title: Adrenomedullin stimulates calcium efflux from adrenal chromaffin cells in culture: possible involvement of an Na+/Ca2+ exchange mechanism.
abstract: 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.
authors.affiliation: Department of Pharmacology, School of Medicine, The University of Tokushima, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Houchi
authors.forename: M
authors.initials: M
authors.lastname: Yoshizumi
authors.forename: M
authors.initials: M
authors.lastname: Shono
authors.forename: Y
authors.initials: Y
authors.lastname: Ishimura
authors.forename: T
authors.initials: T
authors.lastname: Ohuchi
authors.forename: M
authors.initials: M
authors.lastname: Oka
mesh_terms: 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
chemical_list: D000959:Antihypertensive Agents; D002352:Carrier Proteins; D003470:Culture Media; D010455:Peptides; D019831:Sodium-Calcium Exchanger; D053607:Adrenomedullin; D002118:Calcium