Atrial natriuretic peptide stimulates Na+-dependent Ca2+ efflux from freshly isolated adult rat cardiomyocytes.
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.
Yoshizumi
M
M
Department of Pharmacology, University of Tokushima School of Medicine, Japan.
Houchi
H
H
Tsuchiya
K
K
Minakuchi
K
K
Horike
K
K
Kitagawa
T
T
Katoh
I
I
Tamaki
T
T
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*
D009320:Atrial Natriuretic Factor; D012964:Sodium; D002118:Calcium