Regulatory mechanism of calcium efflux from cultured bovine adrenal chromaffin cells induced by extracellular ATP.
The effect of adenosine-5'-triphosphate (ATP) on Ca2+ efflux from cultured bovine adrenal chromaffin cells 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-gamma s), alpha beta-methylene-ATP and adenosine-5'-diphosphate (ADP), but was not by adenosine-5'-monophosphate (AMP) and adenosine. The ATP-stimulated 45Ca2+ efflux was not affected by deprivation of the extracellular Ca2+ and Mg2+, but was dependent on the extracellular Na+ concentrations. ATP increased the influx of 22Na+ into the cells. These results indicate that ATP stimulates extracellular Na(+)-dependent 45Ca2+ efflux from cultured bovine adrenal chromaffin cells, probably through its stimulatory effect on membrane Na+/Ca2+ exchange.
Houchi
H
H
Department of Pharmacology, School of Medicine, University of Tokushima, Japan.
Okuno
M
M
Yoshizumi
M
M
Oka
M
M
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000311:Adrenal Glands / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured / Q000187:drug effects; D002838:Chromaffin System / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors
D000255:Adenosine Triphosphate; D002118:Calcium