Hippocampal estradiol synthesis and its significance for hippocampal synaptic stability in male and female animals

Vierk, Ricardo; Brandt, Nicola; Rune, Gabriele M.

doi:10.1016/j.neuroscience.2014.05.003

Cited by 57 publications

(54 citation statements)

References 91 publications

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“…In line with this idea, the effect of LTZ timescale detected on VOR adaptation could indicate a rapid E2 impact on the molecular pathways leading to synaptic plasticity underling motor memory. This is supported by data demonstrating an effect of LTZ on LTP induction preceding structural remodeling at the synaptic level (Vierk et al 2012(Vierk et al , 2014.…”

Section: Neurosteroid E2 Is Necessary For Vor Adaptationmentioning

confidence: 52%

“…The modulatory role of neurosteroid E2 on synaptic plasticity has been demonstrated in vestibular nuclei, basal ganglia and hippocampus by acute as well as long-lasting inhibition of the E2 pathway, which impairs LTP induction (Grassi et al 2009a(Grassi et al , b, 2010(Grassi et al , 2012Pettorossi et al 2013;Scarduzio et al 2013;Vierk et al 2012Vierk et al , 2014. Consistent with these findings, it has been shown that acute inhibition of E2 synthesis also exerts rapid effects on spatial learning, working memory and fear extinction (Alejandre-Gomez et al 2007;Graham and Milad 2014;Moradpour et al 2006).…”

Section: Introductionmentioning

confidence: 82%

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Acute inhibition of estradiol synthesis impacts vestibulo-ocular reflex adaptation and cerebellar long-term potentiation in male rats

et al. 2017

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The vestibulo-ocular reflex (VOR) adaptation is an ideal model for investigating how the neurosteroid 17 beta-estradiol (E2) contributes to the modification of behavior by regulating synaptic activities. We hypothesized that E2 impacts VOR adaptation by affecting cerebellar synaptic plasticity at the parallel fiber-Purkinje cell (PF) synapse. To verify this hypothesis, we investigated the acute effect of blocking E2 synthesis on gain increases and decreases in adaptation of the VOR in male rats using an oral dose (2.5 mg/kg) of the aromatase inhibitor letrozole. We also assessed the effect of letrozole on synaptic plasticity at the PF synapse in vitro, using cerebellar slices from male rats. We found that letrozole acutely impaired both gain increases and decreases adaptation of the VOR without altering basal ocular-motor performance. Moreover, letrozole prevented long-term potentiation at the PF synapse (PF-LTP) without affecting long-term depression (PF-LTD). Thus, in male rats neurosteroid E2 has a relevant impact on VOR adaptation and affects exclusively PF-LTP. These findings suggest that E2 might regulate changes in VOR adaptation by acting locally on cerebellar and extra-cerebellar synaptic plasticity sites.

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Section: Neurosteroid E2 Is Necessary For Vor Adaptationmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 82%

Acute inhibition of estradiol synthesis impacts vestibulo-ocular reflex adaptation and cerebellar long-term potentiation in male rats

et al. 2017

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“…Spine synapse loss, however, was not seen prior to 48 h after the last injection, which made us assume that synapse loss results from impaired LTP (Vierk et al, 2014), according to the paradigm that LTP induces spines (Engert and Bonhoeffer, 1999).…”

Section: Sex-specific Paracrine Effects Of Sn On Hippocampal Synapticmentioning

confidence: 97%

Sexual neurosteroids and synaptic plasticity in the hippocampus

Fester

Rune

2015

Brain Research

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“…In intact animals, local estrogen formation could be important in terms of maintaining threshold levels of estrogen responsiveness in aromatase-rich regions of the brain, at times in the cycle when circulating E 2 is low [39,40]. It could also contribute to the maintenance of normal synaptic and dendritic structure in structures such as the hippocampus, in which aromatase inhibition results in loss of synaptic connectivity [41]. …”

Section: Discussionmentioning

confidence: 99%

In vitro<b> </b>Autoradiographic Analysis of Regional Changes in Estrogen Receptor Alpha in the Brains of Cycling Female Rats

Bowlby

Brown²,

Hochberg³

et al. 2015

Neuroendocrinology

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Background/Aims: The contributions of the three principal ovarian steroid hormones (estradiol, progesterone and testosterone) to the regulation of estrogen receptor alpha (ERα) levels in the rat brain were examined during the estrous cycle. Methods: Receptor concentrations were measured using an in vitro autoradiographic technique designed to separately quantify free, unoccupied receptors and receptors ‘occupied' by (bound to) endogenous hormone. Results: ERα occupation increased at proestrus and declined at estrus, reflecting changes in circulating estradiol and testosterone levels. Total ERα content followed a pattern that was the inverse of the occupation data, falling over the night of proestrus. Between 2.00 and 10.00 a.m. on the day of estrus, total ERα concentrations recovered in all brain regions except the ventromedial nucleus (VMN), in which ERα binding remained depressed at estrus. Administration of the progesterone antagonist mifepristone on the afternoon of proestrus resulted in recovery of ERα levels in the VMN by the morning of estrus, consistent with the hypothesis that the preovulatory progesterone surge selectively inhibits VMN ERα expression. Residual ERα occupation observed at estrus, when estradiol is not detectable in the serum, likely reflects intracranial aromatization of circulating androgens, since the pattern of receptor occupation observed at this stage of the cycle could be reproduced in ovariectomized rats by replacement with testosterone. Conclusion: These findings indicate that ERα binding in the brain fluctuates during the rat estrous cycle in a region-specific manner and suggest that local aromatization of testosterone may contribute significantly to ERα occupation when circulating estradiol levels are low.

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Hippocampal estradiol synthesis and its significance for hippocampal synaptic stability in male and female animals

Cited by 57 publications

References 91 publications

Acute inhibition of estradiol synthesis impacts vestibulo-ocular reflex adaptation and cerebellar long-term potentiation in male rats

Acute inhibition of estradiol synthesis impacts vestibulo-ocular reflex adaptation and cerebellar long-term potentiation in male rats

Sexual neurosteroids and synaptic plasticity in the hippocampus

In vitro<b> </b>Autoradiographic Analysis of Regional Changes in Estrogen Receptor Alpha in the Brains of Cycling Female Rats

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