Regulation of active cation flux by vanadate in beating rat heart muscle cells in culture.
Looking for a supposed digitalis-like action of compounds of the trace element vanadium, we have investigated the influence of vanadate (Na3VO4) on beating and on active cation flux of [42K+] and [89Rb+] in cultured rat heart muscle cells: Na3VO4(10(-6)-10(-3)M) exerts a positive chronotropic effect and increases contraction velocity and beating automaticity of the cells. Vanadate-induced alteration of beating is paralleled by stimulated uptake of [42K+] and [86Rb+] up to 75%. This stimulation has to be attributed to increased activity of (Na++)-ATPase and cannot solely be explained by the enhanced beating frequency. In contrast to ouabain, vanadate raises intracellular potassium content up to 15% and prevents cell contractures of ouabain-intoxicated heart muscle cells. The experimental data speak against a possible digitalis-like action of vanadate in cultured rat heart muscle cells.
D000818:Animals; D001692:Biological Transport; D002478:Cells, Cultured; D006321:Heart / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D012413:Rubidium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D014638:Vanadates; D014639:Vanadium / Q000494:pharmacology*
D014639:Vanadium; D014638:Vanadates; D010042:Ouabain; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D011188:Potassium