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Rodríguez-Santiago Y, Garay-Canales CA, Nava-Castro KE, Morales-Montor J. Sexual dimorphism in colorectal cancer: molecular mechanisms and treatment strategies. Biol Sex Differ 2024; 15:48. [PMID: 38867310 PMCID: PMC11170921 DOI: 10.1186/s13293-024-00623-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 05/26/2024] [Indexed: 06/14/2024] Open
Abstract
INTRODUCTION Sexual dimorphism significantly influences cancer incidence and prognosis. Notably, females exhibit a lower risk and favorable prognosis for non-reproductive cancers compared to males, a pattern observable beyond the scope of risk behaviors such as alcohol consumption and smoking. Colorectal cancer, ranking third in global prevalence and second in mortality, disproportionately affects men. Sex steroid hormones, particularly estrogens and androgens, play crucial roles in cancer progression, considering epidemiological in vivo and in vitro, in general estrogens imparting a protective effect in females and androgens correlating with an increasing risk of colorectal cancer development. MAIN BODY The hormonal impact on immune response is mediated by receptor interactions, resulting in heightened inflammation, modulation of NF-kB, and fostering an environment conducive to cancer progression and metastasis. These molecules also influence the enteric nervous system, that is a pivotal in neuromodulator release and intestinal neuron stimulation, also contributes to cancer development, as evidenced by nerve infiltration into tumors. Microbiota diversity further intersects with immune, hormonal, and neural mechanisms, influencing colorectal cancer dynamics. A comprehensive understanding of hormonal influences on colorectal cancer progression, coupled with the complex interplay between immune responses, microbiota diversity and neurotransmitter imbalances, underpins the development of more targeted and effective therapies. CONCLUSIONS Estrogens mitigate colorectal cancer risk by modulating anti-tumor immune responses, enhancing microbial diversity, and curbing the pro-tumor actions of the sympathetic and enteric nervous systems. Conversely, androgens escalate tumor growth by dampening anti-tumor immune activity, reducing microbial diversity, and facilitating the release of tumor-promoting factors by the nervous system. These findings hold significant potential for the strategic purposing of drugs to fine-tune the extensive impacts of sex hormones within the tumor microenvironment, promising advancements in colorectal cancer therapies.
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Affiliation(s)
- Yair Rodríguez-Santiago
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Coyoacán, Mexico City, 04510, México
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Edificio D, 1er piso, Circuito de Posgrados, Ciudad Universitaria, Ciudad de México, 04510, México
| | - Claudia Angelica Garay-Canales
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Coyoacán, Mexico City, 04510, México
| | - Karen Elizabeth Nava-Castro
- Grupo de Biología y Química Atmosféricas, Instituto de Ciencias de la Atmósfera y Cambio Climático, Universidad Nacional Autónoma de México, Ciudad Universitaria, CDMX, 04510, México
| | - Jorge Morales-Montor
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Coyoacán, Mexico City, 04510, México.
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Zuloaga DG, Lafrican JJ, Zuloaga KL. Androgen regulation of behavioral stress responses and the hypothalamic-pituitary-adrenal axis. Horm Behav 2024; 162:105528. [PMID: 38503191 PMCID: PMC11144109 DOI: 10.1016/j.yhbeh.2024.105528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/02/2024] [Accepted: 03/06/2024] [Indexed: 03/21/2024]
Abstract
Testosterone is a powerful steroid hormone that can impact the brain and behavior in various ways, including regulating behavioral and neuroendocrine (hypothalamic-pituitary-adrenal (HPA) axis) stress responses. Early in life androgens can act to alter development of brain regions associated with stress regulation, which ultimately impacts the display of stress responses later in life. Adult circulating androgens can also influence the expression of distinct genes and proteins that regulate stress responses. These changes in the brain are hypothesized to underlie the potent effects of androgens in regulating behaviors related to stress and stress-induced activation of the HPA axis. Androgens can induce alterations in these functions through direct binding to the androgen receptor (AR) or following conversion to estrogens and subsequent binding to estrogen receptors including estrogen receptor alpha (ERα), beta (ERβ), and G protein-coupled estrogen receptor 1 (GPER1). In this review, we focus on the role of androgens in regulating behavioral and neuroendocrine stress responses at different stages of the lifespan and the sex hormone receptors involved in regulating these effects. We also review the specific brain regions and cell phenotypes upon which androgens are proposed to act to regulate stress responses with an emphasis on hypothalamic and extended amygdala subregions. This knowledge of androgen effects on these neural systems is critical for understanding how sex hormones regulate stress responses.
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Affiliation(s)
- Damian G Zuloaga
- Department of Psychology, University at Albany, Albany, NY, USA.
| | | | - Kristen L Zuloaga
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, USA
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3
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Mbiydzenyuy NE, Joanna Hemmings SM, Shabangu TW, Qulu-Appiah L. Exploring the influence of stress on aggressive behavior and sexual function: Role of neuromodulator pathways and epigenetics. Heliyon 2024; 10:e27501. [PMID: 38486749 PMCID: PMC10937706 DOI: 10.1016/j.heliyon.2024.e27501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 02/29/2024] [Accepted: 02/29/2024] [Indexed: 03/17/2024] Open
Abstract
Stress is a complex and multifaceted phenomenon that can significantly influence both aggressive behavior and sexual function. This review explores the intricate relationship between stress, neuromodulator pathways, and epigenetics, shedding light on the various mechanisms that underlie these connections. While the role of stress in both aggression and sexual behavior is well-documented, the mechanisms through which it exerts its effects are multifarious and not yet fully understood. The review begins by delving into the potential influence of stress on the Hypothalamic-Pituitary-Adrenal (HPA) axis, glucocorticoids, and the neuromodulators involved in the stress response. The intricate interplay between these systems, which encompasses the regulation of stress hormones, is central to understanding how stress may contribute to aggressive behavior and sexual function. Several neuromodulator pathways are implicated in both stress and behavior regulation. We explore the roles of norepinephrine, serotonin, oxytocin, and androgens in mediating the effects of stress on aggression and sexual function. It is important to distinguish between general sexual behavior, sexual motivation, and the distinct category of "sexual aggression" as separate constructs, each necessitating specific examination. Additionally, epigenetic mechanisms emerge as crucial factors that link stress to changes in gene expression patterns and, subsequently, to behavior. We then discuss how epigenetic modifications can occur in response to stress exposure, altering the regulation of genes associated with stress, aggression, and sexual function. While numerous studies support the association between epigenetic changes and stress-induced behavior, more research is necessary to establish definitive links. Throughout this exploration, it becomes increasingly clear that the relationship between stress, neuromodulator pathways, and epigenetics is intricate and multifaceted. The review emphasizes the need for further research, particularly in the context of human studies, to provide clinical significance and to validate the existing findings from animal models. By better understanding how stress influences aggressive behavior and sexual function through neuromodulator pathways and epigenetic modifications, this research aims to contribute to the development of innovative protocols of precision medicine and more effective strategies for managing the consequences of stress on human behavior. This may also pave way for further research into risk factors and underlying mechanisms that may associate stress with sexual aggression which finds application not only in neuroscience, but also law, ethics, and the humanities in general.
