Estrogens of multiple classes and their role in mental health disease mechanisms

Lifespan Effects of Muscle-Specific Androgen Receptor Overexpression on Body Composition of Male and Female Rats

Androgenic actions of gonadal testosterone are thought to be a major mechanism promoting sex differences in body composition across the lifespan. However, this inference is based on studies of androgen receptor (AR) function in late adolescent or emerging adult rodents. Here we assess body composition and AR expression in skeletal muscle of rats at defined ages, comparing wild-type (WT) to transgenic human skeletal actin-driven AR overexpression (HSAAR) rats which overexpress AR in skeletal muscle. Male and female HSAAR and WT Sprague Dawley rats (N = 288) underwent dual-energy x-ray absorptiometry (DXA) scanning and tissue collection at postnatal day (PND) 1, 10, 21, 42, 70, 183, 243, and 365. Expected sex differences in body composition and muscle mass largely onset with puberty (PND-21), with no associated changes to skeletal muscle AR protein. In adulthood, HSAAR increased tibialis anterior (TA) and extensor digitorum longus mass in males, and reduced the expected gain in gonadal fat mass in both sexes. In WT rats, AR protein was reduced in soleus, but not TA, throughout life. Nonetheless, soleus AR protein expression was greater in male rats than female rats at all ages of sexual development, yet only at PND-70 in TA. Overall, despite muscle AR overexpression effects, results are inconsistent with major sex differences in body composition during sexual development being driven by changes in muscle AR, rather suggesting that changes in ligand promote sexual differentiation of body composition during pubertal timing. Nonetheless, increased skeletal muscle AR in adulthood can be sufficient to increase muscle mass in males, and reduce adipose in both sexes.

Sex differences in cognition following variations in endocrine status

Spatial memory, mediated primarily by the hippocampus, is responsible for orientation in space and retrieval of information regarding location of objects and places in an animal's environment. Since the hippocampus is dense with steroid hormone receptors and is capable of robust neuroplasticity, it is not surprising that changes in spatial memory performance occur following a variety of endocrine alterations. Here, we review cognitive changes in both spatial and nonspatial memory tasks following manipulations of the hypothalamic-pituitary-adrenal and gonadal axes and after exposure to endocrine disruptors in rodents. Chronic stress impairs male performance on numerous behavioral cognitive tasks and enhances or does not impact female cognitive function. Sex-dependent changes in cognition following stress are influenced by both organizational and activational effects of estrogen and vary depending on the developmental age of the stress exposure, but responses to gonadal hormones in adulthood are more similar than different in the sexes. Also discussed are possible underlying neural mechanisms for these steroid hormone-dependent, cognitive effects. Bisphenol A (BPA), an endocrine disruptor, given at low levels during adolescent development, impairs spatial memory in adolescent male and female rats and object recognition memory in adulthood. BPA's negative effects on memory may be mediated through alterations in dendritic spine density in areas that mediate these cognitive tasks. In summary, this review discusses the evidence that endocrine status of an animal (presence or absence of stress hormones, gonadal hormones, or endocrine disruptors) impacts cognitive function and, at times, in a sex-specific manner.

Female specific risk factors for the development of Alzheimer's disease neuropathology and cognitive impairment: Call for a precision medicine approach

Alzheimer's disease (AD) includes a long asymptomatic stage, which precedes the formal diagnosis of dementia. AD biomarker models provide a framework for precision medicine approaches during this stage. However, such approaches have ignored the possible influence of sex on cognition and brain health, despite female sex noted as a major risk factor. Since AD-related changes may emerge in midlife, intervention efforts are being redirected around this period. Midlife coincides with several endocrinological changes, such as the menopausal transition experienced by women. In this narrative review, we discuss evidence for sex-differences in AD neuropathological burden and outline key endocrinological mechanisms for both sexes, focussing on hormonal events throughout the lifespan that may influence female susceptibility to AD neuropathology and dementia onset. We further consider common non-modifiable (genetic) and modifiable (lifestyle and health) risk factors, highlighting possible sex-dependent differential effects for the AD disease course. Finally, we evaluate the studies selected for this review demonstrating sex-differences in cognitive, pathological and health factors, summarising the state of sex differences in AD risk factors. We further provide recommendations for targeted research on female-specific risk factors, to inform personalised strategies for AD-prevention and the promotion of female brain health.

