[Effect of reduced extracellular level of sodium ions on the intracellular level of calcium ions in the cytoplasm of cultured rat cardiomyocytes].
Cytosolic free calcium [( Ca2+]in) was measured using fura-2 in isolated cultured ventricular myocytes of neonatal rat. Exposure of the cardiomyocyte to a solution in which all Na+ have been replaced by impermeable cations results in a 400-600 nmol/l increase of [Ca2+]in. This increase is followed by a slow decrease to the initial level. A decrease of the extracellular calcium concentration from 2.5 to 0.5 mmol./l or increase to 10 mmol/l produced, respectively, decrease and increase of the amplitude of [Ca2+]in rise in response to low-Na+ superfusion. Exposure of cardiomyocytes to low-Na+ solutions also led to a 2-3 fold increase of caffeine++-dependent Ca2+ release from intracellular stores. Changes in [Ca2+]in can be attributed to the operation of a sodium-calcium exchanger in heart cells.
Verkhratskiĭ
A N
AN
Pronchuk
N F
NF
Tepikin
A V
AV
D000818:Animals; D001826:Body Fluids / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003470:Culture Media; D003593:Cytoplasm / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism*; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000378:metabolism*; D009206:Myocardium / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D012964:Sodium / Q000008:administration & dosage / Q000378:metabolism*
D003470:Culture Media; D012964:Sodium; D002118:Calcium
Vliianie snizheniia vnekletochnoĭ kontsentratsii ionov natriia na vnutrikletochnuiu kontsentratsiiu ionov ka'ltsiia v tsitoplazme ku'ltiviruemykh kardiomiotsitov krys.