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Yang J, Villar VAM, Jose PA, Zeng C. Renal Dopamine Receptors and Oxidative Stress: Role in Hypertension. Antioxid Redox Signal 2021; 34:716-735. [PMID: 32349533 PMCID: PMC7910420 DOI: 10.1089/ars.2020.8106] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Significance: The kidney plays an important role in the long-term control of blood pressure. Oxidative stress is one of the fundamental mechanisms responsible for the development of hypertension. Dopamine, via five subtypes of receptors, plays an important role in the control of blood pressure by various mechanisms, including the inhibition of oxidative stress. Recent Advances: Dopamine receptors exert their regulatory function to decrease the oxidative stress in the kidney and ultimately maintain normal sodium balance and blood pressure homeostasis. An aberration of this regulation may be involved in the pathogenesis of hypertension. Critical Issues: Our present article reviews the important role of oxidative stress and intrarenal dopaminergic system in the regulation of blood pressure, summarizes the current knowledge on renal dopamine receptor-mediated antioxidation, including decreasing reactive oxygen species production, inhibiting pro-oxidant enzyme nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase, and stimulating antioxidative enzymes, and also discusses its underlying mechanisms, including the increased activity of G protein-coupled receptor kinase 4 (GRK4) and abnormal trafficking of renal dopamine receptors in hypertensive status. Future Directions: Identifying the mechanisms of renal dopamine receptors in the regulation of oxidative stress and their contribution to the pathogenesis of hypertension remains an important research focus. Increased understanding of the role of reciprocal regulation between renal dopamine receptors and oxidative stress in the regulation of blood pressure may give us novel insights into the pathogenesis of hypertension and provide a new treatment strategy for hypertension.
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Affiliation(s)
- Jian Yang
- Department of Clinical Nutrition, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Van Anthony M Villar
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Pedro A Jose
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Chunyu Zeng
- Department of Cardiology, Fujian Heart Medical Center, Fujian Medical University Union Hospital, Fuzhou, People's Republic of China.,Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China
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2
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Dopamine Receptors and the Kidney: An Overview of Health- and Pharmacological-Targeted Implications. Biomolecules 2021; 11:biom11020254. [PMID: 33578816 PMCID: PMC7916607 DOI: 10.3390/biom11020254] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 02/05/2021] [Accepted: 02/06/2021] [Indexed: 12/21/2022] Open
Abstract
The dopaminergic system can adapt to the different physiological or pathological situations to which the kidneys are subjected throughout life, maintaining homeostasis of natriuresis, extracellular volume, and blood pressure levels. The role of renal dopamine receptor dysfunction is clearly established in the pathogenesis of essential hypertension. Its associations with other pathological states such as insulin resistance and redox balance have also been associated with dysfunction of the dopaminergic system. The different dopamine receptors (D1-D5) show a protective effect against hypertension and kidney disorders. It is essential to take into account the various interactions of the dopaminergic system with other elements, such as adrenergic receptors. The approach to therapeutic strategies for essential hypertension must go through the blocking of those elements that lead to renal vasoconstriction or the restoration of the normal functioning of dopamine receptors. D1-like receptors are fundamental in this role, and new therapeutic efforts should be directed to the restoration of their functioning in many patients. More studies will be needed to allow the development of drugs that can be targeted to renal dopamine receptors in the treatment of hypertension.
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3
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The Role of the Renal Dopaminergic System and Oxidative Stress in the Pathogenesis of Hypertension. Biomedicines 2021; 9:biomedicines9020139. [PMID: 33535566 PMCID: PMC7912729 DOI: 10.3390/biomedicines9020139] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/26/2021] [Accepted: 01/28/2021] [Indexed: 01/11/2023] Open
Abstract
The kidney is critical in the long-term regulation of blood pressure. Oxidative stress is one of the many factors that is accountable for the development of hypertension. The five dopamine receptor subtypes (D1R–D5R) have important roles in the regulation of blood pressure through several mechanisms, such as inhibition of oxidative stress. Dopamine receptors, including those expressed in the kidney, reduce oxidative stress by inhibiting the expression or action of receptors that increase oxidative stress. In addition, dopamine receptors stimulate the expression or action of receptors that decrease oxidative stress. This article examines the importance and relationship between the renal dopaminergic system and oxidative stress in the regulation of renal sodium handling and blood pressure. It discusses the current information on renal dopamine receptor-mediated antioxidative network, which includes the production of reactive oxygen species and abnormalities of renal dopamine receptors. Recognizing the mechanisms by which renal dopamine receptors regulate oxidative stress and their degree of influence on the pathogenesis of hypertension would further advance the understanding of the pathophysiology of hypertension.
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4
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Asmar A, Cramon PK, Asmar M, Simonsen L, Sorensen CM, Madsbad S, Moro C, Hartmann B, Rehfeld JF, Holst JJ, Hovind P, Jensen BL, Bülow J. Increased oral sodium chloride intake in humans amplifies selectively postprandial GLP-1 but not GIP, CCK, and gastrin in plasma. Physiol Rep 2020; 8:e14519. [PMID: 32770661 PMCID: PMC7413881 DOI: 10.14814/phy2.14519] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/03/2020] [Accepted: 07/03/2020] [Indexed: 12/24/2022] Open
Abstract
Human studies have demonstrated that physiologically relevant changes in circulating glucagon-like peptide-1 (GLP-1) elicit a rapid increase in renal sodium excretion when combined with expansion of the extracellular fluid volume. Other studies support the involvement of various gastrointestinal hormones, e.g., gastrin and cholecystokinin (CCK) in a gut-kidney axis, responsible for a rapid-acting feed-forward natriuretic mechanism. This study was designed to investigate the hypothesis that the postprandial GLP-1 plasma concentration is sensitive to the sodium content in the meal. Under fixed sodium intake for 4 days prior to each experimental day, 10 lean healthy male participants were examined twice in random order after a 12-hr fasting period. Arterial blood samples were collected at 10-20-min intervals for 140 min after 75 grams of oral glucose + 6 grams of oral sodium chloride (NaCl) load versus 75 grams of glucose alone. Twenty-four-hour baseline urinary sodium excretions were similar between study days. Arterial GLP-1 levels increased during both oral glucose loads and were significantly higher at the 40-80 min period during glucose + NaCl compared to glucose alone. The postprandial arterial responses of CCK, gastrin, and glucose-dependent insulinotropic polypeptide as well as glucose, insulin, and C-peptide did not differ between the two study days. Arterial renin, aldosterone, and natriuretic peptides levels did not change within subjects or between study days. Angiotensin II levels were significantly lower at the time GLP-1 was higher (60-80 min) during glucose + NaCl. Sodium intake in addition to a glucose load selectively amplifies the postprandial GLP-1 plasma concentration. Thus, GLP-1 may be part of an acute feed-forward mechanism for natriuresis.
