THE EFFECT OF FUROSEMIDE ON CALCIUM ION CONCENTRATION IN MYOCARDIAL-CELLS

The effect of furosemide and ouabain on the intracellular concentratio n of Ca2+ was studied in myocardial cell cultures using Fura-2, a fluo rescent agent, as an intracellular Ca2+ indicator. Introduction of 200 mu M ouabain to the cultured cells increased the intracellular calciu m concentration from an average of 236 nM up to an average of 833 nM, Introduction of 100 mu M furosemide, prior to the administration of ou abain, decreased the ouabain induced Ca2+ elevation to an average of o nly 473 nM, Introduction of 2.5 mM EGTB prior to the administration of ouabain abolished the ouabain induced Ca2+ increase,