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Affiliation(s)
- Ngala Elvis Mbiydzenyuy
- Basic Science Department, School of Medicine, Copperbelt University, P.O Box 71191, Ndola, Zambia
- Division of Medical Physiology, Biomedical Science Research Institute, Stellenbosch University, Private Bag X1, Matieland, 7602, Cape Town South Africa
| | - Sian Megan Joanna Hemmings
- Division of Molecular Biology & Human Genetics, Biomedical Science Research Institute, Stellenbosch University, Private Bag X1, Matieland, 7602, Cape Town South Africa
| | - Thando W. Shabangu
- Division of Medical Physiology, Biomedical Science Research Institute, Stellenbosch University, Private Bag X1, Matieland, 7602, Cape Town South Africa
| | - Lihle Qulu-Appiah
- Division of Medical Physiology, Biomedical Science Research Institute, Stellenbosch University, Private Bag X1, Matieland, 7602, Cape Town South Africa
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Giatti S, Diviccaro S, Cioffi L, Cosimo Melcangi R. Post-Finasteride Syndrome And Post-Ssri Sexual Dysfunction: Two Clinical Conditions Apparently Distant, But Very Close. Front Neuroendocrinol 2024; 72:101114. [PMID: 37993021 DOI: 10.1016/j.yfrne.2023.101114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/31/2023] [Accepted: 11/19/2023] [Indexed: 11/24/2023]
Abstract
Post-finasteride syndrome and post-SSRI sexual dysfunction, are two poorly explored clinical conditions in which men treated for androgenetic alopecia with finasteride or for depression with SSRI antidepressants show persistent side effects despite drug suspension (e.g., sexual dysfunction, psychological complaints, sleep disorders). Because of some similarities in the symptoms, common pathological mechanisms are proposed here. Indeed, as discussed, clinical studies and preclinical data obtained so far suggest an important role for brain modulators (i.e., neuroactive steroids), neurotransmitters (i.e., serotonin, and cathecolamines), and gut microbiota in the context of the gut-brain axis. In particular, the observed interconnections of these signals in these two clinical conditions may suggest similar etiopathogenetic mechanisms, such as the involvement of the enzyme converting norepinephrine into epinephrine (i.e., phenylethanolamine N-methyltransferase). However, despite the current efforts, more work is still needed to advance the understanding of these clinical conditions in terms of diagnostic markers and therapeutic strategies.
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Affiliation(s)
- Silvia Giatti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Silvia Diviccaro
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Lucia Cioffi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Roberto Cosimo Melcangi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy.
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Armbruster D, Lesch KP, Strobel A. The long and the short of it: 5-HTTLPR and moral judgement. Behav Brain Res 2023; 452:114524. [PMID: 37269929 DOI: 10.1016/j.bbr.2023.114524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 04/28/2023] [Accepted: 05/31/2023] [Indexed: 06/05/2023]
Abstract
Differences in moral sentiments are widespread. Increasingly, their biological correlates are investigated to elucidate potential sources of divergent moral attitudes and choices. Serotonin is one such potential modulator. We investigated the effects of a functional serotonergic polymorphism, 5-HTTLPR, which was previously linked to moral choices albeit with inconsistent findings. N = 157 healthy young adults completed a set of congruent and incongruent moral dilemmas. In addition to the traditional moral response score, this set allows by using a process dissociation (PD) approach an estimation a deontological and a utilitarian parameter. While there was no main effect of 5-HTTLPR on any of the three moral judgement parameters, there was an interaction effect between 5-HTTLPR and endocrine status on PD parameters, which was mainly due to the deontological but not the utilitarian parameter. In men and free cycling women, LL homozygotes showed reduced deontological tendencies compared to S allele carriers. Contrariwise, in women using oral contraceptives, LL homozygotes had increased deontology parameter scores. Furthermore, LL genotypes in general reported less difficulty in making harmful choices, which were in addition associated with less negative emotions. The findings suggest that 5-HTTLPR might be involved in modulating cognitive and emotional processes contributing to moral decisions.
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Affiliation(s)
- Diana Armbruster
- Personality Psychology and Assessment, Institute of Psychology, Chemnitz University of Technology, Chemnitz, Germany.
