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Kuralay A, McDonough MC, Resch JM. Control of sodium appetite by hindbrain aldosterone-sensitive neurons. Mol Cell Endocrinol 2024:112323. [PMID: 38936597 DOI: 10.1016/j.mce.2024.112323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Accepted: 06/25/2024] [Indexed: 06/29/2024]
Abstract
Mineralocorticoids play a key role in hydromineral balance by regulating sodium retention and potassium wasting. Through favoring sodium, mineralocorticoids can cause hypertension from fluid overload under conditions of hyperaldosteronism, such as aldosterone-secreting tumors. An often-overlooked mechanism by which aldosterone functions to increase sodium is through stimulation of salt appetite. To drive sodium intake, aldosterone targets neurons in the hindbrain which uniquely express 11β-hydroxysteroid dehydrogenase type 2 (HSD2). This enzyme is a necessary precondition for aldosterone-sensing cells as it metabolizes glucocorticoids - preventing their activation of the mineralocorticoid receptor. In this review, we will consider the role of hindbrain HSD2 neurons in regulating sodium appetite by discussing HSD2 expression in the brain, regulation of hindbrain HSD2 neuron activity, and the circuitry mediating the effects of these aldosterone-sensitive neurons. Reducing the activity of hindbrain HSD2 neurons may be a viable strategy to reduce sodium intake and cardiovascular risk, particularly for conditions of hyperaldosteronism.
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Affiliation(s)
- Ahmet Kuralay
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA; Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, USA
| | - Miriam C McDonough
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA; Molecular Medicine Graduate Program, University of Iowa, Iowa City, IA, USA
| | - Jon M Resch
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA; Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, USA; Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, USA; Molecular Medicine Graduate Program, University of Iowa, Iowa City, IA, USA.
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2
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Pereira ED, Zenatti AA, Menani JV, De Luca LA, Andrade CAF. Inhibition of salty taste and sodium appetite by estrogens in spontaneously hypertensive rats. Front Physiol 2023; 14:1163568. [PMID: 37284542 PMCID: PMC10240049 DOI: 10.3389/fphys.2023.1163568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 04/26/2023] [Indexed: 06/08/2023] Open
Abstract
Estrogen has a well-known effect of reducing salt intake in rats. This mini review focuses on recent findings regarding the interaction of estradiol with brain angiotensin II to control increased sodium palatability that occurs as a result of sodium appetite in spontaneously hypertensive rats.
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Neurobehavioral Mechanisms of Sodium Appetite. Nutrients 2023; 15:nu15030620. [PMID: 36771327 PMCID: PMC9919744 DOI: 10.3390/nu15030620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/05/2023] [Accepted: 01/18/2023] [Indexed: 01/27/2023] Open
Abstract
The objectives of this paper are to first present physiological and ecological aspects of the unique motivational state of sodium appetite, then to focus on systemic physiology and brain mechanisms. I describe how laboratory protocols have been developed to allow the study of sodium appetite under controlled conditions, and focus on two such conditions specifically. The first of these is the presentation a sodium-deficient diet (SDD) for at least one week, and the second is accelerated sodium loss using SDD for 1-2 days coupled with the diuretic furosemide. The modality of consumption is also considered, ranging from a free intake of high concentration of sodium solution, to sodium-rich food or gels, and to operant protocols. I describe the pivotal role of angiotensin and aldosterone in these appetites and discuss whether the intakes or appetite are matched to the physiological need state. Several brain systems have been identified, most recently and microscopically using molecular biological methods. These include clusters in both the hindbrain and the forebrain. Satiation of sodium appetite is often studied using concentrated sodium solutions, but these can be consumed in apparent excess, and I suggest that future studies of satiation might emulate natural conditions in which excess consumption does not occur, using either SDD only as a stimulus, offering a sodium-rich food for the assessment of appetite, or a simple operant task.
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Wang M, Yang Y, Xu Y. Brain nuclear receptors and cardiovascular function. Cell Biosci 2023; 13:14. [PMID: 36670468 PMCID: PMC9854230 DOI: 10.1186/s13578-023-00962-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 01/12/2023] [Indexed: 01/22/2023] Open
Abstract
Brain-heart interaction has raised up increasing attentions. Nuclear receptors (NRs) are abundantly expressed in the brain, and emerging evidence indicates that a number of these brain NRs regulate multiple aspects of cardiovascular diseases (CVDs), including hypertension, heart failure, atherosclerosis, etc. In this review, we will elaborate recent findings that have established the physiological relevance of brain NRs in the context of cardiovascular function. In addition, we will discuss the currently available evidence regarding the distinct neuronal populations that respond to brain NRs in the cardiovascular control. These findings suggest connections between cardiac control and brain dynamics through NR signaling, which may lead to novel tools for the treatment of pathological changes in the CVDs.
