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Faesel N, Koch M, Fendt M. Orexin deficiency modulates the dipsogenic effects of angiotensin II in a sex-dependent manner. Peptides 2024; 171:171127. [PMID: 38043589 DOI: 10.1016/j.peptides.2023.171127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 11/10/2023] [Accepted: 11/28/2023] [Indexed: 12/05/2023]
Abstract
The orexin (hypocretin) neuropeptide system is an important regulator of ingestive behaviors, i.e., it promotes food and water intake. Here, we investigated the role of orexin in drinking induced by the potent dipsogen angiotensin II (ANG II). Specifically, male and female orexin-deficient mice received intracerebroventricular (ICV) injections of ANG II, followed by measuring their water intake within 15 min. We found that lower doses of ANG II (100 ng) significantly stimulated drinking in males but not in females, indicating a general sex-dependent effect that was not affected by orexin deficiency. However, higher doses of ANG II (500 ng) were sufficient to induce drinking in female wild-type mice, while female orexin-deficient mice still did not respond to the dipsogenic properties of ANG II. In conclusion, these results suggest sex-dependent effects in ANG II-induced drinking and further support the sexual dimorphism of orexin system functions.
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Affiliation(s)
- Nadine Faesel
- Institute for Pharmacology and Toxicology, Otto von Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany; Department of Neuropharmacology, Brain Research Institute, University of Bremen, Hochschulring 18, D-28359 Bremen, Germany.
| | - Michael Koch
- Department of Neuropharmacology, Brain Research Institute, University of Bremen, Hochschulring 18, D-28359 Bremen, Germany.
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Otto von Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany; Center for Behavioral Brain Sciences, Otto von Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany.
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2
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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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Oliveira V, Reho JJ, Balapattabi K, Ritter ML, Mathieu NM, Opichka MA, Lu KT, Grobe CC, Silva SD, Wackman KK, Nakagawa P, Segar JL, Sigmund CD, Grobe JL. Chronic intracerebroventricular infusion of angiotensin II causes dose- and sex-dependent effects on intake behaviors and energy homeostasis in C57BL/6J mice. Am J Physiol Regul Integr Comp Physiol 2022; 323:R410-R421. [PMID: 35816717 PMCID: PMC9512112 DOI: 10.1152/ajpregu.00091.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/15/2022] [Accepted: 07/09/2022] [Indexed: 11/22/2022]
Abstract
The renin-angiotensin system (RAS) within the brain is implicated in the control of fluid and electrolyte balance, autonomic functions, blood pressure, and energy expenditure. Mouse models are increasingly used to explore these mechanisms; however, sex and dose dependencies of effects elicited by chronic intracerebroventricular (ICV) angiotensin II (ANG II) infusion have not been carefully established in this species. To examine the interactions among sex, body mass, and ICV ANG II on ingestive behaviors and energy balance, young adult C57BL/6J mice of both sexes were studied in a multiplexed metabolic phenotyping system (Promethion) during chronic infusion of ANG II (0, 5, 20, or 50 ng/h). At these infusion rates, ANG II caused accelerating dose-dependent increases in drinking and total energy expenditure in male mice, but female mice exhibited a complex biphasic response with maximum responses at 5 ng/h. Body mass differences did not account for sex-dependent differences in drinking behavior or total energy expenditure. In contrast, resting metabolic rate was similarly increased by ICV ANG II in a dose-dependent manner in both sexes after correction for body mass. We conclude that chronic ICV ANG II stimulates water intake, resting, and total energy expenditure in male C57BL/6J mice following straightforward accelerating dose-dependent kinetics, but female C57BL/6J mice exhibit complex biphasic responses to ICV ANG II. Furthermore, control of resting metabolic rate by ANG II is dissociable from mechanisms controlling fluid intake and total energy expenditure. Future studies of the sex dependency of ANG II within the brain of mice must be designed to carefully consider the biphasic responses that occur in females.