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Affiliation(s)
- Ali Asmar
- Department of Clinical Physiology, Nuclear Medicine and PET, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Per K. Cramon
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Meena Asmar
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
- Department of EndocrinologyOdense University HospitalOdenseDenmark
| | - Lene Simonsen
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | | | - Sten Madsbad
- Department of EndocrinologyHvidovre HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Cedric Moro
- Institut National de la Santé et de la Recherche Médicale (Inserm) UMR 1048Institute of Metabolic and Cardiovascular DiseasesPaul Sabatier UniversityToulouseFrance
| | - Bolette Hartmann
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
- Novo Nordisk Foundation Center for Basic Metabolic ResearchUniversity of CopenhagenCopenhagenDenmark
| | - Jens F. Rehfeld
- Department of Clinical Biochemistry, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
| | - Jens J. Holst
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
- Novo Nordisk Foundation Center for Basic Metabolic ResearchUniversity of CopenhagenCopenhagenDenmark
| | - Peter Hovind
- Department of Clinical Physiology, Nuclear Medicine and PET, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
| | - Boye L. Jensen
- Department of Cardiovascular and Renal ResearchUniversity of Southern DenmarkOdenseDenmark
| | - Jens Bülow
- Department of Clinical Physiology and Nuclear MedicineBispebjerg and Frederiksberg HospitalUniversity Hospital of CopenhagenCopenhagenDenmark
- Department of Biomedical SciencesUniversity of CopenhagenCopenhagenDenmark
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5
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Igreja B, Pires N, Loureiro A, Wright L, Soares-da-Silva P. Cardiometabolic and Inflammatory Benefits of Sympathetic Down-Regulation with Zamicastat in Aged Spontaneously Hypertensive Rats. ACS Pharmacol Transl Sci 2019; 2:353-360. [PMID: 32259069 PMCID: PMC7089015 DOI: 10.1021/acsptsci.9b00039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Indexed: 11/28/2022]
Abstract
The hyperactivity of the sympathetic nervous system (SNS) plays a major role in the development and progression of several cardiovascular diseases. One strategy to mitigate the SNS overdrive is by restricting the biosynthesis of norepinephrine via the inhibition of dopamine β-hydroxylase (DBH). Zamicastat is a new DBH inhibitor that decreases norepinephrine and increases dopamine levels in peripherally sympathetic-innervated tissues. The cardiometabolic and inflammatory effects of sympathetic down-regulation were evaluated in 50 week old male spontaneously hypertensive rats (SHRs) receiving zamicastat (30 mg/kg/day) for 9 weeks. After 8 weeks of treatment, the blood pressure (BP) and heart rate (HR) were assessed by tail cuff plethysmography. At the end of the study, 24 h urine, plasma, heart, and kidney were collected for biochemical and morphometric analyses. Zamicastat-induced sympathetic down-regulation decreased the high BP in SHRs, with no observed effect on HR. The heart-to-body weight ratio was lower in SHRs treated with zamicastat, whereas the body weight and kidney-to-body weight ratio were similar between both SHR cohorts. Zamicastat-treated SHRs showed reduced 24 h urine output, but the urinary amount of protein excreted and creatinine clearance rate remained unchanged. Zamicastat treatment significantly decreased plasma triglycerides, free fatty acids, and aspartate aminotransferase levels. Aged SHRs showed higher plasma levels of inflammatory markers as compared with age-matched normotensive Wistar-Kyoto rats. The inflammatory benefits attained with DBH inhibition were expressed by a decrease in CRP, MCP-1, IL-5, IL-17α, GRO/KC, MIP-1α, and RANTES plasma levels as compared with untreated SHRs. In conclusion, DBH inhibition decreased norepinephrine levels, reduced end-organ damage, and improved cardiometabolic and inflammatory biomarkers in aged male SHRs.
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Affiliation(s)
- Bruno Igreja
- Department
of Research, BIAL - Portela & C, S.A., Coronado
(S. Mamede e S. Romão) 4747-457, Portugal
| | - Nuno Pires
- Department
of Research, BIAL - Portela & C, S.A., Coronado
(S. Mamede e S. Romão) 4747-457, Portugal
| | - Ana Loureiro
- Department
of Research, BIAL - Portela & C, S.A., Coronado
(S. Mamede e S. Romão) 4747-457, Portugal
| | - Lyndon Wright
- Department
of Research, BIAL - Portela & C, S.A., Coronado
(S. Mamede e S. Romão) 4747-457, Portugal
| | - Patrício Soares-da-Silva
- Department
of Research, BIAL - Portela & C, S.A., Coronado
(S. Mamede e S. Romão) 4747-457, Portugal
- Department
of Biomedicine, Unit of Pharmacology & Therapeutics, Faculty of
Medicine, University of Porto, Porto 4200-319, Portugal
- MedInUP
- Center for Drug Discovery and Innovative Medicines, University of Porto, Porto 4200-319, Portugal
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Luo H, Chen C, Guo L, Xu Z, Peng X, Wang X, Wang J, Wang N, Li C, Luo X, Wang H, Jose PA, Fu C, Huang Y, Shi W, Zeng C. Exposure to Maternal Diabetes Mellitus Causes Renal Dopamine D 1 Receptor Dysfunction and Hypertension in Adult Rat Offspring. Hypertension 2018; 72:962-970. [PMID: 30354705 PMCID: PMC6207228 DOI: 10.1161/hypertensionaha.118.10908] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 08/05/2018] [Indexed: 01/01/2023]
Abstract
Epidemiological and experimental studies suggest that maternal diabetes mellitus programs hypertension that is associated with impaired sodium excretion in the adult offspring. However, the underlying mechanisms are not clear. Because dopamine receptor function is involved in the pathogenesis of hypertension, we hypothesized that impaired renal dopamine D1 receptor function is also involved in the hypertension in offspring of maternal diabetes mellitus. Maternal diabetes mellitus was induced by a single intraperitoneal injection of streptozotocin (35 mg/kg) to pregnant Sprague-Dawley rats at day 0 of gestation. Compared with the offspring of mothers injected with citrate buffer (control mother offspring), the diabetic mother offspring (DMO) had increased systolic blood pressure and impaired D1 receptor-mediated diuresis and natriuresis, accompanied by increased renal PKC (protein kinase C) expression and activity, GRK-2 (G protein-coupled receptor kinase-2) expression, D1 receptor phosphorylation, D1 receptor/Gαs uncoupling, and loss of D1 receptor-mediated inhibition of Na+-K+-ATPase activity in renal proximal tubule cells from DMO. Inhibition of PKC reduced the increased GRK-2 expression and normalized D1 receptor function in primary cultures of renal proximal tubule cells from DMO. In addition, DMO, relative to control mother offspring, in vivo, had increased oxidative stress, indicated by decreased renal glutathione and increased renal malondialdehyde and urine 8-isoprostane. Normalization of oxidative stress with tempol also normalized the renal D1 receptor phosphorylation, D1 receptor-mediated diuresis and natriuresis, and blood pressure in DMO. Our present study indicates that maternal diabetes mellitus-programed hypertension in the offspring is caused by impaired renal D1 receptor function because of oxidative stress that is mediated by increased PKC-GRK-2 activity.
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Affiliation(s)
- Hao Luo
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Caiyu Chen
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Li Guo
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Zaicheng Xu
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Xiaoyu Peng
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Xinquan Wang
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Jialiang Wang
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Na Wang
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Chuanwei Li
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Xiaoli Luo
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Hongyong Wang
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Pedro A. Jose
- Division of Renal Diseases & Hypertension, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Chunjiang Fu
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Yu Huang
- Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Sha Tin, Hong Kong, China
| | - Weibin Shi
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Chunyu Zeng
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
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Takahashi-Iwanaga H, Kimura S, Konno K, Watanabe M, Iwanaga T. Intrarenal signaling mediated by CCK plays a role in salt intake-induced natriuresis. Am J Physiol Renal Physiol 2017; 313:F20-F29. [DOI: 10.1152/ajprenal.00539.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 03/07/2017] [Accepted: 03/10/2017] [Indexed: 11/22/2022] Open
Abstract
The natriuretic hormone CCK exhibits its gene transcripts in total kidney extracts. To test the possibility of CCK acting as an intrarenal mediator of sodium excretion, we examined mouse kidneys by 1) an in situ hybridization technique for CCK mRNA in animals fed a normal- or a high-sodium diet; 2) immuno-electron microscopy for the CCK peptide, 3) an in situ hybridization method and immunohistochemistry for the CCK-specific receptor CCKAR; 4) confocal image analysis of receptor-mediated Ca2+ responses in isolated renal tubules; and 5) metabolic cage experiments for the measurement of urinary sodium excretion in high-salt-fed mice either treated or untreated with the CCKAR antagonist lorglumide. Results showed the CCK gene to be expressed intensely in the inner medulla and moderately in the inner stripe of the outer medulla, with the expression in the latter being enhanced by high sodium intake. Immunoreactivity for the CCK peptide was localized to the rough endoplasmic reticulum of the medullary interstitial cells in corresponding renal regions, confirming it to be a secretory protein. Gene transcripts, protein products, and the functional activity for CCKAR were consistently localized to the late proximal tubule segments (S2 and S3) in the medullary rays, and the outer stripe of the outer medulla. Lorglumide significantly diminished natriuretic responses of mice to a dietary sodium load without altering the glomerular filtration rate. These findings suggest that the medullary interstitial cells respond to body fluid expansion by CCK release for feedback regulation of the late proximal tubular reabsorption.
