Genistein alleviates anxiety-like behaviors in post-traumatic stress disorder model through enhancing serotonergic transmission in the amygdala

Pomegranate (Punica granatum L.) and its phytochemicals as anxiolytic; an underreported effect with therapeutic potential: A systematic review

Anxiety is a mental disorder characterized by excessive concern about possible future threats that, if prolonged, becomes a pathology that must be controlled through psychotherapy and medication. Currently, the pharmacological treatment for anxiety involves the use of antidepressants and benzodiazepines; however, these treatments often come with adverse effects. Thus, there is a need to seek natural compounds that can help alleviate anxiety and reduce these side effects. On the other hand, pomegranate (PG) fruit is known to have important health benefits, which have been compiled in several reviews. However, its anxiolytic effect has not been thoroughly studied, and clinical research on this topic is lacking. The aim of this work was to conduct a systematic review of studies exploring the anxiolytic-like effect of PG and its phytochemicals. Databases such as Pubmed, ScienceDirect, Springer link, Google scholar, Worldwide science, and Web of science were searched for articles using predetermined terms. Inclusion criteria were established, and original articles that met these criteria were selected. The data collected included information on PG part and variety, species, sample size, anxiety model, dose, route and time of administration, reference drug, main results, and the mechanisms of action. Fifty-nine studies were found that reported the anxiolytic-like effect of PG and its phytochemicals such as anthocyanins, flavonoids, tannins, organic acids, and xanthonoids. The literature suggests that the mechanisms of action behind this effect involved the inhibition of the GABAergic receptor, NMDA, CaMKII/CREB pathway; the reduction of oxidative stress, inhibiting TLR4 and nNOS; modulation of cytokines and the expression of NFkB, GAD67, and iNOS, as well as the activation of Nrf2 and AMPK. PG and some of its phytochemicals could be considered as a novel alternative for the treatment of pathological anxiety. This review is the first to document the anxiolytic-like effect of PG.

Dissecting the Relationship Between Neuropsychiatric and Neurodegenerative Disorders

Neurodegenerative diseases (NDDs) and neuropsychiatric disorders (NPDs) are two common causes of death in elderly people, which includes progressive neuronal cell death and behavioral changes. NDDs include Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, and motor neuron disease, characterized by cognitive defects and memory impairment, whereas NPDs include depression, seizures, migraine headaches, eating disorders, addictions, palsies, major depressive disorders, anxiety, and schizophrenia, characterized by behavioral changes. Mounting evidence demonstrated that NDDs and NPDs share an overlapping mechanism, which includes post-translational modifications, the microbiota-gut-brain axis, and signaling events. Mounting evidence demonstrated that various drug molecules, namely, natural compounds, repurposed drugs, multitarget directed ligands, and RNAs, have been potentially implemented as therapeutic agents against NDDs and NPDs. Herein, we highlighted the overlapping mechanism, the role of anxiety/stress-releasing factors, cytosol-to-nucleus signaling, and the microbiota-gut-brain axis in the pathophysiology of NDDs and NPDs. We summarize the therapeutic application of natural compounds, repurposed drugs, and multitarget-directed ligands as therapeutic agents. Lastly, we briefly described the application of RNA interferences as therapeutic agents in the pathogenesis of NDDs and NPDs. Neurodegenerative diseases and neuropsychiatric diseases both share a common signaling molecule and molecular phenomenon, namely, pro-inflammatory cytokines, γCaMKII and MAPK/ERK, chemokine receptors, BBB permeability, and the gut-microbiota-brain axis. Studies have demonstrated that any alterations in the signaling mentioned above molecules and molecular phenomena lead to the pathophysiology of neurodegenerative diseases, namely, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, and neuropsychiatric disorders, such as bipolar disorder, schizophrenia, depression, anxiety, autism spectrum disorder, and post-traumatic stress disorder.

The research progress on the anxiolytic effect of plant-derived flavonoids by regulating neurotransmitters

Phytopharmaceuticals have attracted a lot of attention due to their multicomponent and multiple targets. The natural phenolic chemicals known as flavonoids are found in a wide variety of plants, fruits, vegetables, and herbs. Recently, they have been found to have modulatory effects on anxiety disorders, with current research focusing on the modulation of neurotransmitters. There has not yet been a review of the various natural flavonoid monomer compounds and total plant flavonoids that have been found to have anxiolytic effects. The study on the anti-anxiety effects of plant-derived flavonoids on neurotransmitters was reviewed in this paper. We, therefore, anticipate that further study on the conformational interaction underlying flavonoids' anti-anxiety effects will offer a theoretical framework for the creation of pertinent treatments.

