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Cayupe B, Troncoso B, Morgan C, Sáez-Briones P, Sotomayor-Zárate R, Constandil L, Hernández A, Morselli E, Barra R. The Role of the Paraventricular-Coerulear Network on the Programming of Hypertension by Prenatal Undernutrition. Int J Mol Sci 2022; 23:ijms231911965. [PMID: 36233268 PMCID: PMC9569920 DOI: 10.3390/ijms231911965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/22/2022] [Accepted: 09/28/2022] [Indexed: 11/16/2022] Open
Abstract
A crucial etiological component in fetal programming is early nutrition. Indeed, early undernutrition may cause a chronic increase in blood pressure and cardiovascular diseases, including stroke and heart failure. In this regard, current evidence has sustained several pathological mechanisms involving changes in central and peripheral targets. In the present review, we summarize the neuroendocrine and neuroplastic modifications that underlie maladaptive mechanisms related to chronic hypertension programming after early undernutrition. First, we analyzed the role of glucocorticoids on the mechanism of long-term programming of hypertension. Secondly, we discussed the pathological plastic changes at the paraventricular nucleus of the hypothalamus that contribute to the development of chronic hypertension in animal models of prenatal undernutrition, dissecting the neural network that reciprocally communicates this nucleus with the locus coeruleus. Finally, we propose an integrated and updated view of the main neuroendocrine and central circuital alterations that support the occurrence of chronic increases of blood pressure in prenatally undernourished animals.
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Affiliation(s)
- Bernardita Cayupe
- Centro de Investigación Biomédica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Médicas, Universidad de Santiago de Chile (USACH), Santiago 9170020, Chile
| | - Blanca Troncoso
- Escuela de Enfermería, Facultad de Ciencias Médicas, Universidad de Santiago de Chile, Santiago 9170020, Chile
| | - Carlos Morgan
- Laboratorio de Neurofarmacología y Comportamiento, Escuela de Medicina, Facultad de Ciencias Médicas, Universidad de Santiago de Chile, Santiago 9170020, Chile
| | - Patricio Sáez-Briones
- Laboratorio de Neurofarmacología y Comportamiento, Escuela de Medicina, Facultad de Ciencias Médicas, Universidad de Santiago de Chile, Santiago 9170020, Chile
| | - Ramón Sotomayor-Zárate
- Laboratorio de Neuroquímica y Neurofarmacología, Centro de Neurobiología y Fisiopatología Integrativa, Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Luis Constandil
- Laboratorio de Neurobiología, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170020, Chile
| | - Alejandro Hernández
- Laboratorio de Neurobiología, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170020, Chile
| | - Eugenia Morselli
- Department of Basic Sciences, Faculty of Medicine and Sciences, Universidad San Sebastián, Santiago 7510157, Chile
| | - Rafael Barra
- Centro de Investigación Biomédica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Médicas, Universidad de Santiago de Chile (USACH), Santiago 9170020, Chile
- Correspondence: ; Tel.: +56-983831083
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Hypertension in Prenatally Undernourished Young-Adult Rats Is Maintained by Tonic Reciprocal Paraventricular-Coerulear Excitatory Interactions. Molecules 2021; 26:molecules26123568. [PMID: 34207980 PMCID: PMC8230629 DOI: 10.3390/molecules26123568] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/19/2021] [Accepted: 05/31/2021] [Indexed: 11/17/2022] Open
Abstract
Prenatally malnourished rats develop hypertension in adulthood, in part through increased α1-adrenoceptor-mediated outflow from the paraventricular nucleus (PVN) to the sympathetic system. We studied whether both α1-adrenoceptor-mediated noradrenergic excitatory pathways from the locus coeruleus (LC) to the PVN and their reciprocal excitatory CRFergic connections contribute to prenatal undernutrition-induced hypertension. For that purpose, we microinjected either α1-adrenoceptor or CRH receptor agonists and/or antagonists in the PVN or the LC, respectively. We also determined the α1-adrenoceptor density in whole hypothalamus and the expression levels of α1A-adrenoceptor mRNA in the PVN. The results showed that: (i) agonists microinjection increased systolic blood pressure and heart rate in normotensive eutrophic rats, but not in prenatally malnourished subjects; (ii) antagonists microinjection reduced hypertension and tachycardia in undernourished rats, but not in eutrophic controls; (iii) in undernourished animals, antagonist administration to one nuclei allowed the agonists recover full efficacy in the complementary nucleus, inducing hypertension and tachycardia; (iv) early undernutrition did not modify the number of α1-adrenoceptor binding sites in hypothalamus, but reduced the number of cells expressing α1A-adrenoceptor mRNA in the PVN. These results support the hypothesis that systolic pressure and heart rate are increased by tonic reciprocal paraventricular-coerulear excitatory interactions in prenatally undernourished young-adult rats.
