Figure 4
From: Transient ECM protease activity promotes synaptic plasticity
Long-term potentiation in TG rats that overexpress MMP-9 is altered and can be rescued by applying an MMP inhibitor.
(A) The figure shows the time course of maximal EPSP slopes normalized to baseline in the CA1 region of the hippocampus. Long-term potentiation that was induced by high-frequency stimulation (HFS; 3× 100 Hz; black arrow) of the Schaffer collaterals in the presence of DMSO in slices from MMP-9 TG rats had a lower magnitude (filled red squares; nrats = 6; 130.8% ± 6.2% of baseline) compared with control slices from WT rats (filled gray circles; nrats = 6; 175.7% ± 8.4% of baseline; p = 0.0004). The inhibitor of metalloproteinases, GM6001, was applied immediately after HFS and improved LTP that was evoked in slices from MMP-9 TG rats (filled dark blue squares; nrats = 6; 203.1% ± 16.8% of baseline) compared with slices from the same animals that were treated with the solvent of inhibitor only (filled red squares; p = 0.001). GM6001 application during the recordings from slices that were obtained from WT rats caused LTP destabilization 30 min after LTP induction (filled light blue circles; p = 0.002, compared with DMSO-treated slices from WT rats; filled gray circles). The light blue line marks the time when GM6001 was present in the experimental solution. Error bars represent the SEM. (B) Representative traces of fEPSP 10 min before (black) and 15 and 90 min after (gray) the induction of LTP are shown. Scale bars = 2 mV and 5 ms.
