FIGURE 9.

Induction of PTT-LTP requires GluA2-lacking AMPA receptors. A, time course of fEPSPs before and after perfusion with ISO (1 μm) (gray bar) in the presence of IEM1460 (30 μm) (top black bar) and delivery of the tetanus (bottom black bar). Shown are averages of initial slopes of fEPSP starting after base line had stabilized. Insets at top, examples of fEPSPs immediately before (left) and 30 min after delivery of tetani (right). B and C, time course of fEPSPs in slices perfused with IEM1460 (30 μm; black bar in B) or without this drug (C) before and after delivery of the two 100-Hz/1-s tetani, which were 10 s apart (arrowheads indicate start of first tetani). Insets at top, examples of fEPSPs immediately before (left) and 45 min after LTP induction (right). D, summary data of IEM1460 versus interleaved control experiments. For each experiment, the averages of the fEPSP initial slope values over the 5 min immediately preceding the tetani constitute the base line corresponding to 100%. The bars show the increase in fEPSP responses, which were obtained by averaging the initial slope values measured 40–45 min after the tetani. Left, averages for PTT-LTP in the presence of ISO only and ISO + IEM1460 (**, p < 0.01 for PTT-LTP without versus with IEM1460; two-way ANOVA); right, averages for 2 × 100-Hz LTP without and with IEM1460 present (p = 0.7745; two-way ANOVA). IEM1460 clearly blocked PTT-LTP but had no effect on 2 × 100-Hz LTP. Error bars, S.E.