Roles of NR2B and NR2A subunits in NMDA-induced LTD. (A) NMDA application (30 μM, 4 min) under normal conditions causes initial extinction of EPSPs, followed by recovery and stabilization (n = 15). (B) NR2B inhibitors, Ro25-6981 (0.5 μM) or Ifenprodil (3 μM), do not affect NMDA-induced plasticity (n = 8+4 = 12). (C) In presence of NR2A inhibitor, NVP-AAM077 (0.4 μM), NMDA effects are different compared with control situation, with a shorter recovery phase and much less depression (n = 10). (D) Bar diagram reveals LTD at 60 min after NMDA application as percentage of the initial baseline under the different experimental conditions in A-C. Data are given as mean ± S.E.M. Black bars in A-C indicate the duration of drug treatment. Values are shown averaged for 2 min periods. Inserts illustrate EPSP-traces taken at the indicated time points (a, b). Calibrations: 0.5 mV, 10 ms.