Fig. 2.

Effects of NBQX on coagonist availability during NMDA application: inward currents evoked by picospritzing 10 mM NMDA (40- to 80-ms duration) near the ganglion cell soma. Cells were held at −65 mV, and recordings were made in 0 Mg²⁺, 1 μM TTX, 10 μM strychnine, 50 μM TPMPA, and 50 μM picrotoxinin. Puffs initiated 300 ms into traces. A: raw trace showing that puff-evoked inward currents are blocked by bath-applied AP7. B: bath-applied NBQX did not alter puff-evoked NMDA receptor (NMDAR) currents. C: there was no significant decrease in the average puff-evoked peak inward current by NBQX. D: no significant difference in the average puff-evoked peak inward current was detected between wild-type (wt) and serine racemase knockout (SRKO) RGCs. E: raw traces showing the potentiation of NMDAR currents by d-serine in wt and SRKO RGCs, with or without NBQX in the bathing medium. F: summary of data in E. In wt RGCs, bath-applied d-serine significantly potentiated NMDA currents in ctrl conditions, but in the presence of NBQX this potentiation was larger. In SRKO RGCs, d-serine potentiated NMDA currents greater than in wt RGCs. Unlike wt, there was no further potentiation by d-serine in the presence of NBQX. Number of cells recorded from (n) indicated in parentheses. *P < 0.05 between conditions within genotype; †P < 0.05 between genotypes under same conditions.