Fig. 2
Serotonergic hyper-production and innervation. After fluoxetine injection for 4 weeks, mice were sacrificed. Serotonergic activity was evaluated by extracellular 5-HT concentrations in both the RN and hypothalamus using microdialysis and UHPLC analysis (A) and intracellular 5-HT/c-Fos double positive signals using immunofluorescence analysis in the DRN (B and D). The 5-HT projections into the hypothalamus were confirmed after 7 days injection of FG retrograde tracer, as shown in FG/5-HT double positive cells in DRN (C and E). The 5-HT1A receptor-positive signal and 5-HT1A receptor protein expression (F–H) in the DRN were evaluated. The mRNA levels of 5-HT1A receptor transcriptional repressor and promotor genes were analyzed by real-time PCR (I). The data are expressed as the mean ± SD (n = 3, 4 or 6/group). *p < 0.05 and **p < 0.01 compared to the saline group