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Affiliation(s)
- Mengjie Wang
- grid.508989.50000 0004 6410 7501Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX USA
| | - Yongjie Yang
- grid.508989.50000 0004 6410 7501Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX USA
| | - Yong Xu
- grid.508989.50000 0004 6410 7501Department of Pediatrics, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX USA ,grid.39382.330000 0001 2160 926XDepartment of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX USA
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Wang R, Wang N, Liang W, Lin T, Qiao H. The role of central amygdaloid nucleus in regulating the nongenomic effect of aldosterone on sodium intake in the nucleus tractus solitary. Brain Behav 2022; 12:e2615. [PMID: 35588446 PMCID: PMC9226841 DOI: 10.1002/brb3.2615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/11/2022] [Accepted: 04/20/2022] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE The central nucleus of the amygdala (CeA) has dense downward fiber projections towards the nucleus tractus solitary (NTS) and can modulate the activity of NTS taste neurons. However, whether CeA affects the nongenomic role of aldosterone (ALD) in regulating sodium intake at the NTS level remains unclear. METHODS First, 40 adult male Sprague Dawley rats were divided into five groups, referring to different concentrations of ALD, to observe the sodium intake pattern compared with the vehicle (n = 8). ALD, the mineralocorticoid receptor antagonist spironolactone (SPI), and ALD + SPI were injected into the NTS. Then, the rats were divided into four groups (n = 16): bilateral/unilateral CeA electrolytic lesions, bilateral/unilateral CeA sham lesions. After recovery, one stainless steel 23-gauge cannula with two tubes was implanted into the rat NTS, and all rats underwent a recovery period of 7 days. Then, each group was divided into two subgroups that received aldosterone or control solution injection, and the cumulative intake of 0.3 mol/L NaCl solution was recorded within 30 min. RESULTS Bilateral CeA lesion eliminated the increased 0.3 mol/L NaCl intake induced by aldosterone microinjected into the NTS (CeA lesion: 0.3 ± 0.04 ml/30 min vs. sham lesion: 1.3 ± 0.3 ml/30 min). Unilateral CeA lesion reduced the increased NaCl intake induced by aldosterone microinjected into the NTS compared with the control group (p < .05) in the first 15 min but not in 15-30 min (p > .05). In sham lesion rats, aldosterone (5 ng/0.1 μl) still induced a significant increase in NaCl intake (aldosterone: 1.3 ± 0.3 ml/30 min vs. control: 0.25 ± 0.02 ml/30 min) (p < .05). CONCLUSION The results verified that the complete CeA may play an important role in aldosterone to regulate the nongenomic effect on rapid sodium intake.
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Affiliation(s)
- Rui Wang
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, China
| | - Nan Wang
- Department of Human Anatomy, Shaanxi University of Chinese Medicine, Xi'an, China
| | - Wenhui Liang
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, China
| | - Tingting Lin
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, China
| | - Hu Qiao
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, China
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Callera JC, De Luca LA, Menani JV. Involvement of V1-type vasopressin receptors on NaCl intake by hyperosmotic rats treated with muscimol in the lateral parabrachial nucleus. Neurosci Lett 2022; 778:136601. [DOI: 10.1016/j.neulet.2022.136601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 11/29/2022]
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Signal Transduction of Mineralocorticoid and Angiotensin II Receptors in the Central Control of Sodium Appetite: A Narrative Review. Int J Mol Sci 2021; 22:ijms222111735. [PMID: 34769164 PMCID: PMC8584094 DOI: 10.3390/ijms222111735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/16/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
Sodium appetite is an innate behavior occurring in response to sodium depletion that induces homeostatic responses such as the secretion of the mineralocorticoid hormone aldosterone from the zona glomerulosa of the adrenal cortex and the stimulation of the peptide hormone angiotensin II (ANG II). The synergistic action of these hormones signals to the brain the sodium appetite that represents the increased palatability for salt intake. This narrative review summarizes the main data dealing with the role of mineralocorticoid and ANG II receptors in the central control of sodium appetite. Appropriate keywords and MeSH terms were identified and searched in PubMed. References to original articles and reviews were examined, selected, and discussed. Several brain areas control sodium appetite, including the nucleus of the solitary tract, which contains aldosterone-sensitive HSD2 neurons, and the organum vasculosum lamina terminalis (OVLT) that contains ANG II-sensitive neurons. Furthermore, sodium appetite is under the control of signaling proteins such as mitogen-activated protein kinase (MAPK) and inositol 1,4,5-thriphosphate (IP3). ANG II stimulates salt intake via MAPK, while combined ANG II and aldosterone action induce sodium intake via the IP3 signaling pathway. Finally, aldosterone and ANG II stimulate OVLT neurons and suppress oxytocin secretion inhibiting the neuronal activity of the paraventricular nucleus, thus disinhibiting the OVLT activity to aldosterone and ANG II stimulation.
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Adolf C, Görge V, Heinrich DA, Hoster E, Schneider H, Handgriff L, Künzel H, Sturm L, Beuschlein F, Reincke M. Altered Taste Perception for Sodium Chloride in Patients With Primary Aldosteronism: A Prospective Cohort Study. Hypertension 2021; 77:1332-1340. [PMID: 33641355 DOI: 10.1161/hypertensionaha.120.16440] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Christian Adolf
- From the Medizinische Klinik und Poliklinik IV (C.A., V.G., D.A.H., H.S., L.H., H.K., L.S., F.B., M.R.), Klinikum der Universität München, LMU München, Munich, Germany
| | - Veronika Görge
- From the Medizinische Klinik und Poliklinik IV (C.A., V.G., D.A.H., H.S., L.H., H.K., L.S., F.B., M.R.), Klinikum der Universität München, LMU München, Munich, Germany
| | - Daniel A Heinrich
- From the Medizinische Klinik und Poliklinik IV (C.A., V.G., D.A.H., H.S., L.H., H.K., L.S., F.B., M.R.), Klinikum der Universität München, LMU München, Munich, Germany
| | - Eva Hoster
- Institute for Medical Information Processing, Biometry and Epidemiology (IBE) (E.H.), Klinikum der Universität München, LMU München, Munich, Germany.,Department of Medicine III (E.H.), Klinikum der Universität München, LMU München, Munich, Germany
| | - Holger Schneider
- From the Medizinische Klinik und Poliklinik IV (C.A., V.G., D.A.H., H.S., L.H., H.K., L.S., F.B., M.R.), Klinikum der Universität München, LMU München, Munich, Germany
| | - Laura Handgriff
- From the Medizinische Klinik und Poliklinik IV (C.A., V.G., D.A.H., H.S., L.H., H.K., L.S., F.B., M.R.), Klinikum der Universität München, LMU München, Munich, Germany
| | - Heike Künzel
- From the Medizinische Klinik und Poliklinik IV (C.A., V.G., D.A.H., H.S., L.H., H.K., L.S., F.B., M.R.), Klinikum der Universität München, LMU München, Munich, Germany
| | - Lisa Sturm
- From the Medizinische Klinik und Poliklinik IV (C.A., V.G., D.A.H., H.S., L.H., H.K., L.S., F.B., M.R.), Klinikum der Universität München, LMU München, Munich, Germany
| | - Felix Beuschlein
- From the Medizinische Klinik und Poliklinik IV (C.A., V.G., D.A.H., H.S., L.H., H.K., L.S., F.B., M.R.), Klinikum der Universität München, LMU München, Munich, Germany.,Klinik für Endokrinologie, Diabetologie und Klinische Ernährung, Universitätsspital Zürich, Switzerland (F.B.)