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Affiliation(s)
- Vanessa Oliveira
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - John J Reho
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, Wisconsin
| | | | - McKenzie L Ritter
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Natalia M Mathieu
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Megan A Opichka
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Ko-Ting Lu
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Connie C Grobe
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Sebastião D Silva
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Kelsey K Wackman
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Pablo Nakagawa
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Jeffrey L Segar
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Curt D Sigmund
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Justin L Grobe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin
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4
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Angiotensin II-induced drinking behavior as a method to verify cannula placement into the cerebral ventricles of mice: An evaluation of its accuracy. Physiol Behav 2021; 232:113339. [PMID: 33508314 DOI: 10.1016/j.physbeh.2021.113339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/19/2021] [Accepted: 01/23/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Intracerebroventricular (icv) injections are frequently used in neuroscience research. In addition to histological verification of the injection sites, administration of angiotensin II (ANG II) is often used to verify the injection placements. ANG II is a peptide hormone exerting dipsogenic effects, i.e., it increases drinking, when administered into the cerebral ventricles. This study investigated the accuracy of ANG II-induced drinking as a method to verify icv cannula placements. METHODS Male C57BL/6J mice were implanted with cannulas in the lateral ventricle. Then, icv injections of ANG II were performed and drinking behavior of the mice was recorded. After the behavioral experiment, we histologically verified the cannula placements using dye injections. Based on this, mice were grouped in "icv" and "misplaced". The effects of icv and misplaced ANG II injections on drinking behavior were used to evaluate the accuracy of ANG II-induced drinking as a method to verify icv cannula placements. RESULTS In general, ANG II injections in mice with histologically verified icv cannula placements induced robust drinking responses, while misplaced injections did not. However, there were exceptions in both groups. In about one third of the mice, icv ANG II did not induce drinking or misplaced ANG II injections induced drinking, respectively. CONCLUSION These data demonstrated that ANG II-induced drinking is not a perfectly accurate method to verify icv cannula placements in mice. Therefore, we recommend to not base the decision of in- or excluding experimental subjects solely on this method, but also to histologically verify cannula placements.
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5
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Sandgren JA, Linggonegoro DW, Zhang SY, Sapouckey SA, Claflin KE, Pearson NA, Leidinger MR, Pierce GL, Santillan MK, Gibson-Corley KN, Sigmund CD, Grobe JL. Angiotensin AT 1A receptors expressed in vasopressin-producing cells of the supraoptic nucleus contribute to osmotic control of vasopressin. Am J Physiol Regul Integr Comp Physiol 2018; 314:R770-R780. [PMID: 29364700 PMCID: PMC6032302 DOI: 10.1152/ajpregu.00435.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/03/2018] [Accepted: 01/17/2018] [Indexed: 11/22/2022]
Abstract
Angiotensin II (ANG) stimulates the release of arginine vasopressin (AVP) from the neurohypophysis through activation of the AT1 receptor within the brain, although it remains unclear whether AT1 receptors expressed on AVP-expressing neurons directly mediate this control. We explored the hypothesis that ANG acts through AT1A receptors expressed directly on AVP-producing cells to regulate AVP secretion. In situ hybridization and transgenic mice demonstrated localization of AVP and AT1A mRNA in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN), but coexpression of both AVP and AT1A mRNA was only observed in the SON. Mice harboring a conditional allele for the gene encoding the AT1A receptor (AT1Aflox) were then crossed with AVP-Cre mice to generate mice that lack AT1A in all cells that express the AVP gene (AT1AAVP-KO). AT1AAVP-KO mice exhibited spontaneously increased plasma and serum osmolality but no changes in fluid or salt-intake behaviors, hematocrit, or total body water. AT1AAVP-KO mice exhibited reduced AVP secretion (estimated by measurement of copeptin) in response to osmotic stimuli such as acute hypertonic saline loading and in response to chronic intracerebroventricular ANG infusion. However, the effects of these receptors on AVP release were masked by complex stimuli such as overnight dehydration and DOCA-salt treatment, which simultaneously induce osmotic, volemic, and pressor stresses. Collectively, these data support the expression of AT1A in AVP-producing cells of the SON but not the PVN, and a role for AT1A receptors in these cells in the osmotic regulation of AVP secretion.
