Potentiation of ejaculatory activity by median raphe nucleus lesions in male rats: Effect of p-chlorophenylalanine

Yasuhiko Kondo, Korehito Yamanouchi

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The effect of radiofrequency lesions in the median or dorsal raphe nucleus (MRL or DRL) on copulatory behavior was examined in sexually inexperienced male rats. Three weeks after castration and the brain surgery, all males were subcutaneously implanted with Silastic capsules containing testosterone. In the first behavioral test, the frequency of ejaculation in the MRL group was significantly higher than that in sham and DRL males, but mount and intromission were not. Seven days after the first test, the second test was carried out after treatments with 100 mg/kg p-chlorophenylalanine (PCPA), a serotonin synthesis inhibitor, or saline daily for 4 days in MRL and DRL males. The frequencies of male sexual behavior in PCPA treated DRL males were higher than those in saline treated DRL males. In contrast, even after treatments with PCPA, male sexual activity in MRL males was comparable to those in saline treated MRL males. These results suggest that serotonergic neurons in the median raphe nucleus play an inhibitory role in the regulation of male sexual activity, especially ejaculation. Furthermore, it can be thought that PCPA acts on the median raphe neurons and facilitates ejaculatory behavior.

Original languageEnglish
Pages (from-to)873-879
Number of pages7
JournalEndocrine Journal
Volume44
Issue number6
Publication statusPublished - 1997 Dec

Keywords

  • Ejaculation
  • Male rat
  • Midbrain raphe nuclei
  • Serotonin
  • Sexual behavior

ASJC Scopus subject areas

  • Endocrinology

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