Expression and neuropeptidergic characterization of estrogen receptors (ERα and ERβ) throughout the rat brain: Anatomical evidence of distinct roles of each subtype

Nathalie Laflamme, Rossella E. Nappi, Guy Drolet, Claude Labrie, Serge Rivest

Research output: Contribution to journalArticle

Abstract

The recent cloning of a second estrogen receptor (ER) provided a new tool to investigate and clarify how estrogens are capable of communicating with the brain and influence gene expression and neural function. The purpose of the present study was to define the neuroanatomical organization of each receptor subtype using a side-by-side approach and to characterize the cellular population (s) expressing the ER̄ transcript in the endocrine hypothalamus using immunohistochemistry combined with in situ hybridization. Axonal transport inhibition was accomplished to cause neuropeptide accumulation into the cytoplasm and thus facilitate the detection of all positive luteinizing hormone-releasing hormone (LHRH), corticotropin- releasing factor (CRF), vasopressin (AVP), oxytocin (OT), gastrin-related peptide (GRP), and enkephalin (ENK) neurons. The genes encoding either ERα or -β were expressed in numerous limbic-associated structures, and fine differences were found in terms of intensity and positive signal. Such phenomenon is best represented by the bed nucleus of the stria terminalis (BnST) and preoptic area/anterior hypothalamus, where the expression pattern of both transcripts differed across subnuclei. The novel ER was also found to be expressed quite exclusively in other hypothalamic nuclei, including the supraoptic (SON) and selective compartments (magnocellular and autonomic divisions) of the paraventricular nucleus (PVN). A high percentage of the ERβ-expressing neurons located in the ventro- and dorsomedial PVN are of OT type; 40% of the OT-ir cells forming the medial magnocellular and ventromedial parvocellular PVN showed a clear hybridization signal for ERβ mRNA, whereas a lower percentage (15-20%) of OT neurons were positive in the caudal parvocellular PVN and no double-labeled cells were found in the rostral PVN and other regions of the brain with the exception of the SON. Very few AVP-ir neurons expressing ERβ transcript were found throughout the rat brain, although the medial PVN displayed some scattered double-labeled cells (

Original languageEnglish
Pages (from-to)357-378
Number of pages22
JournalJournal of Neurobiology
Volume36
Issue number3
DOIs
Publication statusPublished - Sep 5 1998

Keywords

  • Corticotropin-releasing factor
  • Enkephalin
  • Gastrin-related peptide
  • Hypothalamus
  • Immunocytochemistry
  • In situ hybridization histochemistry
  • Luteinizing hormone-releasing hormone
  • Ovulatory cycle
  • Oxytocin
  • Reproduction
  • Vasopressin

ASJC Scopus subject areas

  • Neuroscience(all)

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