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Johnson CS, Bains JS, Watts AG. Neurotransmitter diversity in pre-synaptic terminals located in the parvicellular neuroendocrine paraventricular nucleus of the rat and mouse hypothalamus. J Comp Neurol 2018; 526:1287-1306. [PMID: 29424419 DOI: 10.1002/cne.24407] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 01/24/2018] [Accepted: 01/25/2018] [Indexed: 02/02/2023]
Abstract
Virtually all rodent neuroendocrine corticotropin-releasing-hormone (CRH) neurons are in the dorsal medial parvicellular (mpd) part of the paraventricular nucleus of the hypothalamus (PVH). They form the final common pathway for adrenocortical stress responses. Their activity is controlled by sets of GABA-, glutamate-, and catecholamine-containing inputs arranged in an interactive pre-motor network. Defining the nature and arrangement of these inputs can help clarify how stressor type and intensity information is conveyed to neuroendocrine neurons. Here we use immunohistochemistry with high-resolution 3-dimensional image analyses to examine the arrangement of single- and co-occurring GABA, glutamate, and catecholamine markers in synaptophysin-defined pre-synaptic terminals in the PVHmpd of unstressed rats and Crh-IRES-Cre;Ai14 transgenic mice: respectively, vesicular glutamate transporter 2 (VGluT2), vesicular GABA transporter (VGAT), dopamine β-hydroxylase (DBH), and phenylethanolamine n-methyltransferase (PNMT). Just over half of all PVHmpd pre-synaptic terminals contain VGAT, with slightly less containing VGluT2. The vast majority of terminal appositions with mouse CRH neurons occur non-somatically. However, there are significantly more somatic VGAT than VGluT2 appositions. In the rat PVHmpd, about five times as many pre-synaptic terminals contain PNMT than DBH only. However, because epinephrine release has never been detected in the PVH, PNMT terminals may functionally be noradrenergic not adrenergic. PNMT and VGluT2 co-occur in some pre-synaptic terminals indicating the potential for co-transmission of glutamate and norepinephrine. Collectively, these results provide a structural basis for how GABA/glutamate/catecholamine interactions enable adrenocortical responses to fast-onset interosensory stimuli, and more broadly, how combinations of PVH neurotransmitters and neuromodulators interact dynamically to control adrenocortical activity.
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Affiliation(s)
- Caroline S Johnson
- The Department of Biological Sciences, USC Dornsife College of Letters, Arts, and Sciences, and Neuroscience, Graduate Program, University of Southern California, Los Angeles, California
| | - Jaideep S Bains
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada
| | - Alan G Watts
- The Department of Biological Sciences, USC Dornsife College of Letters, Arts, and Sciences, and Neuroscience, Graduate Program, University of Southern California, Los Angeles, California
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Torner L, Plotsky PM, Neumann ID, de Jong TR. Forced swimming-induced oxytocin release into blood and brain: Effects of adrenalectomy and corticosterone treatment. Psychoneuroendocrinology 2017; 77:165-174. [PMID: 28064086 DOI: 10.1016/j.psyneuen.2016.12.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 12/06/2016] [Accepted: 12/08/2016] [Indexed: 01/26/2023]
Abstract
The oxytocin (OXT) system is functionally linked to the HPA axis in a reciprocal and complex manner. Certain stressors are known to cause the simultaneous release of OXT and adrenocorticotrophic hormone (ACTH) followed by corticosterone (CORT). Furthermore, brain OXT attenuates ACTH and CORT responses. Although there are some indications of CORT influencing OXT neurotransmission, specific effects of CORT on neurohypophyseal or intra-hypothalamic release of OXT have not been studied in detail. In the present set of experiments, adult male rats were adrenalectomized (ADX) or sham-operated and fitted with a jugular vein catheter and/or microdialysis probe targeting the hypothalamic paraventricular nucleus (PVN). Blood samples and dialysates were collected before and after forced swimming (FS) and analyzed for CORT, ACTH and AVP concentrations (in plasma) and OXT concentrations (in plasma and dialysates). Experimental treatments included acute infusion of CORT (70 or 175μg/kg i.v.) 5min prior to FS, or subcutaneous placement of 40% CORT pellets resulting in stable CORT levels in the normal basal range. Although ADX did not alter basal OXT concentrations either in plasma or in microdialysates from the PVN, it did cause an exaggerated peripheral secretion of OXT and a blunted intra-PVN release of OXT in response to FS. CORT pellets did not influence either of these ADX-induced effects, while acute infusion of 175μg/kg CORT rescued the stress-induced rise in OXT release within the PVN and modestly increased peripheral OXT secretion. In conclusion, these results indicate that CORT regulates both peripheral and intracerebral OXT release, but in an independent manner. Whereas the peripheral secretion of OXT occurs simultaneously to HPA axis activation in response to FS and is modestly influenced by CORT, HPA axis activation and circulating CORT strongly contribute to the stress-induced stimulation of OXT release within the PVN.
