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Phumsatitpong C, Wagenmaker ER, Moenter SM. Neuroendocrine interactions of the stress and reproductive axes. Front Neuroendocrinol 2021; 63:100928. [PMID: 34171353 PMCID: PMC8605987 DOI: 10.1016/j.yfrne.2021.100928] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 06/17/2021] [Accepted: 06/19/2021] [Indexed: 01/27/2023]
Abstract
Reproduction is controlled by a sequential regulation of the hypothalamo-pituitary-gonadal (HPG) axis. The HPG axis integrates multiple inputs to maintain proper reproductive functions. It has long been demonstrated that stress alters fertility. Nonetheless, the central mechanisms of how stress interacts with the reproductive system are not fully understood. One of the major pathways that is activated during the stress response is the hypothalamo-pituitary-adrenal (HPA) axis. In this review, we discuss several aspects of the interactions between these two neuroendocrine systems to offer insights to mechanisms of how the HPA and HPG axes interact. We have also included discussions of other systems, for example GABA-producing neurons, where they are informative to the overall picture of stress effects on reproduction.
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Affiliation(s)
- Chayarndorn Phumsatitpong
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Elizabeth R Wagenmaker
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Suzanne M Moenter
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States; Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States; Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, United States.
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Phumsatitpong C, De Guzman RM, Zuloaga DG, Moenter SM. A CRH Receptor Type 1 Agonist Increases GABA Transmission to GnRH Neurons in a Circulating-Estradiol-Dependent Manner. Endocrinology 2020; 161:5892962. [PMID: 32798220 PMCID: PMC7547842 DOI: 10.1210/endocr/bqaa140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/06/2020] [Indexed: 12/15/2022]
Abstract
GnRH neurons are central regulators of reproduction and respond to factors affecting fertility, such as stress. Corticotropin-releasing hormone (CRH) is released during stress response. In brain slices from unstressed controls, CRH has opposite, estradiol-dependent effects on GnRH neuron firing depending on the CRH receptor activated; activating CRHR-1 stimulates whereas activating CRHR-2 suppresses activity. We investigated possible direct and indirect mechanisms. Mice were ovariectomized and either not treated further (OVX) or given a capsule producing high positive feedback (OVX + E) or low negative feedback (OVX + low E) physiologic circulating estradiol levels. We tested possible direct effects on GnRH neurons by altering voltage-gated potassium currents. Two types of voltage-gated potassium currents (transient IA and sustained IK) were measured; neither CRHR-1 nor CRHR-2 agonists altered potassium current density in GnRH neurons from OVX + E mice. Further, neither CRH nor receptor-specific agonists altered action potential generation in response to current injection in GnRH neurons from OVX + E mice. To test the possible indirect actions, GABAergic postsynaptic currents were monitored. A CRHR-1 agonist increased GABAergic transmission frequency to GnRH neurons from OVX + E, but not OVX, mice, whereas a CRHR-2 agonist had no effect. Finally, we tested if CRH alters the firing rate of arcuate kisspeptin neurons, which provide an important excitatory neuromodulatory input to GnRH neurons. CRH did not acutely alter firing activity of these neurons from OVX, OVX + E or OVX + low E mice. These results suggest CRH increases GnRH neuron activity in an estradiol-dependent manner in part by activating GABAergic afferents. Mechanisms underlying inhibitory effects of CRH remain unknown.
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Affiliation(s)
| | | | | | - Suzanne M Moenter
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, US
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, US
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, US
- Correspondence: Suzanne M. Moenter; 7725 Med Sci II; 1137 E Catherine St; Ann Arbor, MI 48109-5622. E-mail:
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Di Natale MR, Soch A, Ziko I, De Luca SN, Spencer SJ, Sominsky L. Chronic predator stress in female mice reduces primordial follicle numbers: implications for the role of ghrelin. J Endocrinol 2019; 241:201-219. [PMID: 30959480 DOI: 10.1530/joe-19-0109] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 04/04/2019] [Indexed: 12/17/2022]
Abstract
Chronic stress is a known suppressor of female reproductive function. However, attempts to isolate single causal links between stress and reproductive dysfunction have not yet been successful due to their multi-faceted aetiologies. The gut-derived hormone ghrelin regulates stress and reproductive function and may therefore be pivotal in the neuroendocrine integration of the hypothalamic-pituitary-adrenal (HPA) and -gonadal (HPG) axes. Here, we hypothesised that chronic stress disrupts ovarian follicle maturation and that this effect is mediated by a stress-induced increase in acyl ghrelin and activation of the growth hormone secretatogue receptor (GHSR). We gave C57BL/6J female mice 30 min daily chronic predator stress for 4 weeks, or no stress, and gave them daily GHSR antagonist (d-Lys3-GHRP-6) or saline. Exposure to chronic predator stress reduced circulating corticosterone, elevated acyl ghrelin levels and led to significantly depleted primordial follicle numbers. GHSR antagonism stress-dependently altered the expression of genes regulating ovarian responsiveness to gonadotropins and was able to attenuate the stress-induced depletion of primordial follicles. These findings suggest that chronic stress-induced elevations of acyl ghrelin may be detrimental for ovarian follicle maturation.
