A, Interleaved (vehicle, no inhibitor) mGluR-LTD experiments (control: 80.32 ± 1.56%, n = 18, ELS: 53.50 ± 3.99%, n = 18, P < 0.001, Student’s t-test). B, Inhibition of CaMKII by tatCN21 (2 µM) completely blocked mGluR-LTD in control rats yet mGluR-LTD was still present in ELS rats (control: 93.72 ± 1.31%, n = 11, ELS: 68.39 ± 1.98%, n = 10, P < 0.001, Student’s t-test). Insets show averages of 4 fEPSPs near the numerically indicated time points. Scale bar 0.5 mV × 15 ms. Dashed line indicates baseline; Dashed/dotted line indicates average control mGluR-LTD (vehicle, no inhibitors from (A)) used in subsequent Figures; Dotted line indicates average ELS mGluR-LTD (vehicle, no inhibitors from (A)) used in subsequent Figures.