Effect of extracellular adenosine 5'-triphosphate on Ca2+ efflux from freshly isolated adult rat cardiomyocytes.
The effect of extracellular adenosine 5'-triphosphate (ATP) on Ca2+ efflux from freshly isolated adult rat cardiomyocytes was examined. ATP stimulated the efflux of 45Ca2+ from the cells in a concentration-dependent manner (0.01-1 mM). The 45Ca2+ efflux from the cells was also stimulated by adenosine-5'-O-(3-thiotriphosphate)(ATP-gammas) and alpha,beta-methylene-ATP and adenosine 5'-diphosphate, but not by adenosine 5'-monophosphate and adenosine. The ATP-stimulated 45Ca2+ efflux was not affected by deprivation of the extracellular Ca2+, but was dependent on the presence of extracellular Na+. These results indicate that ATP stimulates extracellular Na+-dependent 45Ca2+ efflux from freshly isolated adult rat cardiomyocytes, probably through its stimulatory effect on the plasma membrane P2 purinoceptors which may couple to Na+/Ca2+ exchange.
Hori
T
T
Department of Cardiovascular Surgery and Pharmacology, School of Medicine, University of Tokushima, Japan.
offhizumi
M
M
Kitagawa
T
T
Chikugo
F
F
Kawahito
T
T
Katoh
I
I
Houchi
H
H
Oka
M
M
D000241:Adenosine / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000187:drug effects*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000241:Adenosine; D002118:Calcium