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Affiliation(s)
- Madeleine R Di Natale
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Alita Soch
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Ilvana Ziko
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Simone N De Luca
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Luba Sominsky
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
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Does kisspeptin participate in GABA-mediated modulation of GnRH and GnRH receptor biosynthesis in the hypothalamic-pituitary unit of follicular-phase ewes? Pharmacol Rep 2019; 71:636-643. [PMID: 31176893 DOI: 10.1016/j.pharep.2019.02.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 02/25/2019] [Accepted: 02/28/2019] [Indexed: 11/24/2022]
Abstract
BACKGROUND The inverse relationship between GnRH transcript level and GABA neurons activity has suggested that GABA at the hypothalamic level may exert a suppressive effect on subsequent steps of the GnRH biosynthesis. In the present study, we analyzed the effects of GABA type A receptor agonist (muscimol) or antagonist (bicuculline) on molecular mechanisms governing GnRH/LH secretion in follicular-phase sheep. METHODS ELISA technique was used to investigate the effects of muscimol and/or bicuculline on levels of post-translational products of genes encoding GnRH ligand and GnRH receptor (GnRHR) in the preoptic area (POA), anterior (AH) and ventromedial (VMH) hypothalamus, stalk/median eminence (SME), and GnRHR in the anterior pituitary (AP). Real-time PCR was chosen for determination of the effect of drugs on kisspeptin (Kiss 1) mRNA level in POA and VMH including arcuate nucleus (VMH/ARC), and on Kiss1 receptor (Kiss1r) mRNA abundance in POA-hypothalamic structures. These analyses were supplemented by RIA method for measurement of plasma LH concentration. RESULTS The study demonstrated that muscimol and bicuculline significantly decreased or increased GnRH biosynthesis in all analyzed structures, respectively, and led to analogous changes in plasma LH concentration. Similar muscimol- and bicuculline-related alterations were observed in levels of GnRHR. However, the expression of Kiss 1 and Kiss1r mRNAs in selected POA-hypothalamic areas of either muscimol- and bicuculline-treated animals remained unaltered. CONCLUSIONS Our data suggest that GABAergic neurotransmission is involved in the regulatory pathways of GnRH/GnRHR biosynthesis and then GnRH/LH release in follicular-phase sheep conceivably via indirect mechanisms that exclude involvement of Kiss 1 neurons.
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Phumsatitpong C, Moenter SM. Estradiol-Dependent Stimulation and Suppression of Gonadotropin-Releasing Hormone Neuron Firing Activity by Corticotropin-Releasing Hormone in Female Mice. Endocrinology 2018; 159:414-425. [PMID: 29069304 PMCID: PMC5761586 DOI: 10.1210/en.2017-00747] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 10/17/2017] [Indexed: 11/19/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) neurons are the final central regulators of reproduction, integrating various inputs that modulate fertility. Stress typically inhibits reproduction but can be stimulatory; stress effects can also be modulated by steroid milieu. Corticotropin-releasing hormone (CRH) released during the stress response may suppress reproduction independent of downstream glucocorticoids. We hypothesized CRH suppresses fertility by decreasing GnRH neuron firing activity. To test this, mice were ovariectomized (OVX) and either implanted with an estradiol capsule (OVX+E) or not treated further to examine the influence of estradiol on GnRH neuron response to CRH. Targeted extracellular recordings were used to record firing activity from green fluorescent protein-identified GnRH neurons in brain slices before and during CRH treatment; recordings were done in the afternoon when estradiol has a positive feedback effect to increase GnRH neuron firing. In OVX mice, CRH did not affect the firing rate of GnRH neurons. In contrast, CRH exhibited dose-dependent stimulatory (30 nM) or inhibitory (100 nM) effects on GnRH neuron firing activity in OVX+E mice; both effects were reversible. The dose-dependent effects of CRH appear to result from activation of different receptor populations; a CRH receptor type-1 agonist increased firing activity in GnRH neurons, whereas a CRH receptor type-2 agonist decreased firing activity. CRH and specific agonists also differentially regulated short-term burst frequency and burst properties, including burst duration, spikes/burst, and/or intraburst interval. These results indicate that CRH alters GnRH neuron activity and that estradiol is required for CRH to exert both stimulatory and inhibitory effects on GnRH neurons.