A causal role of estradiol in human reinforcement learning

The sex hormone estradiol is hypothesized to play a key role in human cognition, and reward processing specifically, via increased dopamine D1-receptor signalling. However, the effect of estradiol on reward processing in men has never been established. To fill this gap, we performed a double-blind placebo-controlled study in which men (N = 100) received either a single dose of estradiol (2 mg) or a placebo. Subjects performed a probabilistic reinforcement learning task where they had to choose between two options with varying reward probabilities to maximize monetary reward. Results showed that estradiol administration increased reward sensitivity compared to placebo. This effect was observed in subjects' choices, how much weight they assigned to their previous choices, and subjective reports about the reward probabilities. Furthermore, effects of estradiol were moderated by reward sensitivity, as measured through the BIS/BAS questionnaire. Using reinforcement learning models, we found that behavioral effects of estradiol were reflected in increased learning rates. These results demonstrate a causal role of estradiol within the framework of reinforcement learning, by enhancing reward sensitivity and learning. Furthermore, they provide preliminary evidence for dopamine-related genetic variants moderating the effect of estradiol on reward processing.

Suicidality and Illness Course Worsening in a Male Patient with Bipolar Disorder during Tamoxifen Treatment for ER+/HER2+ Breast Cancer

PURPOSE

Tamoxifen is a selective estrogenic receptor modulator (SERM) drug. In addition to its common use in breast cancer ER+, Tamoxifen has been object of growing interest in psychiatry as antimanic drug. At the same time, clinical concerns about Tamoxifen's depressogenic effect have been repeatedly raised even without reaching univocal conclusions. We discuss the case of a 45-year-old-male with a diagnosis of Bipolar Disorder type II, treated with Tamoxifen as relapse prevention treatment after surgery for a ER+/HER2+ breast cancer. The patient required two psychiatric admissions in a few-month time span since he showed a progressive worsening of both depressive and anxiety symptoms, with the onset of delusional ideas of hopelessness and failure up to suicidal thoughts. The clinical picture showed poor response to treatment trials based on various associations of mood-stabilising, antidepressants, and antipsychotic drugs. During the second hospitalization, after a multidisciplinary evaluation, the oncologists agreed on Tamoxifen discontinuation upon the severity of the psychiatric condition. The patient underwent a close oncological and psychiatric follow-up during the following 12 months.

METHODS

Psychiatric assessments included the Montgomery-Asberg Depression Rating Scale (MADRS), the Hamilton Depression Scale (HAM-D), the Columbia Suicide Severity Rating Scale (C-SSRS), and the Quality of Life Enjoyment and Satisfaction Questionnaire Short Form (Q-LES-Q-SF). All questionnaires were administered at the time of the second hospitalization and in a one-year follow-up.

RESULTS

Suicidal ideation fully remitted and depressive symptoms markedly and rapidly improved in the aftermath of Tamoxifen discontinuation. The symptomatological improvement remained stable across one-year follow-up.

CONCLUSIONS

Male patients with a mood disorder history constitute a high-risk group as to Tamoxifen psychiatric side effects. The onset or worsening of depressive symptoms or suicidality should be carefully addressed and promptly treated, and clinicians should be encouraged to consider the possibility of discontinue or reduce Tamoxifen therapy after a multidisciplinary evaluation.

The Adaptive Immune System in Multiple Sclerosis: An Estrogen-Mediated Point of View

Multiple sclerosis (MS) is a chronic central nervous system inflammatory disease that leads to demyelination and neurodegeneration. The third trimester of pregnancy, which is characterized by high levels of estrogens, has been shown to be associated with reduced relapse rates compared with the rates before pregnancy. These effects could be related to the anti-inflammatory properties of estrogens, which orchestrate the reshuffling of the immune system toward immunotolerance to allow for fetal growth. The action of these hormones is mediated by the transcriptional regulation activity of estrogen receptors (ERs). Estrogen levels and ER expression define a specific balance of immune cell types. In this review, we explore the role of estradiol (E2) and ERs in the adaptive immune system, with a focus on estrogen-mediated cellular, molecular, and epigenetic mechanisms related to immune tolerance and neuroprotection in MS. The epigenome dynamics of immune systems are described as key molecular mechanisms that act on the regulation of immune cell identity. This is a completely unexplored field, suggesting a future path for more extensive research on estrogen-induced coregulatory complexes and molecular circuitry as targets for therapeutics in MS.

