Inhibition of Na +,K +-ATPase activity in cultured rat cerebellar granule cells prevents the onset of apoptosis induced by low potassium

• Published in: Neuroscience letters 2000-03, Vol.283 (1), p.41-44
• Main Authors: Isaev, N.K., Stelmashook, E.V., Halle, A., Harms, C., Lautenschlager, M., Weih, M., Dirnagl, U., Victorov, I.V., Zorov, D.B.
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphatases - metabolism; Animals; Animals, Newborn; Apoptosis - drug effects; Apoptosis - physiology; Cell culture; Cell death; Cells, Cultured; Cerebellar Cortex - drug effects; Cerebellar Cortex - metabolism; Cerebellar Cortex - pathology; Development; Enzyme Inhibitors - pharmacology; Excitatory Amino Acid Antagonists - pharmacology; Hypoxia; K +-ATPase; Na; Nerve Degeneration - pathology; Nerve Degeneration - physiopathology; Neurons - drug effects; Neurons - metabolism; Neurons - pathology; Neuroprotective Agents - pharmacology; Ouabain; Ouabain - pharmacology; Oxidative Stress - drug effects; Potassium Chloride - metabolism; Potassium Chloride - pharmacology; Potassium Deficiency - physiopathology; Rats; Sodium - antagonists & inhibitors; Sodium - metabolism; Tolerance
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(00)00903-4

In cerebellar granule cells in culture, lowering of extracellular [K +] results in apoptotic death (D'Mello, S.R., Galli, C., Ciotti, T. and Calissano, P., Induction of apoptosis in cerebellar granule neurons by low potassium: inhibition of death by insulin-like growth factor I and cAMP, Proc. Natl. Acad. Sci. USA, 90 (1993) 10989-10993). In this model, we studied the influence of Na +,K +-ATPase inhibition on apoptosis. We demonstrate that cell death (93±2 vs. 46±1.6%) as well as fragmentation of nuclear DNA induced by low extracellular potassium were prevented by addition of ouabain (0.1 mM), a specific inhibitor of the Na +,K +-ATPase. Blockade of glutamatergic N-methyl- d-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors by 5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohepten-5,10-imine hydrogen maleate (MK-801; 20 μM) and 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX; 50 μM) did not inhibit the protective effect of ouabain. 24 h treatment with ouabain also decreased cell death induced by Fe 2+/ascorbic acid (74±2% to 49±3%). We speculate that ouabain pretreatment enhances the resistance against low [K +]-induced apoptosis independent of glutamate-receptor activation. Since this effect can be mimicked by a free-radical generating system, we suggest an antioxidative effect underlying ouabain-induced neuroprotection.