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MESH Headings
- Angiotensin II/administration & dosage
- Angiotensin II/pharmacology
- Animals
- Body Water
- Feeding Behavior
- Injections, Intraventricular
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Osmosis
- Paraventricular Hypothalamic Nucleus/metabolism
- Receptor, Angiotensin, Type 1/biosynthesis
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/physiology
- Sodium, Dietary
- Supraoptic Nucleus/metabolism
- Supraoptic Nucleus/physiology
- Vasoconstrictor Agents/administration & dosage
- Vasoconstrictor Agents/pharmacology
- Vasopressins/biosynthesis
- Vasopressins/physiology
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Affiliation(s)
| | | | - Shao Yang Zhang
- Department of Pharmacology, University of Iowa , Iowa City, Iowa
| | | | | | - Nicole A Pearson
- Department of Pharmacology, University of Iowa , Iowa City, Iowa
| | | | - Gary L Pierce
- Department of Health and Human Physiology, University of Iowa , Iowa City, Iowa
- Center for Hypertension Research, University of Iowa , Iowa City, Iowa
- François M. Abboud Cardiovascular Research Center, University of Iowa , Iowa City, Iowa
| | - Mark K Santillan
- Department of Obstetrics and Gynecology, University of Iowa , Iowa City, Iowa
- Center for Hypertension Research, University of Iowa , Iowa City, Iowa
| | - Katherine N Gibson-Corley
- Department of Pathology, University of Iowa , Iowa City, Iowa
- Center for Hypertension Research, University of Iowa , Iowa City, Iowa
- Fraternal Order of Eagles' Diabetes Research Center, University of Iowa , Iowa City, Iowa
| | - Curt D Sigmund
- Department of Pharmacology, University of Iowa , Iowa City, Iowa
- Center for Hypertension Research, University of Iowa , Iowa City, Iowa
- François M. Abboud Cardiovascular Research Center, University of Iowa , Iowa City, Iowa
| | - Justin L Grobe
- Department of Pharmacology, University of Iowa , Iowa City, Iowa
- Center for Hypertension Research, University of Iowa , Iowa City, Iowa
- François M. Abboud Cardiovascular Research Center, University of Iowa , Iowa City, Iowa
- Iowa Neuroscience Institute, University of Iowa , Iowa City, Iowa
- Obesity Research and Education Initiative, University of Iowa , Iowa City, Iowa
- Fraternal Order of Eagles' Diabetes Research Center, University of Iowa , Iowa City, Iowa
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6
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Deng C, Chen H, Yang N, Feng Y, Hsueh AJW. Apela Regulates Fluid Homeostasis by Binding to the APJ Receptor to Activate Gi Signaling. J Biol Chem 2015; 290:18261-8. [PMID: 25995451 DOI: 10.1074/jbc.m115.648238] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Indexed: 01/06/2023] Open
Abstract
Apela (APJ early endogenous ligand, also known as elabela or toddler) is a recently discovered peptide hormone. Based on genetic studies in zebrafish, apela was found to be important for endoderm differentiation and heart development during embryogenesis. Although common phenotypes of apela and APJ-null zebrafish during embryonic development suggested that apela interacts with the APJ receptor, kinetics of apela binding to APJ and intracellular signaling pathways for apela remain unknown. The role of apela in adults is also uncertain. Using a chimeric apela ligand, we showed direct binding of apela to APJ with high affinity (Kd = 0.51 nm) and the ability of apelin, the known peptide ligand for APJ, to compete for apela binding. Apela, similar to apelin, acts through the inhibitory G protein pathway by inhibiting forskolin-stimulated cAMP production and by inducing ERK1/2 phosphorylation. In adult rats, apela is expressed exclusively in the kidney, unlike the wide tissue distribution of apelin. In vivo studies demonstrated the ability of apela to regulate fluid homeostasis by increasing diuresis and water intake. Dose-response studies further indicated that apela induces 2- and 5-fold higher maximal responses than apelin in ERK1/2 phosphorylation and diuresis/water intake, respectively. After designing an apela antagonist, we further demonstrated the role of endogenous ligand(s) in regulating APJ-mediated fluid homeostasis. Our results identified apela as a potent peptide hormone capable of regulating fluid homeostasis in adult kidney through coupling to the APJ-mediated Gi signaling pathway.
