Figure 8.

Raclopride evokes greater dopamine concentration within the NAc shell compared to the NAc core. A. A representative color plot of increased DA transmission within the NAc shell following i.v. raclopride infusion (1.0 mg/kg; which followed the opioid infusions described above). B. The corresponding [DA] trace associated with the color plot in 7A (taken from the same point in the voltage ramp as the figures described above). Upon visual inspection of the trace, it is clear that there are many DA transients superimposed on the slower rise in [DA] following raclopride infusion. C. [DA] is significantly, and robustly, elevated in the second time bin following raclopride infusion and this lasted the entire recording period. D. A representative color plot is shown from the NAc core and E. the resulting [DA] trace associated with this color plot shows that autoreceptor blockade also causes an increase in DA transients superimposed on a gradual rise in [DA]. F. Quantitative data of raclopride-evoked increases in [DA] within the NAc core show that autoreceptor blockade also significantly increases [DA] in the core. Despite the similarities in the nature of raclopride-evoked increases in phasic DA release, increased [DA] in the shell is significantly higher compared to that evoked within the NAc core from 30 to 120 s following raclopride infusion. Error bars indicate SEM. * indicates statistically significant increases (p < 0.05).