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Affiliation(s)
- Luz Torner
- Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro Social, Morelia, Mexico; Max Planck Institute of Psychiatry, Munich, Germany
| | - Paul M Plotsky
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Inga D Neumann
- Max Planck Institute of Psychiatry, Munich, Germany; Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany.
| | - Trynke R de Jong
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
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Fan QQ, Li L, Wang WT, Yang X, Suo ZW, Hu XD. Activation of α2 adrenoceptors inhibited NMDA receptor-mediated nociceptive transmission in spinal dorsal horn of mice with inflammatory pain. Neuropharmacology 2014; 77:185-92. [DOI: 10.1016/j.neuropharm.2013.09.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 08/17/2013] [Accepted: 09/23/2013] [Indexed: 01/06/2023]
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Wallace J, Jackson RK, Shotton TL, Munjal I, McQuade R, Gartside SE. Characterization of electrically evoked field potentials in the medial prefrontal cortex and orbitofrontal cortex of the rat: modulation by monoamines. Eur Neuropsychopharmacol 2014; 24:321-32. [PMID: 23932190 PMCID: PMC4623163 DOI: 10.1016/j.euroneuro.2013.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 05/31/2013] [Accepted: 07/05/2013] [Indexed: 10/26/2022]
Abstract
Medial prefrontal cortex (mPFC) and orbitofrontal cortex (OFC) play critical roles in cognition and behavioural control. Glutamatergic, GABAergic, and monoaminergic dysfunction in the prefrontal cortex has been hypothesised to underlie symptoms in neuropsychiatric disorders. Here we characterised electrically-evoked field potentials in the mPFC and OFC. Electrical stimulation evoked field potentials in layer V/VI of the mPFC and layer V of the OFC. The earliest component (approximately 2 ms latency) was insensitive to glutamate receptor blockade and was presumed to be presynaptic. Later components were blocked by 6,7-dinitroquinoxaline-2,3-dione (DNQX (20 µM)) and were assumed to reflect monosynaptic (latency 4-6 ms) and polysynaptic activity (latency 6-40 ms) mediated by glutamate via AMPA/kainate receptor. In the mPFC, but not the OFC, the monosynaptic component was also partly blocked by 2-amino-5-phosphonopentanoic acid (AP-5 (50-100µM)) indicating the involvement of NMDA receptors. Bicuculline (3-10 µM) enhanced the monosynaptic component suggesting electrically-evoked and/or glutamate induced GABA release inhibits the monosynaptic component via GABAA receptor activation. There were complex effects of bicuculline on polysynaptic components. In the mPFC both the mono- and polysynaptic components were attenuated by 5-HT (10-100 µM) and NA (30 and 60 µM) and the monosynaptic component was attenuated by DA (100 µM). In the OFC the mono- and polysynaptic components were also attenuated by 5-HT (100 µM), NA (10-100 µM) but DA (10-100 µM) had no effect. We propose that these pharmacologically characterised electrically-evoked field potentials in the mPFC and OFC are useful models for the study of prefrontal cortical physiology and pathophysiology.
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Affiliation(s)
- Joanne Wallace
- Institute of Neuroscience, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Rosanna K Jackson
- Institute of Neuroscience, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Tanya L Shotton
- Institute of Neuroscience, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Ishaana Munjal
- Institute of Neuroscience, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Richard McQuade
- Institute of Neuroscience, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Sarah E Gartside
- Institute of Neuroscience, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
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Blockade of corticosteroid receptors induces anxiolytic-like effects in streptozotocin-induced diabetic mice, and synergizes with diazepam. Behav Pharmacol 2013; 24:320-7. [DOI: 10.1097/fbp.0b013e3283637de2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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8
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Identifying links in the chain: the dynamic coupling of catecholamines, peptide synthesis, and peptide release in hypothalamic neuroendocrine neurons. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2013; 68:421-44. [PMID: 24054156 DOI: 10.1016/b978-0-12-411512-5.00020-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Compared to neurons that communicate using synapses, some neuroendocrine neurons release relatively large quantities of peptide into the vasculature to control neuroendocrine function. Maintaining adequate amounts of peptide for release through controlled biosynthesis is therefore critical for their function. But how neuroendocrine-or in fact, any neuropeptide-neurons link appropriate levels of peptide biosynthesis with the action potentials that drive peptide release is unknown. Here, we review possible mechanisms in paraventricular hypothalamic CRH neuroendocrine neurons to coordinate these processes in response to catecholaminergic inputs. We show that CRH synthesis and release mechanisms are not invariably linked as CRH neurons are activated. Instead, coupling mechanisms exist in the premotor network that provides their synaptic inputs and in their intracellular signal transduction mechanisms, where transmitter-regulated phosphorylation of p44/42 mitogen-activated protein kinases (ERK1/2) may play a prominent role. These versatile and dynamic coupling mechanisms provide a way to link peptide biosynthesis and release.
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9
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Kaminski KL, Watts AG. Intact catecholamine inputs to the forebrain are required for appropriate regulation of corticotrophin-releasing hormone and vasopressin gene expression by corticosterone in the rat paraventricular nucleus. J Neuroendocrinol 2012; 24:1517-26. [PMID: 22831701 PMCID: PMC3502639 DOI: 10.1111/j.1365-2826.2012.02363.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/06/2012] [Accepted: 07/19/2012] [Indexed: 02/04/2023]
Abstract
Corticotrophin-releasing hormone (CRH) neuroendocrine neurones in the paraventricular nucleus of the hypothalamus (PVH) drive adrenocorticotrophic hormone (ACTH) and thereby glucocorticoid release from pituitary corticotrophs and the adrenal cortex, respectively. Glucocorticoids suppress the ability of neuroendocrine corticotrophin-releasing hormone (CRH) neurones to synthesise and release ACTH secretogogues. Despite the importance of glucocorticoids as regulatory signals to CRH neurones in the extended time domain, how and where they act in this capacity is still not fully understood. Ascending catecholamine projections encode important cardiovascular, metabolic and other visceral information to the rat PVH and surrounding hypothalamus. These afferents have previously been implicated as targets for glucocorticoid action, including a role in the feedback regulation of PVH neuroendocrine neurones. To determine the contribution of these neurones to the long-term actions of corticosterone on CRH and vasopressin (AVP) gene expression in the PVH, we used an immunocytotoxin (a conjugate of the cytotoxin saporin and an antibody against dopamine-β-hydroxylase) that specifically ablates adrenergic and noradrenergic neurones. Lesions were administered to intact animals and to adrenalectomised animals with either no corticosterone or corticosterone replacement that provided levels above those required to normalise Crh expression. The ability of elevated levels of corticosterone to suppress Crh expression was abolished in animals lacking catecholaminergic innervation of the PVH. No effect was seen in the absence of corticosterone or in animals with intact adrenals. Furthermore, Avp expression, which is increased in CRH neurones following adrenalectomy, was suppressed in adrenalectomised catecholaminergic-lesioned animals. Interactions between corticosterone and catecholaminergic projections to the hypothalamus therefore make significant contributions to the regulation of Crh and Avp expression. However, the importance of catecholamine inputs is only apparent when circulating corticosterone concentrations are maintained either below or above those required to maintain the activity of the hypothalamic-pituitary-adrenal axis that is seen in intact animals.
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Affiliation(s)
- K L Kaminski
- The Neuroscience Graduate Program and Department of Biological Sciences, USC Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089-2520, USA
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Levy BH, Tasker JG. Synaptic regulation of the hypothalamic-pituitary-adrenal axis and its modulation by glucocorticoids and stress. Front Cell Neurosci 2012; 6:24. [PMID: 22593735 PMCID: PMC3349941 DOI: 10.3389/fncel.2012.00024] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 04/26/2012] [Indexed: 12/12/2022] Open
Abstract
Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in a range of affective and stress-related disorders. The regulatory systems that control HPA activity are subject to modulation by environmental influences, and stressful life events or circumstances can promote subsequent HPA dysregulation. The brain is a major regulator of the HPA axis, and stress-induced plasticity of the neural circuitry involved in HPA regulation might constitute an etiological link between stress and the development of HPA dysregulation. This review focuses on the synaptic regulation of neuroendocrine corticotropin-releasing hormone (CRH) neurons of the hypothalamic paraventricular nucleus, which are the cells through which the brain predominantly exerts its influence on the HPA axis. CRH neuronal activity is largely orchestrated by three neurotransmitters: GABA, glutamate, and norepinephrine. We discuss our current understanding of the neural circuitry through which these neurotransmitters regulate CRH cell activity, as well as the plastic changes in this circuitry induced by acute and chronic stress and the resultant changes in HPA function.