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Affiliation(s)
- Cheng Deng
- From the Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China and Program of Reproductive and Stem Cell Biology, Department of Ob/Gyn, Stanford University School of Medicine, Stanford, California 94305-5317
| | - Haidi Chen
- From the Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China and
| | - Na Yang
- From the Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China and
| | - Yi Feng
- Program of Reproductive and Stem Cell Biology, Department of Ob/Gyn, Stanford University School of Medicine, Stanford, California 94305-5317
| | - Aaron J W Hsueh
- Program of Reproductive and Stem Cell Biology, Department of Ob/Gyn, Stanford University School of Medicine, Stanford, California 94305-5317
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7
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Coble JP, Grobe JL, Johnson AK, Sigmund CD. Mechanisms of brain renin angiotensin system-induced drinking and blood pressure: importance of the subfornical organ. Am J Physiol Regul Integr Comp Physiol 2014; 308:R238-49. [PMID: 25519738 DOI: 10.1152/ajpregu.00486.2014] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is critical for cells to maintain a homeostatic balance of water and electrolytes because disturbances can disrupt cellular function, which can lead to profound effects on the physiology of an organism. Dehydration can be classified as either intra- or extracellular, and different mechanisms have developed to restore homeostasis in response to each. Whereas the renin-angiotensin system (RAS) is important for restoring homeostasis after dehydration, the pathways mediating the responses to intra- and extracellular dehydration may differ. Thirst responses mediated through the angiotensin type 1 receptor (AT1R) and angiotensin type 2 receptors (AT2R) respond to extracellular dehydration and intracellular dehydration, respectively. Intracellular signaling factors, such as protein kinase C (PKC), reactive oxygen species (ROS), and the mitogen-activated protein (MAP) kinase pathway, mediate the effects of central angiotensin II (ANG II). Experimental evidence also demonstrates the importance of the subfornical organ (SFO) in mediating some of the fluid intake effects of central ANG II. The purpose of this review is to highlight the importance of the SFO in mediating fluid intake responses to dehydration and ANG II.
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Affiliation(s)
| | - Justin L Grobe
- Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | | | - Curt D Sigmund
- Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa
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8
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Coble JP, Cassell MD, Davis DR, Grobe JL, Sigmund CD. Activation of the renin-angiotensin system, specifically in the subfornical organ is sufficient to induce fluid intake. Am J Physiol Regul Integr Comp Physiol 2014; 307:R376-86. [PMID: 24965793 DOI: 10.1152/ajpregu.00216.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Increased activity of the renin-angiotensin system within the brain elevates fluid intake, blood pressure, and resting metabolic rate. Renin and angiotensinogen are coexpressed within the same cells of the subfornical organ, and the production and action of ANG II through the ANG II type 1 receptor in the subfornical organ (SFO) are necessary for fluid intake due to increased activity of the brain renin-angiotensin system. We generated an inducible model of ANG II production by breeding transgenic mice expressing human renin in neurons controlled by the synapsin promoter with transgenic mice containing a Cre-recombinase-inducible human angiotensinogen construct. Adenoviral delivery of Cre-recombinase causes SFO-selective induction of human angiotensinogen expression. Selective production of ANG II in the SFO results in increased water intake but did not change blood pressure or resting metabolic rate. The increase in water intake was ANG II type 1 receptor-dependent. When given a choice between water and 0.15 M NaCl, these mice increased total fluid and sodium, but not water, because of an increased preference for NaCl. When provided a choice between water and 0.3 M NaCl, the mice exhibited increased fluid, water, and sodium intake, but no change in preference for NaCl. The increase in fluid intake was blocked by an inhibitor of PKC, but not ERK, and was correlated with increased phosphorylated cyclic AMP response element binding protein in the subfornical organ. Thus, increased production and action of ANG II specifically in the subfornical organ are sufficient on their own to mediate an increase in drinking through PKC.