Dopaminergic Genes Polymorphisms and Prefrontal Cortex Efficiency Among Obese People - Whether Gender is a Differentiating Factor?

BACKGROUND

Obesity is a chronic condition associated with poorer cognitive functioning. Wisconsin Card Sorting Test (WCST) is a useful tool for evaluating executive functions. In this study, we assessed the association between dopaminergic gene polymorphisms: DAT1 (SLC6A3), COMTVal158Met, DRD4 (48-bp variable number of tandem repeats - VNTR) and WCST parameters to investigate the functions of the frontal lobes in obese individuals.

OBJECTIVE

To find the significant correlations between polymorphisms of DAT1, COMTVal158Met, DRD4 and executive functions in obese subjects.

METHODS

The analysis of the frequency of individual alleles was performed in 248 obese patients (179 women, 69 men). Evaluation of the prefrontal cortex function (operating memory and executive functions) was measured with the Wisconsin Card Sorting Test (WCST). Separate analyzes were performed in age subgroups to determine different activities and regulation of genes in younger and older participants.

RESULTS

Scores of WCST parameters were different in the subgroups of women and men and in the age subgroups. Regarding the COMT gene, patients with A/A and G/A polymorphisms showed significantly better WCST results in WCST_P, WCST_CC and WCST_1st. Regarding DAT1 men with L/L and L/S made less non-perseverative errors, which was statistically significant. In DRD4, significantly better WCST_1st results were found only in older women with S allele.

CONCLUSION

Obtained results indicate the involvement of dopaminergic transmission in the regulation of prefrontal cortex function. Data analysis indicates that prefrontal cortex function may ensue, from different elements such as genetic factors, metabolic aspects of obesity, and hormonal activity (estrogen).

Sex and gender differences in schizophrenic psychoses-a critical review

Many sex and gender differences in schizophrenic psychoses have been reported, but few have been soundly replicated. A stable finding is the later age of onset in women compared to men. Gender differences in symptomatology, comorbidity, and neurocognition seem to reflect findings in the general population. There is increasing evidence for estrogens being psychoprotective in women and for hypothalamic-pituitary-gonadal dysfunction in both sexes.More methodologically sound, longitudinal, multi-domain, interdisciplinary research investigating both sex (biological) and gender (psychosocial) factors is required to better understand the different pathogenesis and etiologies of schizophrenic psychoses in women and men, thereby leading to better tailored treatments and improved outcomes.

Evaluation of estrogen and G protein-coupled estrogen receptor 1 (GPER) levels in drug-naïve patients with attention deficit hyperactivity disorder (ADHD)

Estrogen has a crucial role in the regulation of reproductive and neuroendocrine function and exerts its effects through two classes of receptors, nuclear and membrane estrogen receptors (mERs). G protein-coupled estrogen receptor 1 (GPER) is a member of mERs, and despite limited research on the levels of GPER in patients with psychiatric diseases, a role of GPER in such conditions has been suggested. Here we evaluated serum estrogen and GPER levels in children with attention deficit hyperactivity disorder (ADHD) in relation to their age- and gender-matched healthy controls. A total of 82 children were included in the study, 47 drug- naïve patients with ADHD (age: 6-12 years; male/female: 34/13) and 35 healthy controls (age: 6-12 years; male/female: 19/16). The subgroups according to ADHD types were inattentive, hyperactive/impulsive, and combined. Serum estrogen was measured using an immunoassay system, while serum GPER was determined using a commercial sandwich enzyme-linked immunosorbent assay kit. Estrogen levels in children with ADHD were similar as in control group, while GPER levels were significantly lower in ADHD group compared to controls (p < 0.05). Logistic regression analysis showed a significant association between GPER levels and ADHD (p < 0.05), and no association between estrogen levels and ADHD (p > 0.05). No significant differences were found in GPER and estrogen levels between ADHD subgroups (p > 0.05). To the best of our knowledge, this study is the first to investigate estrogen and GPER levels in ADHD. Our preliminary findings suggest a relationship between serum GPER levels and ADHD, and this should be further investigated.

