Activity of coumarin derivatives on NMDA receptor responses. After obtaining a steady-state response to 10 μM L-glutamate plus 10 μM glycine, each compound was tested at 100 μM for the inhibition or potentiation of responses by GluN1/GluN2A (2A), GluN1/GluN2B (2B), GluN1/GluN2D (2D) and in some cases GluN1/GluN2C (2C) receptors. At a concentration of 1 μM UBP658 inhibited agonist stimulated responses on GluN1/GluN2A and GluN1/GluN2B by 26.3 ± 5.9 and 2.3 ± 3.5 %, respectively. Values represent mean % inhibition ± s.e.m., n ≥ 4.