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Affiliation(s)
- Jeffrey P Coble
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Martin D Cassell
- Department of Anatomy and Cell Biology, Roy J. and Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Deborah R Davis
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Justin L Grobe
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Curt D Sigmund
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
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9
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Coble JP, Johnson RF, Cassell MD, Johnson AK, Grobe JL, Sigmund CD. Activity of protein kinase C-α within the subfornical organ is necessary for fluid intake in response to brain angiotensin. Hypertension 2014; 64:141-8. [PMID: 24777977 DOI: 10.1161/hypertensionaha.114.03461] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Angiotensin-II production in the subfornical organ acting through angiotensin-II type-1 receptors is necessary for polydipsia, resulting from elevated renin-angiotensin system activity. Protein kinase C and mitogen-activated protein kinase pathways have been shown to mediate effects of angiotensin-II in the brain. We investigated mechanisms that mediate brain angiotensin-II-induced polydipsia. We used double-transgenic sRA mice, consisting of human renin controlled by the neuron-specific synapsin promoter crossed with human angiotensinogen controlled by its endogenous promoter, which results in brain-specific overexpression of angiotensin-II, particularly in the subfornical organ. We also used the deoxycorticosterone acetate-salt model of hypertension, which exhibits polydipsia. Inhibition of protein kinase C, but not extracellular signal-regulated kinases, protein kinase A, or vasopressin V₁A and V₂ receptors, corrected the elevated water intake of sRA mice. Using an isoform selective inhibitor and an adenovirus expressing dominant negative protein kinase C-α revealed that protein kinase C-α in the subfornical organ was necessary to mediate elevated fluid and sodium intake in sRA mice. Inhibition of protein kinase C activity also attenuated polydipsia in the deoxycorticosterone acetate-salt model. We provide evidence that inducing protein kinase C activity centrally is sufficient to induce water intake in water-replete wild-type mice, and that cell surface localization of protein kinase C-α can be induced in cultured cells from the subfornical organ. These experimental findings demonstrate a role for central protein kinase C activity in fluid balance, and further mechanistically demonstrate the importance of protein kinase C-α signaling in the subfornical organ in fluid intake stimulated by angiotensin-II in the brain.
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Affiliation(s)
- Jeffrey P Coble
- From the Departments of Pharmacology (J.P.C., J.L.G., C.D.S.), Psychology (R.F.J., A.K.J.), and Anatomy and Cell Biology (M.D.C.), Roy J. and Lucille A. Carver College of Medicine, University of Iowa
| | - Ralph F Johnson
- From the Departments of Pharmacology (J.P.C., J.L.G., C.D.S.), Psychology (R.F.J., A.K.J.), and Anatomy and Cell Biology (M.D.C.), Roy J. and Lucille A. Carver College of Medicine, University of Iowa
| | - Martin D Cassell
- From the Departments of Pharmacology (J.P.C., J.L.G., C.D.S.), Psychology (R.F.J., A.K.J.), and Anatomy and Cell Biology (M.D.C.), Roy J. and Lucille A. Carver College of Medicine, University of Iowa
| | - Alan Kim Johnson
- From the Departments of Pharmacology (J.P.C., J.L.G., C.D.S.), Psychology (R.F.J., A.K.J.), and Anatomy and Cell Biology (M.D.C.), Roy J. and Lucille A. Carver College of Medicine, University of Iowa
| | - Justin L Grobe
- From the Departments of Pharmacology (J.P.C., J.L.G., C.D.S.), Psychology (R.F.J., A.K.J.), and Anatomy and Cell Biology (M.D.C.), Roy J. and Lucille A. Carver College of Medicine, University of Iowa
| | - Curt D Sigmund
- From the Departments of Pharmacology (J.P.C., J.L.G., C.D.S.), Psychology (R.F.J., A.K.J.), and Anatomy and Cell Biology (M.D.C.), Roy J. and Lucille A. Carver College of Medicine, University of Iowa.
