Figure 3.

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 7CK (100 µM), L-689, 560 (1 µM), or MK801 (10 µM), which block NMDAR channel flux but not NMDA binding; and by 30 µM AP5, which blocks NMDA binding. The addition of ionomycin (3 µM) restores superoxide production in cultures treated with NMDA plus the channel inhibitors, but not in cultures treated with NMDA + AP5. (b,c) Quantification of results shown in (a) with results from each of n = 3 experiments expressed relative to the NMDA condition. Data are means + s.e.m.; *p < 0.05 vs control.