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Affiliation(s)
- Chayarndorn Phumsatitpong
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109
| | - Suzanne M. Moenter
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan 48109
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Regulation of gonadotropins by urocortin 2 in gonadotropic tumor LβT2 cells. Neurosci Lett 2017; 660:63-67. [PMID: 28851616 DOI: 10.1016/j.neulet.2017.08.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/07/2017] [Accepted: 08/22/2017] [Indexed: 11/23/2022]
Abstract
A close interaction has been shown between the hypothalamo-pituitary-gonadal axis and the hypothalamic-pituitary-adrenal axis. Urocortin 2 (Ucn2) has a very high affinity for the corticotropin-releasing factor (CRF) type 2 (CRF2) receptor. Pituitary Ucn2 regulates expression and secretion of gonadotropins in response to stress. The CRF2 receptor in the pituitary contributes to the modulation of gonadotropins. To explore the possible function of Ucn2 and the CRF2 receptor in pituitary gonadotropic tumor cells, we examined the direct regulation of gonadotropins by Ucn2 in a representative pituitary gonadotropic tumor, mouse LβT2 cells. LβT2 cells were found to express CRF1 receptor and CRF2 receptor mRNA. Ucn2 decreased CRF1 receptor mRNA levels, while it increased CRF2 receptor mRNA levels. Ucn2 directly decreased the mRNA levels of both luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in LβT2 cells. Ucn2 also decreased gonadotropin-releasing hormone receptor (GnRHR) mRNA levels. A selective CRF2 receptor antagonist suppressed the Ucn2-induced decreases in LH, FSH, and GnRHR mRNA levels. Ucn2 acts on gonadotrophs expressing the CRF2 receptor, and inhibits the production of gonadotropins in the pituitary gonadotropic tumor cells. (177 words).
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Sominsky L, Hodgson DM, McLaughlin EA, Smith R, Wall HM, Spencer SJ. Linking Stress and Infertility: A Novel Role for Ghrelin. Endocr Rev 2017; 38:432-467. [PMID: 28938425 DOI: 10.1210/er.2016-1133] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 07/24/2017] [Indexed: 12/23/2022]
Abstract
Infertility affects a remarkable one in four couples in developing countries. Psychological stress is a ubiquitous facet of life, and although stress affects us all at some point, prolonged or unmanageable stress may become harmful for some individuals, negatively impacting on their health, including fertility. For instance, women who struggle to conceive are twice as likely to suffer from emotional distress than fertile women. Assisted reproductive technology treatments place an additional physical, emotional, and financial burden of stress, particularly on women, who are often exposed to invasive techniques associated with treatment. Stress-reduction interventions can reduce negative affect and in some cases to improve in vitro fertilization outcomes. Although it has been well-established that stress negatively affects fertility in animal models, human research remains inconsistent due to individual differences and methodological flaws. Attempts to isolate single causal links between stress and infertility have not yet been successful due to their multifaceted etiologies. In this review, we will discuss the current literature in the field of stress-induced reproductive dysfunction based on animal and human models, and introduce a recently unexplored link between stress and infertility, the gut-derived hormone, ghrelin. We also present evidence from recent seminal studies demonstrating that ghrelin has a principal role in the stress response and reward processing, as well as in regulating reproductive function, and that these roles are tightly interlinked. Collectively, these data support the hypothesis that stress may negatively impact upon fertility at least in part by stimulating a dysregulation in ghrelin signaling.
