Synaptic plasticity in the hippocampus: Effects of estrogen from the gonads or hippocampus?

G. M. Rune, C. Lohse, J. Prange-Kiel, L. Fester, M. Frotscher

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

Different effects of estrogen on synaptic plasticity has been reported. Here, we summarise effects of low, gonad-derived serum estrogen concentrations, of intermediate concentrations, provided by hippocampal cells, and of pharmacological doses of estrogen on synapses and spines and on the expression of synaptic proteins. No effects of low concentrations were found. To study the effects of hippocampus-derived estradiol, we inhibited hippocampal estrogen synthesis by treatment of hippocampal cell cultures with letrozole, an aromatase inhibitor. Alternatively, we used siRNA against Steroidogenic acute regulatory protein (StAR). Spines, synapses, and synaptic proteins were significantly downregulated in response to letrozole and in siRNA-StAR transfected cells. Application of high pharmacological doses of estradiol promoted only synaptophysin expression, a presynaptic protein, but did not increase the number of boutons. Our results point to an essential role of endogenous hippocampal estrogen in hippocampal synaptic plasticity rather than to a direct influence of estrogens derived from peripheral sources, such as the gonads.

Original languageEnglish (US)
Pages (from-to)145-155
Number of pages11
JournalNeurochemical Research
Volume31
Issue number2
DOIs
StatePublished - Feb 1 2006

Keywords

  • Aromatase
  • Estrogen
  • Letrozole
  • Ovariectomy
  • Synaptic plasticity
  • Synaptogenesis

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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