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10
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Ahmed ASF, Dai L, Ho W, Ferguson AV, Sharkey KA. The subfornical organ: a novel site of action of cholecystokinin. Am J Physiol Regul Integr Comp Physiol 2014; 306:R363-73. [PMID: 24430886 DOI: 10.1152/ajpregu.00462.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The subfornical organ (SFO) is an important sensory circumventricular organ implicated in the regulation of fluid homeostasis and energy balance. We investigated whether the SFO is activated by the hormone cholecystokinin (CCK). CCK₁ and CCK₂ receptors were identified in the SFO by RT-PCR. Dissociated SFO neurons that responded to CCK (40/77), were mostly depolarized (9.2 ± 0.9 mV, 30/77), but some were hyperpolarized (-7.3 ± 1.1 mV, 10/77). We next examined the responses of SFO neurons in vivo to CCK (16 μg/kg ip), in the presence and absence of CCK₁ or CCK₂ receptor antagonists (devazepide; 600 μg/kg and L-365,260; 100 μg/kg, respectively), using the functional activation markers c-Fos and phosphorylated extracellular signal-related kinase (p-ERK). The nucleus of the solitary tract (NTS) served as a control for CCK-induced activity. There was a significant increase in c-Fos expression in the NTS (259.2 ± 20.8 neurons) compared with vehicle (47.5 ± 2.5). Similarly, in the SFO, c-Fos was expressed in 40.5 ± 10.6 neurons in CCK-treated compared with 6.6 ± 2.7 in vehicle-treated rats (P < 0.01). Devazepide significantly reduced the effects of CCK in the NTS but not in SFO. L-365,260 blocked the effects of CCK in both brain regions. CCK increased the number of p-ERK neurons in NTS (27.0 ± 4.0) as well as SFO (18.0 ± 4.0), compared with vehicle (8.0 ± 2.6 and 4.3 ± 0.6, respectively; P < 0.05). Both devazepide and L-365,260 reduced CCK-induced p-ERK in NTS, but only L-365,260 reduced it in the SFO. In conclusion, the SFO represents a novel brain region at which circulating CCK may act via CCK₂ receptors to influence central autonomic control.
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Affiliation(s)
- Al-Shaimaa F Ahmed
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada; and
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11
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The lateral neostriatum is necessary for compensatory ingestive behaviour after intravascular dehydration in female rats. Appetite 2013; 71:287-94. [DOI: 10.1016/j.appet.2013.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 09/05/2013] [Accepted: 09/06/2013] [Indexed: 01/03/2023]
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12
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Involvement of brain ANG II in acute sodium depletion induced salty taste changes. ACTA ACUST UNITED AC 2012; 179:15-22. [PMID: 22846885 DOI: 10.1016/j.regpep.2012.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 10/09/2011] [Accepted: 07/20/2012] [Indexed: 02/07/2023]
Abstract
Many investigations have been devoted to determining the role of angiotensin II (ANG II) and aldosterone (ALD) in sodium-depletion-induced sodium appetite, but few were focused on the mechanisms mediating the salty taste changes accompanied with sodium depletion. To further elucidate the mechanism of renin-angiotensin-aldosterone system (RAAS) action in mediating sodium intake behavior and accompanied salty taste changes, the present study examined the salty taste function changes accompanied with sodium depletion induced by furosemide (Furo) combined with different doses of angiotensin converting enzyme (ACE) inhibitor, captopril (Cap). Both the peripheral and central RAAS activity and the nuclei Fos immunoreactivity (Fos-ir) expression in the forebrain area were investigated. Results showed that sodium depletion induced by Furo+low-Cap increased taste preference for hypertonic NaCl solution with amplified brain action of ANG II but without peripheral action, while Furosemide combined with a high dose of captopril can partially inhibit the formation of brain ANG II, with parallel decreased effects on salty taste changes. And the resulting elevating forebrain ANG II may activate a variety of brain areas including SFO, PVN, SON and OVLT in sodium depleted rats injected with Furo+low-Cap, which underlines salty taste function and sodium intake behavioral changes. Neurons in SFO and OVLT may be activated mainly by brain ANG II, while PVN and SON activation may not be completely ANG II dependent. These findings suggested that forebrain derived ANG II may play a critical role in the salty taste function changes accompanied with acute sodium depletion.