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Affiliation(s)
- Luba Sominsky
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria 3083, Australia
| | - Deborah M Hodgson
- School of Psychology, Faculty of Science and IT, The University of Newcastle, New South Wales 2308, Australia
| | - Eileen A McLaughlin
- School of Biological Sciences, Faculty of Science, The University of Auckland, Auckland 1010, New Zealand.,School of Environmental & Life Sciences, Faculty of Science and IT, The University of Newcastle, New South Wales 2308, Australia
| | - Roger Smith
- Mothers and Babies Research Centre, Hunter Medical Research Institute, Lookout Road, New Lambton Heights, New South Wales 2305, Australia.,Priority Research Centre in Reproductive Science, The University of Newcastle, New South Wales 2308, Australia
| | - Hannah M Wall
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria 3083, Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria 3083, Australia
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Camille Melón L, Maguire J. GABAergic regulation of the HPA and HPG axes and the impact of stress on reproductive function. J Steroid Biochem Mol Biol 2016; 160:196-203. [PMID: 26690789 PMCID: PMC4861672 DOI: 10.1016/j.jsbmb.2015.11.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 11/16/2015] [Accepted: 11/26/2015] [Indexed: 11/25/2022]
Abstract
The hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes are regulated by GABAergic signaling at the level of corticotropin-releasing hormone (CRH) and gonadotropin-releasing hormone (GnRH) neurons, respectively. Under basal conditions, activity of CRH and GnRH neurons are controlled in part by both phasic and tonic GABAergic inhibition, mediated by synaptic and extrasynaptic GABAA receptors (GABAARs), respectively. For CRH neurons, this tonic GABAergic inhibition is mediated by extrasynaptic, δ subunit-containing GABAARs. Similarly, a THIP-sensitive tonic GABAergic current has been shown to regulate GnRH neurons, suggesting a role for δ subunit-containing GABAARs; however, this remains to be explicitly demonstrated. GABAARs incorporating the δ subunit confer neurosteroid sensitivity, suggesting a potential role for neurosteroid modulation in the regulation of the HPA and HPG axes. Thus, stress-derived neurosteroids may contribute to the impact of stress on reproductive function. Interestingly, excitatory actions of GABA have been demonstrated in both CRH neurons at the apex of control of the HPA axis and in GnRH neurons which mediate the HPG axis, adding to the complexity for the role of GABAergic signaling in the regulation of these systems. Here we review the effects that stress has on GnRH neurons and HPG axis function alongside evidence supporting GABAARs as a major interface between the stress and reproductive axes.
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Affiliation(s)
- Laverne Camille Melón
- Tufts University School of Medicine, Department of Neuroscience, Boston, MA 02111, United States
| | - Jamie Maguire
- Tufts University School of Medicine, Department of Neuroscience, Boston, MA 02111, United States.
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Busardò FP, Frati P, Sanzo MD, Napoletano S, Pinchi E, Zaami S, Fineschi V. The impact of nandrolone decanoate on the central nervous system. Curr Neuropharmacol 2016; 13:122-31. [PMID: 26074747 PMCID: PMC4462037 DOI: 10.2174/1570159x13666141210225822] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Revised: 10/10/2014] [Accepted: 10/25/2014] [Indexed: 01/31/2023] Open
Abstract
Nandrolone is included in the class II of anabolic androgenic steroids (AAS) which is
composed of 19-nor-testosterone-derivates. In general, AAS is a broad and rapidly increasing group
of synthetic androgens used both clinically and illicitly. AAS in general and nandrolone decanoate
(ND) in particular have been associated with several behavioral disorders. The purpose of this review
is to summarize the literature concerning studies dealing with ND exposure on animal models, mostly
rats that mimic human abuse systems (i.e. supraphysiological doses). We have focused in particular
on researches that have investigated how ND alters the function and expression of neuronal signaling molecules that
underlie behavior, anxiety, aggression, learning and memory, reproductive behaviors, locomotion and reward.
