Effect of varying levels of glucose on oxygen deprivation-induced delayed neuronal cell death in primary cerebrocortical cultures

New in vitro model of traumatic neuronal injury: evaluation of secondary injury and glutamate receptor-mediated neurotoxicity

The multiplicity and complexity of secondary injury processes following brain trauma in vivo make it difficult to elucidate the roles of specific injury mechanisms. As with other areas of CNS injury, such as ischemia, this has led to the development of in vitro models. Here we describe a new trauma model, in which standardized trauma is delivered to neuronal/glial cultures using a special mechanical device that produces concentric circular cuts in the cell layer. Changes in the number of circles (from 1 to 6) allows variation of injury severity. Comparison studies of cell death induced by such trauma in glial and neuronal/glial cultures demonstrated that glial cells are relatively resistant to this injury, and that the cell death after trauma to neuronal/glial cultures reflects primarily neuronal death. Consistent with other in vivo and in vitro studies, glutamate receptor antagonists MK 801 and MCPG were neuroprotective. Thus, this model appears useful for studying glutamatergic mechanisms involved in secondary injury, and may prove useful for evaluating certain pharmacological strategies for CNS trauma.

Pre- and post-synaptic modulators of excitatory neurotransmission: comparative effects on hypoxia/hypoglycemia in cortical cultures

Neuron-enriched cultures from embryonic rat cerebral cortex were exposed to hypoxia and hypoglycemia, and the resulting cellular injury was quantified by measuring lactate dehydrogenase (LDH) release, which was maximal after 20-24 h. The increase in LDH release produced by hypoxia/hypoglycemia was prevented by N-methyl-D-aspartate (NMDA) antagonists, but not by three classes of drugs thought to modulate glutamate release: Ca2+ channel antagonists (nimodipine, omega-conotoxin GVIA, omega-agatoxin-IVA), KATP channel activators (cromakalim, diazoxide), and glutamate transport inhibitors (dihydrokainate, DL-threo-beta-hydroxyaspartate).