Investigation of variants in estrogen receptor genes and perinatal depression

OBJECTIVES

Depressive symptoms are common during pregnancy and after childbirth. Estrogen levels fluctuate greatly during the course of pregnancy and may contribute to mood instability. The first aim of this case-control study was to investigate whether variants in the two estrogen receptor genes might contribute to the genetic susceptibility to pregnancy-related depression using controls that were screened for postnatal depression. The second aim was to uncover new variants in the two estrogen receptor genes.

PATIENTS AND METHODS

Our study sample comprised 554 control subjects who had Edinburgh Postnatal Depression Scale (EPDS) scores below 7 at postnatal screening, and 159 patients with clinically diagnosed pregnancy-related depression. They were genotyped for four single-nucleotide polymorphisms (SNPs) and a dinucleotide repeat in the two genes: estrogen receptor α (ESR1) and estrogen receptor β (ESR2). Fifty-six cases with personal and/or family history of depression of psychiatric disorders were selected for resequencing of the two genes.

RESULTS

There was no statistically significant association with perinatal depression for all five variants. However, there was a trend toward higher frequencies of the genotypes associated with higher risk of depression for rs2077647 and rs4986938 in the case group. From resequencing, two novel ESR1 variants were identified from two different patients.

CONCLUSION

Our study that used screened controls with low EPDS scores and cases with clinically diagnosed pregnancy-related depression could not replicate the association with depression for any of the SNPs for both genotype and allele frequencies. Two novel SNPs were identified and could be further investigated in a larger sample set.

DAT1-Genotype and Menstrual Cycle, but Not Hormonal Contraception, Modulate Reinforcement Learning: Preliminary Evidence

Hormone by genotype interactions have been widely ignored by cognitive neuroscience. Yet, the dependence of cognitive performance on both baseline dopamine (DA) and current 17ß-estradiol (E2) level argues for their combined effect also in the context of reinforcement learning. Here, we assessed how the interaction between the natural rise of E2 in the late follicular phase (FP) and the 40 base-pair variable number tandem repeat polymorphism of the dopamine transporter (DAT1) affects reinforcement learning capacity. 30 women with a regular menstrual cycle performed a probabilistic feedback learning task twice during the early and late FP. In addition, 39 women, who took hormonal contraceptives (HC) to suppress natural ovulation, were tested during the "pill break" and the intake phase of HC. The present data show that DAT1-genotype may interact with transient hormonal state, but only in women with a natural menstrual cycle. We found that carriers of the 9-repeat allele (9RP) experienced a significant decrease in the ability to avoid punishment from early to late FP. Neither homozygote subjects of the 10RP allele, nor subjects from the HC group showed a change in behavior between phases. These data are consistent with neurobiological studies that found that rising E2 may reverse DA transporter function and could enhance DA efflux, which would in turn reduce punishment sensitivity particularly in subjects with a higher transporter density to begin with. Taken together, the present results, although based on a small sample, add to the growing understanding of the complex interplay between different physiological modulators of dopaminergic transmission. They may not only point out the necessity to control for hormonal state in behavioral genetic research, but may offer new starting points for studies in clinical settings.

Serum levels of GPER-1 in euthymic bipolar patients

INTRODUCTION

Estrogen and its receptors have been suggested as playing a role in the pathogenesis of bipolar disorder (BD). Estrogen functions through the estrogen receptors alpha and beta and the recently discovered G-protein-coupled estrogen receptor-1 (GPER-1). The aim of this study was to evaluate serum GPER-1 levels in euthymic BD patients.

PATIENTS AND METHODS

The study population consisted of 38 euthymic outpatients meeting the criteria for BD in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and 35 age- and gender-matched healthy controls. Medical histories were obtained and physical examinations and laboratory tests conducted.

RESULTS

Serum GPER-1 levels were measured in both patients and controls and found to be significantly higher in the BD patients than in controls. These results were not influenced by the medications in use.

CONCLUSION

The results of this study demonstrated that GPER-1 may play a role in BD pathophysiology.

