Sex and regional differences in decrease of serotonin-immunoreactive cells by parachlorophenylalanine in rat raphe nuclei.
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 100mg/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.
Neuroendocrinology, Department of Human Behavior and Environment Sciences, School of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama 359-1192, Japan.
Hiroyuki
H
Ito
Korehito
K
Yamanouchi
D000818:Animals; D005260:Female; D010134:Fenclonine / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D007150:Immunohistochemistry; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects / Q000378:metabolism; D009919:Orchiectomy; D009928:Organ Specificity; D010052:Ovariectomy; D011903:Raphe Nuclei / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism*; D012737:Sex Factors
D012701:Serotonin; D010134:Fenclonine