| | - Klaus-Peter Lesch
- Division of Molecular Psychiatry, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany; Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia; Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, the Netherlands
| | - Alexander Strobel
- Personality and Individual Differences, Faculty of Psychology, Technische Universität Dresden, Dresden, Germany
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Alwhaibi A, Alsanea S, Almadi B, Al-Sabhan J, Alosaimi FD. Androgen deprivation therapy and depression in the prostate cancer patients: review of risk and pharmacological management. Aging Male 2022; 25:101-124. [PMID: 35343371 DOI: 10.1080/13685538.2022.2053954] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Purpose: Despite the effectiveness of androgen deprivation therapy in advanced prostate cancer, serious neuropsychiatric consequences in androgen deprivation therapy (ADT)-treated patients, mainly depression, have been concerning and gained more attention recently. This narrative review aims to shed light on the risk and pharmacological management of ADT-induced depression in PCa patients.Methods: We searched PubMed, Scopus and Google Scholar databases using MESH keywords "Prostate cancer OR prostate neoplasm" AND "Depression" AND "Androgen Deprivation Therapy" AND "antidepressants". Search was limited to English and studies conducted on humans. Studies' titles and abstracts were screened, and further information were obtained from the text, if necessary, to decide whether studies are to be included in this review.Results: Our review revealed 23 studies confirming the occurrence and worsening of depressive symptoms in ADT-treated patients, which frequently require pharmacological interventions; whereas 10 studies indicated otherwise. All studies were prospective, retrospective, cross-sectional or case reports. Based on the incidence of depression provided by the observational studies, the average among ADT-treated patients was 18.23% (range: 2.1-46.9%), while it was 8.42% (range: 1.4-23.3%) in the non-ADT patients. Although several treatments have been used for depression in cancer patients, current knowledge lacks observational and controlled studies as well as clinical guidelines that demonstrate efficacy and safety of antidepressants and guide clinicians to the appropriate treatment in these patients, respectively. On the other side, a few clinical studies have been published regarding the efficacy of selective serotonin reuptake inhibitors, selective serotonin and norepinephrine reuptake inhibitors and/or saftey on other ADT associated adverse effects.Conclusions: Our work supports the recent attention towards mood issues as an adverse effect of ADT, and that greater awareness of this is warranted among clinicians. Clinical studies published regarding the use of antidepressants for other ADT associated adverse effects established the foundation that can be adopted to examine these therapies on ADT-induced depression.
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Affiliation(s)
- Abdulrahman Alwhaibi
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Sary Alsanea
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Bana Almadi
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Jawza Al-Sabhan
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Fahad D Alosaimi
- Department of Psychiatry, College of Medicine, King Saud University, Riyadh, Saudi Arabia
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7
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So SY, Savidge TC. Sex-Bias in Irritable Bowel Syndrome: Linking Steroids to the Gut-Brain Axis. Front Endocrinol (Lausanne) 2021; 12:684096. [PMID: 34093447 PMCID: PMC8170482 DOI: 10.3389/fendo.2021.684096] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 05/03/2021] [Indexed: 12/12/2022] Open
Abstract
Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder that is more common in females. Despite its high global incidence, the disease mechanism is still unclear and therapeutic options remain limited. The sexual dimorphism in IBS incidence suggests that sex steroids play a role in disease onset and symptoms severity. This review considers sex steroids and their involvement in IBS symptoms and the underlying disease mechanisms. Estrogens and androgens play important regulatory roles in IBS symptomology, including visceral sensitivity, gut motility and psychological conditions, possibly through modulating the gut-brain axis. Steroids are regulators of hypothalamic-pituitary-adrenal activity and autonomic nervous system function. They also modulate gut microbiota and enteric nervous systems, impacting serotonin and mast cell signaling. Sex steroids also facilitate bidirectional cross-talk between the microbiota and host following bacterial transformation and recycling of steroids by the intestine. The sex-specific interplay between sex steroids and the host provides neuroendocrinology insight into the pathophysiology, epigenetics and treatment of IBS patients.
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Affiliation(s)
- Sik Yu So
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
- Texas Children’s Microbiome Center, Department of Pathology, Texas Children’s Hospital, Houston, TX, United States
| | - Tor C. Savidge
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
- Texas Children’s Microbiome Center, Department of Pathology, Texas Children’s Hospital, Houston, TX, United States
- *Correspondence: Tor C. Savidge,
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Trujillo V, Valentim-Lima E, Mencalha R, Carbalan QSR, Dos-Santos RC, Felintro V, Girardi CEN, Rorato R, Lustrino D, Reis LC, Mecawi AS. Neonatal Serotonin Depletion Induces Hyperactivity and Anxiolytic-like Sex-Dependent Effects in Adult Rats. Mol Neurobiol 2020; 58:1036-1051. [PMID: 33083963 DOI: 10.1007/s12035-020-02181-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/14/2020] [Indexed: 12/16/2022]
Abstract
The serotoninergic system plays an important role in the ontogeny of the mammalian central nervous system, and changes in serotonin production during development may lead to permanent changes in brain cytoarchitecture and function. The present study investigated the programming effects of neonatal serotonin depletion on behavior and molecular components of the serotoninergic system in adult male and female rats. Subcutaneous para-chlorophenylalanine (pCPA) administration (100 mg kg-1) was performed daily on postnatal days 8-16 to deplete brain serotonin content. During adulthood, elevated plus-maze, open field, social interaction, forced swimming, and food, saline, and sucrose intake tests were performed. Relative expression of serotonin neurotransmission components in several brain areas was determined by qPCR. Additionally, serotonin immunofluorescence and neuropeptide mRNA expression were assessed in dorsal raphe (DRN) and paraventricular (PVN) nuclei, respectively. Rat performance in behavioral tests demonstrated a general increase in locomotor activity and active escape behavior as well as decreased anxiety-like behavior after neonatal brain serotonin depletion. The behavioral programming effects due to neonatal serotonin depletion were more pronounced in females than males. At the gene expression level, the mRNA of Tph1 and Tph2 were lower in DRN while Htr2c was higher in the amygdala of pCPA-treated males, while Htr1a, Htr2c, Oxt, Avp, Crh, and Trh were not different in any treatments or sex in PVN. The results indicate that neonatal serotonin depletion has long-term consequences on locomotion and anxiety-like behavior associated with long-lasting molecular changes in the brain serotoninergic system in adult rats.
