Fig. 1

5-HT and metabolite in the NTS. Tissue content of 5-HT (top), normalized to sample protein content, in the caudal NTS (cNTS) and in the NTS at the level of the Area Postrema (mNTS) after treatment with polyethylene glycol (PEG) or the 0.15 M NaCl vehicle (VEH). 5-HT in the cNTS of PEG-treated rats (PEG-cNTS) was significantly greater than that in the cNTS of VEH-treated rats (VEH-cNTS; 1; p < 0.05) and that in the mNTS of VEH-treated rats (VEH-mNTS; 2; p < 0.05). There were no differences in tissue 5HIAA content (middle). The 5HT:5HIAA ratio (bottom) was significantly greater in the cNTS of PEG-treated rats than that in all other groups (1 significantly greater than VEH-cNTS, 2 significantly greater than VEH-mNTS, 3 significantly greater than PEG-mNTS, all p < 0.05)