The AC inhibitor SQ 22536 inhibited early LTP induced by three tetani. The LTP induced by three tetani was significantly larger than the LTP induced by a single tetanus (p < 0.05). AC inhibitor SQ 22536 (100 μm) inhibited the early LTP induced by three tetani (p < 0.001; n = 7).Insets represent averaged (n = 6) fEPSP from individual experiments taken at 5 min before and 30 min after the tetanus. All calculations and markings are as in Figure 1. Field EPSP between tetani are not shown.