Brain estrogen production and the encoding of recent experience

Vahaba, Daniel M.; Remage‐Healey, Luke

doi:10.1016/j.cobeha.2015.11.005

Cited by 16 publications

(15 citation statements)

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“…Because AI use should further deplete any E2 synthesis in OVX females and GDX males, peripheral E2 levels were analyzed at the end of the treatment phase. Some studies have also reported increased T following AI use (Taylor et al, 2017), and so T levels were also assessed. Cortisol was also measured as a negative control, as there is little evidence that AIs should influence cortisol synthesis (Bajetta et al, 1999;Rossi et al, 2009).…”

Section: Methodsmentioning

confidence: 99%

“…Some studies have also reported increased T following AI use (Taylor et al, 2017), and so T levels were also assessed. Cortisol was also measured as a negative control, as there is little evidence that AIs should influence cortisol synthesis (Bajetta et al, 1999;Rossi et al, 2009). A few minutes before lights on (i.e., 8:30 A.M.), marmosets entered a stainless-steel transport box (34.1 ϫ 20.65 ϫ 30.8 cm) attached to their home cage.…”

Section: Methodsmentioning

confidence: 99%

“…The structural and functional organization of the marmoset brain is comparable with the rhesus or human brain (Chaplin et al, 2013). Marmosets also share many similarities with humans in sleep and thermoregulation patterns (Hoffmann et al, 2012;Gervais et al, 2016), cognitive ability (Spinelli et al, 2004;Yamazaki et al, 2016), and anxiety profiles (Barros et al, 2008;Galvão-Coelho et al, 2008), implicating this species as a strong translational model for studying AI effects on the CNS. Aromatase is expressed in the HPC of marmosets ), suggesting that local estrogen synthesis occurs in this primate, as in humans (for review, see Azcoitia et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Adverse Effects of Aromatase Inhibition on the Brain and Behavior in a Nonhuman Primate

et al. 2018

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Breast cancer patients using aromatase inhibitors (AIs) as an adjuvant therapy often report side effects, including hot flashes, mood changes, and cognitive impairment. Despite long-term use in humans, little is known about the effects of continuous AI administration on the brain and cognition. We used a primate model of human cognitive aging, the common marmoset, to examine the effects of a 4-week daily administration of the AI letrozole (20 g, p.o.) on cognition, anxiety, thermoregulation, brain estrogen content, and hippocampal pyramidal cell physiology. Letrozole treatment was administered to both male and female marmosets and reduced peripheral levels of estradiol (E2), but unexpectedly increased E2 levels in the hippocampus. Spatial working memory and intrinsic excitability of hippocampal neurons were negatively affected by the treatment possibly due to increased hippocampal E2. While no changes in hypothalamic E2 were observed, thermoregulation was disrupted by letrozole in females only, indicating some impact on hypothalamic activity. These findings suggest adverse effects of AIs on the primate brain and call for new therapies that effectively prevent breast cancer recurrence while minimizing side effects that further compromise quality of life.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Adverse Effects of Aromatase Inhibition on the Brain and Behavior in a Nonhuman Primate

et al. 2018

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“…Oestrogens were found to play a role in neuronal plasticity and spine synapse formation . Furthermore, many studies have shown positive effects of oestrogens on cognition . In Alzheimer's disease, oestrogens have been shown to protect neurones against the toxicity of amyloid plaques .…”

Section: Sex Steroid Hormones and Brain Functionmentioning

confidence: 99%

“…25,26 Furthermore, many studies have shown positive effects of oestrogens on cognition. [27][28][29] In Alzheimer's disease, oestrogens have been shown to protect neurones against the toxicity of amyloid plaques. 30 Nevertheless, more studies are necessary 31 because investigators from the Women's Health Initiative Memory Study found that therapy with a combination of oestrogen and progestin increased the risk for dementia in postmenopausal women and did not improve their performance in mild cognitive tasks.…”