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Affiliation(s)
| | - Shunsuke Kimura
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kohtarou Konno
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Toshihiko Iwanaga
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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8
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Affiliation(s)
- Jian Yang
- Department of Nutrition, Daping Hospital, The Third Military Medical University, Chongqing, China.,Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Pedro A Jose
- Division of Renal Disease & Hypertension, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
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9
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Dopamine regulates renal osmoregulation during hyposaline stress via DRD1 in the spotted scat (Scatophagus argus). Sci Rep 2016; 6:37535. [PMID: 27857228 PMCID: PMC5114590 DOI: 10.1038/srep37535] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/01/2016] [Indexed: 01/11/2023] Open
Abstract
Dopamine is an important regulator of renal natriuresis and is critical for the adaptation of many animals to changing environmental salinity. However, the molecular mechanisms through which dopamine promotes this adaptation remain poorly understood. We studied the effects of dopamine on renal hypo-osmoregulation in the euryhaline fish Scatophagus argus (S. argus) during abrupt transfer from seawater (SW) to freshwater (FW). Following the transfer, serum dopamine concentration was decreased, and dopamine activated expression of the dopamine receptor 1 (designated SaDRD1) in the kidney, triggering the osmoregulatory signaling cascade. SaDRD1 protein is expressed in the renal proximal tubule cells in vivo, and is localized to the cell membrane of renal primary cells in vitro. Knockdown of SaDRD1 mRNA by siRNA significantly increased Na+/K+-ATPase (NKA) activity in cultured renal primary cells in vitro, suggesting that expression of SaDRD1 may oppose the activity of NKA. We demonstrate that exogenous dopamine enhances the response of NKA to hyposaline stress after transferring primary renal cells from isosmotic medium to hypoosmotic medium. Our results indicate that dopamine regulation via SaDRD1 ignited the renal dopaminergic system to balance the osmotic pressure through inhibiting NKA activity, providing a new perspective on the hyposaline adaptation of fish.
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Zhang Y, Ren H, Lu X, He D, Han Y, Wang H, Zeng C, Shi W. Inhibition of D4 Dopamine Receptors on Insulin Receptor Expression and Effect in Renal Proximal Tubule Cells. J Am Heart Assoc 2016; 5:e002448. [PMID: 27107134 PMCID: PMC4843542 DOI: 10.1161/jaha.115.002448] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 03/14/2016] [Indexed: 01/11/2023]
Abstract
BACKGROUND Ion transport in the renal proximal tubule (RPT), which is increased in essential hypertension, is regulated by numerous hormones and humoral factors, including insulin and dopamine. Activation of dopamine receptor inhibits sodium reabsorption, whereas activation of insulin receptor increases sodium reabsorption in RPTs, and hyperinsulinemic animals and patients have defective renal dopaminergic system. We presume that there is an inhibition of D4 receptor on insulin receptor expression and effect, and the regulation is lost in spontaneously hypertensive rats (SHRs). METHODS AND RESULTS Insulin receptor expression was determined by immunoblotting, and Na(+)-K(+)-ATPase activity was detected in both Wistar-Kyoto (WKY) and SHR RPT cells. Stimulation of D4 receptor with PD168077 decreased expression of insulin receptors, which was blocked in the presence of the calcium-channel blocker, nicardipine (10(-6) mol/L per 24 hours), in cell culture medium without calcium or in the presence of inositol 1,4,5-trisphosphate (IP3) receptor blocker (2-aminoethyl diphenylborinate [2-ADB]; 10(-6) mol/L per 24 hours), indicating that extracellular calcium entry and calcium release from the endoplasmic reticulum were involved in the signal pathway. Stimulation of the insulin receptor stimulated Na(+)-K(+)-ATPase activity, whereas pretreatment with PD168077 for 24 hours decreased the inhibitory effects of insulin receptor on Na(+)-K(+)-ATPase activity in WKY cells. However, in SHR cells, inhibition of D4 receptor on insulin receptor expression and effect were lost. CONCLUSIONS Activation of D4 receptor inhibits insulin receptor expression in RPT cells from WKY rats. The aberrant inhibition of D4 receptor on insulin receptor expression and effect might be involved in the pathogenesis of essential hypertension.
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MESH Headings
- Animals
- Benzamides/pharmacology
- Calcium/metabolism
- Calcium Channel Blockers/pharmacology
- Cells, Cultured
- Disease Models, Animal
- Essential Hypertension
- Hypertension/genetics
- Hypertension/metabolism
- Hypertension/pathology
- Immunoblotting
- Intracellular Fluid/metabolism
- Kidney Tubules, Proximal/metabolism
- Kidney Tubules, Proximal/pathology
- Piperazines/pharmacology
- RNA/genetics
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Real-Time Polymerase Chain Reaction
- Receptor, Insulin/biosynthesis
- Receptor, Insulin/genetics
- Receptors, Dopamine D4/drug effects
- Receptors, Dopamine D4/metabolism
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Affiliation(s)
- Ye Zhang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China Chongqing Institute of Cardiology, Chongqing, China
| | - Hongmei Ren
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China Chongqing Institute of Cardiology, Chongqing, China
| | - Xi Lu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China Chongqing Institute of Cardiology, Chongqing, China
| | - Duofen He
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China Chongqing Institute of Cardiology, Chongqing, China
| | - Yu Han
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China Chongqing Institute of Cardiology, Chongqing, China
| | - Hongyong Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China Chongqing Institute of Cardiology, Chongqing, China
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China Chongqing Institute of Cardiology, Chongqing, China
| | - Weibin Shi
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China Chongqing Institute of Cardiology, Chongqing, China
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11
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Liu T, Konkalmatt PR, Yang Y, Jose PA. Gastrin decreases Na+,K+-ATPase activity via a PI 3-kinase- and PKC-dependent pathway in human renal proximal tubule cells. Am J Physiol Endocrinol Metab 2016; 310:E565-71. [PMID: 26786777 PMCID: PMC4824137 DOI: 10.1152/ajpendo.00360.2015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 01/08/2016] [Indexed: 12/31/2022]
Abstract
The natriuretic effect of gastrin suggests a role in the coordinated regulation of sodium balance by the gastrointestinal tract and the kidney. The renal molecular targets and signal transduction pathways for such an effect of gastrin are largely unknown. Recently, we reported that gastrin induces NHE3 phosphorylation and internalization via phosphatidylinositol (PI) 3-kinase and PKCα. In this study, we show that gastrin induced the phosphorylation of human Na(+),K(+)-ATPase at serine 16, resulting in its endocytosis via Rab5 and Rab7 endosomes. The gastrin-stimulated phosphorylation of Na(+),K(+)-ATPase was dependent on PI 3-kinase because the phosphorylation was blocked by the PI 3-kinase inhibitor wortmannin. The phosphorylation of Na(+),K(+)-ATPase was also blocked by chelerythrine, a pan-PKC inhibitor, Gö-6976, a conventional PKC (cPKC) inhibitor, and BAPTA-AM, an intracellular calcium chelator, suggesting the importance of cPKC and intracellular calcium in the gastrin signaling pathway. The gastrin-mediated phosphorylation of Na(+),K(+)-ATPase was also inhibited by U-73122, a phospholipase C (PLC) inhibitor. These results suggest that gastrin regulates sodium hydrogen exchanger and pump in renal proximal tubule cells at the apical and basolateral membranes.