Decreased levels of G protein-coupled estrogen receptor in children with autism spectrum disorders

Sex hormones, specially estrogen, and ıt is receptors plays a critical role in the pathogenesis of psychiatric disorders including autism spectrum disorders (ASD). The aim of this study was to investigate the relationship between ASD and G protein-coupled estrogen receptor (GPER), a recently discovered estrogen receptors, and also to study the relation of serum GPER levels with the severity of autistic symptoms. The present study included 45 children with drug naive ASD diagnosed by DSM-V criteria, aged between 3 and 12 years and 40 age- and gender-matched healthy controls. The severity of ASD was evaluated with the Childhood Autism Rating Scale (CARS) total score. The GPER levels in the serum were measured using the quantitative sandwich enzyme immunoassay technique. The serum GPER level was significantly lower in the ASD patients than in the controls. There was a negative significant correlation between the GPER level and the CARS score. There were no significant correlations between GPER level with estradiol and age. In conclusion, this study demonstrated that the decreased serum GPER levels were associated with ASD and GPER may play an important role in the etiology of ASD.

Does Health Perception, Dietary Habits and Lifestyle Effect Optimism? A Quantitative and Qualitative Study

The aim of the study was to investigate the relationship between optimism, general health perception, nutritional habits and lifestyle. A quantitative study was conducted on 500 Greek adults. A standardized questionnaire was used which consisted of the General Health Self-Assessment Questionnaire (GHSAQ), the Life Orientation Test-Revised (GrLOT-R), the dietary habits and lifestyle questionnaire. A qualitative study was conducted through interviews and focus groups. Participants' average score of GrLot-R was 20.47 (±4.017) units. The highest GrLot-R score was statistically correlated to more frequent consumption of fruits, salads, dairy products, olive oil, high-fibre cereals and water and to the lower consumption of canned products. Multivariate analysis showed that optimism is significantly positively predicted by the factors "Vitamin K & A", "Vitamin C", and negatively by "Preservatives." There was also a positive correlation between GrLot-R and GHSAQ. The qualitative study analysis showed that physical exercise, duration/quality of sleeping, family and stress affected participants' optimism. It seems that intrinsic factors as vitamins, preservatives, a healthy lifestyle and extrinsic factors as the family background and the environment that someone is raised, affect the level of optimism.

Estradiol and cognitive function: past, present and future

A historical perspective on estradiol's enhancement of cognitive function is presented, and research, primarily in animals, but also in humans, is reviewed. Data regarding the mechanisms underlying the enhancements are discussed. Newer studies showing rapid effects of estradiol on consolidation of memory through membrane interactions and activation of inter-cellular signaling pathways are reviewed as well as studies focused on traditional genomic mechanisms. Recent demonstrations of intra-neuronal estradiol synthesis and possible actions as a neurosteroid to promote memory are discussed. This information is applied to the critical issue of the current lack of effective hormonal (or other) treatments for cognitive decline associated with menopause and aging. Finally, the critical period hypothesis for estradiol effects is discussed along with novel strategies for hormone/drug development. Overall, the historical record documents that estradiol positively impacts some aspects of cognitive function, but effective therapeutic interventions using this hormone have yet to be realized.

The improvement of spatial memory deficits in APP/V717I transgenic mice by chronic anti-stroke herb treatment

In China, herbal medicine has an extensive history for the treatment of cerebrovascular diseases. Clinical studies have shown that stroke patients are more likely to experience significant memory decline in comparison to their healthy counterparts. Cognition is improved in stroke patients treated with herbal medicine active components, Geniposide (GP) and Geniposide Rg1 (GRg1) (together, called TLJN). However, the effect of TLJN in Alzheimer disease remains unknown. Therefore, we investigated the behavioral effect of TLJN in male and female APP/V717I transgenic (Tg) mice. We conducted two different treatment strategies: (1) pretreatment strategy: medically treated at the age of 3 months which lasted for 3 months; (2) early treatment strategy: medically treated at the age of 6 months which lasted for 4 months. In open field test, locomotor activity and anxiety-like behavior were not affected after TLJN administration in Tg mice. In Morris Water Maze test, spatial learning processes in both genders were improved by TLJN treatments. Furthermore, retrieval processes were significantly improved in the pretreatment strategy for only male mice, which also showed a trend for improved retrieval processes with early treatment. In the inhibitory avoidance test, TLJN enhanced learning processes. In addition, gender differences were found in Tg mice exposed to TLJN treatments. In Tg male mice, significant efficacy was seen at high and middle doses, and in Tg female mice, a low dose was more effective.

