Inhibition of Na(+),K(+)-ATPase activity in cultured rat cerebellar granule cells prevents the onset of apoptosis induced by low potassium.
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 microM) and 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX; 50 microM) 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.
Isaev
N K
NK
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia. isaev@genebee.msu.su
Stelmashook
E V
EV
Halle
A
A
Harms
C
C
Lautenschlager
M
M
Weih
M
M
Dirnagl
U
U
Victorov
I V
IV
Zorov
D B
DB
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D002478:Cells, Cultured; D002525:Cerebellar Cortex / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D009410:Nerve Degeneration / Q000473:pathology* / Q000503:physiopathology*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D011189:Potassium Chloride / Q000378:metabolism / Q000494:pharmacology*; D011191:Potassium Deficiency / Q000503:physiopathology*; D051381:Rats; D012964:Sodium / Q000037:antagonists & inhibitors* / Q000378:metabolism*
D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D018696:Neuroprotective Agents; D010042:Ouabain; D011189:Potassium Chloride; D012964:Sodium; D000251:Adenosine Triphosphatases