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Matuska R, Zelena D, Könczöl K, Papp RS, Durst M, Guba D, Török B, Varnai P, Tóth ZE. Colocalized neurotransmitters in the hindbrain cooperate in adaptation to chronic hypernatremia. Brain Struct Funct 2020; 225:969-984. [PMID: 32200401 PMCID: PMC7166202 DOI: 10.1007/s00429-020-02049-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 02/13/2020] [Indexed: 11/29/2022]
Abstract
Chronic hypernatremia activates the central osmoregulatory mechanisms and inhibits the function of the hypothalamic-pituitary-adrenal (HPA) axis. Noradrenaline (NE) release into the periventricular anteroventral third ventricle region (AV3V), the supraoptic (SON) and hypothalamic paraventricular nuclei (PVN) from efferents of the caudal ventrolateral (cVLM) and dorsomedial (cDMM) medulla has been shown to be essential for the hypernatremia-evoked responses and for the HPA response to acute restraint. Notably, the medullary NE cell groups highly coexpress prolactin-releasing peptide (PrRP) and nesfatin-1/NUCB2 (nesfatin), therefore, we assumed they contributed to the reactions to chronic hypernatremia. To investigate this, we compared two models: homozygous Brattleboro rats with hereditary diabetes insipidus (DI) and Wistar rats subjected to chronic high salt solution (HS) intake. HS rats had higher plasma osmolality than DI rats. PrRP and nesfatin mRNA levels were higher in both models, in both medullary regions compared to controls. Elevated basal tyrosine hydroxylase (TH) expression and impaired restraint-induced TH, PrRP and nesfatin expression elevations in the cVLM were, however, detected only in HS, but not in DI rats. Simultaneously, only HS rats exhibited classical signs of chronic stress and severely blunted hormonal reactions to acute restraint. Data suggest that HPA axis responsiveness to restraint depends on the type of hypernatremia, and on NE capacity in the cVLM. Additionally, NE and PrRP signalization primarily of medullary origin is increased in the SON, PVN and AV3V in HS rats. This suggests a cooperative action in the adaptation responses and designates the AV3V as a new site for PrRP's action in hypernatremia.
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Affiliation(s)
- Rita Matuska
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Dóra Zelena
- Behavioral Neurobiology, Institute of Experimental Medicine, Budapest, Hungary
- Centre for Neuroscience, Szentágothai Research Centre, Institute of Physiology, Medical School, University of Pécs, Pécs, Hungary
| | - Katalin Könczöl
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Rege Sugárka Papp
- Human Brain Tissue Bank and Microdissection Laboratory, Semmelweis University, Budapest, Hungary
| | - Máté Durst
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Dorina Guba
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Bibiana Török
- Behavioral Neurobiology, Institute of Experimental Medicine, Budapest, Hungary
- Janos Szentagothai School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Peter Varnai
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Zsuzsanna E Tóth
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary.
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2
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Schnider P, Bissantz C, Bruns A, Dolente C, Goetschi E, Jakob-Roetne R, Künnecke B, Mueggler T, Muster W, Parrott N, Pinard E, Ratni H, Risterucci C, Rogers-Evans M, von Kienlin M, Grundschober C. Discovery of Balovaptan, a Vasopressin 1a Receptor Antagonist for the Treatment of Autism Spectrum Disorder. J Med Chem 2020; 63:1511-1525. [PMID: 31951127 DOI: 10.1021/acs.jmedchem.9b01478] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We recently reported the discovery of a potent, selective, and brain-penetrant V1a receptor antagonist, which was not suitable for full development. Nevertheless, this compound was found to improve surrogates of social behavior in adults with autism spectrum disorder in an exploratory proof-of-mechanism study. Here we describe scaffold hopping that gave rise to triazolobenzodiazepines with improved pharmacokinetic properties. The key to balancing potency and selectivity while minimizing P-gp mediated efflux was fine-tuning of hydrogen bond acceptor basicity. Ascertaining a V1a antagonist specific brain activity pattern by pharmacological magnetic resonance imaging in the rat played a seminal role in guiding optimization efforts, culminating in the discovery of balovaptan (RG7314, RO5285119) 1. In a 12-week clinical phase 2 study in adults with autism spectrum disorder balovaptan demonstrated improvements in Vineland-II Adaptive Behavior Scales, a secondary end point comprising communication, socialization, and daily living skills. Balovaptan entered phase 3 clinical development in August 2018.
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Affiliation(s)
- Patrick Schnider
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Caterina Bissantz
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Andreas Bruns
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Cosimo Dolente
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Erwin Goetschi
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Roland Jakob-Roetne
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Basil Künnecke
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Thomas Mueggler
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Wolfgang Muster
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Neil Parrott
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Emmanuel Pinard
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Hasane Ratni
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Céline Risterucci
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Mark Rogers-Evans
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Markus von Kienlin
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
| | - Christophe Grundschober
- Pharmaceutical Research and Early Development, Roche Innovation Center Basel , F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124 , 4070 Basel , Switzerland
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3
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Gonzalez AA, Salinas-Parra N, Cifuentes-Araneda F, Reyes-Martinez C. Vasopressin actions in the kidney renin angiotensin system and its role in hypertension and renal disease. VITAMINS AND HORMONES 2019; 113:217-238. [PMID: 32138949 DOI: 10.1016/bs.vh.2019.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Vasopressin, also named antidiuretic hormone (ADH), arginine vasopressin (AVP) is the main hormone responsible for water maintenance in the body through the antidiuretic actions in the kidney. The posterior pituitary into the blood releases vasopressin formed in the hypothalamus. Hypothalamic osmotic neurons are responsible to initiate the cascade for AVP actions. The effects of AVP peptide includes activation of V2 receptors which stimulate the formation of cyclic AMP (cAMP) and phosphorylation of water channels aquaporin 2 (AQP2) in the collecting duct. AVP also has vasoconstrictor effects through V1a receptors in the vasculature, while V1b is found in the nervous system. V1a and b receptors increases intracellular Ca2+ while activation of V2 receptors of signaling pathways are related to cAMP-dependent phosphorylation in kidney collecting ducts acting in coordination to stimulate water and electrolyte homeostasis. AVP potentiate formation of intratubular angiotensin II (Ang II) through V2 receptors-dependent distal tubular renin formation, contributing to Na+ reabsorption. On the same way, Ang II receptors are able to potentiate the effects of V2-dependent stimulation of AQP2 abundance in the plasma membrane. The role of AVP in hypertension and renal disease has been demonstrated in pathological states with the involvement of V2 receptors in the progression of kidney damage in diabetes and also on the stimulation of intracellular pathways linked to the development of polycystic kidney.
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Affiliation(s)
- Alexis A Gonzalez
- Instituto de Química Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
| | - Nicolas Salinas-Parra
- Instituto de Química Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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Skowronska A, Tanski D, Jaskiewicz L, Skowronski MT. Modulation by steroid hormones and other factors on the expression of aquaporin-1 and aquaporin-5. VITAMINS AND HORMONES 2019; 112:209-242. [PMID: 32061342 DOI: 10.1016/bs.vh.2019.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- A Skowronska
- Department of Human Physiology, School of Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland.
| | - D Tanski
- Department of Anatomy and Animal Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - L Jaskiewicz
- Department of Human Physiology, School of Medicine, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - M T Skowronski
- Veterinary Center, University of Nicolaus Copernicus, Torun, Poland
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5
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Johnson RJ, Stenvinkel P, Jensen T, Lanaspa MA, Roncal C, Song Z, Bankir L, Sánchez-Lozada LG. Metabolic and Kidney Diseases in the Setting of Climate Change, Water Shortage, and Survival Factors. J Am Soc Nephrol 2016; 27:2247-56. [PMID: 27283495 PMCID: PMC4978060 DOI: 10.1681/asn.2015121314] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Climate change (global warming) is leading to an increase in heat extremes and coupled with increasing water shortage, provides a perfect storm for a new era of environmental crises and potentially, new diseases. We use a comparative physiologic approach to show that one of the primary mechanisms by which animals protect themselves against water shortage is to increase fat mass as a means for providing metabolic water. Strong evidence suggests that certain hormones (vasopressin), foods (fructose), and metabolic products (uric acid) function as survival signals to help reduce water loss and store fat (which also provides a source of metabolic water). These mechanisms are intricately linked with each other and stimulated by dehydration and hyperosmolarity. Although these mechanisms were protective in the setting of low sugar and low salt intake in our past, today, the combination of diets high in fructose and salty foods, increasing temperatures, and decreasing available water places these survival signals in overdrive and may be accelerating the obesity and diabetes epidemics. The recent discovery of multiple epidemics of CKD occurring in agricultural workers in hot and humid environments may represent harbingers of the detrimental consequences of the combination of climate change and overactivation of survival pathways.
