Figure 4.

Glutamate increases MMP activity in isolated brain capillaries. A, Representative MMP-9 gelatin zymogram of lysate from brain capillaries exposed to 100 μm glutamate. Left, Recombinant MMP-9 (positive control). B, Densitometric analysis of n = 4 gelatin zymograms. Data are mean ± SEM (n = 4 independent experiments) and show the fold change over controls (1.81 ± 0.28-fold; t₍₆₎ = 5.77, p = 0.0012; unpaired t test) for MMP-9 activity in lysate from rat brain capillaries exposed to 100 μm glutamate. C, Total MMP enzyme activity in brain capillaries was measured using the fluorogenic substrate Mca-PLGL-Dpa-AR-NH₂. MMP activity was measured in lysate from isolated brain capillaries exposed to 100 μm glutamate; recombinant rat MMP-2 and rat MMP-9 were used as positive controls. MMP activity is given as AFU; data are mean ± SEM (n = 3 independent experiments). *Significantly lower than control (t₍₄₎ = 3.44, p = 0.026, unpaired t test). **Significantly higher than control, p < 0.01.