Housing Environment Affects Pubertal Onset, Anxiety-like Behavior, and Object Interaction in Male and Female Long Evans Rats

Rodents used for research can be humanely housed in a variety of ways. As such, a vast number of different housing environments are used, but are often not described in research publications. However, many elements of housing environments, including bedding, diet, water bottles, and cage material, can expose rodents to natural and synthetic compounds that can have lasting effects on the body, brain, and behavior. Some environmental items contain endocrine-disrupting compounds (EDCs), which can affect many commonly assessed physiological and behavioral endpoints in rodents. Here, we compare the effects of 2 commonly used housing environments for male and female Long Evans rats on body weight, pubertal onset, and a battery of behavioral tests measuring activity, anxiety-like behavior, and cognition. One standard environment was comparatively high in EDCs (standard rodent chow, plastic cages, plastic water bottles, and corncob bedding), while the other was a relatively low-EDC environment (phytoestrogen-free chow, polysulfone cages, glass water bottles, and wood-chip bedding). As compared with the Standard group, rats raised in the Low-EDC environment reached puberty earlier, displayed less anxiety-like behavior in the elevated plus maze and open field test, and showed less overall object exploration in the novel object recognition task. These effects occurred only if rats had been raised in these conditions since conception. An acute change from one environment to the other in adulthood did not yield these same effects. These results provide further evidence for the effects of common housing environments on development and behavior and highlight the importance of reporting environmental conditions in the literature to promote reproducibility in research using animal subjects.

A prognostic study on the effect of post-traumatic stress disorder on cerebral ischaemia reperfusion-induced stroke

OBJECTIVES

Previous studies have been established that persons who experienced a stroke are soon likely to develop several anxiety disorders. In which one of the major anxiety disorders is Post-traumatic Stress Disorder (PTSD). Yet, the likelihood of PTSD in conjunction with cerebral stroke has not been well described. Hence, we evaluated the impact of PTSD on cerebral stroke in rodents subjected to single prolonged stress (SPS) and bilateral common carotid artery occlusion (BCCAo), respectively.

METHODS

The relation between PTSD and cerebral stroke is evaluated by performing behavioural, biochemical, histopathological, and brain lesion area measurement studies.

RESULTS

Interestingly, SPS + BCCAo induction increased behavioural abnormalities like cognitive impairment and anxiety-like behaviour compared to SPS and BCCAo groups alone. Motor impairment was also observed in SPS + BCCAo rats compared to SPS rats, whereas no change with BCCAo rats. Furthermore, increased brain tissue MDA, acetylcholinesterase, and decreased SOD, catalase, and GSH were observed in SPS + BCCAo subjected rats compared to SPS and BCCAo rats alone. Additionally, SPS + BCCAo induction considerably increased the plasma corticosterone levels and caused severe neurotransmitter alterations. The SPS + BCCAo exposure significantly increased the brain lesion area in comparison with BCCAo rats. Moreover, severe histopathological alterations were observed in the hippocampus (CA1) of SPS + BCCAo rats compared to SPS and BCCAo rats alone.

CONCLUSIONS

In conclusion, our study results suggested that SPS-induced PTSD may aggravate the BCCAo induced cerebral ischaemia-reperfusion injury.

The role of flavonoids in inhibiting IL-6 and inflammatory arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that primarily affects the synovial joints. RA has well-known clinical manifestations and can cause progressive disability and premature death along with socioeconomic burdens. Interleukin-6 (IL-6) has been implicated in the pathology of RA where it can stimulate pannus formation, osteoclastogenesis, and oxidative stress. Flavonoids are plant metabolites with beneficial pharmacological effects, including anti-inflammatory, antioxidant, antidiabetic, anticancer, and others. Flavonoids are polyphenolic compounds found in a variety of plants, vegetables, and fruits. Many flavonoids have demonstrated anti-arthritic activity mediated mainly through the suppression of pro-inflammatory cytokines. This review thoroughly discusses the accumulate data on the role of flavonoids on IL-6 in RA.

