SK2 channel endocytosis requires vesicular exocytosis. a , Time course of the normalized EPSP slope (mean ± SEM) in cells loaded with TeTx (100 nm) from control (closed circles) and TBP-stimulated pathway (open circles). The TBP protocol was delivered at time 0. In most cells, the amount of post-tetanic potentiation was sufficient to induce temporary potentiation in the evoked pathway, but LTP was inhibited 30 min follow TBP stimulation (n = 10). b , Continued time course of the EPSP amplitude normalized to the 10 min period prior to the addition of apamin from control (closed circles) and stimulated pathways (open circles) before and after apamin application. c, d , Similar to panels a and b , except that the cells were loaded with boiled tetanus toxin (100 nm, 95°C for 5 min). LTP was maintained in the TBP-stimulated pathway after 30 min (n = 7). Insets in b and d show representative average of 10 EPSPs, mean ± SM (shaded area), taken from the indicated shaded time points for baseline (left) and after apamin (ap, right) in the TBP pathway (top) and control pathway (bottom). Vertical and horizontal scale bars for the insets are 1 mV and 20 ms ( b ), and 0.5 mV and 20 ms ( d ), respectively.