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Affiliation(s)
- Francesco P Busardò
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Sapienza University of Rome, Viale Regina Elena 336, 00161, Rome, Italy
| | - Paola Frati
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Sapienza University of Rome, Viale Regina Elena 336, 00161, Rome, Italy; ; Neuromed, Istituto Mediterraneo Neurologico (IRCCS), Via Atinense 18, Pozzilli, 86077 Isernia, Italy
| | - Mariantonia Di Sanzo
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Sapienza University of Rome, Viale Regina Elena 336, 00161, Rome, Italy
| | - Simona Napoletano
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Sapienza University of Rome, Viale Regina Elena 336, 00161, Rome, Italy
| | - Enrica Pinchi
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Sapienza University of Rome, Viale Regina Elena 336, 00161, Rome, Italy
| | - Simona Zaami
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Sapienza University of Rome, Viale Regina Elena 336, 00161, Rome, Italy
| | - Vittorio Fineschi
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Sapienza University of Rome, Viale Regina Elena 336, 00161, Rome, Italy
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Chen Z, Meng Z, Wang S, Zhu L, Tian Z. Effects of Nourishing “Yin”-Removing “Fire” Chinese Herb Mixture on the Expression of GABAB Receptors in Hypothalamus of Precocious Puberty Female Rats. Chin Med 2016. [DOI: 10.4236/cm.2016.72008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Li X, Shao B, Lin C, O'Byrne KT, Lin Y. Stress-induced inhibition of LH pulses in female rats: role of GABA in arcuate nucleus. J Mol Endocrinol 2015; 55:9-19. [PMID: 25999179 DOI: 10.1530/jme-15-0084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/21/2015] [Indexed: 12/21/2022]
Abstract
Stress exerts profound inhibitory effects on reproductive function by suppression of the pulsatile release of GnRH and therefore LH. Besides the corticotrophin-releasing factor (CRF), this effect also might be mediated via GABAergic signaling within the arcuate nucleus (ARC) since its inhibitory effects on LH pulses and increased activity during stress. In the present study, we investigated the role of endogenous GABAergic signaling within the ARC in stress-induced suppression of LH pulses. Ovariectomised oestradiol-replaced rats were implanted with bilateral and unilateral cannulae targeting toward the ARC and lateral cerebral ventricle respectively. Blood samples (25 μl) were taken via chronically implanted cardiac catheters every 5 min for 6 h for measurement of LH pulses. Intra-ARC infusion of GABAA receptor antagonist, bicuculline (0.2 pmol in 200 nl artificial cerebrospinal fluid (aCSF) each side, three times at 20-min intervals) markedly attenuated the inhibitory effect of lipopolysaccharide (LPS; 25 μg/kg i.v.) but not restraint (1 h) stress on pulsatile LH secretion. In contrast, restraint but not LPS stress-induced suppression of LH pulse frequency was reversed by intra-ARC administration of GABABR antagonist, CGP-35348 (1.5 nmol in 200 nl aCSF each side, three times at 20-min intervals). Moreover, intra-ARC application of either bicuculline or CGP-35348 attenuated the inhibitory effect of CRF (1 nmol in 4 μl aCSF, i.c.v.) on the LH pulses. These data indicate a pivotal and differential role of endogenous GABAA and GABAB signaling mechanisms in the ARC with respect to mediating immunological and psychological stress-induced suppression of the GnRH pulse generator respectively.
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Affiliation(s)
- XiaoFeng Li
- First Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, ChinaDivision of Women's HealthSchool of Medicine, King's College London, Guy's Campus, London, UKDepartment of Surgery LaboratoryFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China First Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, ChinaDivision of Women's HealthSchool of Medicine, King's College London, Guy's Campus, London, UKDepartment of Surgery LaboratoryFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Bei Shao
- First Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, ChinaDivision of Women's HealthSchool of Medicine, King's College London, Guy's Campus, London, UKDepartment of Surgery LaboratoryFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - ChengCheng Lin
- First Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, ChinaDivision of Women's HealthSchool of Medicine, King's College London, Guy's Campus, London, UKDepartment of Surgery LaboratoryFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Kevin T O'Byrne
- First Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, ChinaDivision of Women's HealthSchool of Medicine, King's College London, Guy's Campus, London, UKDepartment of Surgery LaboratoryFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - YuanShao Lin
- First Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, ChinaDivision of Women's HealthSchool of Medicine, King's College London, Guy's Campus, London, UKDepartment of Surgery LaboratoryFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China First Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, ChinaDivision of Women's HealthSchool of Medicine, King's College London, Guy's Campus, London, UKDepartment of Surgery LaboratoryFirst Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
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Watanabe M, Fukuda A, Nabekura J. The role of GABA in the regulation of GnRH neurons. Front Neurosci 2014; 8:387. [PMID: 25506316 PMCID: PMC4246667 DOI: 10.3389/fnins.2014.00387] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 11/12/2014] [Indexed: 11/13/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) neurons form the final common pathway for the central regulation of reproduction. Gamma-amino butyric acid (GABA) has long been implicated as one of the major players in the regulation of GnRH neurons. Although GABA is typically an inhibitory neurotransmitter in the mature adult central nervous system, most mature GnRH neurons show the unusual characteristic of being excited by GABA. While many reports have provided much insight into the contribution of GABA to the activity of GnRH neurons, the precise physiological role of the excitatory action of GABA on GnRH neurons remains elusive. This brief review presents the current knowledge of the role of GABA signaling in GnRH neuronal activity. We also discuss the modulation of GABA signaling by neurotransmitters and neuromodulators and the functional consequence of GABAergic inputs to GnRH neurons in both the physiology and pathology of reproduction.
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Affiliation(s)
- Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
| | - Junichi Nabekura
- Department of Developmental Physiology, National Institute for Physiological Sciences Okazaki, Japan ; Core Research for Evolutionary Science and Technology, Japan Science and Technology Corporation Saitama, Japan ; Department of Physiological Sciences, The Graduate School for Advanced Study Hayama, Japan
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Grachev P, Li XF, Hu MH, Li SY, Millar RP, Lightman SL, O'Byrne KT. Neurokinin B signaling in the female rat: a novel link between stress and reproduction. Endocrinology 2014; 155:2589-601. [PMID: 24708241 DOI: 10.1210/en.2013-2038] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Acute systemic stress disrupts reproductive function by inhibiting pulsatile gonadotropin secretion. The underlying mechanism involves stress-induced suppression of the GnRH pulse generator, the functional unit of which is considered to be the hypothalamic arcuate nucleus kisspeptin/neurokinin B/dynorphin A neurons. Agonists of the neurokinin B (NKB) receptor (NK3R) have been shown to suppress the GnRH pulse generator, in a dynorphin A (Dyn)-dependent fashion, under hypoestrogenic conditions, and Dyn has been well documented to mediate several stress-related central regulatory functions. We hypothesized that the NKB/Dyn signaling cascade is required for stress-induced suppression of the GnRH pulse generator. To investigate this ovariectomized rats, iv administered with Escherichia coli lipopolysaccharide (LPS) following intracerebroventricular pretreatment with NK3R or κ-opioid receptor (Dyn receptor) antagonists, were subjected to frequent blood sampling for hormone analysis. Antagonism of NK3R, but not κ-opioid receptor, blocked the suppressive effect of LPS challenge on LH pulse frequency. Neither antagonist affected LPS-induced corticosterone secretion. Hypothalamic arcuate nucleus NKB neurons project to the paraventricular nucleus, the major hypothalamic source of the stress-related neuropeptides CRH and arginine vasopressin (AVP), which have been implicated in the stress-induced suppression of the hypothalamic-pituitary-gonadal axis. A separate group of ovariectomized rats was, therefore, used to address the potential involvement of central CRH and/or AVP signaling in the suppression of LH pulsatility induced by intracerebroventricular administration of a selective NK3R agonist, senktide. Neither AVP nor CRH receptor antagonists affected the senktide-induced suppression of the LH pulse; however, antagonism of type 2 CRH receptors attenuated the accompanying elevation of corticosterone levels. These data indicate that the suppression of the GnRH pulse generator by acute systemic stress requires hypothalamic NKB/NK3R signaling and that any involvement of CRH therewith is functionally upstream of NKB.
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Affiliation(s)
- P Grachev
- Division of Women's Health (P.G., X.F.L., M.H.H., S.Y.L., K.T.O.), School of Medicine, King's College London, United Kingdom; Mammal Research Institute (R.P.M.), University of Pretoria, Pretoria, South Africa; Medical Research Council Receptor Biology Unit, University of Cape Town, Cape Town, South Africa; Centre for Integrative Physiology, University of Edinburgh, Scotland; and Henry Wellcome Laboratory for Integrative Neuroscience & Endocrinology (S.L.L.), University of Bristol, Bristol, United Kingdom
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Stress regulation of kisspeptin in the modulation of reproductive function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 784:431-54. [PMID: 23550018 DOI: 10.1007/978-1-4614-6199-9_20] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Stressful stimuli abound in modern society and have shaped evolution through altering reproductive development, behavior, and physiology. The recent identification of kisspeptin as an important component of the hypothalamic regulatory circuits involved in reproductive homeostasis sparked a great deal of research interest that subsequently implicated kisspeptin signaling in the relay of metabolic, environmental, and physiological cues to the hypothalamo-pituitary-gonadal axis. However, although it is widely recognized that exposure to stress profoundly impacts on reproductive function, the roles of kisspeptin within the complex mechanisms underlying stress regulation of reproduction remain poorly understood. We and others have recently demonstrated that a variety of experimental stress paradigms downregulate the expression of kisspeptin ligand and receptor within the reproductive brain. Coincidently, these stressors also inhibit gonadotropin secretion and delay pubertal onset-processes that rely on kisspeptin signaling. However, a modest literature is inconsistent with an exclusively suppressive influence of stress on the reproductive axis and suggests that complicated neural interactions and signaling mechanisms translate the stress response into reproductive perturbations. The purpose of this chapter is to review the evidence for a novel role of kisspeptin signaling in the modulation of reproductive function by stress and to broaden the understanding of this timely phenomenon.
