Fig. 5.

ERK modulation of 50 Hz-induced PTE requires Syn I. (A and B) ERK activation in MF terminals in response to a 50-Hz tetanus was normal in Syn I KO mice. ERK activation is visible in MF terminals of Syn I KO mice in response to a 50-Hz tetanus (B). Note that the immunolabeling pattern for pERK in large MF terminals is similar in both genotypes, despite the absence of Syn I immunoreactivity in mutant slices. (Scale bar, 10 μm.) (C) PTE of MF-CA3 synapses induced with a single 50-Hz burst is similar in hippocampal slices from Syn-I KO mice (●, n = 12) and WT mice (gray triangles, data partially replotted from Fig. 2D). The magnitude and kinetics of this PTE were not affected by the application of ERK inhibitor U0126 (○, n = 11). (D) The duration of PTE induced by 50 Hz in synapsin TKO mice (○, n = 10) was found to be significantly increased with respect to WT animals (●, n = 5).