title: High density lipoproteins increase cytoplasmic free calcium in bovine aortic endothelial cells.
abstract: This study examined the influence of human high density lipoproteins (HDL) on the intracellular free calcium of cultured bovine aortic endothelial cells (BAECs). Intracellular Ca2+ concentration ([Ca2+]i) was determined by a fluorescent calcium indicator, Fura-2. It was found that, in the presence of 1 mmol/L extracellular calcium, HDL resulted in a biphasic elevation of [Ca2+]i in BAECs, consisting of an initial, transient component followed by a lower, but more sustained component. Doses of HDL from 25 to 200 micrograms protein/ml induced marked concentration-dependent elevations of [Ca2+]i in BAECs. The sustained component was abolished by deprivation of extracellular calcium or by pretreatment of endothelial cells with a calcium influx blocker, NiCl2, HDL-induced elevation of [Ca2+]i was attenuated in a concentration-dependent way by an inhibitor of calcium release, tetracaine. Repeated applications of HDL (100 micrograms protein/ml) markedly blunted the initial peak component of the calcium transient of BAECs. These results demonstrate that both intracellular and extracellular calcium pools are responsible for the biphasic elevation of [Ca2+]i induced by HDL in cultured BAECs.
authors.affiliation: Research Section of Pharmacology, Hunan Medical University, Changsha, People's Republic of China.
authors.forename: Z
authors.initials: Z
authors.lastname: Su
authors.forename: Z H
authors.initials: ZH
authors.lastname: Luo
authors.forename: X L
authors.initials: XL
authors.lastname: Niu
authors.forename: Z G
authors.initials: ZG
authors.lastname: Guo
mesh_terms: D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D008075:Lipoproteins, HDL / Q000494:pharmacology*; D009532:Nickel / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013748:Tetracaine / Q000494:pharmacology
chemical_list: D000779:Anesthetics, Local; D008075:Lipoproteins, HDL; D013748:Tetracaine; C022838:nickel chloride; D009532:Nickel; D002118:Calcium