Figure 4
Regional specificity of DAMGO (D-Ala2, N-MePhe4, Gly-ol]-enkephalin) effects on strategy shifting. (a) Photomicrograph of a Neutral Red counterstained section through the LC showing histological verification of the injection site from a representative animal that was injected with DAMGO. The arrowhead points to the LC and the arrow points to the dye, which is localized to the LC. Cb, cerebellum; V, ventricle. (b) Plots of accurate (circles) and missed (squares) injection sites for DAMGO (3 pg) for males (black) and females (red). DAMGO effects from these cases were used for the graphs in c and d. (c) Comparison of the effects of DAMGO (3 pg) microinfused into the LC of male rats (in, n=8), outside of the LC (out, n=5) and ACSF (n=9) on performance in different components of the OSST. The bars indicate the number of trials necessary to reach the criterion for each stage. Vertical lines represent SEM. Asterisks indicate a significant difference compared with both the ACSF and DAMGO out groups (p<0.05). (d) Comparison of the effects of DAMGO (3 pg) microinfused into the LC of female rats (in, n=10), outside of the locus coeruleus (LC; out, n=5) and ACSF (n=14) on performance in different components of the OSST. The bars indicate the number of trials necessary to reach the criterion for each stage. Vertical lines represent SEM. #p<0.05 compared with ACSF. A full color version of this figure is available at the Neuropsychopharmacology journal online.
