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Effect of estrogen on stress‐induced c‐Fos expression in catecholaminergic neurons of ovariectomized rat brain
Author(s) -
Hara Yasuko,
Matuoka Megumi,
Kouno Tomomi,
Takamata Akira,
Ueyama Takashi,
Morimoto Keiko
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a355-a
Subject(s) - ovariectomized rat , locus coeruleus , catecholaminergic cell groups , endocrinology , medicine , c fos , catecholaminergic , rostral ventrolateral medulla , estrogen , hypothalamus , tyrosine hydroxylase , premovement neuronal activity , chemistry , nucleus , biology , medulla oblongata , catecholamine , dopamine , central nervous system , gene expression , neuroscience , biochemistry , gene
Recently we revealed that mild psychological stress evoked by cage‐switch significantly increased c‐Fos expression in ovariectomized rat brain areas: locus coeruleus (LC), the nucleus of the solitary tract (NTS), hypothalamic paraventricular nucleus, etc. The present study investigated whether estrogen affected the stress‐induced expression of c‐Fos in catecholaminergic neurons of ovariectomized rat brain through estrogen receptor (ER). Female rats aged 9wk were ovariectomized and randomly assigned placebo‐treated (P) and estrogen‐treated (E) groups. The P and E groups were implanted with pellets containing either placebo or 17 β‐estradiol (1.5 mg/60‐day release). After 4wk, each group rat underwent cage‐switch for 30 min and was sacrificed at 60 min after the stress. The brains were immunohistochemically processed for c‐Fos and tyrosine hydroxylase (TH) as an identifier of catecholaminergic neurons, and for ER. TH‐positive neurons were found in LC, NTS, and rostral ventrolateral medulla (RVLM) in both P and E groups. In these areas, stress significantly increased c‐Fos+TH double‐labeled neurons in both groups. However, the c‐Fos expression of catecholaminergic neurons was significantly suppressed in LC in the E group. In addition, ER immunoreactive neurons were observed in similar regions in LC. These findings suggest that estrogen affects c‐Fos expression of catecholaminergic neurons in LC.