| | - Martin Reincke
- From the Medizinische Klinik und Poliklinik IV (C.A., V.G., D.A.H., H.S., L.H., H.K., L.S., F.B., M.R.), Klinikum der Universität München, LMU München, Munich, Germany
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9
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Fazan FS, Colombari E, Loewy AD, Geerling JC. Despite increasing aldosterone, elevated potassium is not necessary for activating aldosterone-sensitive HSD2 neurons or sodium appetite. Physiol Rep 2021; 9:e14714. [PMID: 33463885 PMCID: PMC7814482 DOI: 10.14814/phy2.14714] [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: 12/12/2020] [Accepted: 12/15/2020] [Indexed: 11/24/2022] Open
Abstract
Restricting dietary sodium promotes sodium appetite in rats. Prolonged sodium restriction increases plasma potassium (pK), and elevated pK is largely responsible for a concurrent increase in aldosterone, which helps promote sodium appetite. In addition to increasing aldosterone, we hypothesized that elevated potassium directly influences the brain to promote sodium appetite. To test this, we restricted dietary potassium in sodium‐deprived rats. Potassium restriction reduced pK and blunted the increase in aldosterone caused by sodium deprivation, but did not prevent sodium appetite or the activation of aldosterone‐sensitive HSD2 neurons. Conversely, supplementing potassium in sodium‐deprived rats increased pK and aldosterone, but did not increase sodium appetite or the activation of HSD2 neurons relative to potassium restriction. Supplementing potassium without sodium deprivation did not significantly increase aldosterone and HSD2 neuronal activation and only modestly increased saline intake. Overall, restricting dietary sodium activated the HSD2 neurons and promoted sodium appetite across a wide range of pK and aldosterone, and saline consumption inactivated the HSD2 neurons despite persistent hyperaldosteronism. In conclusion, elevated potassium is important for increasing aldosterone, but it is neither necessary nor sufficient for activating HSD2 neurons and increasing sodium appetite.
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Affiliation(s)
- Frederico S Fazan
- Department of Neurology, Iowa Neuroscience Institute, University of Iowa Hospital and Clinics, Iowa City, Iowa, USA.,Department of Physiology and Pathology, São Paulo State University, Araraquara, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, São Paulo State University, Araraquara, Brazil
| | - Arthur D Loewy
- Department of Neuroscience, Washington University School of Medicine in Saint Louis, St Louis, Missouri, USA
| | - Joel C Geerling
- Department of Neurology, Iowa Neuroscience Institute, University of Iowa Hospital and Clinics, Iowa City, Iowa, USA
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Adolf C, Heinrich DA, Holler F, Lechner B, Nirschl N, Sturm L, Görge V, Riester A, Williams TA, Treitl M, Ladurner R, Beuschlein F, Reincke M. Patients With Primary Aldosteronism Respond to Unilateral Adrenalectomy With Long-Term Reduction in Salt Intake. J Clin Endocrinol Metab 2020; 105:5614720. [PMID: 31702016 PMCID: PMC7010311 DOI: 10.1210/clinem/dgz051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 10/17/2019] [Indexed: 01/10/2023]
Abstract
CONTEXT High dietary salt intake is known to aggravate arterial hypertension. This effect could be of particular relevance in the setting of primary aldosteronism (PA), which is associated with cardiovascular damage independent of blood pressure levels. The aim of this study was to determine the impact of therapy on salt intake in PA patients. PATIENTS AND METHODS A total of 148 consecutive PA patients (66 with unilateral and 82 with bilateral PA) from the database of the German Conn's Registry were included. Salt intake was quantified by 24-hour urinary sodium excretion before and after initiation of PA treatment. STUDY DESIGN Observational longitudinal cohort study. SETTING Tertiary care hospital. RESULTS At baseline, unilateral PA patients had a significantly higher urinary sodium excretion than patients with bilateral disease (205 vs 178 mmol/d, P = 0.047). Higher urinary sodium excretion correlated with an increased cardiovascular risk profile including proteinuria, impaired lipid, and glucose metabolism and was associated with higher daily doses of antihypertensive drugs to achieve blood pressure control. In unilateral disease, urinary sodium excretion dropped spontaneously to 176 mmol/d (P = 0.012) 1 year after unilateral adrenalectomy and remained low at 3 years of follow-up (174 mmol/d). In contrast, treatment with mineralocorticoid receptor antagonists (MRA) in bilateral PA patients was not associated with a significant change in urinary sodium excretion at follow-up (179 mmol/d vs 183 mmol/d). CONCLUSION PA patients consuming a high-salt diet, estimated based on urinary sodium excretion, respond to adrenalectomy with a significant reduction of salt intake, in contrast to MRA treatment.
