Figure 5.

NMDA-induced superoxide production requires both Ca²⁺ influx and ligand binding. Images show superoxide production as measured by ethidium fluorescence (red). (a) NMDA-induced superoxide production is prevented by the NMDAR glycine site antagonists 7CK, which blocks NMDAR channel opening but not NMDA binding. The addition of 500 nM Bay K8644 in medium containing 50 mM KCl and 5 mM CaCl₂ restores superoxide production in cultures treated with NMDA + 7CK. Scale bar = 10 µm (b) Quantification of results shown in a, with results from each of n = 4 experiments expressed relative to the NMDA treated condition. *p < 0.01 vs control. (c) Superoxide production induced by the NMDA + 7CK + KCl + Bay K8644 + 5 mM CaCl₂ treatment condition is blocked by the NOX2 inhibitory peptide gp91 ds-Tat (3 µM), but not the control peptide scr-Tat. Data are means + s.e.m; n = 3, *p < 0.01.