Figure 3.

Effects of binary mixtures of N-methyl-D-aspartate (NMDA) receptor inhibitors, each administered at ½ of their respective IC₅₀, on NMDA whole cell currents (n≥6 oocytes tested for each combination). Error bars denote standard errors. Pairs of inhibitors exhibiting additive effects produced a 50% decrease in NMDA receptor current. Ketamine with either CO₂ or H⁺ caused NMDA receptor inhibition that was significantly more than 50%, consistent with a synergistic effect.