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Affiliation(s)
- Richard J Johnson
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado;
| | - Peter Stenvinkel
- Division of Renal Medicine, Department of Clinical Science Intervention and Technology, Karolinska University Hospital, Stockholm, Sweden
| | - Thomas Jensen
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado
| | - Miguel A Lanaspa
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado
| | - Carlos Roncal
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado
| | - Zhilin Song
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado
| | - Lise Bankir
- Institut National de las Santé et de la Recherche Medicalé UMRS 1138, Centre de Recherche des Cordeliers, Paris, France; and
| | - Laura G Sánchez-Lozada
- Laboratory of Renal Physiopathology, Instituto Nacional de Cardiologia Ignacio Chávez, Mexico City, Mexico
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Bernal A, Mahía J, Puerto A. Animal models of Central Diabetes Insipidus: Human relevance of acquired beyond hereditary syndromes and the role of oxytocin. Neurosci Biobehav Rev 2016; 66:1-14. [DOI: 10.1016/j.neubiorev.2016.02.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 02/23/2016] [Accepted: 02/27/2016] [Indexed: 12/18/2022]
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Opposite effects of oxytocin on water intake induced by hypertonic NaCl or polyethylene glycol administration. Physiol Behav 2015; 141:135-42. [PMID: 25617595 DOI: 10.1016/j.physbeh.2015.01.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 12/20/2014] [Accepted: 01/20/2015] [Indexed: 11/21/2022]
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8
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Differential lasting inhibitory effects of oxytocin and food-deprivation on mediobasal hypothalamic polydipsia. Brain Res Bull 2013; 94:40-8. [DOI: 10.1016/j.brainresbull.2013.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 01/30/2013] [Accepted: 02/13/2013] [Indexed: 11/19/2022]
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9
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Park SJ, Kim JH, Shin JI. Insight on mechanism of hyponatraemia induced by low-dose intravenous pulse cyclophosphamide. Nephrol Dial Transplant 2010; 25:3453; author reply 3453-4. [PMID: 20650905 DOI: 10.1093/ndt/gfq429] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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10
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Abstract
There are several mysteries about the normal physiology of pregnancy (1). Renal sodium and water reabsorption occurs despite an increase in total blood volume. Moreover, the renin-angiotensin-aldosterone system (RAAS) is also stimulated in normal pregnancy, even though an increase in total blood volume normally suppresses the RAAS and increases sodium excretion in the nonpregnant state. Water retention also occurs and leads to hypoosmolality in normal pregnancy, even though total blood volume is expanded. On rare occasions, an extreme polyuria occurs in pregnancy that is unresponsive to arginine vasopressin (AVP). The receptors whereby AVP and oxytocin stimulate the principal cell of the collecting duct, vascular smooth muscle, glomerular mesangial and endometrial cells are in need of clarification. The present study proposes potential mechanisms relating to systemic arterial vasodilation to explain some of the apparent dilemmas of pregnancy.
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Affiliation(s)
- R W Schrier
- University of Colorado Denver, Aurora, CO 80045, USA.
