Fig. 7.

Co-localization of MC4-R in prodynorphin-expressing neurons. (A) In situ hybridization analysis of MC4-R mRNA using a ³⁵S-labeled riboprobe demonstrates enrichment of MC4-R expression in the striatum, including the dorsal striatum (DS) and nucleus accumbens (NAc). Co-localization of ³⁵S-labeled MC4-R riboprobe and a digoxigenin-labeled prodynorphin riboprobe (B) in the nucleus accumbens was conducted according to standard procedures. Representative micrographs demonstrate ³⁵S-labeled MC4-R grains over (B) prodynorphin-expressing cells in the nucleus accumbens. (C) The number of MC4-R-positive cells that also express either prodynorphin or proenkepalin was determined. Co-localization of MC4-R with proenkephalin was also determined (not shown). A total of 600 MC4-R-positive cells was identified for each double-labeling condition (100 cells per rat, n = 6). The results are expressed as percent of MC4-R-positive cells that are also positive for either prodynorphin or proenkephalin.