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McKinley MJ, Walker LL, Alexiou T, Allen AM, Campbell DJ, Di Nicolantonio R, Oldfield BJ, Denton DA. Osmoregulatory fluid intake but not hypovolemic thirst is intact in mice lacking angiotensin. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1533-43. [DOI: 10.1152/ajpregu.00848.2007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Water intakes in response to hypertonic, hypovolemic, and dehydrational stimuli were investigated in mice lacking angiotensin II as a result of deletion of the angiotensinogen gene (Agt−/− mice), and in C57BL6 wild-type (WT) mice. Baseline daily water intake in Agt−/− mice was approximately threefold that of WT mice because of a renal developmental disorder of the urinary concentrating mechanisms in Agt−/− mice. Intraperitoneal injection of hypertonic saline (0.4 and 0.8 mol/l NaCl) caused a similar dose-dependent increase in water intake in both Agt−/− and WT mice during the hour following injection. As well, Agt−/− mice drank appropriate volumes of water following water deprivation for 7 h. However, Agt−/− mice did not increase water or 0.3 mol/l NaCl intake in the 8 h following administration of a hypovolemic stimulus (30% polyethylene glycol sc), whereas WT mice increased intakes of both solutions during this time. Osmoregulatory regions of the brain [hypothalamic paraventricular and supraoptic nuclei, median preoptic nucleus, organum vasculosum of the lamina terminalis (OVLT), and subfornical organ] showed an increased number of neurons exhibiting Fos-immunoreactivity in response to intraperitoneal hypertonic NaCl in both Agt−/− mice and WT mice. Polyethylene glycol treatment increased Fos-immunoreactivity in the subfornical organ, OVLT, and supraoptic nuclei in WT mice but only increased Fos-immunoreactivity in the supraoptic nucleus in Agt−/− mice. These data show that brain angiotensin is not essential for the adequate functioning of neural pathways mediating osmoregulatory thirst. However, angiotensin II of either peripheral or central origin is probably necessary for thirst and salt appetite that results from hypovolemia.