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Affiliation(s)
- Christian Adolf
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
| | - Daniel A Heinrich
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
| | - Finn Holler
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
| | - Benjamin Lechner
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
| | - Nina Nirschl
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
| | - Lisa Sturm
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
| | - Veronika Görge
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
| | - Anna Riester
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
| | - Tracy A Williams
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
- Divis
ion of Internal Medicine and Hypertension, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Marcus Treitl
- Klinik und Poliklinik für Radiologie, Klinikum der Universität München, LMU München, Munich, Germany
| | - Roland Ladurner
- Klinik für Viszeral- und Endokrine Chirurgie, Klinikum der Universität München, LMU München, Munich, Germany
| | - Felix Beuschlein
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
- Klinik für Endokrinologie, Diabetologie und Klinische Ernährung, Universitätsspital Zürich, Zurich, Switzerland
| | - Martin Reincke
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Ziemssenstraße, Munich, Germany
- Correspondence and Reprint Requests: Martin Reincke, MD, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Ziemssenstr. 1, 80336 Munich, Germany. E-mail:
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Aldosterone-sensitive HSD2 neurons in mice. Brain Struct Funct 2018; 224:387-417. [PMID: 30343334 DOI: 10.1007/s00429-018-1778-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 10/03/2018] [Indexed: 02/07/2023]
Abstract
Sodium deficiency elevates aldosterone, which in addition to epithelial tissues acts on the brain to promote dysphoric symptoms and salt intake. Aldosterone boosts the activity of neurons that express 11-beta-hydroxysteroid dehydrogenase type 2 (HSD2), a hallmark of aldosterone-sensitive cells. To better characterize these neurons, we combine immunolabeling and in situ hybridization with fate mapping and Cre-conditional axon tracing in mice. Many cells throughout the brain have a developmental history of Hsd11b2 expression, but in the adult brain one small brainstem region with a leaky blood-brain barrier contains HSD2 neurons. These neurons express Hsd11b2, Nr3c2 (mineralocorticoid receptor), Agtr1a (angiotensin receptor), Slc17a6 (vesicular glutamate transporter 2), Phox2b, and Nxph4; many also express Cartpt or Lmx1b. No HSD2 neurons express cholinergic, monoaminergic, or several other neuropeptidergic markers. Their axons project to the parabrachial complex (PB), where they intermingle with AgRP-immunoreactive axons to form dense terminal fields overlapping FoxP2 neurons in the central lateral subnucleus (PBcL) and pre-locus coeruleus (pLC). Their axons also extend to the forebrain, intermingling with AgRP- and CGRP-immunoreactive axons to form dense terminals surrounding GABAergic neurons in the ventrolateral bed nucleus of the stria terminalis (BSTvL). Sparse axons target the periaqueductal gray, ventral tegmental area, lateral hypothalamic area, paraventricular hypothalamic nucleus, and central nucleus of the amygdala. Dual retrograde tracing revealed that largely separate HSD2 neurons project to pLC/PB or BSTvL. This projection pattern raises the possibility that a subset of HSD2 neurons promotes the dysphoric, anorexic, and anhedonic symptoms of hyperaldosteronism via AgRP-inhibited relay neurons in PB.
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Qiao H, Wang N, Yan J. [Role of the central nucleus of the amygdala in regulating the nongenomic effect of aldosterone on sodium intake in rat nucleus tractus solitarius]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2018; 38:1159-1164. [PMID: 30377123 DOI: 10.3969/j.issn.1673-4254.2018.10.02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To reveal the nongenomic effect of aldosterone on the regulation of sodium intake in the nucleus tractus solitarius (NTS) and the role of central nucleus of the amygdala (CeA) in regulating this effect. METHODS Adult male SD rats were divided into four groups and underwent operations to induce bilateral CeA electrolytic lesions (400 μA, 25 s; n=28), bilateral sham CeA lesions (n=28), unilateral CeA lesions (n=28), or unilateral sham CeA lesions (n=26). After 3 days of recovery, the rats received implantation of a stainless steel 23-gauge cannula wih two tubes into the NTS followed by a recovery period of 7 days. The rats in each group were then divided into two subgroups for microinjection of aldosterone (50 ng/μL) or control solution in the NTS, and the cumulative intake within 30 min of 0.3 mol/L NaCl solution was recorded for each rat. RESULTS Bilateral CeA lesions (3 days) eliminated the increased 0.3 mol/L NaCl intake induced by aldosterone microinjected into the NTS (0.3±0.04 mL in CeA lesion group vs 1.3±0.3 mL in sham lesion group). Unilateral CeA lesion (3 days) reduced aldosterone-induced increase of NaCl intake in the first 15 min (P < 0.05) but not in 15-30 min (P > 0.05). In rats with sham lesions, aldosterone (50 ng/μL) still induced a significant increase in NaCl intake[1.3±0.3 mL vs 0.25±0.02 mL in the control group; F (3, 224)=24.0, P < 0.05]. CONCLUSIONS The regulation of sodium intake by aldosterone is subjected to descending facilitatory modulation by the bilateral CeA, and CeA integrity is essential for aldosterone to execute the nongenomic effect in regulating rapid sodium intake.
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Affiliation(s)
- Hu Qiao
- Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an 710004, China.,Department of Physiology and Pathophysiology; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
| | - Nan Wang
- Department of Physiology and Pathophysiology; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
| | - Jianqun Yan
- Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an 710004, China.,Department of Physiology and Pathophysiology; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
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13
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Gasparini S, Melo MR, Andrade-Franzé GMF, Geerling JC, Menani JV, Colombari E. Aldosterone infusion into the 4th ventricle produces sodium appetite with baroreflex attenuation independent of renal or blood pressure changes. Brain Res 2018; 1698:70-80. [PMID: 29928872 DOI: 10.1016/j.brainres.2018.06.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/05/2018] [Accepted: 06/16/2018] [Indexed: 02/07/2023]
Abstract
Aldosterone infusion into the 4th ventricle (4th V), upstream the nucleus of the solitary tract (NTS), produces strong 0.3 M NaCl intake. In the present study, we investigated whether aldosterone infusion into the 4th V activates HSD2 neurons, changes renal excretion, or alters blood pressure and cardiovascular reflexes. Chronic infusion of aldosterone (100 ng/h) into the 4th V increased daily 0.3 M NaCl intake (up to 44 ± 10, vs. vehicle: 5.6 ± 3.4 ml/24 h) and also c-Fos expression in HSD2 neurons in the NTS and in non-HSD2 neurons in the NTS. Natriuresis, diuresis and positive sodium balance were present in rats that ingested 0.3 M NaCl, however, renal excretion was not modified by 4th V aldosterone in rats that had no access to NaCl. 4th V aldosterone also reduced baroreflex sensitivity (-2.8 ± 0.5, vs. vehicle: -5.1 ± 0.9 bpm/mmHg) in animals that had sodium available, without changing blood pressure. The results suggest that sodium intake induced by aldosterone infused into the 4th V is associated with activation of NTS neurons, among them the HSD2 neurons. Aldosterone infused into the 4th V in association with sodium intake also impairs baroreflex sensitivity, without changing arterial pressure.