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Affiliation(s)
- Verónica Trujillo
- Laboratory of Neuroendocrinology, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Botucatu, 862, Edifício de Ciências Biomédicas, 7° andar, Vila Clementino, São Paulo, CEP 04023-062, Brasil
- Departament of Physiology, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Evandro Valentim-Lima
- Laboratory of Neuroendocrinology, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Botucatu, 862, Edifício de Ciências Biomédicas, 7° andar, Vila Clementino, São Paulo, CEP 04023-062, Brasil
| | - Rodrigo Mencalha
- Department of Natural Sciences, Universidade Federal do Acre, Rio Branco, Brazil
| | - Quézia S R Carbalan
- Department of Physiological Sciences, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil
| | - Raoni C Dos-Santos
- Department of Physiological Sciences, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil
| | - Viviane Felintro
- Department of Physiological Sciences, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil
| | - Carlos E N Girardi
- Department of Psychobiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Rodrigo Rorato
- Laboratory of Neuroendocrinology, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Botucatu, 862, Edifício de Ciências Biomédicas, 7° andar, Vila Clementino, São Paulo, CEP 04023-062, Brasil
| | - Danilo Lustrino
- Department of Physiology, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Sergipe, São Cristóvão, Brazil
| | - Luis C Reis
- Department of Physiological Sciences, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil
| | - André S Mecawi
- Laboratory of Neuroendocrinology, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Botucatu, 862, Edifício de Ciências Biomédicas, 7° andar, Vila Clementino, São Paulo, CEP 04023-062, Brasil.
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Sex and the serotonergic underpinnings of depression and migraine. HANDBOOK OF CLINICAL NEUROLOGY 2020; 175:117-140. [PMID: 33008520 DOI: 10.1016/b978-0-444-64123-6.00009-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Most psychiatric disorders demonstrate sex differences in their prevalence and symptomatology, and in their response to treatment. These differences are particularly pronounced in mood disorders. Differences in sex hormone levels are among the most overt distinctions between males and females and are thus an intuitive underpinning for these clinical observations. In fact, treatment with estrogen and testosterone was shown to exert antidepressant effects, which underscores this link. Changes to monoaminergic signaling in general, and serotonergic transmission in particular, are understood as central components of depressive pathophysiology. Thus, modulation of the serotonin system may serve as a mechanism via which sex hormones exert their clinical effects in mental health disorders. Over the past 20 years, various experimental approaches have been applied to identify modes of influence of sex and sex hormones on the serotonin system. This chapter provides an overview of different molecular components of the serotonin system, followed by a review of studies performed in animals and in humans with the purpose of elucidating sex hormone effects. Particular emphasis will be placed on studies performed with positron emission tomography, a method that allows for human in vivo molecular imaging and, therefore, assessment of effects in a clinically representative context. The studies addressed in this chapter provide a wealth of information on the interaction between sex, sex hormones, and serotonin in the brain. In general, they offer evidence for the concept that the influence of sex hormones on various components of the serotonin system may serve as an underpinning for the clinical effects these hormones demonstrate.
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Zuloaga DG, Heck AL, De Guzman RM, Handa RJ. Roles for androgens in mediating the sex differences of neuroendocrine and behavioral stress responses. Biol Sex Differ 2020; 11:44. [PMID: 32727567 PMCID: PMC7388454 DOI: 10.1186/s13293-020-00319-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 07/09/2020] [Indexed: 12/17/2022] Open
Abstract
Estradiol and testosterone are powerful steroid hormones that impact brain function in numerous ways. During development, these hormones can act to program the adult brain in a male or female direction. During adulthood, gonadal steroid hormones can activate or inhibit brain regions to modulate adult functions. Sex differences in behavioral and neuroendocrine (i.e., hypothalamic pituitary adrenal (HPA) axis) responses to stress arise as a result of these organizational and activational actions. The sex differences that are present in the HPA and behavioral responses to stress are particularly important considering their role in maintaining homeostasis. Furthermore, dysregulation of these systems can underlie the sex biases in risk for complex, stress-related diseases that are found in humans. Although many studies have explored the role of estrogen and estrogen receptors in mediating sex differences in stress-related behaviors and HPA function, much less consideration has been given to the role of androgens. While circulating androgens can act by binding and activating androgen receptors, they can also act by metabolism to estrogenic molecules to impact estrogen signaling in the brain and periphery. This review focuses on androgens as an important hormone for modulating the HPA axis and behaviors throughout life and for setting up sex differences in key stress regulatory systems that could impact risk for disease in adulthood. In particular, impacts of androgens on neuropeptide systems known to play key roles in HPA and behavioral responses to stress (corticotropin-releasing factor, vasopressin, and oxytocin) are discussed. A greater knowledge of androgen action in the brain is key to understanding the neurobiology of stress in both sexes.
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Affiliation(s)
| | - Ashley L Heck
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | | | - Robert J Handa
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA.
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Kawabata-Sakata Y, Nishiike Y, Fleming T, Kikuchi Y, Okubo K. Androgen-dependent sexual dimorphism in pituitary tryptophan hydroxylase expression: relevance to sex differences in pituitary hormones. Proc Biol Sci 2020; 287:20200713. [PMID: 32517612 DOI: 10.1098/rspb.2020.0713] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Serotonin is a biogenic monoamine conserved across phyla that is implicated in diverse physiological and behavioural functions. On examining the expression of the rate-limiting enzymes in serotonin synthesis, tryptophan hydroxylases (TPHs), in the teleost medaka (Oryzias latipes), we found that males have much higher levels of tph1 expression as compared with females. This robust sexual dimorphism was found to probably result from the direct stimulation of tph1 transcription by androgen/androgen receptor binding to canonical bipartite androgen-responsive elements in its proximal promoter region. Our results further revealed that tph1 expression occurs exclusively in pro-opiomelanocortin (pomc)-expressing cells and that the resulting serotonin and its derivative melatonin inhibit the expression of the pituitary hormone genes, fshb, sl and tshb. This suggests that serotonin and/or melatonin synthesized in pomc-expressing cells act in a paracrine manner to suppress pituitary hormone levels. Consistent with these findings and the male-biased expression of tph1, the expression levels of fshb, sl and tshb were all higher in females than in males. Taken together, the male bias in tph1 expression and consequent serotonin/melatonin production presumably contribute to sex differences in the expression of pituitary hormones and ultimately in the physiological functions mediated by them.