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Affiliation(s)
| | - Jeffrey G. Tasker
- Neuroscience Program, Tulane University,New Orleans, LA, USA
- Department of Cell and Molecular Biology, Tulane University,New Orleans, LA, USA
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11
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Levy BH, Tasker JG. Synaptic regulation of the hypothalamic-pituitary-adrenal axis and its modulation by glucocorticoids and stress. Front Cell Neurosci 2012. [PMID: 22593735 DOI: 10.3389/fncel.2012.00024.ecollection] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in a range of affective and stress-related disorders. The regulatory systems that control HPA activity are subject to modulation by environmental influences, and stressful life events or circumstances can promote subsequent HPA dysregulation. The brain is a major regulator of the HPA axis, and stress-induced plasticity of the neural circuitry involved in HPA regulation might constitute an etiological link between stress and the development of HPA dysregulation. This review focuses on the synaptic regulation of neuroendocrine corticotropin-releasing hormone (CRH) neurons of the hypothalamic paraventricular nucleus, which are the cells through which the brain predominantly exerts its influence on the HPA axis. CRH neuronal activity is largely orchestrated by three neurotransmitters: GABA, glutamate, and norepinephrine. We discuss our current understanding of the neural circuitry through which these neurotransmitters regulate CRH cell activity, as well as the plastic changes in this circuitry induced by acute and chronic stress and the resultant changes in HPA function.
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Affiliation(s)
- Benjamin H Levy
- Neuroscience Program, Tulane University, New Orleans, LA, USA
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Osterlund CD, Jarvis E, Chadayammuri A, Unnithan R, Weiser MJ, Spencer RL. Tonic, but not phasic corticosterone, constrains stress activatedextracellular-regulated-kinase 1/ 2 immunoreactivity within the hypothalamic paraventricular nucleus. J Neuroendocrinol 2011; 23:1241-51. [PMID: 21929693 PMCID: PMC3220802 DOI: 10.1111/j.1365-2826.2011.02220.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The negative-feedback actions of corticosterone (CORT) depend on both phasic and tonic CORT secretion patterns to regulate hypothalamic-pituitary-adrenal (HPA) axis activity. How these two different CORT secretion pattens influence specific intracellular signal transduction pathway activity within the cellular elements of the HPA axis has not been determined. For example, it is unknown whether CORT has suppressive actions over signal transduction events within medial parvocellular paraventricular nucleus (PVN) corticotrophin-releasing hormone (CRH) neurones, nor whether these suppressive actions are responsible for alterations in PVN transcriptional processes and neurohormone secretion associated with stress. The extracellular-regulated kinase (ERK) is a stress activated intracellular signalling molecule that is potentially subject to glucocorticoid negative-feedback regulation. We tested the ability of CORT to modulate levels of the active (phosphorylated) form of ERK (pERK1/2) in the PVN of rats. Acute psychological stress (restraint) produced a rapid increase in the number of PVN pERK1/2 immunopositive cells within CRH neurones. Absence of tonic CORT via adrenalectomy (ADX) produced no change in basal pERK1/2 cell counts but augmented the increased pERK1/2 cell counts elicited by acute restraint. Treatment of ADX rats with CORT in the drinking water normalised this enhanced pERK1/2 response to stress. By contrast, treatment of ADX rats with a phasic increase in CORT 1 h before restraint had no effect on pERK1/2 cell counts, despite substantially suppressing stress-induced PVN crh gene expression and adrenonocorticotrophic hormone secretion. This tonic CORT inhibition of stress-induced activation of ERK1/2 may involve both alteration of the activity of stress-dependent neural inputs to PVN CRH neurones and alteration within those neurones of stress-dependent intracellular signalling mechanisms associated with ERK activation.
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Affiliation(s)
- C D Osterlund
- Department of Psychology and Neuroscience, University of Colorado, UCB 345, Boulder, CO 80309, USA.
