title: [Ouabain switches Na+ transport to Na+/Na+ equivalent exchange in normal and apoptotic lymphoid cells].
abstract: A theory of change of the ionic fluxes in the lymphoid cells in their transition from normal to apoptosis, we have developed previously, is applied to the analysis of Na+/Na+ exchange fluxes in human lymphoid cells U937 exposed to ouabain. We solve a system of equations describing changes in the intracellular concentrations of Na+, K+ and Cl-, membrane potential and cell volume. It is shown that the Na+ input (I(Na/Na)) flux and output flux through the Na+/Na+ tract increased 4 times in 8 hours after disconnecting Na+/K+ -ATPase for normal cell U937. These fluxes increased 2.6 times for apoptotic cells. The value of I(Na/Na) after 8 hours off pump by ouabain is 97% of the total Na+ input for both cell types. It is concluded that ouabain not only inhibits the Na+/K+ -ATPase, but also increases Na+ exchange fluxes through the Na+/Na+ tract, thereby switching sodium transport across the membrane of lymphoid cells to Na+/Na+ equivalent exchange.
authors.forename: A A
authors.initials: AA
authors.lastname: Rubashkin
mesh_terms: D017209:Apoptosis; D002712:Chlorides / Q000378:metabolism; D006801:Humans; D017136:Ion Transport; D008214:Lymphocytes / Q000378:metabolism*; D008564:Membrane Potentials; D010042:Ouabain / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D002712:Chlorides; D010042:Ouabain; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium