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Młotkowska P, Marciniak E, Misztal A, Misztal T. Effect of Neurosteroids on Basal and Stress-Induced Oxytocin Secretion in Luteal-Phase and Pregnant Sheep. Animals (Basel) 2023; 13:ani13101658. [PMID: 37238088 DOI: 10.3390/ani13101658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/12/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
Oxytocin (OT) is a neuropeptide synthesized in the hypothalamic nuclei that modulates both behavioral and reproductive functions, associated with the increased neurosteroid synthesis in the brain. Therefore, the present study tested the hypothesis that manipulation of central neurosteroid levels could affect oxytocin synthesis and release in non-pregnant and pregnant sheep under both basal and stressful conditions. In Experiment 1, luteal-phase sheep were subjected to a series of intracerebroventricular (icv.) infusions of allopregnanolone (AL, 4 × 15 μg/60 μL/30 min) for 3 days. In Experiment 2, pregnant animals (4th month) received a series of infusions of the neurosteroid synthesis blocker, finasteride (4 × 25 μg/60 μL/30 min), conducted for 3 days. In non-pregnant sheep AL alone was shown to differentially modulate OT synthesis in basal conditions, and strongly inhibit OT response to stress (p < 0.001). In contrast, in pregnant animals, basal and stress-induced OT secretion was significantly (p < 0.001) increased during finasteride infusion compared to controls. In conclusion, we showed that neurosteroids were involved in the control of OT secretion in sheep, particularly under stress and pregnancy conditions and are part of an adaptive mechanism which is responsible for protecting and maintaining pregnancy in harmful situations.
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Affiliation(s)
- Patrycja Młotkowska
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3, 05-110 Jabłonna, Poland
| | - Elżbieta Marciniak
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3, 05-110 Jabłonna, Poland
| | - Anna Misztal
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3, 05-110 Jabłonna, Poland
| | - Tomasz Misztal
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3, 05-110 Jabłonna, Poland
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Kelly AM, Gonzalez Abreu JA, Thompson RR. Beyond sex and aggression: testosterone rapidly matches behavioural responses to social context and tries to predict the future. Proc Biol Sci 2022; 289:20220453. [PMID: 35673866 PMCID: PMC9174716 DOI: 10.1098/rspb.2022.0453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Although androgens are widely studied in the context of aggression, androgenic influences on prosocial behaviours have been less explored. We examined testosterone's (T) influence on prosocial and aggressive responses in a positively valenced social context (interacting with a pairbond partner) and a negatively valenced context (interacting with an intruder) in socially monogamous Mongolian gerbils. T increased and decreased prosocial responses in the same individuals towards a pairbond partner and an intruder, respectively, both within 30 min, but did not affect aggression. T also had persistent effects on prosocial behaviour; males in which T initially increased prosocial responses towards a partner continued to exhibit elevated prosocial responses towards an intruder male days later until a second T injection rapidly eliminated those responses. Thus, T surges can rapidly match behaviour to current social context, as well as prime animals for positive social interactions in the future. Neuroanatomically, T rapidly increased hypothalamic oxytocin, but not vasopressin, cellular responses during interactions with a partner. Together, our results indicate that T can facilitate and inhibit prosocial behaviours depending on social context, that it can influence prosocial responses across rapid and prolonged time scales, and that it affects oxytocin signalling mechanisms that could mediate its context-dependent behavioural influences.
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Affiliation(s)
- Aubrey M. Kelly
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, USA
| | | | - Richmond R. Thompson
- Division of Social Sciences, Oxford College of Emory University, 801 Emory Street, Oxford GA 30054 USA
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Oliveira VEDM, Lukas M, Wolf HN, Durante E, Lorenz A, Mayer AL, Bludau A, Bosch OJ, Grinevich V, Egger V, de Jong TR, Neumann ID. Oxytocin and vasopressin within the ventral and dorsal lateral septum modulate aggression in female rats. Nat Commun 2021; 12:2900. [PMID: 34006875 PMCID: PMC8131389 DOI: 10.1038/s41467-021-23064-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 03/09/2021] [Indexed: 02/03/2023] Open
Abstract
In contrast to male rats, aggression in virgin female rats has been rarely studied. Here, we established a rat model of enhanced aggression in females using a combination of social isolation and aggression-training to specifically investigate the involvement of the oxytocin (OXT) and arginine vasopressin (AVP) systems within the lateral septum (LS). Using neuropharmacological, optogenetic, chemogenetic as well as microdialysis approaches, we revealed that enhanced OXT release within the ventral LS (vLS), combined with reduced AVP release within the dorsal LS (dLS), is required for aggression in female rats. Accordingly, increased activity of putative OXT receptor-positive neurons in the vLS, and decreased activity of putative AVP receptor-positive neurons in the dLS, are likely to underly aggression in female rats. Finally, in vitro activation of OXT receptors in the vLS increased tonic GABAergic inhibition of dLS neurons. Overall, our data suggest a model showing that septal release of OXT and AVP differentially affects aggression in females by modulating the inhibitory tone within LS sub-networks.
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Affiliation(s)
- Vinícius Elias de Moura Oliveira
- Department of Neurobiology and Animal Physiology, Behavioural and Molecular Neurobiology, University of Regensburg, Universitaetstraße, Regensburg, Bavaria, Germany
| | - Michael Lukas
- Department of Neurobiology and Animal Physiology, Neurophysiology, University of Regensburg, Regensburg, Germany
| | - Hannah Nora Wolf
- Department of Neurobiology and Animal Physiology, Behavioural and Molecular Neurobiology, University of Regensburg, Universitaetstraße, Regensburg, Bavaria, Germany
| | - Elisa Durante
- Department of Neurobiology and Animal Physiology, Behavioural and Molecular Neurobiology, University of Regensburg, Universitaetstraße, Regensburg, Bavaria, Germany
| | - Alexandra Lorenz
- Department of Neurobiology and Animal Physiology, Behavioural and Molecular Neurobiology, University of Regensburg, Universitaetstraße, Regensburg, Bavaria, Germany
| | - Anna-Lena Mayer
- Department of Neurobiology and Animal Physiology, Behavioural and Molecular Neurobiology, University of Regensburg, Universitaetstraße, Regensburg, Bavaria, Germany
| | - Anna Bludau
- Department of Neurobiology and Animal Physiology, Behavioural and Molecular Neurobiology, University of Regensburg, Universitaetstraße, Regensburg, Bavaria, Germany
| | - Oliver J Bosch
- Department of Neurobiology and Animal Physiology, Behavioural and Molecular Neurobiology, University of Regensburg, Universitaetstraße, Regensburg, Bavaria, Germany
| | - Valery Grinevich
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Veronica Egger
- Department of Neurobiology and Animal Physiology, Neurophysiology, University of Regensburg, Regensburg, Germany
| | - Trynke R de Jong
- Department of Neurobiology and Animal Physiology, Behavioural and Molecular Neurobiology, University of Regensburg, Universitaetstraße, Regensburg, Bavaria, Germany
- Medische Biobank Noord-Nederland B.V., Groningen, Netherlands
| | - Inga D Neumann
- Department of Neurobiology and Animal Physiology, Behavioural and Molecular Neurobiology, University of Regensburg, Universitaetstraße, Regensburg, Bavaria, Germany.
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4
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Kelly AM, Wilson LC. Aggression: Perspectives from social and systems neuroscience. Horm Behav 2020; 123:104523. [PMID: 31002771 DOI: 10.1016/j.yhbeh.2019.04.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 04/14/2019] [Accepted: 04/15/2019] [Indexed: 01/16/2023]
Abstract
Exhibiting behavioral plasticity in order to mount appropriate responses to dynamic and novel social environments is crucial to the survival of all animals. Thus, how animals regulate flexibility in the timing, duration, and intensity of specific behaviors is of great interest to biologists. In this review, we discuss how animals rapidly respond to social challenges, with a particular focus on aggression. We utilize a conceptual framework to understand the neural mechanisms of aggression that is grounded in Wingfield and colleagues' Challenge Hypothesis, which has profoundly influenced how scientists think about aggression and the mechanisms that allow animals to exhibit flexible responses to social instability. Because aggressive behavior is rooted in social interactions, we propose that mechanisms modulating prosocial behavior may be intricately tied to mechanisms of aggression. Therefore, in order to better understand how aggressive behavior is mediated, we draw on perspectives from social neuroscience and discuss how social context, species-typical behavioral phenotype, and neural systems commonly studied in relation to prosocial behavior (i.e., neuropeptides) contribute to organizing rapid responses to social challenges. Because complex behaviors are not the result of one mechanism or a single neural system, we consider how multiple neural systems important for prosocial and aggressive behavior (i.e., neuropeptides and neurosteroids) interact in the brain to produce behavior in a rapid, context-appropriate manner. Applying a systems neuroscience perspective and seeking to understand how multiple systems functionally integrate to rapidly modulate behavior holds great promise for expanding our knowledge of the mechanisms underlying social behavioral plasticity.
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Affiliation(s)
- Aubrey M Kelly
- Department of Psychology, Emory University, Atlanta, GA 30322, USA.
| | - Leah C Wilson
- Department of Biology, Bowdoin College, Brunswick, ME 04011, USA
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5
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Lagunes-Merino O, Rodríguez-Landa JF, Caba M, Carro-Juárez M, García-Orduña F, Saavedra-Vélez M, Puga-Olguín A, de Jesús Rovirosa-Hernández M. Acute effect of an infusion of Montanoa tomentosa on despair-like behavior and activation of oxytocin hypothalamic cells in Wistar rats. J Tradit Complement Med 2020; 10:45-51. [PMID: 31956557 PMCID: PMC6957806 DOI: 10.1016/j.jtcme.2019.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/28/2018] [Accepted: 01/29/2019] [Indexed: 11/30/2022] Open
Abstract
Background and aim In Mexican traditional medicine, Montanoa tomentosa (Mt) has been used as a remedy for reproductive impairments and mood swings. In pre-clinical research, both the extract and some of its active metabolites have produced oxytocinergic-like effects on female reproductive organs; however, there are no detailed studies of its effects on mood swing and brain structures. The aim of this study, was to analyze the behavioral effects of acute administration of a Mt infusion on male rats, during the Open Field (OFT) and Forced Swim (FST) Tests, and their association with the activation of oxytocin (OXT) cells, indicated by Fos protein (Fos/OXT) in the paraventricular (PVN) and supraoptic nuclei (SON). Experimental procedure 52 adult male Wistar rats were assigned to two conditions; with FST (n = 8), or without (n = 5). Each integrated condition included four groups [Control, Vehicle, Fluoxetine (Flx; 10 mg/kg), and Mt (50 mg/kg), p.o.]. Results and conclusion Mt and Flx treatment produced an anti-despair-like effect on the FST, but no significant changes in locomotor activity. Also, the Mt infusion -but not Flx-significantly increased the number of Fos/OXT cells in the PVN and SON, regardless of the condition, compared to the control and vehicle groups. These results show that Mt, but not Flx, produces an anti-despair-like effect that could be associated with the activation of OXT cells in PVN and SON. This study thus contributes to our knowledge of the pharmacological activity of Mt infusions, which could be a natural antidepressant agent with future clinical relevance.
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Affiliation(s)
- Omar Lagunes-Merino
- Doctorado en Neuroetología, Universidad Veracruzana, Xalapa, Veracruz, 91190, Mexico
| | | | - Mario Caba
- Centro de Investigaciones Biomédicas, Universidad Veracruzana, Xalapa, Veracruz, 91190, Mexico
| | - Miguel Carro-Juárez
- Escuela de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Tlaxcala, Tlaxcala, 90000, Mexico
| | | | | | - Abraham Puga-Olguín
- Doctorado en Neuroetología, Universidad Veracruzana, Xalapa, Veracruz, 91190, Mexico
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The Role of the Oxytocin/Arginine Vasopressin System in Animal Models of Autism Spectrum Disorder. ADVANCES IN ANATOMY EMBRYOLOGY AND CELL BIOLOGY 2017; 224:135-158. [DOI: 10.1007/978-3-319-52498-6_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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7
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Ludwig M, Apps D, Menzies J, Patel JC, Rice ME. Dendritic Release of Neurotransmitters. Compr Physiol 2016; 7:235-252. [PMID: 28135005 DOI: 10.1002/cphy.c160007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Release of neuroactive substances by exocytosis from dendrites is surprisingly widespread and is not confined to a particular class of transmitters: it occurs in multiple brain regions, and includes a range of neuropeptides, classical neurotransmitters, and signaling molecules, such as nitric oxide, carbon monoxide, ATP, and arachidonic acid. This review is focused on hypothalamic neuroendocrine cells that release vasopressin and oxytocin and midbrain neurons that release dopamine. For these two model systems, the stimuli, mechanisms, and physiological functions of dendritic release have been explored in greater detail than is yet available for other neurons and neuroactive substances. © 2017 American Physiological Society. Compr Physiol 7:235-252, 2017.
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Affiliation(s)
- Mike Ludwig
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - David Apps
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - John Menzies
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Jyoti C Patel
- Department of Neurosurgery, New York University School of Medicine, New York, USA
| | - Margaret E Rice
- Department of Neurosurgery, New York University School of Medicine, New York, USA.,Department of Neuroscience and Physiology, New York University School of Medicine, New York, USA
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8
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Rahmani B, Ghasemi R, Dargahi L, Ahmadiani A, Haeri A. Neurosteroids; potential underpinning roles in maintaining homeostasis. Gen Comp Endocrinol 2016; 225:242-250. [PMID: 26432100 DOI: 10.1016/j.ygcen.2015.09.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 09/14/2015] [Accepted: 09/28/2015] [Indexed: 12/31/2022]
Abstract
The neuroactive steroids which are synthesized in the brain and nervous system are known as "Neurosteroids". These steroids have crucial functions such as contributing to the myelination and organization of the brain connectivity. Under the stressful circumstances, the concentrations of neurosteroid products such as allopregnanolone (ALLO) and allotetrahydrodeoxycorticosterone (THDOC) alter. It has been suggested that these stress-derived neurosteroids modulate the physiological response to stress. Moreover, it has been demonstrated that the hypothalamic-pituitary-adrenal (HPA) axis mediates the physiological adaptation following stress in order to maintain homeostasis. Although several regulatory pathways have been introduced, the exact role of neurosteroids in controlling HPA axis is not clear to date. In this review, we intend to discern specific pathways associated with regulation of HPA axis in which neuroactive steroids have the main role. In this respect, we propose pathways that may be initiated after neurosteroidogenesis in different brain subregions following acute stress which are potentially capable of activating or inhibiting the HPA axis.
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Affiliation(s)
- Behrouz Rahmani
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Rasoul Ghasemi
- Department of Physiology and Neurophysiology Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Leila Dargahi
- NeuroBiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abolhassan Ahmadiani
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Ali Haeri
- Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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9
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Kumar J, Völlm B, Palaniyappan L. Oxytocin affects the connectivity of the precuneus and the amygdala: a randomized, double-blinded, placebo-controlled neuroimaging trial. Int J Neuropsychopharmacol 2015; 18:pyu051. [PMID: 25522395 PMCID: PMC4376540 DOI: 10.1093/ijnp/pyu051] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Although oxytocin is one of the most widely studied neuropeptides in recent times, the mechanistic process by which it modulates social-affective behavior in the brain is not yet clearly understood. Thus, to understand the neurophysiological basis of oxytocin effects, we used resting-state functional MRI to examine the effects of intranasal oxytocin on brain connectivity in healthy males. METHODS Using a randomized, double-blinded, placebo-controlled, crossover design, 15 healthy male volunteers received 24 IU intranasal oxytocin or placebo prior to resting-state functional MRI acquisition at 3T. RESULTS We found that oxytocin significantly reduced the degree centrality of the right precuneus (P<.05). Oxytocin also reduced connectivity between the bilateral amygdalae and between the right precuneus and the right and left amygdala (P<.05). Although there were no significant changes in regional homogeneity at the whole brain level, posthoc results showed a reduction involving the right precuneus (P<.05). CONCLUSIONS These results show that oxytocin affects one of the key centers in the brain for social cognition and introspective processing, the precuneus, and enhances our understanding of how oxytocin can modulate brain networks at rest. An improved understanding of the neurophysiological effects of oxytocin can be important in terms of evaluating the mechanisms that are likely to underlie the clinical responses observed upon long-term oxytocin administration.
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Affiliation(s)
| | | | - Lena Palaniyappan
- Translational Neuroimaging in Mental Health, Division of Psychiatry and Applied Psychology, University of Nottingham, Nottingham, United Kingdom (Ms Kumar, Dr Völlm, and Dr Palaniyappan); Nottinghamshire Healthcare NHS Trust, Nottingham, United Kingdom (Drs Völlm and Palaniyappan).
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10
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Vargas-Martínez F, Uvnäs-Moberg K, Petersson M, Olausson HA, Jiménez-Estrada I. Neuropeptides as neuroprotective agents: Oxytocin a forefront developmental player in the mammalian brain. Prog Neurobiol 2014; 123:37-78. [DOI: 10.1016/j.pneurobio.2014.10.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 10/06/2014] [Indexed: 02/07/2023]
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Brunton PJ, Russell JA, Hirst JJ. Allopregnanolone in the brain: protecting pregnancy and birth outcomes. Prog Neurobiol 2014; 113:106-36. [PMID: 24012715 DOI: 10.1016/j.pneurobio.2013.08.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/12/2013] [Accepted: 08/25/2013] [Indexed: 01/09/2023]
Abstract
A successful pregnancy requires multiple adaptations in the mother's brain that serve to optimise foetal growth and development, protect the foetus from adverse prenatal programming and prevent premature delivery of the young. Pregnancy hormones induce, organise and maintain many of these adaptations. Steroid hormones play a critical role and of particular importance is the progesterone metabolite and neurosteroid, allopregnanolone. Allopregnanolone is produced in increasing amounts during pregnancy both in the periphery and in the maternal and foetal brain. This review critically examines a role for allopregnanolone in both the maternal and foetal brain during pregnancy and development in protecting pregnancy and birth outcomes, with particular emphasis on its role in relation to stress exposure at this time. Late pregnancy is associated with suppressed stress responses. Thus, we begin by considering what is known about the central mechanisms in the maternal brain, induced by allopregnanolone, that protect the foetus(es) from exposure to harmful levels of maternal glucocorticoids as a result of stress during pregnancy. Next we discuss the central mechanisms that prevent premature secretion of oxytocin and consider a role for allopregnanolone in minimising the risk of preterm birth. Allopregnanolone also plays a key role in the foetal brain, where it promotes development and is neuroprotective. Hence we review the evidence about disruption to neurosteroid production in pregnancy, through prenatal stress or other insults, and the immediate and long-term adverse consequences for the offspring. Finally we address whether progesterone or allopregnanolone treatment can rescue some of these deficits in the offspring.
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Affiliation(s)
- Paula J Brunton
- Division of Neurobiology, The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Scotland, UK.
| | - John A Russell
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Scotland, UK
| | - Jonathan J Hirst
- Mothers and Babies Research Centre, School of Biomedical Sciences, University of Newcastle, Newcastle, N.S.W., Australia
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12
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Brown CH, Bains JS, Ludwig M, Stern JE. Physiological regulation of magnocellular neurosecretory cell activity: integration of intrinsic, local and afferent mechanisms. J Neuroendocrinol 2013; 25:678-710. [PMID: 23701531 PMCID: PMC3852704 DOI: 10.1111/jne.12051] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Revised: 05/08/2013] [Accepted: 05/20/2013] [Indexed: 01/12/2023]
Abstract
The hypothalamic supraoptic and paraventricular nuclei contain magnocellular neurosecretory cells (MNCs) that project to the posterior pituitary gland where they secrete either oxytocin or vasopressin (the antidiuretic hormone) into the circulation. Oxytocin is important for delivery at birth and is essential for milk ejection during suckling. Vasopressin primarily promotes water reabsorption in the kidney to maintain body fluid balance, but also increases vasoconstriction. The profile of oxytocin and vasopressin secretion is principally determined by the pattern of action potentials initiated at the cell bodies. Although it has long been known that the activity of MNCs depends upon afferent inputs that relay information on reproductive, osmotic and cardiovascular status, it has recently become clear that activity depends critically on local regulation by glial cells, as well as intrinsic regulation by the MNCs themselves. Here, we provide an overview of recent advances in our understanding of how intrinsic and local extrinsic mechanisms integrate with afferent inputs to generate appropriate physiological regulation of oxytocin and vasopressin MNC activity.
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Affiliation(s)
- C H Brown
- Department of Physiology and Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand.
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13
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Forostyak O, Romanyuk N, Verkhratsky A, Sykova E, Dayanithi G. Plasticity of calcium signaling cascades in human embryonic stem cell-derived neural precursors. Stem Cells Dev 2013; 22:1506-21. [PMID: 23294113 PMCID: PMC3653370 DOI: 10.1089/scd.2012.0624] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 01/07/2013] [Indexed: 01/15/2023] Open
Abstract
Human embryonic stem cell-derived neural precursors (hESC NPs) are considered to be a promising tool for cell-based therapy in central nervous system injuries and neurodegenerative diseases. The Ca(2+) ion is an important intracellular messenger essential for the regulation of various cellular functions. We investigated the role and physiology of Ca(2+) signaling to characterize the functional properties of CCTL14 hESC NPs during long-term maintenance in culture (in vitro). We analyzed changes in cytoplasmic Ca(2+) concentration ([Ca(2+)]i) evoked by high K(+), adenosine-5'-triphosphate (ATP), glutamate, γ-aminobutyric acid (GABA), and caffeine in correlation with the expression of various neuronal markers in different passages (P6 through P10) during the course of hESC differentiation. We found that only differentiated NPs from P7 exhibited significant and specific [Ca(2+)]i responses to various stimuli. About 31% of neuronal-like P7 NPs exhibited spontaneous [Ca(2+)]i oscillations. Pharmacological and immunocytochemical assays revealed that P7 NPs express L- and P/Q-type Ca(2+) channels, P2X2, P2X3, P2X7, and P2Y purinoreceptors, glutamate receptors, and ryanodine (RyR1 and RyR3) receptors. The ATP- and glutamate-induced [Ca(2+)]i responses were concentration-dependent. Higher glutamate concentrations (over 100 μM) caused cell death. Responses to ATP were observed in the presence or in the absence of extracellular Ca(2+). These results emphasize the notion that with time in culture, these cells attain a transient period of operative Ca(2+) signaling that is predictive of their ability to act as stem elements.
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Affiliation(s)
- Oksana Forostyak
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Nataliya Romanyuk
- Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Alexei Verkhratsky
- School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Eva Sykova
- Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Department of Neuroscience, Second Medical Faculty, Charles University, Prague, Czech Republic
| | - Govindan Dayanithi
- Department of Molecular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Institut National de la Santé et de la Recherche Médicale, Unité de recherche U710, Université Montpellier 2, Montpellier; and Ecole Pratique des Hautes Etudes, Paris, France
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14
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Modulation/physiology of calcium channel sub-types in neurosecretory terminals. Cell Calcium 2012; 51:284-92. [PMID: 22341671 DOI: 10.1016/j.ceca.2012.01.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/11/2012] [Accepted: 01/22/2012] [Indexed: 11/21/2022]
Abstract
The hypothalamic-neurohypophysial system (HNS) controls diuresis and parturition through the release of arginine-vasopressin (AVP) and oxytocin (OT). These neuropeptides are chiefly synthesized in hypothalamic magnocellular somata in the supraoptic and paraventricular nuclei and are released into the blood stream from terminals in the neurohypophysis. These HNS neurons develop specific electrical activity (bursts) in response to various physiological stimuli. The release of AVP and OT at the level of neurohypophysis is directly linked not only to their different burst patterns, but is also regulated by the activity of a number of voltage-dependent channels present in the HNS nerve terminals and by feedback modulators. We found that there is a different complement of voltage-gated Ca(2+) channels (VGCC) in the two types of HNS terminals: L, N, and Q in vasopressinergic terminals vs. L, N, and R in oxytocinergic terminals. These channels, however, do not have sufficiently distinct properties to explain the differences in release efficacy of the specific burst patterns. However, feedback by both opioids and ATP specifically modulate different types of VGCC and hence the amount of AVP and/or OT being released. Opioid receptors have been identified in both AVP and OT terminals. In OT terminals, μ-receptor agonists inhibit all VGCC (particularly R-type), whereas, they induce a limited block of L-, and P/Q-type channels, coupled to an unusual potentiation of the N-type Ca(2+) current in the AVP terminals. In contrast, the N-type Ca(2+) current can be inhibited by adenosine via A(1) receptors leading to the decreased release of both AVP and OT. Furthermore, ATP evokes an inactivating Ca(2+)/Na(+)-current in HNS terminals able to potentiate AVP release through the activation of P2X2, P2X3, P2X4 and P2X7 receptors. In OT terminals, however, only the latter receptor type is probably present. We conclude by proposing a model that can explain how purinergic and/or opioid feedback modulation during bursts can mediate differences in the control of neurohypophysial AVP vs. OT release.
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Oberlander JG, Porter DM, Penatti CAA, Henderson LP. Anabolic androgenic steroid abuse: multiple mechanisms of regulation of GABAergic synapses in neuroendocrine control regions of the rodent forebrain. J Neuroendocrinol 2012; 24:202-14. [PMID: 21554430 PMCID: PMC3168686 DOI: 10.1111/j.1365-2826.2011.02151.x] [Citation(s) in RCA: 22] [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] [Indexed: 12/14/2022]
Abstract
Anabolic androgenic steroids (AAS) are synthetic derivatives of testosterone originally developed for clinical purposes but are now predominantly taken at suprapharmacological levels as drugs of abuse. To date, almost 100 different AAS compounds that vary in metabolic fate and physiological effects have been designed and synthesised. Although they are administered for their ability to enhance muscle mass and performance, untoward side effects of AAS use include changes in reproductive and sexual behaviours. Specifically, AAS, depending on the type of compound administered, can delay or advance pubertal onset, lead to irregular oestrous cyclicity, diminish male and female sexual behaviours, and accelerate reproductive senescence. Numerous brains regions and neurotransmitter signalling systems are involved in the generation of these behaviours, and are potential targets for both chronic and acute actions of the AAS. However, critical to all of these behaviours is neurotransmission mediated by GABA(A) receptors within a nexus of interconnected forebrain regions that includes the medial preoptic area, the anteroventral periventricular nucleus and the arcuate nucleus of the hypothalamus. We review how exposure to AAS alters GABAergic transmission and neural activity within these forebrain regions, taking advantage of in vitro systems and both wild-type and genetically altered mouse strains, aiming to better understand how these synthetic steroids affect the neural systems that underlie the regulation of reproduction and the expression of sexual behaviours.
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Affiliation(s)
- Joseph G. Oberlander
- Department of Physiology and Neurobiology, Dartmouth Medical School, Hanover, NH 03755 USA
| | - Donna M. Porter
- 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
| | - 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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Viero C, Shibuya I, Kitamura N, Verkhratsky A, Fujihara H, Katoh A, Ueta Y, Zingg HH, Chvatal A, Sykova E, Dayanithi G. REVIEW: Oxytocin: Crossing the bridge between basic science and pharmacotherapy. CNS Neurosci Ther 2010; 16:e138-56. [PMID: 20626426 PMCID: PMC2972642 DOI: 10.1111/j.1755-5949.2010.00185.x] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Is oxytocin the hormone of happiness? Probably not. However, this small nine amino acid peptide is involved in a wide variety of physiological and pathological functions such as sexual activity, penile erection, ejaculation, pregnancy, uterus contraction, milk ejection, maternal behavior, osteoporosis, diabetes, cancer, social bonding, and stress, which makes oxytocin and its receptor potential candidates as targets for drug therapy. In this review, we address the issues of drug design and specificity and focus our discussion on recent findings on oxytocin and its heterotrimeric G protein‐coupled receptor OTR. In this regard, we will highlight the following topics: (i) the role of oxytocin in behavior and affectivity, (ii) the relationship between oxytocin and stress with emphasis on the hypothalamo–pituitary–adrenal axis, (iii) the involvement of oxytocin in pain regulation and nociception, (iv) the specific action mechanisms of oxytocin on intracellular Ca2+ in the hypothalamo neurohypophysial system (HNS) cell bodies, (v) newly generated transgenic rats tagged by a visible fluorescent protein to study the physiology of vasopressin and oxytocin, and (vi) the action of the neurohypophysial hormone outside the central nervous system, including the myometrium, heart and peripheral nervous system. As a short nine amino acid peptide, closely related to its partner peptide vasopressin, oxytocin appears to be ideal for the design of agonists and antagonists of its receptor. In addition, not only the hormone itself and its binding to OTR, but also its synthesis, storage and release can be endogenously and exogenously regulated to counteract pathophysiological states. Understanding the fundamental physiopharmacology of the effects of oxytocin is an important and necessary approach for developing a potential pharmacotherapy.
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Affiliation(s)
- Cedric Viero
- Department of Cardiology, Wales Heart Research Institute, Cardiff University, UK
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17
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Katoh A, Fujihara H, Ohbuchi T, Onaka T, Young WS, Dayanithi G, Yamasaki Y, Kawata M, Suzuki H, Otsubo H, Suzuki H, Murphy D, Ueta Y. Specific expression of an oxytocin-enhanced cyan fluorescent protein fusion transgene in the rat hypothalamus and posterior pituitary. J Endocrinol 2010; 204:275-85. [PMID: 20026620 PMCID: PMC2922867 DOI: 10.1677/joe-09-0289] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We have generated rats bearing an oxytocin (OXT)-enhanced cyan fluorescent protein (eCFP) fusion transgene designed from a murine construct previously shown to be faithfully expressed in transgenic mice. In situ hybridisation histochemistry revealed that the Oxt-eCfp fusion gene was expressed in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) in these rats. The fluorescence emanating from eCFP was observed only in the SON, the PVN, the internal layer of the median eminence and the posterior pituitary (PP). In in vitro preparations, freshly dissociated cells from the SON and axon terminals showed clear eCFP fluorescence. Immunohistochemistry for OXT and arginine vasopressin (AVP) revealed that the eCFP fluorescence co-localises with OXT immunofluorescence, but not with AVP immunofluorescence in the SON and the PVN. Although the expression levels of the Oxt-eCfp fusion gene in the SON and the PVN showed a wide range of variations in transgenic rats, eCFP fluorescence was markedly increased in the SON and the PVN, but decreased in the PP after chronic salt loading. The expression of the Oxt gene was significantly increased in the SON and the PVN after chronic salt loading in both non-transgenic and transgenic rats. Compared with wild-type animals, euhydrated and salt-loaded male and female transgenic rats showed no significant differences in plasma osmolality, sodium concentration and OXT and AVP levels, suggesting that the fusion gene expression did not disturb any physiological processes. These results suggest that our new transgenic rats are a valuable new tool to identify OXT-producing neurones and their terminals.
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Affiliation(s)
- Akiko Katoh
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
- Department of Otorhynolaryngology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
| | - Hiroaki Fujihara
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
| | - Toyoaki Ohbuchi
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
- Department of Otorhynolaryngology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
| | - Tatsushi Onaka
- Department of Physiology, Jichi Medical School, Tochigi 329-0498, Japan
| | - W. Scott Young
- Section on Neural Gene Expression, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892-4483, USA
| | - Govindan Dayanithi
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Science of the Czech Republic, EU Research Centre of Excellence, Prague, Czech Republic
| | - Yuka Yamasaki
- Department of Anatomy and Neurobiology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Mitsuhiro Kawata
- Department of Anatomy and Neurobiology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Hitoshi Suzuki
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
| | - Hiroki Otsubo
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
| | - Hideaki Suzuki
- Department of Otorhynolaryngology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
| | - David Murphy
- Molecular Neuroendocrinology Research Group, The Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Dorothy Hodgkin Building, Bristol BS1 3NY, UK
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
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18
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Pueta M, Abate P, Haymal OB, Spear NE, Molina JC. Ethanol exposure during late gestation and nursing in the rat: effects upon maternal care, ethanol metabolism and infantile milk intake. Pharmacol Biochem Behav 2008; 91:21-31. [PMID: 18602418 PMCID: PMC2568972 DOI: 10.1016/j.pbb.2008.06.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 05/20/2008] [Accepted: 06/11/2008] [Indexed: 11/23/2022]
Abstract
Ethanol experiences, during late gestation as well as during nursing, modify the behavioral dynamics of the dam/pup dyad, and leads to heightened ethanol intake in the offspring. This study focuses on: a) behavioral and metabolic changes in intoxicated dams with previous exposure to ethanol during pregnancy and b) infantile consumption of milk when the dam is either under the effects of ethanol or sober. Pregnant rats received water, 1.0 or 2.0 g/kg ethanol, and were administered with water or ethanol during the postpartum period. Intoxication during nursing disrupted the capability of the dam to retrieve the pups and to adopt a crouching posture. These disruptions were attenuated when dams had exposure to ethanol during pregnancy. Ethanol experiences during gestation did not affect pharmacokinetic processes during nursing, whereas progressive postpartum ethanol experience resulted in metabolic tolerance. Pups suckling from intoxicated dams, with previous ethanol experiences, ingested more milk than did infants suckling from ethanol-intoxicated dams without such experience. Ethanol gestational experience results in subsequent resistance to the drug's disruptions in maternal care. Consequently, better maternal care by an intoxicated dam with ethanol experience during gestation facilitates access of pups to milk which could be contaminated with ethanol.
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Affiliation(s)
- Mariana Pueta
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC - CONICET), Córdoba, C.P 5016, Argentina.
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19
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McMurray MS, Cox ET, Jarrett TM, Williams SK, Walker CH, Johns JM. Impact of gestational cocaine treatment or prenatal cocaine exposure on early postpartum oxytocin mRNA levels and receptor binding in the rat. Neuropeptides 2008; 42:641-52. [PMID: 18579201 PMCID: PMC2614125 DOI: 10.1016/j.npep.2008.05.003] [Citation(s) in RCA: 10] [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: 02/25/2008] [Revised: 05/08/2008] [Accepted: 05/10/2008] [Indexed: 12/30/2022]
Abstract
Prior research reported decreased oxytocin levels in specific brain regions correlated with disruptions in maternal care following gestational cocaine treatment in rats. Similarly, prenatal exposure to cocaine impaired subsequent maternal behavior in adulthood, but behavioral alterations were not associated with decreases in oxytocin levels in the same brain regions as were found in their cocaine-treated rat dams. To determine if other aspects of the oxytocin system are disrupted by cocaine treatment or prenatal exposure to cocaine during critical time points associated with maternal care, oxytocin mRNA transcription and receptor binding were examined on postpartum day two in relevant brain regions following gestational treatment with, or prenatal exposure to, either cocaine or saline. We hypothesized that oxytocin mRNA levels and receptor binding would be differentially affected by cocaine in the early postpartum period of dams and their offspring. Our findings indicate that gestational cocaine treatment resulted in significant increases in oxytocin mRNA levels in only the paraventricular nucleus of cocaine-treated dams, with almost significant increases in both generations in the supraoptic nucleus, but no significant effects of cocaine on receptor binding in either generation of dams. These findings indicate that in addition to oxytocin levels, cocaine treatment or prenatal exposure primarily affects oxytocin mRNA synthesis, with little effect on receptor binding in specific brain regions associated with maternal behavior in the early postpartum period of the rat.
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Affiliation(s)
- M S McMurray
- Department of Psychology, The University of North Carolina at Chapel Hill, 436 Taylor Hall, CB# 7096, Chapel Hill, NC 27599, USA.
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20
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Neuroactive steroids modulate HPA axis activity and cerebral brain-derived neurotrophic factor (BDNF) protein levels in adult male rats. Psychoneuroendocrinology 2007; 32:1062-78. [PMID: 17928160 DOI: 10.1016/j.psyneuen.2007.09.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 09/04/2007] [Accepted: 09/04/2007] [Indexed: 11/21/2022]
Abstract
Depression is characterized by hypothalamo-pituitary-adrenocortical (HPA) axis hyperactivity. In this major mood disorder, neurosteroids and neurotrophins, particularly brain-derived neurotrophic factor (BDNF), seem to be implicated and have some antidepressant effects. BDNF is highly involved in regulation of the HPA axis, whereas neurosteroids effects have never been clearly established. In this systematic in vivo study, we showed that the principal neuroactive steroids, namely dehydroepiandrosterone (DHEA), pregnenolone (PREG) and their sulfate esters (DHEA-S and PREG-S), along with allopregnanolone (ALLO), stimulated HPA axis activity, while also modulating central BDNF contents. In detail, DHEA, DHEA-S, PREG, PREG-S and ALLO induced corticotropin-releasing hormone (CRH) and/or arginine vasopressin (AVP) synthesis and release at the hypothalamic level, thus enhancing plasma adrenocorticotropin hormone (ACTH) and corticosterone (CORT) concentrations. This stimulation of the HPA axis occurred concomitantly with BDNF modifications at the hippocampus, amygdala and hypothalamus levels. We showed that these neurosteroids induced rapid effects, probably via neurotransmitter receptors and delayed effects perhaps after metabolization in other neuroactive steroids. We highlighted that they had peripheral effects directly at the adrenal level by inducing CORT release, certainly after estrogenic metabolization. In addition, we showed that, at the dose used, only DHEA, DHEA-S and PREG-S had antidepressant effects. In conclusion, these results highly suggest that part of the HPA axis and antidepressant effects of neuroactive steroids could be mediated by BDNF, particularly at the amygdala level. They also suggest that neurosteroids effects on central BDNF could partially explain the trophic properties of these molecules.
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21
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Klein S, Jurkevich A, Grossmann R. Sexually dimorphic immunoreactivity of galanin and colocalization with arginine vasotocin in the chicken brain (Gallus gallus domesticus). J Comp Neurol 2007; 499:828-39. [PMID: 17048233 DOI: 10.1002/cne.21132] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The bed nucleus of the stria terminalis medialis (BSTM) of adult chickens (Gallus gallus domesticus) was previously shown to synthesize arginine vasotocin (AVT) in males only and coincides spatially and temporally with steroid activity regulating male reproductive behavior. Galanin has been shown to be a potent modulator of the behavioral and neuroendocrine responses in the mammalian BSTM and in other sexually dimorphic brain regions. In the present study of adult chickens the morphological relationship of AVT and galanin was examined by immunohistochemical analysis of two limbic structures, the BSTM and the lateral septum (SL). The analysis also included the hypothalamic nuclei supraopticus (SON) and paraventricularis (PVN). In males galanin and AVT were both synthesized in the BSTM, while in females neither galanin nor AVT was present. Furthermore, in the males galanin and AVT were colocalized in the majority of neurons within BSTM and in fibers of the SL. In both sexes galanin neurons in the PVN were scattered between the distinct clusters of AVT neurons and there was no colocalization of galanin and AVT in single PVN neurons. Furthermore, AVT immunoreactivity was significantly higher in the SON than in the PVN in both sexes. In the SON, galanin was colocalized with AVT in significantly more neurons in hens than in males (P </= 0.05%). These results demonstrate that the distributions of galanin and AVT are sexually dimorphic not only in the limbic BSTM but also in the hypothalamic SON. It is tempting to speculate that galanin in the SON is involved in regulation of oviposition as an AVT-dependent female-specific function.
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Affiliation(s)
- Sabine Klein
- Department of Functional Genomics and Bioregulation, Institute for Animal Science Mariensee, Federal Agricultural Research Center (FAL), 31535 Neustadt, Germany
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22
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Steroid modulation of GABAA receptor-mediated transmission in the hypothalamus: effects on reproductive function. Neuropharmacology 2007; 52:1439-53. [PMID: 17433821 DOI: 10.1016/j.neuropharm.2007.01.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 01/30/2007] [Accepted: 01/31/2007] [Indexed: 10/23/2022]
Abstract
The hypothalamus, the seat of neuroendocrine control, is exquisitely sensitive to gonadal steroids. For decades it has been known that androgens, estrogens and progestins, acting through nuclear hormone receptors, elicit both organizational and activational effects in the hypothalamus and basal forebrain that are essential for reproductive function. While changes in gene expression mediated by these classical hormone pathways are paramount in governing both sexual differentiation and the neural control of reproduction, it is also clear that steroids impart critical control of neuroendocrine functions through non-genomic mechanisms. Specifically, endogenous neurosteroid derivatives of deoxycorticosterone, progesterone and testosterone, as well and synthetic anabolic androgenic steroids that are self-administered as drugs of abuse, elicit acute effects via allosteric modulation of gamma-aminobutyric acid type A receptors. GABAergic transmission within the hypothalamus and basal forebrain is a key regulator of pubertal onset, the expression of sexual behaviors, pregnancy and parturition. Summarized here are the known actions of steroid modulators on GABAergic transmission within the hypothalamus/basal forebrain, with a focus on the medial preoptic area and the supraoptic/paraventricular nuclei that are known to be central players in the control of reproduction.
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23
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Viéro C, Méchaly I, Aptel H, Puech S, Valmier J, Bancel F, Dayanithi G. Rapid inhibition of Ca2+ influx by neurosteroids in murine embryonic sensory neurones. Cell Calcium 2006; 40:383-91. [PMID: 16769113 DOI: 10.1016/j.ceca.2006.04.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 04/09/2006] [Accepted: 04/24/2006] [Indexed: 10/24/2022]
Abstract
The non-genomic role of neuroactive steroids on [Ca2+]i transients induced by GABA receptor activation was investigated in cultured dorsal root ganglia (DRG) neurones at embryonic stage E13. [Ca2+]i measurements were performed with Fura-2 fast fluorescence microfluorimetry. Application of the GABAA receptor agonist muscimol (Musci) evoked an increase in [Ca2+]i, confirming the excitatory effect of GABA at this embryonic stage. The muscimol-induced [Ca2+]i response was inhibited by progesterone (Proges) and its primary metabolite allopregnanolone (Allo) in a rapid, reversible and dose-dependent manner. These calcium transients were suppressed in the absence of external Ca2+ or in the presence of Ni2+ + Cd2+ suggesting an involvement of voltage-activated Ca2+ channels. In contrast, none of these steroids affected the resting [Ca2+]i nor exhibited any inhibitory effect on 50 mM KCl-induced [Ca2+]i increases. In view of the well-established potentiation of GABAA receptor by direct binding of neurosteroids, the inhibitory effects described in this study seem to involve distinct mechanisms. This new inhibitory effect of progesterone is observed at low and physiological concentrations, is rapid and independent of RU38486, an antagonist of the classic progesterone receptor, probably involving a membrane receptor. Using RT-PCR, we demonstrated the expression of progesterone receptor membrane component 1 (Pgrmc1), encoding 25-Dx, a membrane-associated progesterone binding protein in DRG neurones at different stages of development. In conclusion, we describe for the first time a rapid effect of progestins on embryonic DRG neurones involving an antagonistic effect of progesterone and allopregnanolone on GABAA receptors.