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Affiliation(s)
- Tianbing Liu
- Center for Molecular Physiology Research, Children's Research Institute, Children's National Medical Center, Washington, DC
| | - Prasad R Konkalmatt
- Departments of Medicine and Physiology, University of Maryland School of Medicine, Baltimore, Maryland; Division of Renal Diseases and Hypertension, Department of Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC; and
| | - Yu Yang
- Center for Molecular Physiology Research, Children's Research Institute, Children's National Medical Center, Washington, DC; Departments of Medicine and Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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Igreja B, Wright LC, Soares-da-Silva P. Sustained high blood pressure reduction with etamicastat, a peripheral selective dopamine β-hydroxylase inhibitor. ACTA ACUST UNITED AC 2015; 10:207-16. [PMID: 26803288 DOI: 10.1016/j.jash.2015.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 12/03/2015] [Accepted: 12/16/2015] [Indexed: 11/25/2022]
Abstract
The aim of the present study was to evaluate the influence of chronic inhibition of dopamine ß-hydroxylase by etamicastat on the development of hypertension in the spontaneously hypertensive rat (SHR) and the sustainability of effects on the systolic and diastolic blood pressure in the SHR and the normotensive Wistar-Kyoto rat (WKY). WKY and SHR received etamicastat (10 mg/kg/d) from 5 weeks of age for 35 weeks in drinking water, and cardiovascular assessments were performed on a weekly basis. Etamicastat reduced systolic and diastolic blood pressure when SHRs reached the age of 16 weeks with mean decreases of 37 and 32 mm Hg, respectively, for the subsequent for 24 weeks of treatment, but did not prevent the increase in blood pressure (BP) aged between 5 and 11 week. The BP lowering effect of etamicastat in SHR was reversible on discontinuation and quickly resumed after reinstatement of therapy and was not accompanied by changes in heart rate. Etamicastat affected neither BP nor heart rate in WKY during 36 weeks of treatment. Etamicastat reduced urinary excretion of norepinephrine to a similar extent in WKY and SHR, accompanied by significant increases in urinary dopamine in SHR. Chronic administration of etamicastat did not adversely affected development of animals. Chronic dopamine ß-hydroxylase inhibition with etamicastat effectively decreases BP, although does not prevent the development of hypertension in the SHR.
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Affiliation(s)
- Bruno Igreja
- Department of Research and Development, BIAL-Portela & C(a), S.A., Portugal
| | - Lyndon C Wright
- Department of Research and Development, BIAL-Portela & C(a), S.A., Portugal
| | - Patricio Soares-da-Silva
- Department of Research and Development, BIAL-Portela & C(a), S.A., Portugal; Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Portugal; MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal.
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Activation of the D4 dopamine receptor attenuates proliferation and migration of vascular smooth muscle cells through downregulation of AT1a receptor expression. Hypertens Res 2015; 38:588-96. [PMID: 25832920 DOI: 10.1038/hr.2015.48] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 12/14/2014] [Accepted: 12/16/2014] [Indexed: 12/19/2022]
Abstract
Angiotensin (Ang) II has an important role in the vascular smooth muscle cell (VSMC) proliferation and migration and subsequently in the development of vascular diseases, whereas dopamine has the opposite effect. Previous studies have shown an interaction between dopamine and AT(1) receptors in the kidney. The dopamine D(4) receptor is expressed in arteries and has an inhibitory effect on VSMC proliferation. We hypothesized that the D(4) receptor, through its interaction with the AT(1a) receptor, may have an inhibitory effect on Ang II-mediated VSMC proliferation and migration, which could have a pivotal role in hypertension-induced vascular remodeling. In the current study, we found that Ang II markedly induced the proliferation and migration of A10 cells, which was inhibited by the D(4) receptor agonist PD168077. The activation of the D(4) receptor by PD168077 inhibited AT(1a) receptor expression in a concentration- and time-dependent manner. These effects were attenuated by silencing the D(4) receptor with a D(4) receptor-targeting small interfering RNA. The D(4) receptor-mediated inhibition of AT(1) receptor function involved protein kinase A (PKA). The activation of the D(4) receptor by PD168077 increased PKA activity in A10 cells, and the presence of a PKA inhibitor (PKA inhibitor 14-22, 10(-7) mol l(-1) per 24 h) blocked the inhibitory effect of the D(4) receptor on AT(1) receptor expression and function. The inhibitory effect of the D(4) receptor on AT(1) receptor expression and function was preserved in VSMCs (primary culture) from spontaneously hypertensive rats relative to VSMCs from Wistar-Kyoto rats. In conclusion, our data provide insight into the regulatory role of the D(4) receptor on AT(1a) receptor expression and function in VSMCs and suggest that targeting the action of the D(4) receptor may represent an effective therapeutic approach for the treatment of cardiovascular diseases.
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Chen K, Deng K, Wang X, Wang Z, Zheng S, Ren H, He D, Han Y, Asico LD, Jose PA, Zeng C. Activation of D4 dopamine receptor decreases angiotensin II type 1 receptor expression in rat renal proximal tubule cells. Hypertension 2014; 65:153-60. [PMID: 25368031 DOI: 10.1161/hypertensionaha.114.04038] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The dopaminergic and renin-angiotensin systems interact to regulate blood pressure. Disruption of the D4 dopamine receptor gene in mice produces hypertension that is associated with increased renal angiotensin type 1 (AT1) receptor expression. We hypothesize that the D4 receptor can inhibit AT1 receptor expression and function in renal proximal tubule cells from Wistar-Kyoto (WKY) rats, but the D4 receptor regulation of AT1 receptor is aberrant in renal proximal tubule cells from spontaneously hypertensive rats (SHRs). The D4 receptor agonist, PD168077, decreased AT1 receptor protein expression in a time- and concentration-dependent manner in WKY cells. By contrast, in SHR cells, PD168077 increased AT1 receptor protein expression. The inhibitory effect of D4 receptor on AT1 receptor expression in WKY cells was blocked by a calcium channel blocker, nicardipine, or calcium-free medium, indicating that calcium is involved in the D4 receptor-mediated signaling pathway. Angiotensin II increased Na(+)-K(+) ATPase activity in WKY cells. Pretreatment with PD168077 decreased the stimulatory effect of angiotensin II on Na(+)-K(+) ATPase activity in WKY cells. In SHR cells, the inhibitory effect of D4 receptor on angiotensin II-mediated stimulation of Na(+)-K(+) ATPase activity was aberrant; pretreatment with PD168077 augmented the stimulatory effect of AT1 receptor on Na(+)-K(+) ATPase activity in SHR cells. This was confirmed in vivo; pretreatment with PD128077 for 1 week augmented the antihypertensive and natriuretic effect of losartan in SHRs but not in WKY rats. We suggest that an aberrant interaction between D4 and AT1 receptors may play a role in the abnormal regulation of sodium excretion in hypertension.
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Affiliation(s)
- Ken Chen
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.)
| | - Kun Deng
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.)
| | - Xiaoyan Wang
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.)
| | - Zhen Wang
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.)
| | - Shuo Zheng
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.)
| | - Hongmei Ren
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.)
| | - Duofen He
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.)
| | - Yu Han
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.)
| | - Laureano D Asico
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.)
| | - Pedro A Jose
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.)
| | - Chunyu Zeng
- From the Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); Chongqing Institute of Cardiology, Chongqing, People's Republic of China (K.C., K.D., Z.W., S.Z., H.R., D.H., Y.H., C.Z.); and Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD (X.W., L.D.A., P.A.J.).
