Synergistic effects of DL-AP3 and forskolin on the LTP induction in the Fmr1 KO mice. (A) Forskolin (10 μM) did not induce chemical LTP in the ACC without pairing training (n = 9 slices/4 mice). (B) Forskolin (10 μM) failed to induce LTP in the Fmr1 KO mice (n = 8 slices/4 mice). LTP in the presence of forskolin (10 μM) is similar to the control in the Fmr1 WT mice (n = 12 slices/4 mice). (C) Bath application of SKF81297 (5μM) and DL-AP3 (10 μM) induced similar LTP as control in Fmr1 WT mice (n = 10 slices/4 mice). Combining forskolin with DL-AP3 partially rescued LTP in the Fmr1 KO mice (n = 11 slices/4 mice). (D) LTP facilitation by SKF81297 (5 μM) was blocked by AP5 (50 μM) (n = 10 slices/3 mice). (E) LTP facilitation by SKF81297 (5 μM) was blocked by 10 mM BAPTA in the pipette solution (n = 10 slices/3 mice). (F) Summary of the effects of forskolin or/and DL-AP3 on the LTP induction. * p < 0.05, ** p < 0.01 compared with WT; &p < 0.05 compared with forskolin in KO mice.