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Affiliation(s)
- Cédric Viéro
- INSERM U 583, Institut des Neurosciences de Montpellier, Hôpital St Eloi, BP 74103, 80 rue Augustin Fliche, F-34091 Montpellier, Cedex 5, France
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24
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Russell JA, Brunton PJ. Neuroactive steroids attenuate oxytocin stress responses in late pregnancy. Neuroscience 2006; 138:879-89. [PMID: 16310312 DOI: 10.1016/j.neuroscience.2005.09.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Revised: 08/03/2005] [Accepted: 09/08/2005] [Indexed: 01/27/2023]
Abstract
In late pregnant rats neuroendocrine stress responses, expressed as increased oxytocin secretion and activation of the hypothalamo-pituitary-adrenal axis, are attenuated. These adaptations preserve the oxytocin store for parturition and prevent pre-term birth, and protect the fetuses from adverse programming by exposure to excess glucocorticoid. Mechanisms of adaptations for oxytocin neurones are reviewed, using challenge with systemic interleukin-1beta, simulating activation of immune signaling by infection, as a stressor of special relevance in pregnancy. In virgin rats, systemic interleukin-1beta stimulates the firing of oxytocin neurones, and hence oxytocin secretion, but interleukin-1beta has no effects in late pregnant rats. This lack of response is reversed by naloxone treatment just before interleukin-1beta administration, indicating endogenous opioid suppression of oxytocin responses in late pregnancy. This opioid presynaptically inhibits noradrenergic terminals impinging on oxytocin neurones. Finasteride pretreatment, inhibiting progesterone conversion to allopregnanolone, a positive GABA(A) receptor allosteric modifier, also restores an oxytocin response to interleukin-1beta. This finasteride effect is reversed by allopregnanolone treatment. In virgin rats allopregnanolone attenuates the oxytocin response to interleukin-1beta, which is exaggerated by naloxone. The effects of naloxone and finasteride in late pregnant rats in restoring an oxytocin response to interleukin-1beta are not additive. Accordingly, allopregnanolone may both enhance GABA inhibition of oxytocin neurone responses to interleukin-1beta, and induce opioid suppression of noradrenaline release onto oxytocin neurones.
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Affiliation(s)
- J A Russell
- Laboratory of Neuroendocrinology, Centre for Integrative Physiology, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Hugh Robson Building, UK.
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25
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Yu KL, Tamada Y, Suwa F, Fang YR, Tang CS. Age-related changes in oxytocin-, arginine vasopressin- and nitric oxide synthase-expressing neurons in the supraoptic nucleus of the rat. Life Sci 2006; 78:1143-8. [PMID: 16426642 DOI: 10.1016/j.lfs.2005.06.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Accepted: 06/22/2005] [Indexed: 10/25/2022]
Abstract
Many histochemical investigations indicated that the oxytocin (OXY), the arginine vasopressin (AVP) and the nitric oxide synthase (NOS) have been synthesized in the supraoptic nucleus (SON) neurons. The objective of this study was to examine the age-related expression of the OXY, the AVP and the NOS in the SON of the young adult (2-month-old) and the aged (24-month-old) rats. The histochemistry for reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d; marker for the NOS) and the double labeling histochemistry for the OXY/NADPH-d or the AVP/NADPH-d were employed, and the quantitative analysis was performed with a computer-assisted image processing system. In comparison of the young adult and the aged group, the cell number, the cell size and the reactive density of the NOS-expressing neurons showed a significant increase along with age, and these evidences suggested the age-related increase of the nitric oxide (NO) production. The age-related significant increase was not detected in the number of the OXY/NOS-expressing neurons in the dorsal part, but was detected in the number of the AVP/NOS-expressing neurons in the ventral part. Based on our histochemical findings and reports demonstrated by other authors, we attempted to discuss the physiological role of NOS for the secretion of posterior pituitary hormones along with age.
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Affiliation(s)
- Kwong-Leung Yu
- Department of Anesthesiology and Pain Management, Kaohsiung Medical University, 100, Shi-Chun 1st Road, San-Ming District, Kaohsiung, Taiwan, ROC
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26
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Ueta Y, Fujihara H, Serino R, Dayanithi G, Ozawa H, Matsuda KI, Kawata M, Yamada J, Ueno S, Fukuda A, Murphy D. Transgenic expression of enhanced green fluorescent protein enables direct visualization for physiological studies of vasopressin neurons and isolated nerve terminals of the rat. Endocrinology 2005; 146:406-13. [PMID: 15375027 DOI: 10.1210/en.2004-0830] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have generated transgenic rats expressing an arginine vasopressin (AVP)-enhanced green fluorescent protein (eGFP) fusion gene. The expression of the eGFP gene and strong fluorescence were observed in the supraoptic nucleus (SON), the paraventricular nucleus (PVN), and the suprachiasmatic nucleus (SCN) in transgenic rats. The hypothalamo-neurohypophyseal tract, isolated SON neurons, and isolated axon terminals in the neurohypophysis also showed robust eGFP fluorescence. Water deprivation for 2 d increased the fluorescence of the eGFP in the SON and the PVN but not the SCN. The whole-cell patch-clamp technique was then used to record the electrical activities specifically identifying eGFP-expressing SON, PVN, and SCN AVP neurons in in vitro brain slice preparations. The AVP-eGFP transgenic rats are a unique new tool with which to study the physiological role of AVP-secreting neurons in the central nervous system and the dynamics of the regulation of AVP secretion in the living neurons and their axon terminals.
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Affiliation(s)
- Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
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27
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Abstract
A baby sucks at a mother's breast for comfort and, of course, for milk. Milk is made in specialized cells of the mammary gland, and for a baby to feed, the milk must be released into a collecting chamber from where it can be extracted by sucking. Milk "let-down" is a reflex response to the suckling and kneading of the nipple--and sometimes in response to the sight, smell, and sound of the baby--and is ultimately affected by the secretion of oxytocin. Oxytocin has many physiological roles, but its only irreplaceable role is to mediate milk let-down: oxytocin-deficient mice cannot feed their young; the pups suckle but no milk is let down, and they will die unless cross-fostered. Most other physiological roles of oxytocin, including its role in parturition, are redundant in the sense that the roles can be assumed by other mechanisms in the absence of oxytocin throughout development and adult life. Nevertheless, physiological function in these roles can be altered or impaired by acute interventions that alter oxytocin secretion or change the actions of oxytocin. Here we focus on the diverse stimuli that regulate oxytocin secretion and on the apparent diversity of the roles for oxytocin.
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Affiliation(s)
- Gareth Leng
- Centre for Integrative Physiology, The University of Edinburgh College of Medicine and Veterinary Sciences, Edinburgh EH8 9XD, United Kingdom
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