Adrenomedullin stimulates calcium efflux from adrenal chromaffin cells in culture: possible involvement of an Na+/Ca2+ exchange mechanism.
The effect of adrenomedullin, a hypotensive peptide, on Ca2+ efflux from cultured bovine adrenal chromaffin cells was examined. Adrenomedullin stimulated the efflux of 45Ca2+ from the cells in a concentration-dependent manner (10(-7)M - 3x10(-6)M). Adrenomedullin did not increase the intracellular free Ca2+ ([Ca2+]i) level and catecholamine secretion. The adrenomedullin-stimulated 45Ca2+ efflux was not inhibited by incubation with Ca2+-free medium, but was inhibited by incubation with Na+-free medium. These results indicate that adrenomedullin 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, The University of Tokushima, Japan.
Yoshizumi
M
M
Shono
M
M
Ishimura
Y
Y
Ohuchi
T
T
Oka
M
M
D000313:Adrenal Medulla / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D053607:Adrenomedullin; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D002838:Chromaffin System / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D003470:Culture Media; D010455:Peptides / Q000494:pharmacology*; D019831:Sodium-Calcium Exchanger; D013268:Stimulation, Chemical
D000959:Antihypertensive Agents; D002352:Carrier Proteins; D003470:Culture Media; D010455:Peptides; D019831:Sodium-Calcium Exchanger; D053607:Adrenomedullin; D002118:Calcium