Female ovarian steroids influence mood and cognition, an effect presumably mediated by the serotonergic system. A key receptor in this interplay may be the 5-HT1A receptor subtype. We gave adult ovariectomized female rats subcutaneous pellets containing different dosages of 17 beta -estradiol alone or in combination with progesterone, or placebo pellets, for 2 weeks. 5-HT1A receptor mRNA levels were analyzed by in situ hybridization in the dorsal hippocampus, dorsal and median raphe nuclei, and entorhinal cortex. Estradiol treatment alone reduced 5-HT1A gene expression in the dentate gyrus and the CA2 region (17 and 19% decrease, respectively). Estradiol combined with progesterone supplementation increased 5-HT1A gene expression versus placebo in the CA1 and CA2 subregions of the dorsal hippocampus (16 and 30% increase, respectively). Concomitantly, 5-HT1A mRNA expression was decreased by 13% in the ventrolateral part of the dorsal raphe nuclei, while no changes were found in the median raphe nucleus and entorhinal cortex. Chronic effects of ovarian hormones on 5-HT1A receptor mRNA expression appear tissue-specific and involve hippocampal subregions and the raphe nuclei. Modulation of 5-HT1A receptor gene expression may be of importance for gonadal steroid effects on mood and cognition. Copyright (C) 2001 S.Karger AG, Basel.
|Number of pages||8|
|Publication status||Published - Aug 2001|