Fig. 9.

BAPTA-AM pretreatment is ineffective when neurons are directly challenged with NMDA. A, Slice cultures were pretreated with 100 μm of either BAPTA-AM, EGTA-AM, or APTRA-AM, and were then challenged with either 10, 40, or 100 μm NMDA for 60 min (9–11 slices per group). The chelators had no impact on the time course and extent of neurotoxicity produced by the mild and severe NMDA insults (10 and 100 μm NMDA, respectively). The intermediate insult (40 μm NMDA) caused increased neurodegeneration in the presence of BAPTA-AM (asterisks, p< 0.05). B, C, Representative experiments with 40 μm NMDA, in which BAPTA-AM, but not EGTA-AM or APTRA-AM, potentiated NMDA toxicity (n = 8–10 slices in NMDA groups, 4–6 slices in control groups). Dotted boxes, Groups included in ANOVA, followed by Newman–Keuls procedure for multiple comparisons (p indicates comparisons to BAPTA + NMDA-treated group).