Differential effects of estradiol on neural and emotional stress response in postmenopausal women with remitted Major Depressive Disorder

Role of estrogen in sex differences in memory, emotion and neuropsychiatric disorders

Estrogen regulates a wide range of neuronal functions in the brain, such as dendritic spine formation, remodeling of synaptic plasticity, cognition, neurotransmission, and neurodevelopment. Estrogen interacts with intracellular estrogen receptors (ERs) and membrane-bound ERs to produce its effect via genomic and non-genomic pathways. Any alterations in these pathways affect the number, size, and shape of dendritic spines in neurons associated with psychiatric diseases. Increasing evidence suggests that estrogen fluctuation causes changes in dendritic spine density, morphology, and synapse numbers of excitatory and inhibitory neurons differently in males and females. In this review, we discuss the role of estrogen hormone in rodents and humans based on sex differences. First, we explain estrogen role in learning and memory and show that a high estrogen level alleviates the deficits in learning and memory. Secondly, we point out that estrogen produces a striking difference in emotional memories in men and women, which leads them to display sex-specific differences in underlying neuronal signaling. Lastly, we discuss that fluctuations in estrogen levels in men and women are related to neuropsychiatric disorders, including schizophrenia, autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), bipolar disorder (BPD), major depressive disorder (MDD), substance use disorder (SUD), and anxiety disorders.

Altered Sexual Response-Related Functional Connectivity and Morphometric Changes Influenced by Sex Hormones across Menopausal Status

Our study retrospectively investigated differential patterns of the functional connectivity (FC) of core brain regions synchronous with morphometric changes associated with sexual dysfunction in menopausal women, and their correlations with sexual hormones. Twenty-three premenopausal women (mean age: 41.52 ± 7.38 years) and 21 menopausal women (mean age: 55.52 ± 2.80 years) underwent sex hormone level measurements with high-resolution T1 and functional magnetic resonance imaging (MRI) during rest, neutral, and sexual arousal conditions. Analysis of covariance adjusted for age was used to compare the FC and gray matter (GM) volume between the two groups. Menopausal women showed lower GM volumes in the superior frontal gyrus (SFG), superior temporal pole, parahippocampal gyrus (PHG), hippocampus (Hip), amygdala (Amg), and cerebellum (Cb) compared to premenopausal women (p < 0.05). In addition, compared to premenopausal women, menopausal women showed decreased FC of seed regions involved in the SFG, frontal eye fields, and Amg, as well as target regions involved in the PHG, Hip, inferior frontal gyrus, Cb, and vermis (p < 0.005). Furthermore, the FC between the right Amg and right Cb and between the left Amg and right Cb during sexual arousal in both groups was positively correlated with total estrogen and estradiol levels, respectively (p < 0.01). The GM volume values in the right Amg and right Cb were positively correlated with total estrogen and estradiol levels (p < 0.05). Our study demonstrated an association between menopause-related differential FC and GM volume variations and fluctuating sex hormones. Our findings highlight that overlapping brain regions with functional alterations and morphometric changes are closely linked with menopausal symptom-related decreases in sexual arousal and hormone levels.

Neuroendocrine pathogenesis of perimenopausal depression

With the development of social economics and the increase of working pressure, more and more women are suffering from long-term serious stress and showing symptoms of perimenopausal depression (PMD). The incidence rate of PMD is increasing, and the physical and mental health are seriously affected. However, due to the lack of accurate knowledge of pathophysiology, its diagnosis and treatment cannot be accurately executed. By consulting the relevant literature in recent years, this paper elaborates the neuroendocrine mechanism of perimenopausal depression from the aspects of epigenetic changes, monoamine neurotransmitter and receptor hypothesis, glial cell-induced neuroinflammation, estrogen receptor, interaction between HPA axis and HPG axis, and micro-organism-brain gut axis. The purpose is to probe into new ways of treatment of PMD by providing new knowledge about the neuroendocrine mechanism and treatment of PMD.

Monoamine Neurotransmitters Control Basic Emotions and Affect Major Depressive Disorders

Major depressive disorder (MDD) is a common and complex mental disorder, that adversely impacts an individual’s quality of life, but its diagnosis and treatment are not accurately executed and a symptom-based approach is utilized in most cases, due to the lack of precise knowledge regarding the pathophysiology. So far, the first-line treatments are still based on monoamine neurotransmitters. Even though there is a lot of progress in this field, the mechanisms seem to get more and more confusing, and the treatment is also getting more and more controversial. In this study, we try to review the broad advances of monoamine neurotransmitters in the field of MDD, and update its effects in many advanced neuroscience studies. We still propose the monoamine hypothesis but paid special attention to their effects on the new pathways for MDD, such as inflammation, oxidative stress, neurotrophins, and neurogenesis, especially in the glial cells, which have recently been found to play an important role in many neurodegenerative disorders, including MDD. In addition, we will extend the monoamine hypothesis to basic emotions; as suggested in our previous reports, the three monoamine neurotransmitters play different roles in emotions: dopamine—joy, norepinephrine—fear (anger), serotonins—disgust (sadness). Above all, this paper tries to give a full picture of the relationship between the MDD and the monoamine neurotransmitters such as DA, NE, and 5-HT, as well as their contributions to the Three Primary Color Model of Basic Emotions (joy, fear, and disgust). This is done by explaining the contribution of the monoamine from many sides for MDD, such the digestive tract, astrocytes, microglial, and others, and very briefly addressing the potential of monoamine neurotransmitters as a therapeutic approach for MDD patients and also the reasons for its limited clinical efficacy, side effects, and delayed onset of action. We hope this review might offer new pharmacological management of MDD.