(A) Light microscope images of neuronal cultures after 20 min of exposure to 0

3, 0.6, and 1.0 mM NMDA followed by 24-h recovery. Cells were stained with trypan blue (dark blue) and TUNEL (brown); methyl green was used as the counterstain. (B) Mean cell counts for trypan blue– and TUNEL-stained cells in WT and PrP-null cultures. (C) Light microscope images showing TUNEL-stained neurons from PrP-null mice in the presence of NMDA and NMDA + APV. (D) Percentage of TUNEL-positive neurons from PrP-null mice in response to NMDA and NMDA + APV. The drug concentrations were 1 mM NMDA and 100 μM APV. Data are represented as mean ± SEM (error bars), with statistical significance denoted as *, P < 0.05 and **, P < 0.001. Data were obtained from four culture rounds, and six random fields were imaged per condition. Bar, 100 μm.<p><b>Copyright information:</b></p><p>Taken from "Prion protein attenuates excitotoxicity by inhibiting NMDA receptors"</p><p></p><p>The Journal of Cell Biology 2008;181(3):551-565.</p><p>Published online 5 May 2008</p><p>PMCID:PMC2364707.</p><p>