Activation of human GluN2C and GluN2D receptors. (A–D) Currents from patches containing a presumed single human GluN1/GluN2C (A and B) or a GluN1/GluN2D (C and D) receptor in response to 1-s glutamate applications. See Table 2 for additional details. (E and F) Dwell time histogram of the latency to first opening for GluN1/GluN2C (E) or GluN1/GluN2D (F) receptors. Both histograms were best fit by two exponentials (dashed lines).