Activation of human GluN2A and GluN2B receptors in response to brief synaptic-like (2-ms) glutamate applications. (A) Currents from a patch containing a single human GluN1/GluN2A receptor in response to a 2-ms glutamate application (see Table 3). External solution is our standard at pH 7.4 with an energy-based internal (see Materials and methods). The bottom trace is the summed response to multiple (50 total) glutamate applications. (B) Dwell time histogram of the latency to first opening. The histogram was best fit by two exponentials (dashed lines). (C) Overlay of dwell time histograms of the latency to first opening for 1-s or 2-ms (red) applications. (D and E) Mean (±SEM) efficiency (η) of activation (left) and average latency (right) for GluN2A- (D) or GluN2B- (E) containing receptors. ****P < 0.0001, Student’s t test: GluN2A efficiency, P < 0.0001, latency, P = 0.21; GluN2B efficiency, P = 0.73, latency, P = 0.19. Note for synaptic-like glutamate applications, the success rate and efficiency are the same.