Neuroprotection by EP1 receptor antagonists and a COX-2 inhibitor in neuronal-enriched cultures. The effect of varying concentrations of Ono 8711 on neuronal survival to NMDA treatment was assessed using the assay outlined in Figure 1 (see methods). Cultures were either pretreated with the drug vehicle DMSO (veh), or the concentration of the drug indicated below each bar. The cultures were then treated with a concentration of NMDA that leaves only about 20% survival in the non-drug treated cultures (average [NMDA] = 15 μM). The percent survival for the treatments indicated was determined and plotted as percent surviving neurons. The shaded region of the bar graph shows the survival obtained with NMDA alone and the unshaded portion of the bar indicates the additional neuronal survival resulting from co-treatment with the drug indicated. In each experiment, the neuronal cell numbers were counted from four fields (similar to that shown in Figure 1) from each treatment and averaged. The results shown were then average from at least four independent experiments. (* indicates P < 0.05 and ** indicates P < 0.01 in comparison to vehicle treatment, # indicates a < 0.05 in comparison to the concentrations (3,10 and 30 nM) of Ono 8711, by ANOVA, Tukey-Kramer multiple comparison test). The 100 nM Ono 8711 was not significantly different from the vehicle control. Error bars are standard error of the mean (SEM).