Genistein, a Natural Isoflavone, Alleviates Seizure-Induced Respiratory Arrest in DBA/1 Mice

Objective: Sudden unexpected death in epilepsy (SUDEP) is a fatal event that ranks second in years of potential life lost among neurological disorders. Seizure-induced respiratory arrest (S-IRA) is the primary instigator leading to death in many SUDEP cases. However, there are currently no effective preventive strategies against S-IRA other than the seizure control. Therefore, it is critical to develop new avenues to prevent SUDEP by investigating the pharmacological interventions of S-IRA. In the present study, we examined the effect of genistein, an isoflavone found in various dietary vegetables, on the incidence of S-IRA in DBA/1 mice.

Methods: DBA/1 mice exhibited generalized seizures and S-IRA when subjected to acoustic stimulation. Genistein was intraperitoneally administered alone or in combination with an adrenoceptor antagonist and a serotonin (5-HT) receptor antagonist, respectively. The effects of drug treatments on S-IRA incidence and seizure behaviors were examined.

Results: The incidence of S-IRA in DBA/1 mice was significantly reduced 2 h after injection of genistein at 1–90 mg/kg as compared with that in the vehicle control. Genistein could block S-IRA without interfering with any component of seizures, especially at relatively lower dosages. The S-IRA-suppressing effect of genistein was reversed by an α2 adrenoceptor antagonist but was not altered by an α1 antagonist. The inhibitory effect of genistein on S-IRA was not affected by a 5-HT₃ or 5-HT_2A receptor antagonist.

Significance: Our data show that genistein reduces S-IRA incidence and can specifically block S-IRA in DBA/1 mice. Its suppressing effect on S-IRA is dependent on activating α2 adrenoceptors. Our study suggests that genistein, a dietary supplement, is potentially useful to prevent SUDEP in at-risk patients.

Cellular and molecular mechanisms of genistein in prevention and treatment of diseases: An overview

Genistein is the simplest secondary metabolite in soybeans and belongs to a group of compounds called isoflavones. It is a phytoestrogen and it makes up more than 60% of soy isoflavones. Studies have shown the anti-inflammatory, anti-apoptotic, and anti-angiogenic effects of genistein in addition to its modulatory effects on steroidal hormone receptors. In this review, we discuss the pharmacologic and therapeutic effects of genistein on various diseases. PRACTICAL APPLICATIONS: In this review, we have discussed the therapeutic effects of genistein as the main constituent of soybeans on health conditions. Its antioxidant, anti-inflammatory, anti-apoptotic and, anti-angiogenic effects need more attention. The pharmacological properties of genistein make this natural isoflavone a potential treatment for various diseases such as postmenopausal symptoms, cancer, bone, brain, and heart diseases. Special emphasis should be given to it, resulting in using it in clinical as a safe, potent, and bioactive molecule.

Mental Health Benefits of Exercise and Genistein in Elderly Rats

Elderly is a part of life that is associated with physical and mental disorders. The present study aimed to investigate the effect of 8 weeks of high-intensity interval training (HIIT) along with genistein (Ge) on memory, anxiety, physical persistence and aerobic power in elderly rats. Forty elderly rats were randomly assigned to five groups of eight rats including 1) control (C), 2) sham (Sh), 3) HIIT, 4) HIIT+Ge, and 5)Ge. During 8-week groups 3 and 4 performed HIIT for three sessions per week and groups 4 and 5 received 60 mg/kg/day Ge peritoneally. Physical persistence (by forced swimming test), memory (by shuttle box and Y maze tests), anxiety (by elevated plus-maze test) and aerobic power (by exhaustive running on treadmill) were measured. HIIT, Ge, and HIIT+Ge significantly increased physical persistence and memory (P ≤0.05), HIIT and HIIT+Ge significantly decrease anxiety and increased aerobic power (P ≤0.05) and HIIT+Ge had higher effect on the decrease of anxiety and increase of memory compared to HIIT and Ge (P≤0.05). Although HIIT and Ge alone can enhance physical persistence, memory and anxiety in elderly rats nevertheless it seems that HIIT simultaneously with Ge has more favorable mental health benefits compared to HIIT and Ge alone.