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15
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Kageyama K. Regulation of gonadotropins by corticotropin-releasing factor and urocortin. Front Endocrinol (Lausanne) 2013; 4:12. [PMID: 23431022 PMCID: PMC3576618 DOI: 10.3389/fendo.2013.00012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 01/30/2013] [Indexed: 02/05/2023] Open
Abstract
While stress activates the hypothalamic-pituitary-adrenal (HPA) axis, it suppresses the hypothalamic-pituitary-gonadal (HPG) axis. Corticotropin-releasing factor (CRF) is a major regulatory peptide in the HPA axis during stress. Urocortin 1 (Ucn1), a member of the CRF family of peptides, has a variety of physiological functions and both CRF and Ucn1 contribute to the stress response via G protein-coupled seven transmembrane receptors. Ucn2 and Ucn3, which belong to a separate paralogous lineage from CRF, are highly selective for the CRF type 2 receptor (CRF(2) receptor). The HPA and HPG axes interact with each other, and gonadal function and reproduction are suppressed in response to various stressors. In this review, we focus on the regulation of gonadotropins by CRF and Ucn2 in pituitary gonadotrophs and of gonadotropin-releasing hormone (GnRH) via CRF receptors in the hypothalamus. In corticotrophs, stress-induced increases in CRF stimulate Ucn2 production, which leads to the inhibition of gonadotropin secretion via the CRF(2) receptor in the pituitary. GnRH in the hypothalamus is regulated by a variety of stress conditions. CRF is also involved in the suppression of the HPG axis, especially the GnRH pulse generator, via CRF receptors in the hypothalamus. Thus, complicated regulation of GnRH in the hypothalamus and gonadotropins in the pituitary via CRF receptors contributes to stress responses and adaptation of gonadal functions.
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Affiliation(s)
- Kazunori Kageyama
- *Correspondence: Kazunori Kageyama, Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori 036-8562, Japan. e-mail:
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Oberlander JG, Penatti CAA, Porter DM, Henderson LP. The Buzz about anabolic androgenic steroids: electrophysiological effects in excitable tissues. Neuroendocrinology 2012; 96:141-51. [PMID: 22576754 PMCID: PMC3488447 DOI: 10.1159/000339123] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 04/23/2012] [Indexed: 01/04/2023]
Abstract
Anabolic androgenic steroids (AAS) comprise a large and growing class of synthetic androgens used clinically to promote tissue-building in individuals suffering from genetic disorders, injuries, and diseases. Despite these beneficial therapeutic applications, the predominant use of AAS is illicit: these steroids are self-administered to promote athletic performance and body image. Hand in hand with the desired anabolic actions of the AAS are untoward effects on the brain and behavior. While the signaling routes by which the AAS impose both beneficial and harmful actions may be quite diverse, key endpoints are likely to include ligand-gated and voltage-dependent ion channels that govern the activity of electrically excitable tissues. Here, we review the known effects of AAS on molecular targets that play critical roles in controlling electrical activity, with a specific focus on the effects of AAS on neurotransmission mediated by GABA(A) receptors in the central nervous system.
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Affiliation(s)
- Joseph G. Oberlander
- Department of Physiology and Neurobiology, Dartmouth Medical School, Hanover, NH 03755 USA
| | - Carlos A. A. Penatti
- Departamento de Ciências Médicas, Universidade Nove de Julho - UNINOVE, São Paulo, SP 01504-000 Brasil
| | - Donna M. Porter
- Department of Physiology and Neurobiology, Dartmouth Medical School, Hanover, NH 03755 USA
| | - Leslie P. Henderson
- Department of Physiology and Neurobiology, Dartmouth Medical School, Hanover, NH 03755 USA
- To Whom Correspondence Should be Addressed:
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