Figure 5. Ifenprodil but not PEAQX inhibited the increases in [Ca²⁺]_c mediated by reversal of Na⁺/Ca²⁺ exchanger triggered by gramicidin or by Na⁺/NMDG replacement.

The experiments illustrated in this Figure were performed with “older” (13-16 DIV) neurons. Neurons were loaded with 2.6μM Fura-2FF-AM. In A-C, where indicated, neurons were treated with 5μM gramicidin (Gram), 1μM ifenprodil, or 5μM PEAQX. In E-G, where indicated, NaCl in the bath solution was substituted for equimolar NMDG and neurons were treated with 1μM ifenprodil, or 5μM PEAQX. In all experiments, the bath solution was supplemented with 1μM tetrodotoxin, 5μM nifedipine, and 1 mM ouabain. The time scale shown in panel C is applicable to traces in A and B. The time scale shown in panel G is applicable to traces in E and F. In D, statistical analysis of gramicidin-induced [Ca²⁺]_c changes over time. Data are mean±SEM, *p<0.01 compared to vehicle, n=3. In H, statistical analysis of Na⁺/NMDG-induced [Ca²⁺]_c changes over time. Data are mean±SEM, *p<0.05, **p<0.01 compared to vehicle (0.2% DMSO), n=3.