Agonist-induced current responses of coexpressed mutant NMDAR subunits. Mean current responses elicited by application of glycine alone (Gly, 10 μM) or together with 100μM glutamate (Glu) for NR1/NR2 and NR1/NR3 diheteromers assembled from wild type or mutant subunits. White bars represent mean amplitudes after the application of glycine, black bars denote mean responses after the coapplication of glutamate/glycine; all current amplitudes are shown in nA. The right diagram depicts the ratio of glycine- to glutamate/glycine-induced current responses for each combination. Data shown here are mean values ± SEM, n = 11-48 for NR1/NR2 combinations, n = 5-45 for NR1/NR3 diheteromers; *p < 0.05; **p < 0.01; ***p < 0.005 (Student's t-test).