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Affiliation(s)
- S Gasparini
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil; Departament of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - M R Melo
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil
| | - G M F Andrade-Franzé
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil
| | - J C Geerling
- Departament of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - J V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil
| | - E Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
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15
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Abstract
Fierce debate has developed whether low-sodium intake, like high-sodium intake, could be associated with adverse outcome. The debate originates in earlier epidemiological studies associating high-sodium intake with high blood pressure and more recent studies demonstrating a higher cardiovascular event rate with both low- and high-sodium intake. This brings into question whether we entirely understand the consequences of high- and (very) low-sodium intake for the systemic hemodynamics, the kidney function, the vascular wall, the immune system, and the brain. Evolutionarily, sodium retention mechanisms in the context of low dietary sodium provided a survival advantage and are highly conserved, exemplified by the renin-angiotensin system. What is the potential for this sodium-retaining mechanism to cause harm? In this paper, we will consider current views on how a sodium load is handled, visiting aspects including the effect of sodium on the vessel wall, the sympathetic nervous system, the brain renin-angiotensin system, the skin as "third compartment" coupling to vascular endothelial growth factor C, and the kidneys. From these perspectives, several mechanisms can be envisioned whereby a low-sodium diet could potentially cause harm, including the renin-angiotensin system and the sympathetic nervous system. Altogether, the uncertainties preclude a unifying model or practical clinical guidance regarding the effects of a low-sodium diet for an individual. There is a very strong need for fundamental and translational studies to enhance the understanding of the potential adverse consequences of low-salt intake as an initial step to facilitate better clinical guidance.
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Affiliation(s)
- Branko Braam
- Department of Medicine, University of Alberta, Edmonton, AB, Canada. .,Department of Physiology, University of Alberta, Edmonton, AB, Canada. .,Department of Medicine / Division of Nephrology and Immunology, University of Alberta Hospital, 11-132 CSB Clinical Sciences Building, Edmonton, AB, T6G 2G3, Canada.
| | - Xiaohua Huang
- Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - William A Cupples
- Biomedical Physiology & Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Shereen M Hamza
- Department of Medicine, University of Alberta, Edmonton, AB, Canada.,Department of Physiology, University of Alberta, Edmonton, AB, Canada
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16
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Roncari CF, David RB, De Paula PM, Colombari DS, De Luca Jr. LA, Colombari E, Menani JV. The lateral parabrachial nucleus and central angiotensinergic mechanisms in the control of sodium intake induced by different stimuli. Behav Brain Res 2017. [DOI: 10.1016/j.bbr.2017.06.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Joëls M, de Kloet ER. 30 YEARS OF THE MINERALOCORTICOID RECEPTOR: The brain mineralocorticoid receptor: a saga in three episodes. J Endocrinol 2017. [PMID: 28634266 DOI: 10.1530/joe-16-0660] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In 1968, Bruce McEwen discovered that 3H-corticosterone administered to adrenalectomised rats is retained in neurons of hippocampus rather than those of hypothalamus. This discovery signalled the expansion of endocrinology into the science of higher brain regions. With this in mind, our contribution highlights the saga of the brain mineralocorticoid receptor (MR) in three episodes. First, the precloning era dominated by the conundrum of two types of corticosterone-binding receptors in the brain, which led to the identification of the high-affinity corticosterone receptor as the 'promiscuous' MR cloned in 1987 by Jeff Arriza and Ron Evans in addition to the classical glucocorticoid receptor (GR). Then, the post-cloning period aimed to disentangle the function of the brain MR from that of the closely related GR on different levels of biological complexity. Finally, the synthesis section that highlights the two faces of brain MR: Salt and Stress. 'Salt' refers to the regulation of salt appetite, and reciprocal arousal, motivation and reward, by a network of aldosterone-selective MR-expressing neurons projecting from nucleus tractus solitarii (NTS) and circumventricular organs. 'Stress' is about the limbic-forebrain nuclear and membrane MRs, which act as a switch in the selection of the best response to cope with a stressor. For this purpose, activation of the limbic MR promotes selective attention, memory retrieval and the appraisal process, while driving emotional expressions of fear and aggression. Subsequently, rising glucocorticoid concentrations activate GRs in limbic-forebrain circuitry underlying executive functions and memory storage, which contribute in balance with MR-mediated actions to homeostasis, excitability and behavioural adaptation.
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Affiliation(s)
- Marian Joëls
- Department of Translational NeuroscienceBrain Center Rudolf Magnus, University Medical Center, Utrecht, The Netherlands
- University of GroningenUniversity Medical Center, Groningen, The Netherlands
| | - E Ronald de Kloet
- Division of EndocrinologyDepartment of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
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18
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Schütten MTJ, Houben AJHM, de Leeuw PW, Stehouwer CDA. The Link Between Adipose Tissue Renin-Angiotensin-Aldosterone System Signaling and Obesity-Associated Hypertension. Physiology (Bethesda) 2017; 32:197-209. [PMID: 28404736 DOI: 10.1152/physiol.00037.2016] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 11/22/2022] Open
Abstract
Obese individuals frequently develop hypertension, which is for an important part attributable to renin-angiotensin-aldosterone system (RAAS) overactivity. This review summarizes preclinical and clinical evidence on the involvement of dysfunctional adipose tissue in RAAS activation and on the renal, central, and vascular mechanisms linking RAAS components to obesity-associated hypertension.
