抄録
Recently we showed 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 altered the stress-induced expression of c-Fos in catecholaminergic neurons of ovariectomized rat brain. 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 cessation of the stress. The rats were perfused, and the brains were immunohistochemically processed for c-Fos and tyrosine hydroxylase (TH) as an indentifier of catecholaminergic neurons. TH-positive neurons were found in LC, NTS, and rostral ventrolateral medulla (RVLM) in both P and E groups. In these areas, cage-switch stress significantly increased c-Fos+TH labeling in both two groups. However, the stress-induced c-Fos expression of catecholaminergic neurons tended to be suppressed in LC in the E group compared with the P group.These findings suggest that estrogen affects c-Fos expression of catecholaminergic neurons in LC. [Jpn J Physiol 55 Suppl:S229 (2005)]