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Affiliation(s)
- Yukika Kawabata-Sakata
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.,Department of Pathophysiology, Tokyo Medical University, Shinjuku, Tokyo 160-8402, Japan
| | - Yuji Nishiike
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| | - Thomas Fleming
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| | - Yukiko Kikuchi
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| | - Kataaki Okubo
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
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Tang S, Zhou X, Hu K, Liu P, Xiong M, Li H. The role of gonadal hormones in the hypoglossal discharge activity of rats exposed to chronic intermittent hypoxia. Brain Res Bull 2019; 149:175-183. [DOI: 10.1016/j.brainresbull.2019.04.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/15/2019] [Accepted: 04/18/2019] [Indexed: 10/27/2022]
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13
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Giatti S, Diviccaro S, Panzica G, Melcangi RC. Post-finasteride syndrome and post-SSRI sexual dysfunction: two sides of the same coin? Endocrine 2018; 61:180-193. [PMID: 29675596 DOI: 10.1007/s12020-018-1593-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/05/2018] [Indexed: 12/27/2022]
Abstract
Sexual dysfunction is a clinical condition due to different causes including the iatrogenic origin. For instance, it is well known that sexual dysfunction may occur in patients treated with antidepressants like selective serotonin reuptake inhibitors (SSRI). A similar side effect has been also reported during treatment with finasteride, an inhibitor of the enzyme 5alpha-reductase, for androgenetic alopecia. Interestingly, sexual dysfunction persists in both cases after drug discontinuation. These conditions have been named post-SSRI sexual dysfunction (PSSD) and post-finasteride syndrome (PFS). In particular, feeling of a lack of connection between the brain and penis, loss of libido and sex drive, difficulty in achieving an erection and genital paresthesia have been reported by patients of both conditions. It is interesting to note that the incidence of these diseases is probably so far underestimated and their etiopathogenesis is not sufficiently explored. To this aim, the present review will report the state of art of these two different pathologies and discuss, on the basis of the role exerted by three different neuromodulators such as dopamine, serotonin and neuroactive steroids, whether the persistent sexual dysfunction observed could be determined by common mechanisms.
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Affiliation(s)
- Silvia Giatti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Silvia Diviccaro
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Giancarlo Panzica
- Dipartimento di Neuroscienze "Rita Levi Montalcini", Università degli studi di Torino, Neuroscience Institute Cavallieri Ottolenghi (NICO), Orbassano, Italy
| | - Roberto Cosimo Melcangi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy.
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Hildebrandt T, Heywood A, Wesley D, Schulz K. Defining the Construct of Synthetic Androgen Intoxication: An Application of General Brain Arousal. Front Psychol 2018; 9:390. [PMID: 29651261 PMCID: PMC5885244 DOI: 10.3389/fpsyg.2018.00390] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/08/2018] [Indexed: 01/01/2023] Open
Abstract
Synthetic androgens (i. e., anabolic-androgenic steroids) are the primary component to the majority of problematic appearance and performance enhancing drug (APED) use. Despite evidence that these substances are associated with increased risk for aggression, violence, body image disturbances, and polypharmacy and can develop a pattern of chronic use consistent with drug dependence, there are no formal definitions of androgen intoxication. Consequently, the purpose of this paper is to establish a testable theory of androgen intoxication. We present evidence and theorize that synthetic androgen intoxication can be defined by a pattern of poor self-regulation characterized by increased propensity for a range of behaviors (e.g., aggression, sex, drug seeking, exercise, etc.) via androgen mediated effects on general brain arousal. This theory posits that androgens reduce threshold for emotional reactivity, motor response, and alertness to sensory stimuli and disrupt inhibitory control over the behaviors associated with synthetic androgen use. These changes result from alteration to basic neurocircuitry that amplifies limbic activation and reduces top-down cortical control. The implications for this definition are to inform APED specific hypotheses about the behavioral and psychological effects of APED use and provide a basis for establishing clinical, legal, and public health guidelines to address the use and misuse of these substances.
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Affiliation(s)
- Tom Hildebrandt
- Eating and Weight Disorders Program, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Ashley Heywood
- Eating and Weight Disorders Program, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Daniel Wesley
- Eating and Weight Disorders Program, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Kurt Schulz
- Eating and Weight Disorders Program, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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15
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Testosterone levels in healthy men correlate negatively with serotonin 4 receptor binding. Psychoneuroendocrinology 2017; 81:22-28. [PMID: 28426945 DOI: 10.1016/j.psyneuen.2017.03.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/14/2017] [Indexed: 12/20/2022]
Abstract
The serotonergic system integrates sex steroid information and plays a central role in mood and stress regulation, cognition, appetite and sleep. This interplay may be critical for likelihood of developing depressive episodes, at least in a subgroup of sensitive individuals. The serotonin 4 receptor (5-HT4R) indexes central serotonergic tonus, which may be related to endogenous sex-steroid levels in the mentally healthy state even though this remains elusive. Here we evaluate if peripheral levels of estradiol and testosterone are associated with 5-HT4R binding as imaged by [11C]SB207145 positron emission tomography in a group of 41 healthy men. We estimated global 5-HT4R binding using a latent variable model framework, which models shared correlation between 5-HT4R across multiple brain regions (hippocampus, amygdala, posterior and anterior cingulate, thalamus, pallidostriatum and neocortex). We tested whether testosterone and estradiol predict global 5-HT4R, adjusting for age. We found that testosterone, but not estradiol, correlated negatively with global 5-HT4R levels (p=0.02) suggesting that men with high levels of testosterone have higher cerebral serotonergic tonus. Our findings corroborate the link between sex hormone levels and serotonin signalling. Future longitudinal studies in clinical relevant populations are needed to elucidate the potential importance of testosterone in the pathophysiology of e.g. major depression and its treatment.
