Magnesium removal induces paroxysmal neuronal firing and NMDA receptor-mediated neuronal degeneration in cortical cultures.
Removal of extracellular Mg2+ triggered the onset of repetitive excitatory discharges in cultured murine cortical neurons, detected by recording with patch electrodes in the whole cell configuration. The discharges were suppressed by 100 microM D-2-amino-5-phosphonovalerate. Over the next 24-72 h substantial numbers of neurons, but not glia, degenerated, releasing lactate dehydrogenase to the bathing medium. The neuronal death induced by removal of extracellular Mg2+ could be attenuated by either 3 microM tetrodotoxin or 50 microM dextrorphan, and thus likely reflects excessive activation of N-methyl-D-aspartate receptors triggered by excitatory discharges. This Mg2+ removal model may be a useful model in which to study certain aspects of epileptic neocortical injury.
Rose
K
K
Department of Neurology, Stanford University Medical Center, CA 94305.
Christine
C W
CW
Choi
D W
DW
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000200:Action Potentials; D000818:Animals; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism / Q000502:physiology*; D008274:Magnesium / Q000502:physiology*; D051379:Mice; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology*
D016194:Receptors, N-Methyl-D-Aspartate; D015763:2-Amino-5-phosphonovalerate; D008274:Magnesium