(A) Active and inactive lever pressing during
self-administration and extinction for rats used to quantify MMP-2,9 activity.
(B) Representative examples of FITC-gelatin fluorescence
corresponding to MMP-2,9 activity in NAcore from each treatment group. Dashed
line outlines the anterior commissure (ac) and injection site that were
masked-out for quantification. Bar= 0.5 mm. (C) Increase in MMP-2,9
(mean ± SEM normalized integrated density of fluorescence reported in
arbitrary units) after cue-induced reinstatement in animals self-administering
saline (Coc-Cue-Sal) was reversed by 10 min cocaine access (Coc-Cue-Coc). Data
from 4–6 coronal slices were averaged per rat, and the number in the bar
refers to number of rats in each group. (D) Negative correlation
between active lever pressing and the integrated density of fluorescence
indicative of MMP-2,9 activity in Coc-Cue-Sal animals, but no correlation was
found in the Coc-Cue-Coc rats. These data are derived from the data shown in
figure 4C and behavior was quantified as described in Figure 2 legend.
*p< 0.05, comparing all groups to extinction baseline (Ext)
using a Dunnett’s post hoc test.