Sex and regional differences in decrease of serotonin-immunoreactive cells by parachlorophenylalanine in rat raphe nuclei

Hiroyuki Ito, Korehito Yamanouchi

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To determine sex and regional differences in the properties of serotonin (5-HT) neurons of the raphe nuclei, the responsiveness to parachlorophenylalanine (PCPA) of 5-HT neurons in the dorsal and median raphe nuclei (DR and MR) and the nucleus raphe magnus (RMg) was analyzed by counting 5-HT-immunoreactive (5-HT-ir) cells. Gonadectomized male (OCX) and female (OVX) rats were treated with 100. mg/kg b.wt PCPA or saline daily for 4 days. The brains were removed and fixed one day after the last injection. Frozen sections were stained with serotonin antibody and the numbers of 5-HT-ir cells in the raphe nuclei were counted. As a result, in female rats, the densities of 5-HT-ir cells in these 3 raphe nuclei were almost the same when compared the PCPA-treated and saline-treated groups. On the other hand, in male rats, the densities of 5-HT-ir cells in the DR and MR of PCPA-treated rats were lower than in saline-treated rats. In the male RMg, no difference was seen. These results suggest that responsiveness of 5-HT neurons to PCPA in the DR and MR, but not in the RMg, were sexually dimorphic.

Original languageEnglish
Pages (from-to)33-39
Number of pages7
JournalNeuroscience Research
Issue number1
Publication statusPublished - 2010 May



  • 5-HT immunoreactive cell
  • Parachlorophenylalanine
  • Raphe nuclei
  • Sex difference

ASJC Scopus subject areas

  • Neuroscience(all)

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