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Affiliation(s)
- Monica T J Schütten
- Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Alfons J H M Houben
- Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Peter W de Leeuw
- Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Coen D A Stehouwer
- Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
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19
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Rapid stimulation of sodium intake combining aldosterone into the 4th ventricle and the blockade of the lateral parabrachial nucleus. Neuroscience 2017; 346:94-101. [DOI: 10.1016/j.neuroscience.2017.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 01/04/2017] [Accepted: 01/04/2017] [Indexed: 12/17/2022]
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20
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Qiao H, Hu B, Zhou H, Yan J, Jia R, Lu B, Sun B, Luo X, Fan Y, Wang N. Aldosterone induces rapid sodium intake by a nongenomic mechanism in the nucleus tractus solitarius. Sci Rep 2016; 6:38631. [PMID: 27934887 PMCID: PMC5146675 DOI: 10.1038/srep38631] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 11/11/2016] [Indexed: 01/27/2023] Open
Abstract
The purpose of this study was to determine whether aldosterone has a rapid action in the nucleus tractus solitarius (NTS) that increases sodium intake, and to examine whether this effect of aldosterone, if present, is mediated by G protein-coupled estrogen receptor (GPER). Adult male Sprague-Dawley rats with a stainless-steel cannula in the NTS were used. Aldosterone was injected into the NTS at the doses of 1, 5, 10 and 20 ng 0.1 μl−1. A rapid dose-related increase of 0.3 M NaCl intake was induced within 30 min and this increase was not suppressed by the mineralocorticoid receptor (MR) antagonist spironolactone (10 ng 0.1 μl−1). Water intake was not affected by aldosterone. The GPER agonist G-1 produced a parallel and significant increase in sodium intake, while pre-treatment with GPER antagonist G15 (10 ng 0.1 μl−1) blocked the G-1 or aldosterone-induced rapid sodium intake. In addition, sodium intake induced by sodium depletion or low-sodium diet fell within 30 min after injection into the NTS of the MR antagonist spironolactone, while G15 had no effect. Our results confirm previous reports, and support the hypothesis that aldosterone evokes rapid sodium intake through a non-genomic mechanism involving GPER in NTS.
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Affiliation(s)
- Hu Qiao
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Xi'an Jiaotong University College of Stomatology, 98# Xiwu Road, Xi'an, Shaanxi 710000, P.R. China.,Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Science, 76# W. Yanta Road, Xi'an, Shaanxi 710061, P.R. China.,Department of Orthodontics, Xi'an Jiaotong University College of Stomatology, 98# Xiwu Road, Xi'an, Shaanxi 710000, P.R. China
| | - Bo Hu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Science, 76# W. Yanta Road, Xi'an, Shaanxi 710061, P.R. China
| | - Hong Zhou
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Xi'an Jiaotong University College of Stomatology, 98# Xiwu Road, Xi'an, Shaanxi 710000, P.R. China.,Department of Orthodontics, Xi'an Jiaotong University College of Stomatology, 98# Xiwu Road, Xi'an, Shaanxi 710000, P.R. China
| | - Jianqun Yan
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Xi'an Jiaotong University College of Stomatology, 98# Xiwu Road, Xi'an, Shaanxi 710000, P.R. China.,Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Science, 76# W. Yanta Road, Xi'an, Shaanxi 710061, P.R. China
| | - Ru Jia
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Science, 76# W. Yanta Road, Xi'an, Shaanxi 710061, P.R. China
| | - Bo Lu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Science, 76# W. Yanta Road, Xi'an, Shaanxi 710061, P.R. China
| | - Bo Sun
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Science, 76# W. Yanta Road, Xi'an, Shaanxi 710061, P.R. China
| | - Xiao Luo
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Science, 76# W. Yanta Road, Xi'an, Shaanxi 710061, P.R. China
| | - Yuanyuan Fan
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Science, 76# W. Yanta Road, Xi'an, Shaanxi 710061, P.R. China
| | - Nan Wang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Science, 76# W. Yanta Road, Xi'an, Shaanxi 710061, P.R. China
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21
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Jarvie BC, Palmiter RD. HSD2 neurons in the hindbrain drive sodium appetite. Nat Neurosci 2016; 20:167-169. [PMID: 27918529 DOI: 10.1038/nn.4451] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 11/02/2016] [Indexed: 12/11/2022]
Abstract
Sodium-depleted animals develop an appetite for aversive concentrations of sodium. Here we show that chemogenetic activation of aldosterone-sensitive neurons that express 11β-hydroxysteroid dehydrogenase type 2 (HSD2) in the nucleus of the solitary tract is sufficient to drive consumption of sodium-containing solutions in mice, independently of thirst or hunger. These HSD2-positive neurons are necessary for full expression of sodium appetite and have distinct downstream targets that are activated during sodium depletion.