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11
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Callewaere C, Fernette B, Raison D, Mechighel P, Burlet A, Calas A, Kitabgi P, Parsadaniantz SM, Rostène W. Cellular and subcellular evidence for neuronal interaction between the chemokine stromal cell-derived factor-1/CXCL 12 and vasopressin: regulation in the hypothalamo-neurohypophysial system of the Brattleboro rats. Endocrinology 2008; 149:310-9. [PMID: 17901225 PMCID: PMC2194606 DOI: 10.1210/en.2007-1097] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We previously described a colocalization between arginine vasopressin (AVP) and the chemokine stromal cell-derived factor-1alpha (SDF-1) in the magnocellular neurons of both the hypothalamic supraoptic and paraventricular nucleus as well as the posterior pituitary. SDF-1 physiologically affects the electrophysiological properties of AVP neurons and consequently AVP release. In the present study, we confirm by confocal and electron microscopy that AVP and SDF-1 have a similar cellular distribution inside the neuronal cell and can be found in dense core vesicles in the nerve terminals in the posterior pituitary. Because the Brattleboro rats represent a good model of AVP deficiency, we tested in these animals the fate of SDF-1 and its receptor CXCR4. We identified by immunohistochemistry that both SDF-1 and CXCR4 immunoreactivity were strongly decreased in Brattleboro rats and were strictly correlated with the expression of AVP protein in supraoptic nucleus, paraventricular nucleus, and the posterior pituitary. We observed by real-time PCR an increase in SDF-1 mRNA in both heterozygous and homozygous rats. The effect on the SDF-1/CXCR4 system was not linked to peripheral modifications of kidney water balance because it could not be restored by chronic infusion of deamino-8D-ariginine-vasopressin, an AVP V2-receptor agonist. These original data further suggest that SDF-1 may play an essential role in the regulation of water balance.
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Affiliation(s)
- Céline Callewaere
- Institut National de la Santé et de la Recherche Médicale Unité 732, Université Pierre et Marie Curie, Hôpital Saint-Antoine, 75571 Paris Cedex 12, France
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12
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Li C, Wang W, Summer SN, Westfall TD, Brooks DP, Falk S, Schrier RW. Molecular mechanisms of antidiuretic effect of oxytocin. J Am Soc Nephrol 2007; 19:225-32. [PMID: 18057218 DOI: 10.1681/asn.2007010029] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Oxytocin is known to have an antidiuretic effect, but the mechanisms underlying this effect are not completely understood. We infused oxytocin by osmotic minipump into vasopressin-deficient Brattleboro rats for five days and observed marked antidiuresis, increased urine osmolality, and increased solute-free water reabsorption. Administration of oxytocin also significantly increased the protein levels of aquaporin-2 (AQP2), phosphorylated AQP2 (p-AQP2), and AQP3 in the inner medulla and in the outer medulla plus cortex. Immunohistochemistry demonstrated increased AQP2 and p-AQP2 expression and trafficking to the apical plasma membrane of principal cells in the collecting duct, and increased AQP3 expression in the basolateral membrane. These oxytocin-induced effects were blocked by treatment with the vasopressin V2 receptor antagonist SR121463B, but not by treatment with the oxytocin receptor antagonist GW796679X. We conclude that vasopressin V2 receptors mediate the antidiuretic effects of oxytocin, including increased expression and apical trafficking of AQP2, p-AQP2, and increased AQP3 protein expression.
