Figure 7.
R/hCRF facilitated a DA-mediated increase of putative BLA–mPFC EPSCs in the presence of raclopride, a D2/3-like antagonist, in chronic cocaine-treated rats. A, Left, Application of raclopride (10 μm), a D2-like antagonist, unmasked tonic inhibitory action of D2/3 receptors at the synapse, thus increasing EPSCs (127.0 ± 1.4%; paired t = −19.17; p < 0.05). Right, DA (10 μm) caused a significant increase of EPSCs (112.2 ± 1.8%; p < 0.01), which returned to baseline (100.1 ± 3.1% after 20 min washout; p > 0.05 when compared with baseline with raclopride). R/hCRF (50 nm) enhanced DA (10 μm) effects on EPSCs. Note that raclopride (10 μm) is present throughout. B, Plots depict amplitude of EPSCs (percentage of baseline) as a function of time in each treatment group. Top, Representative averaged traces of EPSCs taken at different time points, indicated by numbers. Bottom, Input conductance is plotted as a function of time.