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Chang CC, Chang HA, Fang WH, Chang TC, Huang SY. Gender-specific association between serotonin transporter polymorphisms (5-HTTLPR and rs25531) and neuroticism, anxiety and depression in well-defined healthy Han Chinese. J Affect Disord 2017; 207:422-428. [PMID: 27788383 DOI: 10.1016/j.jad.2016.08.055] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/17/2016] [Accepted: 08/23/2016] [Indexed: 02/07/2023]
Abstract
BACKGROUND A tri-allelic serotonin transporter promoter polymorphism (5-HTTLPR/rs25531) more effectively determines the levels of transcriptional efficacy than that with the bi-allelic 5-HTTLPR polymorphism in vitro. Both are reportedly associated with personality traits of negative emotionality, but with conflicting findings. One explanation for this is that a gender difference may play a role in genetic contribution. Here, we hypothesized that the tri-allelic genotype of the serotonin transporter is more closely linked to neuroticism, an anxiety- and depression-related trait, than the bi-allelic variation, particularly in a gender-dependent way. METHODS The genotypes of the 5-HTTLPR and rs25531 loci were determined in 1139 well-defined physically and mentally healthy Han Chinese (550 men, 589 women; mean age 38.3±10.3 years). All participants completed the neuroticism measure of the short-form Maudsley Personality Inventory (MPI). The levels of anxiety and depression were assessed by the Beck Anxiety Inventory (BAI) and the Beck Depression Inventory (BDI), respectively. RESULTS A significant tri-allelic genotype-by-gender interaction effect was found in the MPI-neuroticism measure. S'S' homozygotes were associated with higher neuroticism than L' allele carriers in men. Also, both the BAI and BDI scores were higher in the S'S' homozygotic men. In the bi-allelic analyses, however, there was only an association between SS genotype and MPI-neuroticism in men. LIMITATIONS Sub-analyses by gender-stratification may reduce the statistical power. CONCLUSIONS Our findings confirm that gender differences exist in the genetic contributions of the serotonin transporter in human neuroticism, and anxiety/depression. Our data provide further support for rs25531, strengthening the effects of 5-HTTLPR.
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Affiliation(s)
- Chuan-Chia Chang
- Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Hsin-An Chang
- Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Wen-Hui Fang
- Department of Family and Community Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Tieh-Ching Chang
- Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - San-Yuan Huang
- Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.
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17
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Nikmahzar E, Jahanshahi M, Ghaemi A, Naseri GR, Moharreri AR, Lotfinia AA. Hippocampal serotonin-2A receptor-immunoreactive neurons density increases after testosterone therapy in the gonadectomized male mice. Anat Cell Biol 2016; 49:259-272. [PMID: 28127501 PMCID: PMC5266105 DOI: 10.5115/acb.2016.49.4.259] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/06/2016] [Accepted: 12/09/2016] [Indexed: 12/15/2022] Open
Abstract
The change of steroid levels may also exert different modulatory effects on the number and class of serotonin receptors present in the plasma membrane. The effects of chronic treatment of testosterone for anxiety were examined and expression of 5-HT2A serotonergic receptor, neuron, astrocyte, and dark neuron density in the hippocampus of gonadectomized male mice was determined. Thirty-six adult male NMRI mice were randomly divided into six groups: intact-no testosterone treatment (No T), gonadectomy (GDX)-No T, GDX-Vehicle, GDX-6.25 mg/kg testosterone (T), GDX-12.5 mg/kg T, and GDX-25 mg/kg T. Anxiety-related behavior was evaluated using elevated plus maze apparatus. The animals were anesthetized after 48 hours after behavioral testing, and decapitated and micron slices were prepared for immunohistochemical as well as histopathological assessment. Subcutaneous injection of testosterone (25 mg/kg) may induce anxiogenic-like behavior in male mice. In addition, immunohistochemical data reveal reduced expression of 5-HT2A serotonergic receptor after gonadectomy in all areas of the hippocampus. However, treatment with testosterone could increase the mean number of dark neurons as well as immunoreactive neurons in CA1 and CA3 area, dose dependently. The density of 5-HT2A receptor-immunoreactive neurons may play a crucial role in the induction of anxiety like behavior. As reduction in such receptor expression have shown to significantly enhance anxiety behaviors. However, replacement of testosterone dose dependently enhances the number of 5-HT2A receptor-immunoreactive neurons and interestingly also reduced anxiety like behaviors.
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Affiliation(s)
- Emsehgol Nikmahzar
- Neuroscience Research Center, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
| | - Mehrdad Jahanshahi
- Department of Anatomy, Neuroscience Research Center, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
| | - Amir Ghaemi
- Shefa Neuroscience Research Center, Tehran, Iran
| | - Gholam Reza Naseri
- Department of Anatomy, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
| | - Ali Reza Moharreri
- Department of Anatomy, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
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18
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Reproductive steroid receptors and actions in the locus coeruleus of male macaques: Part of an aggression circuit? Prog Neuropsychopharmacol Biol Psychiatry 2016; 71:210-22. [PMID: 27083854 PMCID: PMC4996758 DOI: 10.1016/j.pnpbp.2016.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 03/29/2016] [Accepted: 04/06/2016] [Indexed: 11/23/2022]
Abstract
This study was initiated to determine whether the noradrenergic (NE) neurons of the locus coeruleus (LC) could mediate the stimulatory action of androgens on serotonin-related gene expression in male macaques. These experiments follow our observations that serotonin neurons lack androgen receptors (ARs), and yet respond to androgens. Male Japanese macaques (Macaca fuscata) were castrated for 5-7months and then treated for 3months with [1] placebo, [2] T (testosterone), [3] DHT (dihydrotestosterone; non-aromatizable androgen) plus ATD (steroidal aromatase inhibitor), or [4] FLUT (Flutamide; androgen antagonist) plus ATD (n=5/group). The noradrenergic (NE) innervation of the raphe was determined with immunolabeling of axons with an antibody to dopamine-β-hydroxylase (DBH). Immunolabeling of tyrosine hydroxylase (TH) dendrites and corticotropin releasing hormone (CRH) axons innervating the LC was also determined. Due to the longer treatment period employed, the expression of the cognate nuclear receptors was sought. Androgen receptor (AR), estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) immunostaining was accomplished. Quantitative image analysis was applied and immunopositive neurons or axons with boutons were measured. Double-label of NE neurons for each receptor plus TH determined whether the receptors were localized in NE neurons. Androgens with or without aromatase activity significantly stimulated DBH axon density in the raphe (ANOVA, p=0.006), and LC dendritic TH (ANOVA, p<0.0001), similar to serotonin-related mRNA expression in the raphe. There were significantly more AR-positive neurons in T- and DHT+ATD-treated groups compared to placebo or FLUT+ATD-treated groups (ANOVA, p=0.0014). There was no difference in the number of positive-neurons stained for ERα or ERβ. The CRH axon density in the LC was significantly reduced with aromatase inhibition, suggesting that CRH depends on estrogen, not androgens (ANOVA, p=0.0023). Double-immunohistochemistry revealed that NE neurons did not contain AR. Rather, AR-positive nuclei were found in neighboring cells that are likely neurons. However, >80% of LC NE neurons contained ERα or ERβ. In conclusion, the LC NE neurons may transduce the stimulatory effect of androgens on serotonin-related gene expression. Since LC NE neurons lack AR, the androgenic stimulation of dendritic TH and axonal DBH may be indirectly mediated by other neurons. Estrogen, either from metabolism of T or from de novo synthesis, appears necessary for robust CRH innervation of the LC, which differs from female macaques.
