Figure 8.
LTDGABA in the VP is lost after extinction of cocaine self-administration. A, Time course of GABA eIPSCs after HFS (vertical dashed line) in yoked saline (filled) and cocaine-extinguished (open) rats. Yoked saline data are the same as presented in Figure 6A. Number of cells and rats in legend is the same for B–D. B, Average eIPSC amplitude taken from 18 to 24 min in A. In yoked saline rats the eIPSC was inhibited to 62.1 ± 12.5% of baseline, whereas in cocaine-extinguished rats there was no change (112.8 ± 12% of baseline). C, Time course of the PPR in the same experiment shown in A. The PPR was elevated only in yoked saline rats and the elevation was synchronous with the LTDGABA shown in A. D, Average PPR during 18–24 min from experiment depicted in A. PPR was elevated in yoked saline rats to 165.4 ± 23.18 but remained unchanged in cocaine-extinguished rats. Coc, Cocaine-extinguished. #p < 0.05 compared with 100% using a one-sample t test. *p < 0.05 compared with control condition using one-way ANOVA and Dunnett's multiple-comparison post hoc analysis. Data presented as mean ± SEM.