Figure 3.

NRG-1β acts postsynaptically on AMPA receptors to reverse LTP. For both experiments, NRG-1β was perfused for 10 min starting 20 min after TBS. A, B, PPF ratios are not modified by NRG-1β. A, Representative traces of the first (P1) and second (P2) evoked EPSPs at 50 ms interpulse intervals recorded before, and at 10 and 50 min after, TBS. Calibration: 10 ms, 1 mV. B, PPF ratios from potentiated slices stimulated at 50-200 ms intervals before (○) and after (•) NRG-1β perfusion (n = 12). C, D, NRG-1β selectively reduces AMPAR EPSCs in potentiated slices. C, Representative EPSCs recorded at holding potentials of-70 and +40 mV measured -5, 15, 30, and 50 min relative to TBS. Calibration: 10 ms, 100 pA. NMDAR EPSCs were measured at 50 ms (dotted lines) to reduce contribution of AMPAR currents. D, Quantification of voltage-clamp results: AMPAR (□) and NMDAR (▪). Comparisons are between AM-PAR EPSCs at 15 min to EPSCs at 30 and 50 min (n = 10; ^*p < 0.05; ^**p < 0.001). Data are expressed as mean ± SEM.