Fig. 3: Glutamate induces cell death in rat hippocampal neurons through the activation of NMDARs in a P2Y1R-dependent manner.

a The exposure of rat cultured hippocampal neurons to glutamate (100 µM) for 30 min induced a decrease in cell viability 24 h later, which was prevented by the NMDAR antagonist MK801 and mimicked by the exposure to NMDA (100 µM) for 30 min. Data are mean ± SEM of the percentage of MTT reduction vs. respective control, quantified from 4 to 7 different cultures, analyzing triplicates per condition per culture. **p < 0.01 one-sample t test (hypothetical value of 100); ^#p < 0.05 unpaired t test for glutamate + MK801 vs. glutamate alone. b NMDA-induced neuronal death was prevented either by PPADS (10 µM) or MRS2179 (10 µM). The data are mean ± SEM of the percentage of dead cells (propidium iodide incorporation) quantified from four cultures analyzing 300 cells per condition per culture. ***p < 0.001 one-way ANOVA with Sidak’s test for NMDA vs. untreated. c The intrahippocampal administration of 120 nmol of quinolinic acid (QA) in rats caused hippocampal neuronal death 24 h later, measured as Fluoro-Jade C-positive cells (FJC⁺), as depicted in the representative images (scale bars, 200 µm) and quantified in the histogram. The co-administration of 1 nmol of MRS2500 significantly attenuated the number of FJC⁺ cells in DG and CA3 regions. The mean ± SEM number of FJC⁺ per slice was quantified from 4 animals per group and analyzing 12 coronal sections separated successively by 240 µm and representing the entire hippocampus from each animal. *p < 0.05 one-way ANOVA with Sidak’s test