Section: Sex Steroid Hormones and Brain Functionmentioning

confidence: 99%

Sex steroid hormones and brain function:PETimaging as a tool for research

Moraga-Amaro

Waarde

Doorduin

et al. 2018

J Neuroendocrinology

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Sex steroid hormones are major regulators of sexual characteristic among species. These hormones, however, are also produced in the brain. Steroidal hormone-mediated signalling via the corresponding hormone receptors can influence brain function at the cellular level and thus affect behaviour and higher brain functions. Altered steroid hormone signalling has been associated with psychiatric disorders, such as anxiety and depression.Neurosteroids are also considered to have a neuroprotective effect in neurodegenerative diseases. So far, the role of steroid hormone receptors in physiological and pathological conditions has mainly been investigated post mortem on animal or human brain tissues. To study the dynamic interplay between sex steroids, their receptors, brain function and behaviour in psychiatric and neurological disorders in a longitudinal manner, however, noninvasive techniques are needed. Positron emission tomography (PET) is a non-invasive imaging tool that is used to quantitatively investigate a variety of physiological and biochemical parameters in vivo. PET uses radiotracers aimed at a specific target (eg, receptor, enzyme, transporter) to visualise the processes of interest. In this review, we discuss the current status of the use of PET imaging for studying sex steroid hormones in the brain. So far, PET has mainly been investigated as a tool to measure (changes in) sex hormone receptor expression in the brain, to measure a key enzyme in the steroid synthesis pathway (aromatase) and to evaluate the effects of hormonal treatment by imaging specific downstream processes in the brain. Although validated radiotracers for a number of targets are still warranted, PET can already be a useful technique for steroid hormone research and facilitate the translation of interesting findings in animal studies to clinical trials in patients. K E Y W O R D Sandrogen receptor, neuroimaging, oestrogen receptor, positron emission tomography, sex steroid hormones | INTRODUCTIONSex steroid hormones are a family of steroidal hormones that can be divided into 3 classes: oestrogens, progestins and androgens. These hormones are major regulators of sexual functions, including the reproductive cycle, reproductive physiology and the development of accessory reproductive organs.1 However, our vision of the function of these hormones has been expanded because they not only regulate sexual behaviour, but also affect brain functions, such as memory, 2 anxiety-related behaviour 3 and other functions at the cellular level. 4 Sex steroid hormones are mainly synthesised by the ovaries and testis. The hypothalamic-pituitary-gonadal (HPG) axis is the main system by which the production and release of sex steroids is regulated. 5 Circulating sex hormones can stimulate the release ofThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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A brain for all seasons: An in vivo MRI perspective on songbirds

Orije

Linden

2022

J Exp Zool Pt A

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Seasonality in songbirds includes not only reproduction but also seasonal changes in singing behavior and its neural substrate, the song control system (SCS). Prior research mainly focused on the role of sex steroids on this seasonal SCS neuroplasticity in males. In this review, we summarize the advances made in the field of seasonal neuroplasticity by applying in vivo magnetic resonance imaging (MRI) in male and female starlings, analyzing the entire brain, monitoring birds longitudinally and determining the neuronal correlates of seasonal variations in plasma hormone levels and song behavior. The first MRI studies in songbirds used manganese enhanced MRI to visualize the SCS in a living bird and validated previously described brain volume changes related to different seasons and testosterone. MRI studies with testosterone implantation established how the consequential boost in singing was correlated to structural changes in the SCS, indicating activity-induced neuroplasticity as song proficiency increased. Next, diffusion tensor MRI explored seasonal neuroplasticity in the entire brain, focusing on networks beyond the SCS, revealing that other sensory systems and even the cerebellum, which is important for the integration of sensory perception and song behavior, experience neuroplasticity starting in the photosensitive period. Functional MRI showed that olfactory, and auditory processing was modulated by the seasons.The convergence of seasonal variations in so many sensory and sensorimotor systems resembles multisensory neuroplasticity during the critical period early in life.This sheds new light on seasonal songbirds as a model for unlocking the brain by recreating seasonally the permissive circumstances for heightened neuroplasticity.

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Brain estrogen production and the encoding of recent experience

Cited by 16 publications

References 62 publications

Adverse Effects of Aromatase Inhibition on the Brain and Behavior in a Nonhuman Primate

Adverse Effects of Aromatase Inhibition on the Brain and Behavior in a Nonhuman Primate

Sex steroid hormones and brain function:PETimaging as a tool for research

A brain for all seasons: An in vivo MRI perspective on songbirds

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