Interactions between estradiol, BDNF and dendritic spines in promoting memory

Several lines of evidence have converged to indicate that memory formation involves plasticity of dendritic spines in the medial prefrontal cortex (PFC) and the hippocampus. Memory varies with estrogen levels throughout the lifespan of the female. Generally, increased levels of estrogen are related to greater dendritic spine density on pyramidal cells in the PFC and the hippocampus and to improved memory function. Brain-derived neurotrophic factor (BDNF) is a growth factor which increases dendritic spines and enhances memory function. Estrogens increase BDNF levels in the PFC and the hippocampus. In the present review we provide evidence that estradiol and BDNF may work in concert to enhance cognition. In adult females, fluctuations in recognition memory following ovariectomy and estradiol replacement, during the estrous cycle, in pregnancy and with aging are accompanied by similar changes in circulating estradiol, BDNF levels and spine density alterations in the PFC and the hippocampus. In addition, both estradiol and BDNF induce spine plasticity via rapid membrane effects and slower transcriptional regulation via the CREB pathway. Moreover, estradiol increases BDNF levels through action on nuclear receptors. While the exact mechanism(s) for the influence of estrogens and BDNF on memory remain unclear, this combination may provide the basis for new and more effective strategies for treating age-related and neurodegenerative memory loss.

Estrogens facilitate memory processing through membrane mediated mechanisms and alterations in spine density

Estrogens exert sustained, genomically mediated effects on memory throughout the female life cycle, but here we review new studies documenting rapid effects of estradiol on memory, which are exerted through membrane-mediated mechanisms. Use of recognition memory tasks in rats shows that estrogens enhance memory consolidation within 1h. 17α-Estradiol is more potent than 17β-estradiol, and the dose response relationship between estrogens and memory is an inverted U shape. Use of specific estrogen receptor (ER) agonists suggests mediation by an ERβ-like membrane receptor. Enhanced memory is associated with increased spine density and altered noradrenergic activity in the medial prefrontal cortex and hippocampus within 30 min of administration. The environmental chemical, bisphenol-A, rapidly antagonizes enhancements in memory in both sexes possibly through actions on spines. Thus, estradiol and related compounds exert rapid alterations in cognition through non-genomic mechanisms, a finding which may provide a basis for better understanding and treating memory impairments.

Social dominance in female monkeys: dopamine receptor function and cocaine reinforcement

BACKGROUND

Brain imaging and behavioral studies suggest an inverse relationship between dopamine (DA) D2/D3 receptors and vulnerability to cocaine abuse, although most research has used males. For example, male monkeys that become dominant in a social group have significant elevations in D2/D3 receptor availability and are less vulnerable to cocaine reinforcement.

METHODS

DA D2/D3 receptor availability was assessed in female cynomolgus monkeys (n = 16) with positron emission tomography (PET) while they were individually housed, 3 months after stable social hierarchies had formed, and again when individually housed. In addition, PET was used to examine changes in dopamine transporter (DAT) availability after social hierarchy formation. After imaging studies were complete, monkeys received implantation with indwelling intravenous catheters and self-administered cocaine (.001-.1 mg/kg/injection) under a fixed-ratio 30 schedule of reinforcement. Acquisition of cocaine reinforcement occurred when response rates were significantly higher than when saline was self-administered.

RESULTS

Neither DAT nor D2/D3 receptor availability in the caudate nucleus and putamen was predictive of social rank, but both significantly changed after formation of social hierarchies. DA D2/D3 receptor availability significantly increased in females that became dominant, whereas DAT availability decreased in subordinate females. Dominant female monkeys acquired cocaine reinforcement at significantly lower doses than subordinate monkeys.

CONCLUSIONS

The relationship between D2/D3 receptor availability and vulnerability to cocaine reinforcement seems, on the basis of these findings, opposite in females and males. These data indicate that the social environment profoundly affects the DA system but does so in ways that have different functional consequences for females than for males.

Non-genomic effects of xenoestrogen mixtures

Xenoestrogens (XEs) are chemicals derived from a variety of natural and anthropogenic sources that can interfere with endogenous estrogens by either mimicking or blocking their responses via non-genomic and/or genomic signaling mechanisms. Disruption of estrogens' actions through the less-studied non-genomic pathway can alter such functional end points as cell proliferation, peptide hormone release, catecholamine transport, and apoptosis, among others. Studies of potentially adverse effects due to mixtures and to low doses of endocrine-disrupting chemicals have recently become more feasible, though few so far have included actions via the non-genomic pathway. Physiologic estrogens and XEs evoke non-monotonic dose responses, with different compounds having different patterns of actions dependent on concentration and time, making mixture assessments all the more challenging. In order to understand the spectrum of toxicities and their mechanisms, future work should focus on carefully studying individual and mixture components across a range of concentrations and cellular pathways in a variety of tissue types.