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Affiliation(s)
- Brooke C Jarvie
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Richard D Palmiter
- Department of Biochemistry, University of Washington, Seattle, Washington, USA.,Howard Hughes Medical Institute, University of Washington, Seattle, Washington, USA
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22
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Haque M, Wilson R, Sharma K, Mills NJ, Teruyama R. Localisation of 11β-Hydroxysteroid Dehydrogenase Type 2 in Mineralocorticoid Receptor Expressing Magnocellular Neurosecretory Neurones of the Rat Supraoptic and Paraventricular Nuclei. J Neuroendocrinol 2015; 27:835-49. [PMID: 26403275 PMCID: PMC5019266 DOI: 10.1111/jne.12325] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 09/15/2015] [Accepted: 09/17/2015] [Indexed: 01/29/2023]
Abstract
An accumulating body of evidence suggests that the activity of the mineralocorticoid, aldosterone, in the brain via the mineralocorticoid receptor (MR) plays an important role in the regulation of blood pressure. MR was recently found in vasopressin and oxytocin synthesising magnocellular neurosecretory cells (MNCs) in both the paraventricular (PVN) and supraoptic (SON) nuclei in the hypothalamus. Considering the physiological effects of these hormones, MR in these neurones may be an important site mediating the action of aldosterone in blood pressure regulation within the brain. However, aldosterone activation of MR in the hypothalamus remains controversial as a result of the high binding affinity of glucocorticoids to MR at substantially higher concentrations compared to aldosterone. In aldosterone-sensitive epithelia, the enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) prevents glucocorticoids from binding to MR by converting glucocorticoids into inactive metabolites. The present study aimed to determine whether 11β-HSD2, which increases aldosterone selectivity, is expressed in MNCs. Specific 11β-HSD2 immunoreactivity was found in the cytoplasm of the MNCs in both the SON and PVN. In addition, double-fluorescence confocal microscopy demonstrated that MR-immunoreactivity and 11β-HSD2-in situ hybridised products are colocalised in MNCs. Lastly, single-cell reverse transcriptase-polymerase chain reaction detected MR and 11β-HSD2 mRNAs from cDNA libraries derived from single identified MNCs. These findings strongly suggest that MNCs in the SON and PVN are aldosterone-sensitive neurones.
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Affiliation(s)
- M Haque
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - R Wilson
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - K Sharma
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - N J Mills
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - R Teruyama
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
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23
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Gomez-Sanchez EP. Brain mineralocorticoid receptors in cognition and cardiovascular homeostasis. Steroids 2014; 91:20-31. [PMID: 25173821 PMCID: PMC4302001 DOI: 10.1016/j.steroids.2014.08.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 07/10/2014] [Accepted: 08/04/2014] [Indexed: 12/20/2022]
Abstract
Mineralocorticoid receptors (MR) mediate diverse functions supporting osmotic and hemodynamic homeostasis, response to injury and inflammation, and neuronal changes required for learning and memory. Inappropriate MR activation in kidneys, heart, vessels, and brain hemodynamic control centers results in cardiovascular and renal pathology and hypertension. MR binds aldosterone, cortisol and corticosterone with similar affinity, while the glucocorticoid receptor (GR) has less affinity for cortisol and corticosterone. As glucocorticoids are more abundant than aldosterone, aldosterone activates MR in cells co-expressing enzymes with 11β-hydroxydehydrogenase activity to inactivate them. MR and GR co-expressed in the same cell interact at the molecular and functional level and these functions may be complementary or opposing depending on the cell type. Thus the balance between MR and GR expression and activation is crucial for normal function. Where 11β-hydroxydehydrogenase 2 (11β-HSD2) that inactivates cortisol and corticosterone in aldosterone target cells of the kidney and nucleus tractus solitarius (NTS) is not expressed, as in most neurons, MR are activated at basal glucocorticoid concentrations, GR at stress concentrations. An exception may be pre-autonomic neurons of the PVN which express MR and 11β-HSD1 in the absence of hexose-6-phosphate dehydrogenase required to generate the requisite cofactor for reductase activity, thus it acts as a dehydrogenase. MR antagonists, valuable adjuncts to the treatment of cardiovascular disease, also inhibit MR in the brain that are crucial for memory formation and exacerbate detrimental effects of excessive GR activation on cognition and mood. 11β-HSD1 inhibitors combat metabolic and cognitive diseases related to glucocorticoid excess, but may exacerbate MR action where 11β-HSD1 acts as a dehydrogenase, while non-selective 11β-HSD1&2 inhibitors cause injurious disruption of MR hemodynamic control. MR functions in the brain are multifaceted and optimal MR:GR activity is crucial. Therefore selectively targeting down-stream effectors of MR specific actions may be a better therapeutic goal.
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Affiliation(s)
- Elise P Gomez-Sanchez
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS 39216, USA.
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24
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Fu Y, Vallon V. Mineralocorticoid-induced sodium appetite and renal salt retention: evidence for common signaling and effector mechanisms. Nephron Clin Pract 2014; 128:8-16. [PMID: 25376899 DOI: 10.1159/000368264] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
An increase in renal sodium chloride (salt) retention and an increase in sodium appetite are the body's responses to salt restriction or depletion in order to restore salt balance. Renal salt retention and increased sodium appetite can also be maladaptive and sustain the pathophysiology in conditions like salt-sensitive hypertension and chronic heart failure. Here we review the central role of the mineralocorticoid aldosterone in both the increase in renal salt reabsorption and sodium appetite. We discuss the working hypothesis that aldosterone activates similar signaling and effector mechanisms in the kidney and brain, including the mineralocorticoid receptor, the serum- and glucocorticoid-induced kinase SGK1, the ubiquitin ligase NEDD4-2, and the epithelial sodium channel ENaC. The latter also mediates the gustatory salt sensing in the tongue, which is required for the manifestation of increased salt intake. Effects of aldosterone on both the brain and kidney synergize with the effects of angiotensin II. Thus, mineralocorticoids appear to induce similar molecular pathways in the kidney, brain, and possibly tongue, which could provide opportunities for more effective therapeutic interventions. Inhibition of renal salt reabsorption is compensated by stimulation of salt appetite and vice versa; targeting both mechanisms should be more effective. Inhibiting the arousal to consume salty food may improve a patient's compliance to reducing salt intake. While a better understanding of the molecular mechanisms is needed and will provide new therapeutic options, current pharmacological interventions that target both salt retention and sodium appetite include mineralocorticoid receptor antagonists and potentially inhibitors of angiotensin II and ENaC.