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Wang X, Luo H, Chen C, Chen K, Wang J, Cai Y, Zheng S, Yang X, Zhou L, Jose PA, Zeng C. Prenatal lipopolysaccharide exposure results in dysfunction of the renal dopamine D1 receptor in offspring. Free Radic Biol Med 2014; 76:242-50. [PMID: 25236748 PMCID: PMC6873924 DOI: 10.1016/j.freeradbiomed.2014.08.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 07/23/2014] [Accepted: 08/11/2014] [Indexed: 12/31/2022]
Abstract
Adverse environment in early life can modulate the adult phenotype, including blood pressure. Lipopolysaccharide (LPS) exposure in utero results in increased blood pressure in the offspring, but the exact mechanisms are not clear. Studies have shown that the renal dopamine D1 receptor (D1R) plays an important role in maintaining sodium homeostasis and normal blood pressure; dysfunction of D1R is associated with oxidative stress and hypertension. In this study, we determined if dysfunction of the renal D1R is involved in fetal-programmed hypertension, and if oxidative stress contributes to this process. Pregnant Sprague-Dawley (SD) rats were intraperitoneally injected with LPS (0.79 mg/kg) or saline at gestation days 8, 10, and 12. As compared with saline-injected (control) dams, offspring of LPS-treated dams had increased blood pressure, decreased renal sodium excretion, and increased markers of oxidative stress. In addition, offspring of LPS-treated dams had decreased renal D1R expression, increased D1R phosphorylation, and G protein-coupled receptor kinase type 2 (GRK2) and type 4 (GRK4) protein expression, and impaired D1R-mediated natriuresis and diuresis. All of the findings in the offspring of LPS-treated dams were normalized after treatment with TEMPOL, an oxygen free radical scavenger. In conclusion, prenatal LPS exposure, via an increase in oxidative stress, impairs renal D1R function and leads to hypertension in the offspring. Normalization of renal D1R function by amelioration of oxidative stress may be a therapeutic target of fetal programming of hypertension.
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Affiliation(s)
- Xinquan Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Hao Luo
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Caiyu Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Ken Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Jialiang Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Yue Cai
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Shuo Zheng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Xiaoli Yang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China
| | - Lin Zhou
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China.
| | - Pedro A Jose
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, People's Republic of China; Chongqing Institute of Cardiology, Chongqing, People's Republic of China.
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Fu J, Han Y, Wang H, Wang Z, Liu Y, Chen X, Cai Y, Guan W, Yang D, Asico LD, Zhou L, Jose PA, Zeng C. Impaired dopamine D1 receptor-mediated vasorelaxation of mesenteric arteries in obese Zucker rats. Cardiovasc Diabetol 2014; 13:50. [PMID: 24559270 PMCID: PMC3938077 DOI: 10.1186/1475-2840-13-50] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 02/20/2014] [Indexed: 12/18/2022] Open
Abstract
Background Obesity plays an important role in the pathogenesis of hypertension. Renal dopamine D1-like receptor-mediated diuresis and natriuresis are impaired in the obese Zucker rat, an obesity-related hypertensive rat model. The role of arterial D1 receptors in the hypertension of obese Zucker rats is not clear. Methods Plasma glucose and insulin concentrations and blood pressure were measured. The vasodilatory response of isolated mesenteric arteries was evaluated using a small vessel myograph. The expression and phosphorylation of D1 receptors were quantified by co-immunoprecipitation and immunoblotting To determine the effect of hyperinsulinemia and hyperglycemia on the function of the arterial D1 receptor, we studied obese Zucker rats (six to eight-weeks old) fed (6 weeks) vehicle or rosiglitazone, an insulin sensitizer (10 mg/kg per day) and lean Zucker rats (eight to ten-weeks old), fed high-fat diet to induce hyperinsulinemia or injected intraperitoneally with streptomycin (STZ) to induce hyperglycemia. Results In obese Zucker rats, the vasorelaxant effect of D1-like receptors was impaired that could be ascribed to decreased arterial D1 receptor expression and increased D1 receptor phosphorylation. In these obese rats, rosiglitazone normalized the arterial D1 receptor expression and phosphorylation and improved the D1-like receptor-mediated vasorelaxation. We also found that D1 receptor-dependent vasorelaxation was decreased in lean Zucker rats with hyperinsulinemia or hyperglycemia but the D1 receptor dysfunction was greater in the former than in the latter group. The ability of insulin and glucose to decrease D1 receptor expression and increase its phosphorylation were confirmed in studies of rat aortic smooth muscle cells. Conclusions Both hyperinsulinemia and hyperglycemia caused D1 receptor dysfunction by decreasing arterial D1 receptor expression and increasing D1 receptor phosphorylation. Impaired D1 receptor-mediated vasorelaxation is involved in the pathogenesis of obesity-related hypertension.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Lin Zhou
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P,R, China.
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Armando I, Villar VAM, Jones JE, Lee H, Wang X, Asico LD, Yu P, Yang J, Escano CS, Pascua-Crusan AM, Felder RA, Jose PA. Dopamine D3 receptor inhibits the ubiquitin-specific peptidase 48 to promote NHE3 degradation. FASEB J 2013; 28:1422-34. [PMID: 24308971 DOI: 10.1096/fj.13-243840] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The dopamine D3 receptor (D3R) is crucial in the regulation of blood pressure and sodium balance, in that Drd3 gene ablation in mice results in hypertension and failure to excrete a dietary salt load. The mechanism responsible for the renal sodium retention in these mice is largely unknown. We now offer and describe a novel mechanism by which D3R decreases sodium transport in the long term by inhibiting the deubiquitinylating activity of ubiquitin-specific peptidase 48 (USP48), thereby promoting Na(+)-H(+) exchanger (NHE)-3 degradation. We found that stimulation with the D3R-specific agonist PD128907 (1 μM, 30 min) promoted the interaction and colocalization among D3R, NHE3, and USP48; inhibited USP48 activity (-35±6%, vs. vehicle), resulting in increased ubiquitinylated NHE3 (+140±10%); and decreased NHE3 expression (-50±9%) in human renal proximal tubule cells (hRPTCs). USP48 silencing decreased NHE3's half-life (USP48 siRNA t1/2=6.1 h vs. vehicle t1/2=12.9 h), whereas overexpression of USP48 increased NHE3 half-life (t1/2=21.8 h), indicating that USP48 protects NHE3 from degradation via deubiquitinylation. USP48 accounted for ∼30% of the total deubiquitinylating activity in these cells. Extending our studies in vivo, we found that pharmacologic blockade of D3R via the D3R-specific antagonist GR103691 (1 μg/kg/min, 4 d) in C57Bl/6J mice increased renal NHE3 expression (+310±15%, vs. vehicle), whereas an innovative kidney-restricted Usp48 silencing via siRNA (3 μg/d, 7 d) increased ubiquitinylated NHE3 (+250±30%, vs. controls), decreased total NHE3 (-23±2%), and lowered blood pressure (-24±2 mm Hg), compared with that in control mice that received either the vehicle or nonsilencing siRNA. Our data demonstrate a crucial role for the dynamic interaction between D3R and USP48 in the regulation of NHE3 expression and function.
