Figure 3.
Effect of stimulation of medullary raphe MC4-Rs via parenchymal injection of 10 pmol MTII on TIBAT (A), spontaneous activity (B), 24-h food intake (C), and change in body weight (D). Line graphs represent across-rat average parameter measurements through the 8-h recording period. The bracketed time period on the line graph x-axis indicates the periods used in the histograms. Histograms represent means + sem. *, P < 0.05; **, P < 0.005. E, Reconstruction of injection sites based on microscopical analysis of dye injection at the same volume (100 nl) as the melanocortin agonist. Microscopical analysis revealed that seven of eight rats had placements within the medullary raphe (RPa, raphe obscurus, raphe magnus). Solid line ovals indicate instances where the dye injection placement was within the medullary raphe (positive placements). Dotted line circles represent negative placements (injection sites that were judged to be outside of medullary raphe). Placements shown were between −10.52 and −11.60 mm from bregma (54).