title: Atrial natriuretic peptide stimulates Na+-dependent Ca2+ efflux from freshly isolated adult rat cardiomyocytes.
abstract: In the present study, we examined the effect of atrial natriuretic peptide (ANP) on Ca2+ efflux from freshly isolated adult rat cardiomyocytes. Rat ANP(1-28) stimulated the efflux of 45Ca2+ from the cells in a concentration-dependent manner (10(-8) M to 10(-6) M). The 45Ca2+ efflux was not affected by removal of extracellular Ca2+, but was dependent on the presence of extracellular Na+. In addition, rat ANP(1-28) caused 22Na+ influx into the cells. The 45Ca2+ efflux was also stimulated by C-type natriuretic peptide-22 (CNP-22), but not by rat brain natriuretic peptide-45 (BNP-45). It was also observed that both rat ANP(1-28) and CNP-22 stimulated guanosine 3',5'-cyclic monophosphate production within the cells. These results indicate that ANP stimulates Na+-dependent 45Ca2+ efflux from freshly isolated adult rat cardiomyocytes, probably through Na+/Ca2+ exchange, and that the stimulatory effect of ANP on Ca2+ efflux may be mediated via the natriuretic peptide receptor which has been shown to couple to guanylate cyclase. Since it is reported that Na+/Ca2+ exchange is important in calcium homeostasis within cells, ANP may play a role in the extrusion of intracellular Ca2+ from isolated adult rat cardiomyocytes.
authors.affiliation: Department of Pharmacology, University of Tokushima School of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yoshizumi
authors.forename: H
authors.initials: H
authors.lastname: Houchi
authors.forename: K
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: K
authors.initials: K
authors.lastname: Minakuchi
authors.forename: K
authors.initials: K
authors.lastname: Horike
authors.forename: T
authors.initials: T
authors.lastname: Kitagawa
authors.forename: I
authors.initials: I
authors.lastname: Katoh
authors.forename: T
authors.initials: T
authors.lastname: Tamaki
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D017136:Ion Transport / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism*
chemical_list: D009320:Atrial Natriuretic Factor; D012964:Sodium; D002118:Calcium