Fig. 8
From: p97 regulates GluA1 homomeric AMPA receptor formation and plasma membrane expression
Overexpression of p97 promotes the formation and retention of GluA1-homo AMPARs and prevents LTP. AAV viral vector containing GFP or YFP-p2a-p97 was injected into the ventricle of mice at P0. mEPSCs (a–f) or evoked EPSCs (g, i) were recorded in visually identified GFP- or YFP-positive CA1 pyramidal neurons in hippocampal slices prepared at P14–21. Overexpression of p97 significantly decreased the amplitude and frequency of mEPSCs (a–c; n = 9 cells, *p < 0.05, **p < 0.01, two-tailed t test), and this was reversed by including p97 inhibitor DBeQ in the recording pipette (d–f; n = 9 cells, *p < 0.05, **p < 0.01, two-tailed paired t test). From a to f are represented traces (a, d), cumulative probability plots of inter-event intervals and amplitudes (b, e), and bar graphs of averaged frequencies and amplitudes of mEPSCs recorded in GFP or YFP-p2a-p97 (p97) expression cells (c), or in YFP-p2a-p97 expression cells with DBeQ (11 μM) added in the pipette solution 0–5 min (p97 basal) and 15–20 min (p97 DBeQ) after the formation of whole-cell configuration (f). g Overexpression of YFP-p2a-p97 (Red line with empty circles), but not GFP (blue line with empty squares), abolished paired-stimulation protocol to induce LTP at CA1 synapses. However, in neurons infected with p97, DBeQ (11 μM) contained in the recording pipette (black line with empty triangles) significantly increased baseline synaptic transmission, and occluded the further induction of LTP (GFP: n = 5 cells; p97: n = 7 cells; p97 + DBeQ: n = 8 cells). h Representative image shows GFP-positive neurons in CA1 region for recording. i In neurons expressing GFP, the paired stimulation reliably induced LTP only in control, nontreated neurons (black line with squares), but not in neurons treated with PhTx (10 μM, Red line with circles) applied just before the stimulation. j Bar graphs of averaged EPSCs recorded 25–30 min after paired stimulation show PhTx totally blocked LTP (Control: n = 5 cells; PhTx: n = 6 cells; **p < 0.01, two-tailed t test). The error bars represent SEM