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Affiliation(s)
- Ines Armando
- 2Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, 20 Penn St., HSF II, Ste. S003C, Baltimore, MD, USA 21201,
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Chen K, Fu C, Chen C, Liu L, Ren H, Han Y, Yang J, He D, Zhou L, Yang Z, Zhang L, Jose PA, Zeng C. Role of GRK4 in the regulation of arterial AT1 receptor in hypertension. Hypertension 2013; 63:289-96. [PMID: 24218433 DOI: 10.1161/hypertensionaha.113.01766] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
G-protein-coupled receptor kinase 4 (GRK4) gene variants, via impairment of renal dopamine receptor and enhancement of renin-angiotensin system functions, cause sodium retention and increase blood pressure. Whether GRK4 and the angiotensin type 1 receptor (AT(1)R) interact in the aorta is not known. We report that GRK4 is expressed in vascular smooth muscle cells of the aorta. Heterologous expression of the GRK4γ variant 142V in A10 cells increased AT(1)R protein expression and AT(1)R-mediated increase in intracellular calcium concentration. The increase in AT(1)R expression was related to an increase in AT(1)R mRNA expression via the NF-κB pathway. As compared with control, cells expressing GRK4γ 142V had greater NF-κB activity with more NF-κB bound to the AT(1)R promoter. The increased AT(1)R expression in cells expressing GRK4γ 142V was also associated with decreased AT(1)R degradation, which may be ascribed to lower AT(1)R phosphorylation. There was a direct interaction between GRK4γ and AT(1)R that was decreased by GRK4γ 142V. The regulation of AT(1)R expression by GRK4γ 142V in A10 cells was confirmed in GRK4γ 142V transgenic mice; AT(1)R expression was higher in the aorta of GRK4γ 142V transgenic mice than control GRK4γ wild-type mice. Angiotensin II-mediated vasoconstriction of the aorta was also higher in GRK4γ 142V than in wild-type transgenic mice. This study provides a mechanism by which GRK4, via regulation of arterial AT(1)R expression and function, participates in the pathogenesis of conduit vessel abnormalities in hypertension.
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Affiliation(s)
- Ken Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, PR China.
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Chen Y, Asico LD, Zheng S, Villar VAM, He D, Zhou L, Zeng C, Jose PA. Gastrin and D1 dopamine receptor interact to induce natriuresis and diuresis. Hypertension 2013; 62:927-33. [PMID: 24019399 DOI: 10.1161/hypertensionaha.113.01094] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Oral NaCl produces a greater natriuresis and diuresis than the intravenous infusion of the same amount of NaCl. Gastrin is the major gastrointestinal hormone taken up by renal proximal tubule (RPT) cells. We hypothesized that renal gastrin and dopamine receptors interact to synergistically increase sodium excretion, an impaired interaction of which may be involved in the pathogenesis of hypertension. In Wistar-Kyoto rats, infusion of gastrin induced natriuresis and diuresis, which was abrogated in the presence of a gastrin (cholecystokinin B receptor [CCKBR]; CI-988) or a D1-like receptor antagonist (SCH23390). Similarly, the natriuretic and diuretic effects of fenoldopam, a D1-like receptor agonist, were blocked by SCH23390, as well as by CI-988. However, the natriuretic effects of gastrin and fenoldopam were not observed in spontaneously hypertensive rats. The gastrin/D1-like receptor interaction was also confirmed in RPT cells. In RPT cells from Wistar-Kyoto but not spontaneously hypertensive rats, stimulation of either D1-like receptor or gastrin receptor inhibited Na(+)-K(+)-ATPase activity, an effect that was blocked in the presence of SCH23390 or CI-988. In RPT cells from Wistar-Kyoto and spontaneously hypertensive rats, CCKBR and D1 receptor coimmunoprecipitated, which was increased after stimulation of either D1 receptor or CCKBR in RPT cells from Wistar-Kyoto rats; stimulation of one receptor increased the RPT cell membrane expression of the other receptor, effects that were not observed in spontaneously hypertensive rats. These data suggest that there is a synergism between CCKBR and D1-like receptors to increase sodium excretion. An aberrant interaction between the renal CCK BR and D1-like receptors (eg, D1 receptor) may play a role in the pathogenesis of hypertension.
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Affiliation(s)
- Yue Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, China.
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Liu T, Jose PA. Gastrin induces sodium-hydrogen exchanger 3 phosphorylation and mTOR activation via a phosphoinositide 3-kinase-/protein kinase C-dependent but AKT-independent pathway in renal proximal tubule cells derived from a normotensive male human. Endocrinology 2013; 154:865-75. [PMID: 23275470 PMCID: PMC3548178 DOI: 10.1210/en.2012-1813] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Gastrin is natriuretic, but its renal molecular targets and signal transduction pathways are not fully known. In this study, we confirmed the existence of CCKBR (a gastrin receptor) in male human renal proximal tubule cells and discovered that gastrin induced S6 phosphorylation, a downstream component of the phosphatidylinositol 3 kinase (PI3 kinase)-mammalian target of rapamycin pathway. Gastrin also increased the phosphorylation of sodium-hydrogen exchanger 3 (NHE3) at serine 552, caused its internalization, and decreased its expression at the cell surface and NHE activity. The phosphorylation of NHE3 and S6 was dependent on PI3 kinases because it was blocked by 2 different PI3-kinase inhibitors, wortmannin and LY294,002. The phosphorylation of NHE3 and S6 was not affected by the protein kinase A inhibitor H-89 but was blocked by a pan-PKC (chelerythrine) and a conventional PKC (cPKC) inhibitor (Gö6976) (10 μM) and an intracellular calcium chelator, 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, tetra(acetoxymethyl)-ester, suggesting the importance of cPKC and intracellular calcium in the gastrin signaling pathway. The cPKC involved was probably PKCα because it was phosphorylated by gastrin. The gastrin-mediated phosphorylation of NHE3, S6, and PKCα was via phospholipase C because it was blocked by a phospholipase C inhibitor, U73122 (10 μM). The phosphorylation (activation) of AKT, which is usually upstream of mammalian target of rapamycin in the classic PI3 kinase-AKT-p70S6K signaling pathway, was not affected, suggesting that the gastrin-induced phosphorylation of NHE3 and S6 is dependent on both PI3 kinase and PKCα but not AKT.
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Affiliation(s)
- Tianbing Liu
- Center for Molecular Physiology Research, Children's Research Institute, Children's National Medical Center, 111 Michigan Avenue, Washington, DC 20010, USA.
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Huang H, Ren H, Chen C, Wang X, Yang J, Han Y, He D, Zhou L, Asico LD, Jose PA, Zeng C. D3 dopamine receptor regulation of D5 receptor expression and function in renal proximal tubule cells. Hypertens Res 2012; 35:639-47. [PMID: 22297482 DOI: 10.1038/hr.2012.11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Dopamine receptor, via D(1)-like and D(2)-like receptors, increases sodium excretion in kidney. We have reported positive interactions between D(3) and D(1) receptors in renal proximal tubule (RPT) cells. These reports, however do not preclude that there may be also interaction between D(3) and D(5) receptors, because of the lack of selective D(1) and D(5) receptor agonists or antagonists. We hypothesize that D(3) receptors can regulate D(5) receptors, and that D(3) receptor regulation of D(5) receptors in RPTs is impaired in spontaneously hypertensive rats (SHRs). It showed that a D(3) receptor agonist, PD128907, by the activation of protein kinase C activity, increased the expression of D(5) receptors in a concentration- and time-dependent manner in RPT cells from Wistar-Kyoto (WKY) rats. The stimulatory effect of the D(3) receptor on D(5) receptor expression was impaired in RPT cells from SHRs. The effect of D(3) receptor on D(5) receptor is functionally relevant; stimulation of D(5) receptor decreases Na(+)-K(+) adenosine triphosphatase (ATPase) activity in WKY cells. Pretreatment with D(3) receptor agonist for 24 h enhances the D(5) receptor expression and D(5) receptor-mediated inhibitory effect on Na(+)-K(+) ATPase activity in WKY cells, but decreases them in SHR cells. The effect of D(3) receptor on D(5) receptor expression and function was also confirmed in the D(5) receptor-transfected HEK293 cells. It indicates that activation of D(3) receptor increases D(5) receptor expression and function. Altered regulation of D(3) receptor on D(5) receptors may have a role in the pathogenesis of hypertension.
