Energetic demands of the Na+/K+ ATPase in mammalian astrocytes
Article first published online: 6 DEC 1998
Copyright © 1997 Wiley-Liss, Inc.
Volume 21, Issue 1, pages 35–45, September 1997
How to Cite
Silver, I. A. and Erecińska, M. (1997), Energetic demands of the Na+/K+ ATPase in mammalian astrocytes. Glia, 21: 35–45. doi: 10.1002/(SICI)1098-1136(199709)21:1<35::AID-GLIA4>3.0.CO;2-0
- Issue published online: 6 DEC 1998
- Article first published online: 6 DEC 1998
- Manuscript Accepted: 27 JAN 1997
- NIH. Grant Number: NS 28329
- Na+/K+ pump;
- C6 cells
Cultured astrocytes and cell lines derived therefrom maintain a high energy level ([ATP]/[ADP]) through operation of oxidative phosphorylation and glycolysis. The contribution from the latter to total ATP production is 25–32%. A powerful Na+/K+ pump maintains potassium, sodium, and calcium gradients out of equilibrium. [Na+]i is about 20 mM, [K+]i is 130 mM and [Ca2+]i is less than 100 nM. Under non-stimulated conditions, the Na+/K+ ATPase consumes 20% of astrocytic ATP production. Inhibition of the pump by ouabain decreases energy expenditure, raises [creatine phosphate]/[creatine], and leads to a leakage of sodium, potassium, and calcium ions. Decrease in the pump function via a fall in [ATP] also collapses ion gradients; the rate and extent of the fall correlates positively with cellular energy state. Under “normal” conditions (i.e., when ATP production pathways are not inhibited), there appears to be no preferential utilization of energy produced by either glycolysis or oxidative phosphorylation for the support of pump function. GLIA 21:35–45, 1997. © 1997 Wiley-Liss, Inc.