Spinal cord injuries are a major source of persistent disability with limited chance of full recovery. It would, therefore, be important to understand the initial mechanisms underlying spinal cord injury to protect patients from damage intensification. In fact, acute spinal cord injury evolves rapidly to produce secondary damage even to initially spared areas with consequential loss of locomotion. Regardless of their aetiology (trauma, vascular or cancer origin, etc), spinal lesions are thought to include the combined effects of excitotoxicity and stroke-like metabolic perturbations. To clarify the relative contribution by excitotoxicity and toxic metabolites to dysfunction of locomotor networks, we used, as a model, the in vitro thoraco-lumbar spinal cord of the neonatal rat treated (1 h) with either kainate (a powerful glutamate receptor agonist) or a pathological medium (containing free radicals and hypoxic/aglycemic conditions), or their combination. After washout, electrophysiological responses were monitored for 24 h and cell damage analyzed histologically. While kainate suppressed fictive locomotion irreversibly, intrinsic network bursting induced by synaptic inhibition block persisted. This result was associated with significant neuronal loss around the central canal and the ventral grey matter. Comparatively less damage was found in the white matter. Combining kainate with the pathological medium evoked extensive, irreversible damage to the spinal cord and no electrophysiological response. The pathological medium alone slowed down fictive locomotion and intrinsic bursting: these oscillatory patterns, however, remained throughout without regaining their control properties. This phenomenon was associated with depression of synaptic transmission and preferential damage to glial cells, while neurons were comparatively spared. Our model suggests distinct roles of excitotoxicity and metabolic dysfunction in the damage of locomotor networks, indicating that different strategies might be necessary to treat the early pathological processes involved in the acute spinal cord lesion.