title: Effects of endothelin-11-31 on cell viability and [Ca2+]i in cultured neonatal rat cardiomyocytes
abstract: We previously found that endothelin-1(1-31) (ET-1(1-31)) exhibited a pro-arrhythmogenic effect in isolated rat hearts. In this study, we further investigated the effects of ET-1(1-31) on a cell viability and observed [Ca(2+)](i) in cultured cardiomyocytes. Cultured neonatal rat cardiomyocytes were treated with 0.1, 1, and 10 nM ET-1(1-31) for 24h in the presence or absence of ET(A) receptor antagonist (BQ(123)) or phosphoramidon, a NEP/ECE inhibitor. Cell injury was evaluated by supernatant lactate dehydrogenase (LDH) assay, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content. Cell viability was assessed by MTT assay. [Ca(2+)](i) was measured with Fluo-3/AM under a laser confocal microscope. 1) ET-1(1-31) dose-dependently increased LDH release and decreased cell viability. 2) LDH and MDA levels were significantly elevated and SOD activity decreased after administration of 1 nM ET-1(1-31) for 24h, and these changes were markedly attenuated by 1 uM BQ(123). 3) Exposure to 10 nM ET 1(1-31) caused a continuous increase in [Ca(2+)](i) to cultured beating cardiomyocytes and termination of [Ca(2+)](i) transient within 6 min, and this change was reversed by 1 uM BQ(123) and attenuated by 0.5 mM phosphoramidon. These results suggest that ET-1(1-31) could cause cell injury, and that the effect of ET-1(1-31) on [Ca(2+)](i) transients is mainly mediated by ET(A) receptor and partially attributed to the conversion of ET-1(1-31) to ET-1(1-21).
authors.affiliation: Department of Physiology, College of Basic Medical Sciences, Second Military Medical University, Shanghai, China.
authors.forename: A-J
authors.initials: AJ
authors.lastname: Ren
authors.forename: X
authors.initials: X
authors.lastname: Yuan
authors.forename: L
authors.initials: L
authors.lastname: Lin
authors.forename: Y-X
authors.initials: YX
authors.lastname: Pan
authors.forename: Y-W
authors.initials: YW
authors.lastname: Qing
authors.forename: W-J
authors.initials: WJ
authors.lastname: Yuan
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D065130:Endothelin A Receptor Antagonists; D019332:Endothelin-1 / Q000031:analogs & derivatives* / Q000494:pharmacology; D000072396:Endothelin-Converting Enzymes; D006020:Glycopeptides / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D018613:Microscopy, Confocal; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*; D010456:Peptides, Cyclic / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044022:Receptor, Endothelin A / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors
chemical_list: D065130:Endothelin A Receptor Antagonists; D019332:Endothelin-1; D006020:Glycopeptides; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D011480:Protease Inhibitors; D044022:Receptor, Endothelin A; C114932:endothelin-1 (1-31); D008315:Malondialdehyde; D007770:L-Lactate Dehydrogenase; D013482:Superoxide Dismutase; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; D000072396:Endothelin-Converting Enzymes; C072247:cyclo(Trp-Asp-Pro-Val-Leu); C008890:phosphoramidon