The Calcium/Calmodulin-Dependent Kinases II and IV as Therapeutic Targets in Neurodegenerative and Neuropsychiatric Disorders

CaMKII and CaMKIV are calcium/calmodulin-dependent kinases playing a rudimentary role in many regulatory processes in the organism. These kinases attract increasing interest due to their involvement primarily in memory and plasticity and various cellular functions. Although CaMKII and CaMKIV are mostly recognized as the important cogs in a memory machine, little is known about their effect on mood and role in neuropsychiatric diseases etiology. Here, we aimed to review the structure and functions of CaMKII and CaMKIV, as well as how these kinases modulate the animals’ behavior to promote antidepressant-like, anxiolytic-like, and procognitive effects. The review will help in the understanding of the roles of the above kinases in the selected neurodegenerative and neuropsychiatric disorders, and this knowledge can be used in future drug design.

Antidepressant-Like Effects of Hesperidin in Animal Model of Post-Traumatic Stress Disorder

OBJECTIVE

Post-traumatic stress disorder (PTSD) is a psychiatric disorder characterized by depression and anxiety, that arises due to an imbalance of neurotransmitters in response to excessive stress. Hesperidin (HSD) is a naturally occurring flavonoid shown to exert a variety of biological activities, including antioxidant, anti-inflammatory, and neuroprotective effects.

METHODS

This study was used the open field test (OFT) and forced swimming test (FST) to examine the effects of HSD on the depression-like response of rats after exposure to a single prolonged stress (SPS) leading to the dysregulation of the serotonergic activation system. Male rats were given HSD (20, 50, and 100 mg/kg, intraperitoneal injection, n=6-7 per group) once daily for 14 days after exposure to SPS. The influence of administration of HSD on SPS-induced behavioral responses and concentrations of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), and monoamine oxidase-A (MAO-A) in the rat brain were also investigated using enzyme-linked immunoassays (ELISAs).

RESULTS

Daily HSD administration signifificantly improved depression-like behaviors in the FST (P0.05), increased the number of lines crossed in the central zone of the OFT (P0.01), and reduced freezing behavior both in contextual and cued fear conditioning. HSD treatment also attenuated the reduction in SPS-induced 5-HT concentrations in the hippocampus and amygdala. This increase in 5-HT concentrations during HSD treatment was partially attributed to a decrease in the 5-HIAA/5-HT ratio in the hippocampus of rats with PTSD. Furthermore, HSD treatment inhibited activity of MAO-A and decreases of tryptophan hydroxylase-1 expression in the hippocampus.

CONCLUSION

HSD was shown to exert antidepressant effects in rats exposed to SPS, suggesting that this natural flflavonoid may be an effective medicine for PTSD.

Genistein Prevents Single Prolonged Stress-Induced Cognitive Impairment in a Post-Traumatic Stress Disorder Rat Model via Activation of the Serotonergic System

Post-traumatic stress disorder (PTSD) is a stress-associated mental disorder characterized by an imbalance of neurotransmitters in response to traumatic events or fear. Genistein (GEN), a natural isoflavone, has been shown to exhibit neuroprotective effects. Here, we used the Morris water maze (MWM) and object recognition task (ORT) tests to examine the effects of GEN on cognitive impairment in rats after exposure to single prolonged stress (SPS), and its interaction with the serotonergic system. After exposure to SPS, male rats received GEN (2, 4, and 10 mg/kg, i.p.) for 14 days. Daily GEN administration significantly improved cognitive function in the ORT and MWM tests. GEN treatment also inhibited SPS-induced decreases in serotonin (5-HT) levels in the medial prefrontal cortex and hippocampus. These increased 5-HT concentrations in response to GEN treatment could be partially attributed to the ratio of 5-hydroxyindoleacetic acid/5-HT in the hippocampus. Our findings suggest that GEN significantly attenuates SPS-induced memory deficits in rats and may represent an effective therapeutic option for the treatment of PTSD.

Silibinin prevents depression-like behaviors in a single prolonged stress rat model: the possible role of serotonin

Background

Post-traumatic stress disorder (PTSD) is an extreme mood disorder that occurs after experiencing extreme stress, and patients with this disorder are known to accompany with symptoms of depression, anxiety, and memory impairments. Silibinin (SIL) is a natural polyphenolic flavonoid and is the main active ingredient of silymarin, which is primarily extracted from the milk thistle. Although some studies have assessed the properties of this flavonoid, the potential of SIL as a treatment for PTSD patients and its mechanisms of action have yet to be fully elucidated.