Menstrual exacerbation of schizophrenia symptoms

OBJECTIVE

To better understand premenstrual exacerbations of schizophrenia in women and weigh treatment options.

METHOD

A PubMed literature search was conducted, using the search terms 'schizophrenia', 'psychosis', 'menstrual exacerbation', 'hormones' and assessing relevance to premenstrual exacerbation of schizophrenia symptoms.

RESULTS

Exacerbations are usually distinguishable from periodic or menstrual psychosis, a relatively rare condition. Controversy continues about whether low estrogen periods of the month lead to an increase in schizophrenia symptoms among women of reproductive age or whether some women suffer from both schizophrenia and premenstrual dysphoric disorder (PMDD). No treatment trials of specific interventions have been conducted so that physicians must decide on a case-by-case basis whether to raise antipsychotic doses premenstrually, try estrogens or estrogen/progesterone combinations or selective estrogen receptor modulators, or target PMDD symptoms.

CONCLUSION

Clinicians need to be aware of premenstrual symptom aggravation in a large minority of women with schizophrenia. Treatment strategies will depend on the nature of the symptoms that are exacerbated. Optimal treatment needs to be adjusted to the individual woman.

Neuroprotective effects of 17β-estradiol rely on estrogen receptor membrane initiated signals

Besides its crucial role in many physiological events, 17β-estradiol (E2) exerts protective effects in the central nervous system. The E2 effects are not restricted to the brain areas related with the control of reproductive function, but rather are widespread throughout the developing and the adult brain. E2 actions are mediated through estrogen receptors (i.e., ERα and ERβ) belonging to the nuclear receptor super-family. As members of the ligand-regulated transcription factor family, classically, the actions of ERs in the brain were thought to mediate only the E2 long-term transcriptional effects. However, a growing body of evidence highlighted rapid, membrane initiated E2 effects in the brain that are independent of ER transcriptional activities and are involved in E2-induced neuroprotection. The aim of this review is to focus on the rapid effects of E2 in the brain highlighting the specific role of the signaling pathway(s) of the ERβ subtype in the neuroprotective actions of E2.

Anxiolytic effects and neuroanatomical targets of estrogen receptor-β (ERβ) activation by a selective ERβ agonist in female mice

The dichotomous anxiogenic and anxiolytic properties of estrogens have been reported to be mediated by two distinct neural estrogen receptors (ER), ERα and ERβ, respectively. Using a combination of pharmacological and genetic approaches, we confirmed that the anxiolytic actions of estradiol are mediated by ERβ and extended and these observations to demonstrate the neuroanatomical targets involved in ERβ activation in these behavioral responses. We examined the effects of the biologically active S-enantiomer of diarylpropionitrile (S-DPN) on anxiety-related behavioral measures, the corresponding stress hormonal response to hypothalamo-pituitary-adrenal axis reactivity, and potential sites of neuronal activation in mutant female mice carrying a null mutation for ERβ gene (βERKO). S-DPN administration significantly reduced anxiety-like behaviors in the open field, light-dark exploration, and the elevated plus maze (EPM) in ovariectomized wild-type (WT) mice, but not in their βERKO littermates. Stress-induced corticosterone (CORT) and ACTH were also attenuated by S-DPN in the WT mice but not in the βERKO mice. Using c-fos induction after elevated plus maze, as a marker of stress-induced neuronal activation, we identified the anterodorsal medial amygdala and bed nucleus of the stria terminalis as the neuronal targets of S-DPN action. Both areas showed elevated c-fos mRNA expression with S-DPN treatment in the WT but not βERKO females. These studies provide compelling evidence for anxiolytic effects mediated by ERβ, and its neuroanatomical targets, that send or receive projections to/from the paraventricular nucleus, providing potential indirect mode of action for the control of hypothalamo-pituitary-adrenal axis function and behaviors.