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Crews EC, Rowland NE. Role of angiotensin in body fluid homeostasis of mice: effect of losartan on water and NaCl intakes. Am J Physiol Regul Integr Comp Physiol 2004; 288:R638-44. [PMID: 15528393 DOI: 10.1152/ajpregu.00525.2004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is known that mice injected peripherally with ANG II do not show a drinking response but that cFos immunoreactivity (ir) is induced in brain regions similar to those in rats. We now show in Crl:CD1(ICR) mice that peripheral injection of the ANG II type 1 receptor antagonist losartan was sufficient to prevent this induction of Fos-ir in the subfornical organ (SFO). Injection of ANG II into the lateral cerebral ventricle produced a robust water intake in mice and induced Fos-ir in SFO, as well as in median preoptic (MnPO) and paraventricular (PVN) nuclei. Peripheral injection of losartan blocked this drinking response and prevented the induction of Fos-ir in each of these brain regions. Hypovolemia produced by polyethylene glycol (PEG) produced a robust water intake but no evidence of sodium appetite, and it induced Fos-ir in SFO, MnPO, and PVN. Peripheral injection of losartan did not affect this drinking response. Fos-ir induced by PEG in SFO and MnPO was reduced by treatment with losartan, while that induced in the PVN was further increased by losartan. Sodium depletion with furosemide and low-sodium diet produced a strong sodium appetite and induced Fos-ir in SFO and MnPO. Treatment with losartan completely blocked the sodium appetite, as well as the induction of Fos-ir in these brain regions. These data indicate that endogenous production of ANG II and action at forebrain receptors is critically involved in depletion-related sodium appetite in mice. The absence of an effect of losartan on PEG-induced drinking suggests the critical involvement of other factor(s) such as arterial or venous baroreceptor input, and we discuss how this factor could also explain why peripheral ANG II is not dipsogenic in mice.
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Affiliation(s)
- Emily C Crews
- Department of Psychology, University of Florida, P.O. Box 112250, Gainesville, FL 32611-2250, USA
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Abstract
This paper reviews the experiments, which demonstrate conclusively the involvement of the abdominal vagus nerve in normal expression of most aspects of thirst in rats, by Gerard P. Smith and his colleagues published between 1975 and 1984. The nature of that vagal contribution differs with the type of primary thirst signal. Thus, there is no clear or unitary answer concerning whether the contribution of the vagus nerve is purely sensory, or some general tonic action within the central nervous system. Subsequent studies using cFos mapping of intracellular dehydration in conjunction with vagotomy and/or hepatic manipulations are also reviewed and further illustrate the involvement of abdominal information, both in the initiation as well as the termination of drinking. Many of the questions that were raised by Smith during these pioneering studies remain unaddressed and unanswered.
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Affiliation(s)
- Neil E Rowland
- Department of Psychology, University of Florida, P.O. Box 112250, UF, Gainesville, FL 32611-2250, USA.
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Rowland NE, Farnbauch LJ, Crews EC. Sodium deficiency and salt appetite in ICR: CD1 mice. Physiol Behav 2004; 80:629-35. [PMID: 14984796 DOI: 10.1016/j.physbeh.2003.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2003] [Revised: 09/29/2003] [Accepted: 11/07/2003] [Indexed: 11/24/2022]
Abstract
Using an outbred strain of mouse, we examined several characteristics of sodium appetite induced by depletion. We found that an appetite for 0.15 M NaCl solution was stimulated 24 h after injection of furosemide and access to a low-sodium diet, but not by low-sodium diet alone. When the duration of exposure to low-sodium diet was increased from 1 to 7 days, there was no additional effect on either the appetite or the blood plasma changes including elevated hematocrit ratio, protein and aldosterone concentrations, and plasma renin activity (PRA). Mice also showed an appetite for hypertonic (0.5 M) NaCl in solutions or in a gel matrix; the intakes of these two were comparable but the gel measurement was gravimetric so maybe more accurate. In the same study, we showed that single injections of either 10 or 40 mg/kg furosemide followed by a 24-h low-sodium diet produced similar appetites, but that 2.5 mg/kg had a submaximal effect. Lastly, we further validated the use of the gel matrix by showing in chronically depleted mice that intake was inversely related to NaCl concentration in the range 0.5-1.5 M, and that appetite was selective for sodium but not the anion with which it was paired.
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Affiliation(s)
- Neil E Rowland
- Department of Psychology, University of Florida, PO Box 112250, Gainesville, FL 32611-2250, USA.
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Skøtt O. Angiotensin II and control of sodium and water intake in the mouse. Am J Physiol Regul Integr Comp Physiol 2003; 284:R1380-1. [PMID: 12736173 DOI: 10.1152/ajpregu.00106.2003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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