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Affiliation(s)
- Chunling Li
- Department of Medicine, University of Colorado School of Medicine, Denver, Colorado, USA
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Joo KW, Jeon US, Kim GH, Park J, Oh YK, Kim YS, Ahn C, Kim S, Kim SY, Lee JS, Han JS. Antidiuretic action of oxytocin is associated with increased urinary excretion of aquaporin-2. Nephrol Dial Transplant 2004; 19:2480-6. [PMID: 15280526 DOI: 10.1093/ndt/gfh413] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The antidiuretic effect of oxytocin in humans is controversial. Urinary excretion of aquaporin-2 (AQP2) can be used as an index of the action of vasopressin on the kidney. We investigated whether exogenous oxytocin affects urinary concentration and urinary AQP2 excretion in human beings. METHODS Oxytocin was administered intravenously at a rate of 20 mU/min in 10 healthy volunteers, seven patients with central diabetes insipidus (CDI) and three patients with nephrogenic diabetes insipidus (NDI). On the next day, 2 micro g of 1-desamino-8-d-arginine vasopressin (dDAVP) was injected subcutaneously. Two-hour urine was collected before and after the administration of oxytocin and dDAVP, and urinary AQP2 was measured semi-quantitatively by western analysis. RESULTS Urine volume and free water clearance were decreased, and urine osmolality was increased by the administration of oxytocin or dDAVP in the normal volunteers and CDI patients. Urinary AQP2 excretion was increased by oxytocin infusion in the normal volunteers (from 34+/-12 to 326+/-120 densitometry unit (DU)/2 h) and in the CDI group (from 8+/-2 to 227+/-92 DU/2 h) (P<0.05), but not in the NDI group. dDAVP also had a similar but more potent effect on the urinary excretion of AQP2 in the normal and CDI groups. CONCLUSIONS Oxytocin has an antidiuretic effect and increases the urinary excretion of AQP2 in humans whose urinary concentration mechanism is preserved. These results suggest that AQP2 might have a regulatory role in the antidiuretic action of oxytocin in humans.
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Affiliation(s)
- Kwon Wook Joo
- Department of Internal Medicine, Seoul National University, Clinical Research Institute of Seoul National University Hospital, 28, Yongun-dong, Chongno-gu, Seoul 110-744, South Korea
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Klein JD, Gunn RB, Roberts BR, Sands JM. Down-regulation of urea transporters in the renal inner medulla of lithium-fed rats. Kidney Int 2002; 61:995-1002. [PMID: 11849454 DOI: 10.1046/j.1523-1755.2002.00210.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Lithium is commonly used to treat bipolar psychiatric disorders but can cause reduced urine concentrating ability. METHODS To test whether lithium alters UT-A1 or UT-B urea transporter protein abundance or UT-A1 phosphorylation, rats were fed a standard diet supplemented with LiCl for 10 or 25 days, and then compared to pair-fed control rats. To investigate another potential mechanism for decreased urea transport, inner medullary collecting duct (IMCD) suspensions from lithium-fed or control rats were incubated with 32P-orthophosphate to measure the phosphorylation of UT-A1. RESULTS In lithium-fed rats (25 days), UT-A1 abundance was reduced to 50% of control rats in IM tip and to 25% in IM base, and UT-B abundance was reduced to 40% in IM base. Aquaporin-2 (AQP2) protein abundance was reduced in both IM regions. Vasopressin (100 pmol/L) increased UT-A1 phosphorylation in IMCD suspensions from control but not from lithium-fed rats; a higher vasopressin concentration (100 nmol/L) increased UT-A1 phosphorylation in control and lithium-fed rats. CONCLUSIONS Decreases in UT-A1, UT-B, and AQP2 protein abundance, and/or vasopressin-stimulated phosphorylation of UT-A1, can contribute to the reduced urine concentrating ability that occurs in lithium-treated rats.
