Preventing nicotine-induced GluA1 enrichment with antibody x-linking blocks the corresponding increase in mEPSC amplitude. A, Representative traces from control and nicotine-treated cells after antibody x-linking of surface GluA1s. B, Cumulative histograms of mEPSC interevent intervals in control versus nicotine-treated cells after antibody x-linking of surface GluA1s (Ctrl vs Nic, p < 0.0001, n = 2700, 2600 events; KS). C, Cumulative histograms of mEPSC amplitudes in controls and nicotine-treated cells after antibody x-linking (Ctrl vs Nic, n = 2600, 2800 events; p < 0.0001, KS, due to more small events in nicotine-treated cells; no difference was seen in larger events, unlike results obtained before x-linking as in Fig. 1).