TAT-KLCpCDK inhibited LTD and AMPAR internalization in hippocampal neurons. (A) TAT-KLCpCDK peptide significantly inhibited AMPA-induced internalization in cultured hippocampal neurons (N = 3, n = 56, one-way ANOVA, Bonferroni's multiple comparison test, **P < 0.01; Student's t test, unpaired, two-tailed, n = 11 per group, #P = 0.0489). (B) The effect of TAT-KLCpCDK on the formation of LTD in hippocampal slices from rats compared with TAT-Con (Student's t test, unpaired, two-tailed, n = 6–7 cells, *P = 0.00011). (C) The effect of TAT-KLCpCDK on the formation of LTP in hippocampal slices from rats (n = 6).