Estrogen receptors and the regulation of neural stress responses

It is now well established that estrogens can influence a panoply of physiological and behavioral functions. In many instances, the effects of estrogens are mediated by the 'classical' actions of two different estrogen receptors (ERs), ERα or ERβ. ERα and ERβ appear to have opposing actions in the control of stress responses and modulate different neurotransmitter or neuropeptide systems. Studies elucidating the molecular mechanisms for such regulatory processes are currently in progress. Furthermore, the use of ERα and ERβ knockout mouse lines has allowed the exploration of the importance of these receptors in behavioral responses such as anxiety-like and depressive-like behaviors. This review examines some of the recent advances in our knowledge of hormonal control of neuroendocrine and behavioral responses to stress and underscore the importance of these receptors as future therapeutic targets for control of stress-related signaling pathways.

Cocaine alters dendritic spine density in cortical and subcortical brain regions of the postpartum and virgin female rat

Cocaine use during pregnancy induces profound neural and behavioral deficits in both mother and offspring. The present study was designed to compare the effects of cocaine exposure on spine density of postpartum and virgin female rat brains. Timed, pregnant, primiparous rats were injected with either cocaine (30 mg/kg) or saline, once daily, from gestational day 8 to 20. Twenty-four hours after giving birth, dam brains were processed for Golgi-impregnation. Virgin females were also injected with the same dose of cocaine or saline for 12 days and sacrificed 24 h after the last injection for comparison. Pregnant rats had significantly greater spine density in the medial amygdala (MeA) and medial preoptic area (MPOA) and lower spine density in CA1 than virgin females independent of cocaine treatment. Cocaine significantly increased dendritic spine density on the apical branch of pyramidal cells in the prefrontal cortex (PFC, 15%), both apical (13%) and basal (14.8%) branches of CA1 and cells in the MeA (28%) of pregnant rats. In the MPOA, cocaine administration resulted in a decrease in dendritic spine density (14%) in pregnant rats. In virgin females, cocaine had fewer effects but did increase dendritic spine density on both branches of CA1 neurons and in the MeA. The present study is the first to demonstrate that spine density differs between pregnant and virgin females and that pregnancy makes the brain more vulnerable to cocaine, which has important clinical implications.

Estradiol and ERβ agonists enhance recognition memory, and DPN, an ERβ agonist, alters brain monoamines

Effects of estradiol benzoate (EB), ERα-selective agonist, propyl pyrazole triol (PPT) and ERβ-selective agonists, diarylpropionitrile (DPN) and Compound 19 (C-19) on memory were investigated in OVX rats using object recognition (OR) and placement (OP) memory tasks. Treatments were acute (behavior 4h later) or sub chronic (daily injections for 2 days with behavior 48 h later). Objects were explored in sample trials (T1), and discrimination between sample (old) and new object/location in recognition trials (T2) was examined after 2-4h inter-trial delays. Subjects treated sub chronically with EB, DPN, and C-19, but not PPT, discriminated between old and new objects and objects in old and new locations, suggesting that, at these doses and duration of treatments, estrogenic interactions with ERβ contribute to enhancements in recognition memory. Acute injections of DPN, but not PPT, immediately after T1, also enhanced discrimination for both tasks (C19 was not investigated). Effects of EB, DPN and PPT on anxiety and locomotion, measured on elevated plus maze and open field, did not appear to account for the mnemonic enhancements. Monoamines and metabolites were measured following DPN treatment in subjects that did not receive behavioral testing. DPN was associated with alterations in monoamines in several brain areas: indexed by the metabolite, 3-methoxy-4-hydroxyphenylglycol (MHPG), or the MHPG/norepinephrine (NE) ratio, NE activity was increased by 60-130% in the prefrontal cortex (PFC) and ventral hippocampus, and NE activity was decreased by 40-80% in the v. diagonal bands and CA1. Levels of the dopamine (DA) metabolite, homovanillic acid (HVA), increased 100% in the PFC and decreased by 50% in the dentate gyrus following DPN treatment. The metabolite of serotonin, 5-hydroxyindole acetic acid (5-HIAA), was increased in the PFC and CA3, by approximately 20%. No monoaminergic changes were noted in striatum or medial septum. Results suggest that ERβ mediates sub chronic and acute effects of estrogens on recognition memory and that memory enhancements by DPN may occur, in part, through alterations in monoaminergic containing systems primarily in PFC and hippocampus.