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19
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Joseph JF, Parr MK. Synthetic androgens as designer supplements. Curr Neuropharmacol 2016; 13:89-100. [PMID: 26074745 PMCID: PMC4462045 DOI: 10.2174/1570159x13666141210224756] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/25/2014] [Accepted: 10/25/2014] [Indexed: 01/02/2023] Open
Abstract
Anabolic androgenic steroids (AAS) are some of the most common performance
enhancing drugs (PED) among society. Despite the broad spectrum of adverse effects and legal
consequences, AAS are illicitly marketed and distributed in many countries. To circumvent existing
laws, the chemical structure of AAS is modified and these designer steroids are sold as nutritional
supplements mainly over the Internet. Several side effects are linked with AAS abuse. Only little is
known about the pharmacological effects and metabolism of unapproved steroids due to the absence
of clinical studies. The large number of designer steroid findings in dietary supplements and the
detection of new compounds combined with legal loopholes for their distribution in many countries
show that stricter regulations and better information policy are needed.
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Affiliation(s)
- Jan Felix Joseph
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195 Berlin, Germany
| | - Maria Kristina Parr
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195 Berlin, Germany
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20
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Bethea CL, Reddy AP. Ovarian steroids regulate gene expression related to DNA repair and neurodegenerative diseases in serotonin neurons of macaques. Mol Psychiatry 2015; 20:1565-78. [PMID: 25600110 PMCID: PMC4508249 DOI: 10.1038/mp.2014.178] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 10/28/2014] [Accepted: 11/13/2014] [Indexed: 12/26/2022]
Abstract
Depression often accompanies the perimenopausal transition and it often precedes overt symptomology in common neurodegenerative diseases (NDDs, such as Alzheimer's, Parkinson's, Huntington, amyotrophic lateral sclerosis). Serotonin dysfunction is frequently found in the different etiologies of depression. We have shown that ovariectomized (Ovx) monkeys treated with estradiol (E) for 28 days supplemented with placebo or progesterone (P) on days 14-28 had reduced DNA fragmentation in serotonin neurons of the dorsal raphe nucleus, and long-term Ovx monkeys had fewer serotonin neurons than intact controls. We questioned the effect of E alone or E+P (estradiol supplemented with progesterone) on gene expression related to DNA repair, protein folding (chaperones), the ubiquitin-proteosome, axon transport and NDD-specific genes in serotonin neurons. Ovx macaques were treated with placebo, E or E+P (n=3 per group) for 1 month. Serotonin neurons were laser captured and subjected to microarray analysis and quantitative real-time PCR (qRT-PCR). Increases were confirmed with qRT-PCR in five genes that code for proteins involved in repair of strand breaks and nucleotide excision. NBN1, PCNA (proliferating nuclear antigen), GADD45A (DNA damage-inducible), RAD23A (DNA damage recognition) and GTF2H5 (gene transcription factor 2H5) significantly increased with E or E+P treatment (all analysis of variance (ANOVA), P<0.01). Chaperone genes HSP70 (heat-shock protein 70), HSP60 and HSP27 significantly increased with E or E+P treatment (all ANOVA, P<0.05). HSP90 showed a similar trend. Ubiquinase coding genes UBEA5, UBE2D3 and UBE3A (Parkin) increased with E or E+P (all ANOVA, P<0.003). Transport-related genes coding kinesin, dynein and dynactin increased with E or E+P treatment (all ANOVA, P<0.03). SCNA (α-synuclein) and ADAM10 (α-secretase) increased (both ANOVA, P<0.02) but PSEN1 (presenilin1) decreased (ANOVA, P<0.02) with treatment. APP decreased 10-fold with E or E+P administration. Newman-Keuls post hoc comparisons indicated variation in the response to E alone versus E+P across the different genes. In summary, E or E+P increased gene expression for DNA repair mechanisms in serotonin neurons, thereby rendering them less vulnerable to stress-induced DNA fragmentation. In addition, E or E+P regulated four genes encoding proteins that are often misfolded or malfunctioning in neuronal populations subserving overt NDD symptomology. The expression and regulation of these genes in serotonergic neurons invites speculation that they may mediate an underlying disease process in NDDs, which in turn may be ameliorated or delayed with timely hormone therapy in women.
