The neurotoxicity of the glutamate receptor agonists N-methyl-d-aspartate (NMDA), (±)-α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), and kainate was quantitatively assessed in murine spinal cord and cortical cultures prepared under identical conditions. Compared with cortical neurons, spinal neurons were less vulnerable to NMDA (EC₅₀ for 24 h exposure about 30μM versus 10 μM in cortical cultures) and more vulnerable to AMPA (EC₅₀ 5 μM versus 12 μM) and kainate (EC₅₀ 20 μM versus 50 μM). Neurons subject to kainate-activated cobalt uptake, a marker of calcium-permeable AMPA/kainate channels, were resistant to NMDA in both systems; these cells were significantly more prevalent in spinal cord cultures. Both the AMPA/kainate antagonist GYKI-52466 and the NMDA antagonist MK-801 attenuated spinal cord neuronal loss due to glucose deprivation; however, GYKI-52466 was more effective. These results support the hypothesis that AMPA/kainate receptor activation may play a significant role in excitototic injury to spinal cord neurons.