The regulation of the intracellular sodium ion concentration in cultured chick embryo heart cells.
Using digital imaging microscopy with the fluorescent indicator sodium-binding benzofuran isophtalate, we examined the cytosolic Na+ concentration ([Na+]i) in individual chick embryo heart cells. Inhibition of the Na(+)-H+ exchanger using Na(+)-free (Li+ substituted) medium and inhibition of the Na(+)-efflux through the Na(+)-Ca2+ exchanger using Ca(2+)-free medium didn't change the [Na+]i. The opening of voltage-dependent Na+ channels with veratridine (150 micrograms/ml) and inhibition of the Na(+)-K(+)-Cl(-)-cotransporter with bumetanide (10 microM) led to an increase in [Na+]i by 107% and 86%, respectively, suggesting that the Na+ channels and the Na(+)-K(+)-Cl- cotransporter predominantly regulate the [Na+]i in cultured chick embryo heart cells.
Ahlemeyer
B
B
Institut für Biochemie und Endokrinologie, Justus-Liebig-Universität Giessen, Germany.
Weintraut
H
H
Schoner
W
W
D000818:Animals; D002034:Bumetanide / Q000494:pharmacology; D002478:Cells, Cultured; D002642:Chick Embryo; D005456:Fluorescent Dyes; D006321:Heart / Q000187:drug effects; D006706:Homeostasis; D007700:Kinetics; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D009206:Myocardium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D014701:Veratridine / Q000494:pharmacology
D005456:Fluorescent Dyes; D002034:Bumetanide; D014701:Veratridine; D012964:Sodium