Methods

After exposure to a model of single prolonged stress (SPS), the open field test (OFT) and forced swimming test (FST), were used to investigate the effects of SIL on anxiety- and depression-like symptoms in male rats. The rats received of SIL (25, 50, and 100 mg/kg) for 14 days following exposure to SPS.

Results

Administration of SIL significantly improved anxiety-like behaviors in the OFT, depression-like behaviors in the FST, and freezing behavior in fear conditioning test. SIL also increased levels of serotonin in the hippocampus (Hipp) and amygdala, and enhanced expression of tryptophan hydroxylase-1 mRNA in the Hipp. The administration of SIL also inhibited SPS-induced decreases dopamine levels and increases norepinephrine levels in the Hipp.

Conclusions

Taken together, the present findings suggest that SIL can be a useful therapeutic ingredient for the treatment of trauma stress-associated symptoms, including PTSD-induced anxiety and depression caused by PTSD.

Dietary phytoestrogens modulate aggression and activity in social behavior circuits of male mice

Phytoestrogens comprise biologically active constituents of human and animal diet that can impact on systemic and local estrogen functions in the brain. Here we report on the importance of dietary phytoestrogens for maintaining activity in a brain circuit controlling aggressive and social behavior of male mice. After six weeks of low-phytoestrogen chronic diet (diadzein plus genistein <20 μg/g) a reduction of intermale aggression and altered territorial marking behavior could be observed, compared to littermates on a standard soy-bean based diet (300 μg/g). Further, mice on low-phyto diet displayed a decrease in sociability and a reduced preference for social odors, indicating a general disturbance of social behavior. Underlying circuits were investigated by analysing the induction of the activity marker c-Fos upon social encounter. Low-phyto diet led to a markedly reduced c-Fos induction in the medial as well as the cortical amygdala, the lateral septum, medial preoptic area and bed nucleus of the stria terminalis. No difference between groups was observed in the olfactory bulb. Together our data suggest that dietary phytoestrogens critically modulate social behavior circuits in the male mouse brain.

Genistein as Potential Therapeutic Candidate for Menopausal Symptoms and Other Related Diseases

Plant-derived compounds have recently attracted greater interest in the field of new therapeutic agent development. These compounds have been widely screened for their pharmacological effects. Polyphenols, such as soy-derived isoflavones, also called phytoestrogens, have been extensively studied due to their ability to inhibit carcinogenesis. These compounds are chemically similar to 17β-estradiol, and mimic the binding of estrogens to its receptors, exerting estrogenic effects in target organs. Genistein is an isoflavone derived from soy-rich products and accounts for about 60% of total isoflavones found in soybeans. Genistein has been reported to exhibit several biological effects, such as anti-tumor activity (inhibition of cell proliferation, regulation of the cell cycle, induction of apoptosis), improvement of glucose metabolism, impairment of angiogenesis in both hormone-related and hormone-unrelated cancer cells, reduction of peri-menopausal and postmenopausal hot flashes, and modulation of antioxidant effects. Additionally, epidemiological and clinical studies have reported health benefits of genistein in many chronic diseases, such as cardiovascular disease, diabetes, and osteoporosis, and aid in the amelioration of typical menopausal symptoms, such as anxiety and depression. Although the biological effects are promising, certain limitations, such as low bioavailability, biological estrogenic activity, and effects on target organs, have limited the clinical applications of genistein to some extent. Moreover, studies report that modification of its molecular structure may eliminate the biological estrogenic activity and its effects on target organs. In this review, we summarize the potential benefits of genistein on menopause symptoms and menopause-related diseases like cardiovascular, osteoporosis, obesity, diabetes, anxiety, depression, and breast cancer.

Genistein Modifies Hamster Behavior and Expression of Inflammatory Factors following Subchronic Unpredictable Mild Stress

BACKGROUND

Previous studies have pointed to the protective role of genistein against stress adaptations although neuromolecular mechanisms are not yet fully known. With this work, we evaluated the influence of such a phytoestrogen on hamster behavioral and molecular activities following exposure to subchronic unpredictable mild stress.