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Affiliation(s)
- Hefei Huang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China
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Desai AJ, Miller LJ. Sensitivity of cholecystokinin receptors to membrane cholesterol content. Front Endocrinol (Lausanne) 2012; 3:123. [PMID: 23087674 PMCID: PMC3475150 DOI: 10.3389/fendo.2012.00123] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Accepted: 10/01/2012] [Indexed: 12/18/2022] Open
Abstract
Cholesterol represents a structurally and functionally important component of the eukaryotic cell membrane, where it increases lipid order, affects permeability, and influences the lateral mobility and conformation of membrane proteins. Several G protein-coupled receptors have been shown to be affected by the cholesterol content of the membrane, with functional impact on their ligand binding and signal transduction characteristics. The effects of cholesterol can be mediated directly by specific molecular interactions with the receptor and/or indirectly by altering the physical properties of the membrane. This review focuses on the importance and differential effects of membrane cholesterol on the activity of cholecystokinin (CCK) receptors. The type 1 CCK receptor is quite sensitive to its cholesterol environment, while the type 2 CCK receptor is not. The possible structural basis for this differential impact is explored and the implications of pathological states, such as metabolic syndrome, in which membrane cholesterol may be increased and CCK1R function may be abnormal are discussed. This is believed to have substantial potential importance for the development of drugs targeting the CCK receptor.
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Affiliation(s)
| | - Laurence J. Miller
- *Correspondence: Laurence J. Miller, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 13400 E. Shea Blvd., Scottsdale, AZ 85259, USA. e-mail:
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Asghar M, Tayebati SK, Lokhandwala MF, Hussain T. Potential dopamine-1 receptor stimulation in hypertension management. Curr Hypertens Rep 2011; 13:294-302. [PMID: 21633929 DOI: 10.1007/s11906-011-0211-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The role of dopamine receptors in blood pressure regulation is well established. Genetic ablation of both dopamine D1-like receptor subtypes (D1, D5) and D2-like receptor subtypes (D2, D3, D4) results in a hypertensive phenotype in mice. This review focuses on the dopamine D1-like receptor subtypes D1 and D5 (especially D1 receptors), as they play a major role in regulating sodium homeostasis and blood pressure. Studies mostly describing the role of renal dopamine D1-like receptors are included, as the kidneys play a pivotal role in the maintenance of sodium homeostasis and the long-term regulation of blood pressure. We also attempt to describe the interaction between D1-like receptors and other proteins, especially angiotensin II type 1 and type 2 receptors, which are involved in the maintenance of sodium homeostasis and blood pressure. Finally, we discuss a new concept of renal D1 receptor regulation in hypertension that involves oxidative stress mechanisms.
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Affiliation(s)
- Mohammad Asghar
- Heart and Kidney Institute, College of Pharmacy, University of Houston, Houston, TX 77204, USA.
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Abstract
Dopamine is an important regulator of systemic blood pressure via multiple mechanisms. It affects fluid and electrolyte balance by its actions on renal hemodynamics and epithelial ion and water transport and by regulation of hormones and humoral agents. The kidney synthesizes dopamine from circulating or filtered L-DOPA independently from innervation. The major determinants of the renal tubular synthesis/release of dopamine are probably sodium intake and intracellular sodium. Dopamine exerts its actions via two families of cell surface receptors, D1-like receptors comprising D1R and D5R, and D2-like receptors comprising D2R, D3R, and D4R, and by interactions with other G protein-coupled receptors. D1-like receptors are linked to vasodilation, while the effect of D2-like receptors on the vasculature is variable and probably dependent upon the state of nerve activity. Dopamine secreted into the tubular lumen acts mainly via D1-like receptors in an autocrine/paracrine manner to regulate ion transport in the proximal and distal nephron. These effects are mediated mainly by tubular mechanisms and augmented by hemodynamic mechanisms. The natriuretic effect of D1-like receptors is caused by inhibition of ion transport in the apical and basolateral membranes. D2-like receptors participate in the inhibition of ion transport during conditions of euvolemia and moderate volume expansion. Dopamine also controls ion transport and blood pressure by regulating the production of reactive oxygen species and the inflammatory response. Essential hypertension is associated with abnormalities in dopamine production, receptor number, and/or posttranslational modification.
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Affiliation(s)
- Ines Armando
- Children’s National Medical Center—Center for Molecular Physiology Research, Washington, District of Columbia
| | - Van Anthony M. Villar
- Children’s National Medical Center—Center for Molecular Physiology Research, Washington, District of Columbia
| | - Pedro A. Jose
- Children’s National Medical Center—Center for Molecular Physiology Research, Washington, District of Columbia
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Role of Gα(12)- and Gα(13)-protein subunit linkage of D(3) dopamine receptors in the natriuretic effect of D(3) dopamine receptor in kidney. Hypertens Res 2011; 34:1011-6. [PMID: 21633357 DOI: 10.1038/hr.2011.70] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The D(3) dopamine receptor is the major D(2)-like receptor that regulates sodium transport in the renal proximal tubule (RPT) and helps maintain blood pressure in the normal range. In Wistar-Kyoto (WKY) rats chronically fed high-salt diet, the intrarenal arterial infusion of a D(3) receptor agonist, PD128907, increased absolute and fractional sodium excretion. We have reported that Gα(12) and Gα(13), which participate in the signal transduction of the D(5) receptor, are expressed in RPTs. As the D(3) receptor is also expressed in RPTs, we hypothesized that it may also interact with Gα(12)/Gα(13) in RPTs from WKY rats. There were co-localization and co-immunoprecipitation of D(3) receptor and Gα(12)/Gα(13) in renal brush border membranes (BBMs) and RPT cells. The intrarenal infusion of PD128907 (1 μg kg(-1) min(-1)) that increased sodium excretion also increased the co-immunoprecipitations of D(3)/Gα(12) and D(3)/Gα(13) in renal BBMs; their co-immunoprecipitation was confirmed in RPT cells. As Gα(12) and Gα(13) increase sodium pump and transporter activity (for example, Na(+)-K(+)-ATPase, NHE3), an increased association of D(3) receptors with Gα(12)/Gα(13) receptors after D(3) receptor activation may be a mechanism to prevent Gα(12)/Gα(13)-mediated stimulation of sodium transport (and thus enhance natriuresis). We conclude that a D(3) receptor interaction with Gα(12)/Gα(13) that increases sodium excretion may have a role in the regulation of blood pressure.
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Zhang Y, Fu C, Ren H, He D, Wang X, Asico LD, Jose PA, Zeng C. Impaired stimulatory effect of ETB receptor on D₃ receptor in immortalized renal proximal tubule cells of spontaneously hypertensive rats. Kidney Blood Press Res 2011; 34:75-82. [PMID: 21228598 DOI: 10.1159/000323135] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 11/23/2010] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Activation of renal D₃ receptor induces natriuresis and diuresis in Wistar-Kyoto (WKY) rats; in the presence of ETB receptor antagonist, the natriuretic effect of D₃ receptor in WKY rats is reduced. We hypothesize that ETB receptor activation may regulate D₃ receptor expression in renal proximal tubule (RPT) cells from WKY rats, which is impaired in RPT cells from spontaneously hypertensive rats (SHRs). METHODS D₃ receptor expression was determined by immunoblotting; the D₃/ETB receptor linkage was checked by coimmunoprecipitation; Na(+)-K(+)-ATPase activity was determined as the rate of inorganic phosphate released in the presence or absence of ouabain. RESULTS In RPT cells from WKY rats, the ETB receptor agonist BQ3020 increased D₃ receptor protein. In contrast, in RPT cells from SHRs, BQ3020 did not increase D₃ receptor. There was coimmunoprecipitation between D₃ and ETB receptors in RPT cells from WKY and SHRs. Activation of ETB receptor increased D₃/ETB coimmunoprecipitation in RPT cells from WKY rats, but not from SHRs. The basal levels of D₃/ETB receptor coimmunoprecipitation were greater in RPT cells from WKY rats than in those from SHRs. Stimulation of D₃ receptor inhibited Na(+)-K(+)-ATPase activity, which was augmented by the pretreatment with the ETB receptor agonist BQ3020 in WKY RPT cells, but not in SHR RPT cells. CONCLUSION ETB receptors regulate and physically interact with D₃ receptors differently in WKY rats and SHRs. The impaired natriuretic effect in SHRs may be, in part, related to impaired ETB and D₃ receptor interactions.
