Microglial influence on NMDA-induced neuronal death. Neuronal-enriched cultures were incubated with or without microglial transwell cultures for 48 hours and were exposed to varying concentrations of NMDA. Neuronal death was assessed as depicted in Figure 1 after 20 hours of continuous NMDA exposure. The results are the average of two independent experiments. Error bars for each concentration of NMDA represent the SEM.