A linked active transport system for Na+ and K+ in a glial cell line.
Ouabain (5 X 10(-4) M) induced a 6-fold increase in intracellular Na+ and a 65% loss of cellular K+ in C6 glial cells which was accompanied by a 12 mV decrease in the resting membrane potential. Following ouabain washout intracellular ion  concentrations and the membrane potential returned to control levels suggesting that C6 is capable of active Na+ transport which is linked to uptake of K+. A portion of K+ uptake under steady-state conditions is also active since K+ influx was reduced 32% by ouabain. Five mM cyanide significantly increased cell Na+ and significantly decreased cell K+ and the membrane potential. The similarity in the ratio of Na+ gained/K+ lost (ouabain 1.24, cyanide 1.41) suggests that the two agents inhibit the same ion transport system. Decreased temperature had the paradoxical effect of increasing intracellular K+ while significantly decreasing both membrane potential and K+ influx. Part of this effect may be due to the marked reduction in K+ efflux at low temperature. At 6 degrees C cell loss of K+ was much less than loss of K+ with ouabain at 37 degrees C. The observation of a linked Na+-K+ transport system in C6 cell confirms the hypothesis that coupled active Na+-K+ exchange occurs in glial cells and suggests that ionic transport may regulate certain aspects of glial metabolism.
D000818:Animals; D001693:Biological Transport, Active; D002478:Cells, Cultured; D003486:Cyanides / Q000494:pharmacology; D003864:Depression, Chemical; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013696:Temperature
D003486:Cyanides; D009419:Nerve Tissue Proteins; D010042:Ouabain; D012964:Sodium; D011188:Potassium