METHODS

The motor behaviors of hamsters (n = 28) were analyzed using elevated plus maze (EPM) test, hole board (HB) test, and forced swim test (FST). In addition, neurodegeneration events were assessed with amino cupric silver stain, while expression variations of tropomyosin receptor kinase B (TrkB), nuclear factor kappa-B1 (NF-κB1), and heat shock protein 70 (Hsp70) mRNAs were highlighted in limbic neuronal fields via in situ hybridization.

RESULTS

Genistein accounted for increased motor performances in EPM and HB tests but reduced immobility during FST, which were correlated with diminished argyrophilic signals in some limbic neuronal fields. Contextually, upregulated Hsp70 and TrkB mRNAs occurred in hippocampal (HIP) and hypothalamic neuronal fields. Conversely, diminished NF-κB1 levels were mainly obtained in HIP.

CONCLUSION

Hormonal neuroprotective properties of genistein corroborating anxiolytic and antidepressant role(s) through elevated expression levels of stress proteins and trophic factors may constitute novel therapeutic measures against emotional and stress-related motor performances.

Tetramethylpyrazine reverses anxiety-like behaviors in a rat model of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a trauma-induced psychiatric disorder characterized by impaired fear extermination, hyperarousal, and anxiety that may involve the release of monoamines in the fear circuit. The reported pharmacological properties of tetramethylpyrazine (TMP) include anti-cancer, anti-diabetic, anti-atherosclerotic, and neuropsychiatric activities. However, the anxiolytic-like effects of TMP and its mechanism of action in PTSD are unclear. This study measured several anxiety-related behavioral responses to examine the effects of TMP on symptoms of anxiety in rats after single prolonged stress (SPS) exposure by reversing the serotonin (5-HT) and hypothalamic-pituitary-adrenal (HPA) axis dysfunction. Rats were given TMP (10, 20, or 40 mg/kg, i.p.) for 14 days after SPS exposure. Administration of TMP significantly reduced grooming behavior, increased the time spent and number of visits to the open arm in the elevated plus maze test, and significantly increased the number of central zone crossings in the open field test. TMP administration significantly reduced the freezing response to contextual fear conditioning and significantly restored the neurochemical abnormalities and the SPS-induced decrease in 5-HT tissue levels in the prefrontal cortex and hippocampus. The increased 5-HT concentration during TMP treatment might be partially attribute to the tryptophan and 5-hydroxyindoleacetic acid mRNA level expression in the hippocampus of rats with PTSD. These findings support a role for reducing the altered serotonergic transmission in rats with PTSD. TMP simultaneously attenuated the HPA axis dysfunction. Therefore, TMP may be useful for developing an agent for treating psychiatric disorders, such those observed in patients with PTSD.

Aqueous Extract of Pomegranate Alone or in Combination with Citalopram Produces Antidepressant-Like Effects in an Animal Model of Menopause: Participation of Estrogen Receptors

It has been reported that the aqueous extract of pomegranate (AE-PG) has polyphenols with estrogenic-like activities. The present work determines if AE-PG alone or in combination with the selective serotonin reuptake inhibitor, citalopram, has antidepressant-like effects. It was also analyzed the participation of estrogen receptors (ER). AE-PG (0.1, 1.0, 10, or 100 mg/kg) was evaluated in ovariectomized female Wistar rats subjected to the forced swimming test. The effects induced by AE-PG were compared with those of citalopram (2.5, 5.0, 10, and 20.0 mg/kg) and 17β-estradiol (E2; 2.5 5.0, and 10 μg/rat). Likewise, the combination of suboptimal doses of AE-PG (0.1 mg/kg) plus citalopram (2.5 mg/kg) was evaluated. To determine if ER participates in the antidepressant-like action of pomegranate, the estrogen antagonist tamoxifen (15 mg/kg) was administered with AE-PG (1 mg/kg). AE-PG produced antidepressant-like actions with a similar behavioral profile induced by citalopram and E2. Suboptimal doses of citalopram plus AE-PG produced antidepressant-like effects. Tamoxifen was able to block AE-PG's antidepressant-like actions. These results confirm the participation of ER in AE-PG's antidepressant-like effects. Furthermore, the additive effects observed with the combined treatment of AE-PG plus citalopram could be advantageous in the treatment of depressive disorders, such as menopause.