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Shin SY, Han TH, Lee SY, Han SK, Park JB, Erdelyi F, Szabo G, Ryu PD. Direct Corticosteroid Modulation of GABAergic Neurons in the Anterior Hypothalamic Area of GAD65-eGFP Mice. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2011; 15:163-9. [PMID: 21860595 DOI: 10.4196/kjpp.2011.15.3.163] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 06/15/2011] [Accepted: 06/15/2011] [Indexed: 02/07/2023]
Abstract
Corticosterone is known to modulate GABAergic synaptic transmission in the hypothalamic paraventricular nucleus. However, the underlying receptor mechanisms are largely unknown. In the anterior hypothalamic area (AHA), the sympathoinhibitory center that project GABAergic neurons onto the PVN, we examined the expression of glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) of GABAergic neurons using intact GAD65-eGFP transgenic mice, and the effects of corticosterone on the burst firing using adrenalectomized transgenic mice. GR or MR immunoreactivity was detected from the subpopulations of GABAergic neurons in the AHA. The AHA GABAergic neurons expressed mRNA of GR (42%), MR (38%) or both (8%). In addition, in brain slices incubated with corticosterone together with RU486 (MR-dominant group), the proportion of neurons showing a burst firing pattern was significantly higher than those in the slices incubated with vehicle, corticosterone, or corticosterone with spironolactone (GR-dominant group; 64 vs. 11~14%, p< 0.01 by χ(2)-test). Taken together, the results show that the corticosteroid receptors are expressed on the GABAergic neurons in the AHA, and can mediate the corticosteroid-induced plasticity in the firing pattern of these neurons. This study newly provides the experimental evidence for the direct glucocorticoid modulation of GABAergic neurons in the AHA in the vicinity of the PVN.
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Affiliation(s)
- Seung Yub Shin
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Korea
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Wamsteeker JI, Bains JS. A synaptocentric view of the neuroendocrine response to stress. Eur J Neurosci 2010; 32:2011-21. [DOI: 10.1111/j.1460-9568.2010.07513.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Michelini LC, Stern JE. Exercise-induced neuronal plasticity in central autonomic networks: role in cardiovascular control. Exp Physiol 2009; 94:947-60. [PMID: 19617267 PMCID: PMC2922747 DOI: 10.1113/expphysiol.2009.047449] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is now well established that brain plasticity is an inherent property not only of the developing but also of the adult brain. Numerous beneficial effects of exercise, including improved memory, cognitive function and neuroprotection, have been shown to involve an important neuroplastic component. However, whether major adaptive cardiovascular adjustments during exercise, needed to ensure proper blood perfusion of peripheral tissues, also require brain neuroplasticity, is presently unknown. This review will critically evaluate current knowledge on proposed mechanisms that are likely to underlie the continuous resetting of baroreflex control of heart rate during/after exercise and following exercise training. Accumulating evidence indicates that not only somatosensory afferents (conveyed by skeletal muscle receptors, baroreceptors and/or cardiopulmonary receptors) but also projections arising from central command neurons (in particular, peptidergic hypothalamic pre-autonomic neurons) converge into the nucleus tractus solitarii (NTS) in the dorsal brainstem, to co-ordinate complex cardiovascular adaptations during dynamic exercise. This review focuses in particular on a reciprocally interconnected network between the NTS and the hypothalamic paraventricular nucleus (PVN), which is proposed to act as a pivotal anatomical and functional substrate underlying integrative feedforward and feedback cardiovascular adjustments during exercise. Recent findings supporting neuroplastic adaptive changes within the NTS-PVN reciprocal network (e.g. remodelling of afferent inputs, structural and functional neuronal plasticity and changes in neurotransmitter content) will be discussed within the context of their role as important underlying cellular mechanisms supporting the tonic activation and improved efficacy of these central pathways in response to circulatory demand at rest and during exercise, both in sedentary and in trained individuals. We hope this review will stimulate more comprehensive studies aimed at understanding cellular and molecular mechanisms within CNS neuronal networks that contribute to exercise-induced neuroplasticity and cardiovascular adjustments.
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Affiliation(s)
- Lisete C Michelini
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of Sao Paulo, Sao Paulo, Brazil
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Bibliography. Current world literature. Diabetes and the endocrine pancreas II. Curr Opin Endocrinol Diabetes Obes 2008; 15:383-93. [PMID: 18594281 DOI: 10.1097/med.0b013e32830c6b8e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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