Ifenprodil blocks the adaptive change of the NMDAR response to the effects of 80 mM ethanol. Brain slices were pretreated with ifenprodil (5 μM, Ifen) for 30 min and then continued in the presence (Ifen + E45) or the absence (Ifen) of 45 mM ethanol for 3 h. Representative traces show NMDA EPSC responses during baseline (BSL), 80 mM ethanol application (EtOH), and during washout (Wash) from ifenprodil-treated brain slices only (A) or in ifenprodil + 45 mM ethanol-treated brain slices (B). Dotted lines show the baseline and the extent of ethanol inhibition. C, the time course of the NMDA EPSC responses during the experiment. The duration of the 80 mM ethanol application is shown by the solid line. D, plots of the average response change from control (Con), 45 mM ethanol (E45, 17.3 ± 5.2%), ifenprodil-treated (Ifen, −27.3 ± 4.2%, n = 10), and ifenprodil + E45-treated (Ifen + E45, −29.8 ± 4.7%, n = 7) slices. Scale bars in A and B, 25 pA and 25 ms. ***, p < 0.001.