Fig. 2.

Relationship between the glutamate binding site and AICP activity. (A) Representative two-electrode voltage-clamp recordings of responses at rat GluN1/2A and GluN1/2C receptors to 100 µM glycine alone, 10 AICP alone, 100 µM glycine plus 10 µM AICP, or 100 µM glutamate plus 100 µM glycine. The mean responses normalized to control (glutamate plus glycine) ± S.E.M. from 6 to 8 oocytes are listed below the respective ligand applications. (B) Concentration–response data for AICP at rat NMDA receptor subtypes in in the presence of either 30, 100, or 300 µM glutamate. Data are mean ± S.D. from 3 to 16 oocytes and are normalized to the maximal response to glycine (100 µM) plus the corresponding concentration of glutamate (30, 100, or 300 µM) measured in the same recording. The EC₅₀ values and relative agonist efficacies (i.e., maximal responses relative to glycine) are listed in Supplemental Table 1.