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Affiliation(s)
- Yiling Fu
- Department of Medicine, University of California San Diego, La Jolla, Calif., USA
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25
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Abstract
The primary adrenal cortical steroid hormones, aldosterone, and the glucocorticoids cortisol and corticosterone, act through the structurally similar mineralocorticoid (MR) and glucocorticoid receptors (GRs). Aldosterone is crucial for fluid, electrolyte, and hemodynamic homeostasis and tissue repair; the significantly more abundant glucocorticoids are indispensable for energy homeostasis, appropriate responses to stress, and limiting inflammation. Steroid receptors initiate gene transcription for proteins that effect their actions as well as rapid non-genomic effects through classical cell signaling pathways. GR and MR are expressed in many tissues types, often in the same cells, where they interact at molecular and functional levels, at times in synergy, others in opposition. Thus the appropriate balance of MR and GR activation is crucial for homeostasis. MR has the same binding affinity for aldosterone, cortisol, and corticosterone. Glucocorticoids activate MR in most tissues at basal levels and GR at stress levels. Inactivation of cortisol and corticosterone by 11β-HSD2 allows aldosterone to activate MR within aldosterone target cells and limits activation of the GR. Under most conditions, 11β-HSD1 acts as a reductase and activates cortisol/corticosterone, amplifying circulating levels. 11β-HSD1 and MR antagonists mitigate inappropriate activation of MR under conditions of oxidative stress that contributes to the pathophysiology of the cardiometabolic syndrome; however, MR antagonists decrease normal MR/GR functional interactions, a particular concern for neurons mediating cognition, memory, and affect.
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Affiliation(s)
- Elise Gomez-Sanchez
- G.V.(Sonny) Montgomery V.A. Medical Center and Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - Celso E. Gomez-Sanchez
- G.V.(Sonny) Montgomery V.A. Medical Center and Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi
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26
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Menani JV, De Luca LA, Johnson AK. Role of the lateral parabrachial nucleus in the control of sodium appetite. Am J Physiol Regul Integr Comp Physiol 2014; 306:R201-10. [PMID: 24401989 DOI: 10.1152/ajpregu.00251.2012] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In states of sodium deficiency many animals seek and consume salty solutions to restore body fluid homeostasis. These behaviors reflect the presence of sodium appetite that is a manifestation of a pattern of central nervous system (CNS) activity with facilitatory and inhibitory components that are affected by several neurohumoral factors. The primary focus of this review is on one structure in this central system, the lateral parabrachial nucleus (LPBN). However, before turning to a more detailed discussion of the LPBN, a brief overview of body fluid balance-related body-to-brain signaling and the identification of the primary CNS structures and humoral factors involved in the control of sodium appetite is necessary. Angiotensin II, mineralocorticoids, and extracellular osmotic changes act on forebrain areas to facilitate sodium appetite and thirst. In the hindbrain, the LPBN functions as a key integrative node with an ascending output that exerts inhibitory influences on forebrain regions. A nonspecific or general deactivation of LPBN-associated inhibition by GABA or opioid agonists produces NaCl intake in euhydrated rats without any other treatment. Selective LPBN manipulation of other neurotransmitter systems [e.g., serotonin, cholecystokinin (CCK), corticotrophin-releasing factor (CRF), glutamate, ATP, or norepinephrine] greatly enhances NaCl intake when accompanied by additional treatments that induce either thirst or sodium appetite. The LPBN interacts with key forebrain areas that include the subfornical organ and central amygdala to determine sodium intake. To summarize, a model of LPBN inhibitory actions on forebrain facilitatory components for the control of sodium appetite is presented in this review.
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Affiliation(s)
- Jose V Menani
- Department of Physiology and Pathology, School of Dentistry, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil; and Departments of Psychology, Pharmacology and Health, and Human Physiology and the Cardiovascular Center, University of Iowa, Iowa City, Iowa
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27
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Koneru B, Bathina CS, Cherry BH, Mifflin SW. Mineralocorticoid receptor in the NTS stimulates saline intake during fourth ventricular infusions of aldosterone. Am J Physiol Regul Integr Comp Physiol 2013; 306:R61-6. [PMID: 24259463 DOI: 10.1152/ajpregu.00434.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The purpose of this study was to determine whether neurons within the nucleus tractus solitarius (NTS) that express the mineralocorticoid receptor (MR) play a role in aldosterone stimulation of salt intake. Adult Wistar-Kyoto (WKY) rats received microinjections into the NTS of a short-hairpin RNA (shRNA) for the MR, to site specifically reduce levels of the MR by RNA interference (shRNA; n = 9) or scrambled RNA as a control (scRNA; n = 8). After injection of the viral construct, aldosterone-filled osmotic minipumps were implanted subcutaneously and connected to a cannula extending into the fourth ventricle to infuse aldosterone at a rate of 25 ng/h. Before and after surgeries, rats had ad libitum access to normal sodium (0.26%) rat chow and two graduated drinking bottles filled with either distilled water or 0.3 M NaCl. Before the surgeries, basal saline intake was 1.6 ± 0.6 ml in the scRNA group and 1.56 ± 0.6 ml in the shRNA group. Twenty-four days postsurgery, saline intake was elevated to a greater extent in the scRNA group (5.9 ± 1.07 ml) than in the shRNA group (2.41 ± 0.6 ml). Post mortem immunohistochemistry revealed a significant reduction in the number of NTS neurons exhibiting immunoreactivity for MR in shRNA-injected rats (23 ± 1 cells/section) versus scRNA-injected rats (33 ± 2 cells/section; P = 0.008). shRNA did not alter the level of 11-β-hydroxysteroid dehydrogenase type II (HSD2) protein in the NTS as judged by the number of HSD2 immunoreactive neurons. These results suggest that fourth ventricular infusions of aldosterone stimulate saline intake, and that this stimulation is at least in part mediated by hindbrain NTS neurons that express MR.
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Affiliation(s)
- Bhuvaneswari Koneru
- Department of Integrative Physiology, Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
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