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Affiliation(s)
- Cynthia L. Bethea
- Division of Reproductive Sciencesm, Oregon National Primate Research Center Beaverton, OR 97006, Division of Neuroscience Oregon National Primate Research Center Beaverton, OR 97006, Department of Obstetrics and Gynecology Oregon Health and Science University Portland, OR 97201
| | - Arubala P. Reddy
- Division of Reproductive Sciencesm, Oregon National Primate Research Center Beaverton, OR 97006
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21
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Bethea CL, Phu K, Kim A, Reddy AP. Androgen metabolites impact CSF amines and axonal serotonin via MAO-A and -B in male macaques. Neuroscience 2015; 301:576-89. [PMID: 26086546 DOI: 10.1016/j.neuroscience.2015.06.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/02/2015] [Accepted: 06/11/2015] [Indexed: 01/11/2023]
Abstract
A number of studies have shown that mutations or deletions of the monoamine oxidase-A (MAO-A) gene cause elevated CNS serotonin and elevated impulsive aggression in humans and animal models. In addition, low cerebrospinal fluid (CSF) 5-hydroxyindole acetic acid (5HIAA) has been documented in a limited number of violent criminal populations and in macaques that exhibit impulsive aggression. To reconcile these different analyses, we hypothesized that CSF 5HIAA reflected degradation of serotonin by the activity of MAO-A; and that low MAO-A activity would result in lower CSF 5HIAA, but overall higher serotonin in the CNS. To test this hypothesis, male Japanese macaques (Macaca fuscata) were castrated, rested for 5-7months, and then treated for 3months with [1] placebo, [2] testosterone (T), [3] dihydrotestosterone (DHT; non-aromatizable androgen) and 1,4,6-androstatriene-3,17-dione (ATD) (steroidal aromatase inhibitor), or [4] flutamide (FLUT; androgen antagonist) and ATD (n=5/group). These treatments enable isolation of androgen and estrogen activities. In the dorsal raphe, MAO-A and MAO-B expressions were determined with in situ hybridization (ISH) and protein expression of aromatase was determined with immunohistochemistry (IHC). CSF concentrations of 5HIAA, 3-methoxy-4-hydroxyphenylglycol (MHPG), and homovanillic acid (HVA) were determined with liquid chromatography/mass spectrometry (LC/MS). From the same animals, previously published data on serotonin axon density were used as a proxy for CNS serotonin. Aromatase conversion of T to estrogen (E) suppressed MAO-A (positive pixel area, p=0.0045), but androgens increased MAO-B (positive pixel area, p=0.014). CSF 5HIAA was suppressed by conversion of T to E (Cohen's d=0.6). CSF 5HIAA was positively correlated with MAO-A-positive pixel area (r(2)=0.78). CSF 5HIAA was inversely correlated with serotonin axon-positive pixel area (r(2)=0.69). In summary, CSF 5HIAA reflects MAO-A activity rather than global serotonin. Low CSF 5HIAA may, in this paradigm, reflect higher serotonin activity. Androgens lower MAO-A activity via metabolism to E, thus elevating CNS serotonin and decreasing CSF 5HIAA. Since androgens increase certain types of aggression, these data are consistent with studies demonstrating that lower MAO-A activity is associated with elevated serotonin and increased aggression.
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Affiliation(s)
- C L Bethea
- Division of Reproductive and Development Science, Oregon National Primate Research Center, Beaverton, OR 97006, United States; Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006, United States; Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR 97201, United States.
| | - K Phu
- Division of Reproductive and Development Science, Oregon National Primate Research Center, Beaverton, OR 97006, United States
| | - A Kim
- Division of Reproductive and Development Science, Oregon National Primate Research Center, Beaverton, OR 97006, United States
| | - A P Reddy
- Division of Reproductive and Development Science, Oregon National Primate Research Center, Beaverton, OR 97006, United States
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22
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Bethea CL, Phu K, Belikova Y, Bethea SC. Localization and regulation of reproductive steroid receptors in the raphe serotonin system of male macaques. J Chem Neuroanat 2015; 66-67:19-27. [PMID: 25908331 DOI: 10.1016/j.jchemneu.2015.04.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/02/2015] [Accepted: 04/03/2015] [Indexed: 02/01/2023]
Abstract
We previously showed that tryptophan hydroxylase 2 (TPH2) and serotonin reuptake transporter (SERT) mRNAs are increased by the androgens, testosterone (T) and dihydrotestosterone (DHT) in serotonin neurons of male macaques. In addition, we observed that serotonin in axons of a terminal region were markedly decreased by aromatase inhibition and lack of estradiol (E) from metabolism of T. These observations implicated androgen receptors (AR) and estrogen receptors (ER) in the transduction of steroid hormone actions in serotonin neurons. Due to the longer treatment period employed, the expression of the cognate nuclear receptors was sought. We used single and double immunohistochemistry to quantitate and phenotypically localize AR, ERα and ERβ in the dorsal raphe of male macaques. Male Japanese macaques (Macaca fuscata) were castrated for 5-7 months and then treated for 3 months with [1] placebo, [2] T, [3] DHT (non-aromatizable androgen) plus ATD (steroidal aromatase inhibitor), or [4] Flutamide (FLUT; androgen antagonist) plus ATD (n = 5/group). After single labeling of each receptor, quantitative image analysis was applied and receptor positive neurons were counted. Double-label of raphe neurons for each receptor plus TPH2 determined whether the receptors were localized in serotonin neurons. There were significantly more AR-positive neurons in T- and DHT+ATD-treated groups (p = 0.0014) compared to placebo or FLUT+ATD-treated groups. There was no difference in the number of positive-neurons stained for ERα or ERβ⋅ Double-immunohistochemistry revealed that serotonin neurons did not contain AR. Rather, AR-positive nuclei were found in neighboring cells that are likely neurons. However, approximately 40% of dorsal raphe serotonin neurons contained ERα or ERβ⋅ In conclusion, the stimulatory effect of androgens on TPH2 and SERT mRNA expression is mediated indirectly by neighboring neurons contain AR. The stimulatory effect of E, derived from T metabolism, on serotonin transport is partially mediated directly via nuclear ERs.
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Affiliation(s)
- Cynthia L Bethea
- Division of Reproductive Sciences, Oregon National Primate Research Center, Beaverton, OR 97006, United States; Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006, United States; Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR 97201, United States.
| | - Kenny Phu
- Division of Reproductive Sciences, Oregon National Primate Research Center, Beaverton, OR 97006, United States
| | - Yelena Belikova
- Division of Reproductive Sciences, Oregon National Primate Research Center, Beaverton, OR 97006, United States
| | - Sarah C Bethea
- Division of Reproductive Sciences, Oregon National Primate Research Center, Beaverton, OR 97006, United States
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