Calcium elevation in cultured heart cells: its role in cell injury.
Inhibition of the Na+-K+ pump in cultured embryonic chick heart cells promotes the elevation of intracellular Ca2+ and is a useful manipulation to study the relationship between Ca2+ and myocardial cell injury. One hour of Na+-K+ pump inhibition resulted in a fourfold increase in cell Na+, a 50% decline in cell K+, and a 5- to 10-fold increase in cell Ca2+, 45% of which is mitochondrial. The degree of cell injury induced by Ca2+ loading was evaluated by monitoring the content of adenosine 5'-triphosphate (ATP) and the release of the intracellular enzyme lactate dehydrogenase (LDH). Under these conditions ATP content declined by 25-30% and LDH release increased from 1 to 1.4% of the total LDH. Furthermore, cells subjected to 1 h of Na+-K+ pump inhibition and returned to control solution for 5 h showed that Ca2+ decreased to near control levels and ATP content was restored. Although inhibition of Na+-K+ transport caused a large increase in cell Ca2+, neither Na+-K+ pump inhibition nor elevation in total cell Ca2+ per se resulted in irreversible myocardial cell injury.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000378:metabolism / Q000633:toxicity*; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002478:Cells, Cultured; D002642:Chick Embryo; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008929:Mitochondria, Heart / Q000378:metabolism; D009206:Myocardium / Q000473:pathology; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism
D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D000255:Adenosine Triphosphate; D012964:Sodium; D007770:L-Lactate Dehydrogenase; D011188:Potassium; D002118:Calcium