Short-term block of Na+/K+-ATPase in neuro-glial cell cultures of cerebellum induces glutamate dependent damage of granule cells

Granule cells in a dissociated neuro-glial cell culture of cerebellum when exposed to ouabain (10(-3) M) for 25 min apparently swell, increase their [ Ca2+](i) with obvious depolarization of the mitochondrial membrane. In 3 h after ouabain was omitted from the solution, 62 +/- 3% of granule cells had pycnotic nuclei. The supplement of a solution with competitive specific an tagonist of NMDA receptors, L-2-amino-7-phosphonoheptanoate (10(-4) M, APH) together with ouabain prevented cells from swelling, mitochondrial deenerg ization, neuronal death and increase of [Ca2+](i). These data suggest that cellular Na+/K+-ATPase inactivation in neuro-glial cell cultures of cerebel lum leads to glutamate (Glu) accumulation, hyperstimulation of glutamate re ceptors, higher Ca2+ and Na+ influxes into the cells through the channels a ctivated by Glu, This process leads to cell swelling, mitochondrial deenerg ization and death of granule cells. Possibly, the decrease of Na+/K+-ATPase activity in brain cells can lead to the onset of at least some chronic neu rological disorders. (C) 1999 Federation of European Biochemical Societies.