Fig. 2: Analysis of AMPAR-mEPSCs and mIPSCs in hippocampal DG, CA3, and CA1 principal neurons from WT and Xpnpep1^–/– mice.

a–c Sample traces of AMPAR-mEPSCs measured in dentate granule cells (a), CA3 pyramidal neurons (b), and CA1 pyramidal neurons (c) from WT and Xpnpep1^–/– mice. AMPAR-mEPSCs were recorded at a holding potential of –70 mV in the presence of TTX, AP-5, and picrotoxin in the bathing solution. d Mean amplitude (left) and frequency (right) of AMPAR-mEPSCs show intact AMPAR-mediated synaptic transmission throughout the hippocampus of Xpnpep1^–/– mice. DG; n = 18 cells (3 mice) in each group; t₍₃₄₎ = 0.83 and p = 0.41 for mEPSC amplitude; t₍₃₄₎ = 0.74 and p = 0.46 for mEPSC frequency. CA3; n = 20 cells (3 mice) in each group; t₍₃₈₎ = 0.36 and p = 0.72 for mEPSC amplitude; t₍₃₈₎ = 1.24 and p = 0.22 for mEPSC frequency. CA1; n = 25 cells (5 mice) in each group; t₍₄₈₎ = –0.22 and p = 0.82 for mEPSC amplitude; t₍₄₈₎ = –1.67 and p = 0.10 for mEPSC frequency. Student’s t test. e–g Sample traces of mIPSCs measured in dentate granule cells (e), CA3 pyramidal neurons (f), and CA1 pyramidal neurons (g) from WT and Xpnpep1^–/– mice. During the mIPSC recordings, the membrane potential was held at –70 mV in the presence of blockers for NMDARs (AP-5), AMPARs (NBQX), and Na⁺ channels (TTX). h Quantification of mIPSC amplitudes (left) and frequencies (right) in DG, CA3, and CA1 principal neurons from WT and Xpnpep1^–/– mice. DG; n = 18 cells (3 mice) in each group; t₍₃₄₎ = 0.39 and p = 0.70 for mIPSC amplitude; t₍₃₄₎ = –1.50 and p = 0.14 for mIPSC frequency; Student’s t test. CA3; n = 20 cells (3 mice) in each group; t₍₃₈₎ = –1.52 and p = 0.14 for mIPSC amplitude; t₍₃₈₎ = –0.57 and p = 0.57 for mIPSC frequency; Student’s t test. CA1; n = 18 cells (3 mice) in each group; t₍₃₄₎ = –2.96 and p = 0.0056 by Student’s t test, and U = 74, Z = –2.78, and p = 0.005 by Mann–Whitney test for mIPSC amplitude; t₍₃₄₎ = –0.51 and p = 0.61 by Student’s t test, and U = 162, Z = 0, and p = 1.0 by Mann–Whitney test for mIPSC frequency.