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Affiliation(s)
- Janet D Klein
- Renal Division, Department of Medicine, Emory University School of Medicine, 1639 Pierce Drive, Atlanta, GA, USA
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15
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Serradeil-Le Gal C. An overview of SR121463, a selective non-peptide vasopressin V(2) receptor antagonist. CARDIOVASCULAR DRUG REVIEWS 2002; 19:201-14. [PMID: 11607038 DOI: 10.1111/j.1527-3466.2001.tb00065.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
SR121463 is a selective, orally active, non-peptide antagonist of vasopressin (AVP) V(2) receptors with powerful aquaretic properties in various animal species and humans. SR121463 belongs to a new class of drugs, called aquaretics, which are capable of inducing free-water excretion without affecting electrolyte balance. SR121463 displays high affinity for animal and human V(2) receptors and exhibits a remarkably selective V(2) receptor profile. SR121463 and [(3)H]SR121463 are used, therefore, as selective probes for characterization and labeling of V(2) receptors. In various functional studies in vitro, SR121463 behaves as a potent antagonist. It inhibits AVP-stimulated human renal adenylyl cyclase and dDAVP (1-desamino, 8-D arginine-vasopressin)-induced relaxation of rat aorta. SR121463 also behaves as an inverse agonist in cells expressing a constitutively activated human V(2) receptor mutant. In vitro, SR121463 rescued misfolded V(2) AVP receptor mutants by increasing cell surface expression and restoring V(2) function. In normally hydrated conscious rats, dogs and monkeys, SR121463, by either i.v. or p.o. administration, induced a dose-dependent aquaresis with no major changes in urinary Na+ and K+ excretion (unlike classical diuretics). In cirrhotic rats with ascites and impaired renal function, a 10-day treatment with SR121463 totally corrected hyponatremia and restored normal urine excretion. In a model of diabetic nephropathy in rats, SR121463 strongly reduced albumin excretion. SR121463 was also effective at extrarenal V(2) (or V(2)-like) receptors involved in vascular relaxation or clotting factor release in vitro and in vivo. In the rabbit model of ocular hypertension, SR121463 by either single or repeated instillation, decreased intraocular pressure. After acute and chronic administration to rats, dogs or healthy human volunteers, SR121463 was well absorbed and well tolerated. In all species studied the drug produced pronounced aquaresis without any agonist effect. Thus, SR121463 is a potent, orally active and selective antagonist at V(2) receptors with powerful aquaretic properties. It is a useful tool for further exploration of function of renal or extrarenal V(2) receptors. Pure V(2) receptor antagonists are likely to be therapeutically useful in several water-retaining diseases such as hyponatremia, Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH), congestive heart failure, liver cirrhosis, and other disorders possibly mediated by V(2) receptors (e.g., glaucoma).
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Affiliation(s)
- C Serradeil-Le Gal
- Sanofi-Synthélabo Recherche, Exploratory Research Department, 195 route d'Espagne, 31036 Toulouse Cedex, France.
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16
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Nicco C, Wittner M, DiStefano A, Jounier S, Bankir L, Bouby N. Chronic exposure to vasopressin upregulates ENaC and sodium transport in the rat renal collecting duct and lung. Hypertension 2001; 38:1143-9. [PMID: 11711512 DOI: 10.1161/hy1001.092641] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vasopressin is known to acutely stimulate sodium transport in the renal collecting duct. We investigated the long-term regulation by vasopressin of the epithelial sodium channel (ENaC) in the rat kidney. Five-day infusion of dDAVP (a V(2) receptor agonist) to Brattleboro rats lacking vasopressin induced a marked increase in beta- and gamma-subunit ENaC mRNA levels in the renal cortex (beta, 85%; gamma, 100%), with no change in alpha-ENaC mRNA. Expression of beta- and gamma-ENaC mRNAs was also enhanced in lung (beta, 49%; gamma, 33%) but not in distal colon (an organ devoid of V(2) receptors). Similar results were obtained in Sprague Dawley rats after either partial water restriction or dDAVP infusion for 5 days. Transepithelial voltage and transepithelial sodium and water net fluxes were measured in isolated perfused cortical collecting ducts of Brattleboro rats. Acute addition of 2x10(-10) mol/L dDAVP to the bath increased sodium and water fluxes in the same proportion, and to a far greater extent in dDAVP-infused than in control Brattleboro rats (change in Na(+) net flux, 337+/-30 versus 49+/-11 pmol. min(-1). mm(-1), respectively; P<0.001). These effects were abolished by amiloride. Extrarenal water losses, partly originating from the lung, were reduced by high plasma vasopressin level. This study shows that vasopressin increases sodium transport in the renal collecting duct and probably in the lung, through a differential transcriptional regulation of ENaC subunits. This effect is followed by isoosmotic water reabsorption and likely contributes to the process of water conservation. It could lead to less efficient sodium excretion, however, and thus participate in some forms of salt-sensitive hypertension.
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Affiliation(s)
- C Nicco
- INSERM Unité 367, Institut du Fer à Moulin, Paris, France
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