Estrogen acts on maternal circuitry to establish maternal behaviour in otherwise non-maternal rats. The precise mechanisms by which estrogen primes maternal circuitry are unknown; however, the medial preoptic area (MPOA) stimulates maternal behaviour whilst the medial amygdala (MeA) inhibits it. This thesis aimed to address the link between estrogen sensitivity, astroglia and maternal behaviour. Maternal care influences maternal behaviour of female offspring. One mechanism underlying this influence is differential estrogen sensitivity within the MPOA. Estrogen receptor alpha (ERalpha) expression was examined in offspring of High and Low licking/grooming (LG) dams within the MPOA. Enhanced expression ERalpha was limited to the medial preoptic nucleus in offspring of High LG dams and the anteroventral periventricular nucleus in Low LG dams. Adult nulliparous offspring of High and Low LG dams were assessed for maternal responsiveness using the pup sensitization paradigm. Offspring of Highs showed maternal behaviour significantly earlier than offspring of Lows. Brains of pup-exposed and pup-naive High and Low offspring were analyzed for astroglial markers glial fibrillary acidic protein (GFAP) and glutamine synthetase. Pup-naive animals showed more GFAP positive cells within the posteroventral MeA, with no differences within the MPOA and no effect of maternal care. Glutamine synthetase, a glial-derived enzyme necessary for glutamate production, showed greater expression within the MeA of High LG pup-naive animals; with no maternal care differences observed in pup-experienced animals. Thus, long-lasting changes within maternal circuitry established in early life are reflected in regionally specific enhanced estrogen sensitivity and latency to display maternal behaviour, but the effects are less clear with respect to astroglia.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.112541 |
| Date | January 2007 |
| Creators | McAllister, Kelli. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Division of Neuroscience.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002699703, proquestno: AAIMR51309, Theses scanned by UMI/ProQuest. |
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