Calcium Exchanger; D002118:Calcium