Figure 3.

Protonophore addition induces a rapid collapse of Ca²⁺ homeostasis that is blocked with MK-801. A, B, Neurons were loaded with TMRM (30 nm) and Fluo-4 (3 μm) for 30 min at 37°C and exposed to FCCP (2 μm) in the presence of oligomycin (2 μg/ml) with (A) or without (B) MK-801 (10 μm). A rapid increase in cytosolic Ca²⁺ accompanied the FCCP addition in neurons that did not have MK-801 present (experiments were repeated 3 times for each condition, with similar results). C, Neurons were treated with a combination of FCCP (2 μm), oligomycin (2 μg/ml), and MK-801 (10 μm) for 30 min, and ATP levels were measured moles ATP/μg protein. All data were normalized to control values for comparison between experiments (experiments were performed in triplicate in 3 separate cultures;**p < 0.001; *p < 0.01 difference from control). Error bars indicate SEM. Oligo, Oligomycin; Arb units, arbitrary units.