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Affiliation(s)
- Ye Zhang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
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Zeng C, Jose PA. Dopamine receptors: important antihypertensive counterbalance against hypertensive factors. Hypertension 2010; 57:11-7. [PMID: 21098313 DOI: 10.1161/hypertensionaha.110.157727] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing City 400042, China.
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Wang X, Li F, Jose PA, Ecelbarger CM. Reduction of renal dopamine receptor expression in obese Zucker rats: role of sex and angiotensin II. Am J Physiol Renal Physiol 2010; 299:F1164-70. [PMID: 20810614 DOI: 10.1152/ajprenal.00604.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Dopamine produced by renal proximal tubules increases sodium excretion via a decrease in renal sodium reabsorption. Dopamine natriuresis is impaired in obese Zucker rats; however, the mechanism is not fully understood. To test the hypothesis that renal expression of one or more of the subtypes are altered in these rats, we measured whole kidney protein levels by immunoblotting of D1-like (D1R and D5R) and D2-like (D2R, D3R, and D4R) dopamine receptors in both male and female obese and lean Zucker rats. In obese males on 1% NaCl diet, D1R, D2R, D4R, and D5R were decreased, while D3R was increased, relative to lean rats. Under a 4% NaCl diet, D2R and D3R levels in obese rats were restored to lean levels. 4% NaCl diet reduced D5R in both body types, relative to 1% NaCl diet. Female rats had higher expression of D1R and D3R than did male; however, the sex difference for D1R was markedly blunted in obese rats. In obese rats, dietary candesartan (angiotensin II type 1 receptor blocker) normalized downregulated D1R and D2R, but either decreased (D3R), did not affect (D4R), or further downregulated (D5R) the other subtypes. Candesartan also decreased D4R in lean rats. In summary, reduced renal protein levels of D1R, D2R, D4R, and D5R in obese Zucker rats could induce salt sensitivity and elevate blood pressure. Increased angiotensin II type 1 receptor activity may be mechanistically involved in the decreased expression of D1R and D2R in obese rats. Finally, reduced D1R and D3R in male rats may contribute to sex differences in blood pressure.
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Affiliation(s)
- Xiaoyan Wang
- Bldg D, Rm 392, Georgetown Univ., 4000 Reservoir Rd NW, Washington, DC 20007, USA
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Wang X, Luo Y, Escano CS, Yang Z, Asico L, Li H, Jones JE, Armando I, Lu Q, Sibley DR, Eisner GM, Jose PA. Upregulation of renal sodium transporters in D5 dopamine receptor-deficient mice. Hypertension 2010; 55:1431-7. [PMID: 20404220 DOI: 10.1161/hypertensionaha.109.148643] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
D(5) dopamine receptor (D(5)R)-deficient (D(5)(-/-)) mice have hypertension that is aggravated by an increase in sodium intake. The present experiments were designed to test the hypothesis that a dysregulation of renal sodium transporters is related to the salt sensitivity in D(5)(-/-) mice. D(5)R was expressed in the renal proximal tubule, thick ascending limb, distal convoluted tubule, and cortical and outer medullary collecting ducts in D(5)(+/+) mice. On a control Na(+) diet, renal protein expressions of NKCC2 (sodium-potassium-2 chloride cotransporter), sodium chloride cotransporter, and alpha and gamma subunits of the epithelial sodium channel were greater in D(5)(-/-) than in D(5)(+/+) mice. Renal renin abundance and urine aldosterone levels were similar but renal angiotensin II type 1 receptor (AT(1)R) protein expression was increased in D(5)(-/-) mice. An elevated Na(+) diet increased further the elevated blood pressure of D(5)(-/-) mice but did not affect the normal blood pressure of D(5)(+/+) mice. The increased levels of NKCC2, sodium chloride cotransporter, and alpha and gamma subunits of the epithelial sodium channel persisted with the elevated Na(+) diet and unaffected by chronic AT(1)R blockade (losartan) in D(5)(-/-) mice. The expressions of proximal sodium transporters NHE3 (sodium hydrogen exchanger type 3) and NaPi2 (sodium phosphate cotransporter type 2) were increased by the elevated Na(+) diet in D(5)(-/-) mice; the increased expression of NHE3 but not NaPi2 was abolished by AT(1)R blockade. Our findings suggest that the increased protein expression of sodium transporters/channels in distal nephron segments may be the direct consequence of the disruption of D(5)R, independent of the renin-angiotensin aldosterone system.
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Affiliation(s)
- Xiaoyan Wang
- Center for Molecular Physiology Research, Children's National Medical Center, Washington, DC 20010, USA.
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Jose PA, Soares-da-Silva P, Eisner GM, Felder RA. Dopamine and G protein-coupled receptor kinase 4 in the kidney: role in blood pressure regulation. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1259-67. [PMID: 20153824 DOI: 10.1016/j.bbadis.2010.02.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 02/05/2010] [Accepted: 02/07/2010] [Indexed: 12/11/2022]
Abstract
Complex interactions between genes and environment result in a sodium-induced elevation in blood pressure (salt sensitivity) and/or hypertension that lead to significant morbidity and mortality affecting up to 25% of the middle-aged adult population worldwide. Determining the etiology of genetic and/or environmentally-induced high blood pressure has been difficult because of the many interacting systems involved. Two main pathways have been implicated as principal determinants of blood pressure since they are located in the kidney (the key organ responsible for blood pressure regulation), and have profound effects on sodium balance: the dopaminergic and renin-angiotensin systems. These systems counteract or modulate each other, in concert with a host of intracellular second messenger pathways to regulate sodium and water balance. In particular, the G protein-coupled receptor kinase type 4 (GRK4) appears to play a key role in regulating dopaminergic-mediated natriuresis. Constitutively activated GRK4 gene variants (R65L, A142V, and A486V), by themselves or by their interaction with other genes involved in blood pressure regulation, are associated with essential hypertension and/or salt-sensitive hypertension in several ethnic groups. GRK4γ 142Vtransgenic mice are hypertensive on normal salt intake while GRK4γ 486V transgenic mice develop hypertension only with an increase in salt intake. GRK4 gene variants have been shown to hyperphosphorylate, desensitize, and internalize two members of the dopamine receptor family, the D(1) (D(1)R) and D(3) (D(3)R) dopamine receptors, but also increase the expression of a key receptor of the renin-angiotensin system, the angiotensin type 1 receptor (AT(1)R). Knowledge of the numerous blood pressure regulatory pathways involving angiotensin and dopamine may provide new therapeutic approaches to the pharmacological regulation of sodium excretion and ultimately blood pressure control.
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Affiliation(s)
- Pedro A Jose
- Children's National Medical Center, George Washington University for the Health Sciences, Washington, DC, USA.
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D3 dopamine receptor regulation of ETB receptors in renal proximal tubule cells from WKY and SHRs. Am J Hypertens 2009; 22:877-83. [PMID: 19390510 DOI: 10.1038/ajh.2009.80] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The dopaminergic and endothelin systems, by regulating sodium transport in the renal proximal tubule (RPT), participate in the control of blood pressure. The D(3) and ETB receptors are expressed in RPTs, and D(3) receptor function in RPTs is impaired in spontaneously hypertensive rats (SHRs). Therefore, we tested the hypothesis that D(3) receptors can regulate ETB receptors, and that D(3) receptor regulation of ETB receptors in RPTs is impaired in SHRs. METHODS ETB receptor expression in RPT cells was measured by immunoblotting and reverse transcriptase-PCR and ETB receptor function by measuring Na(+)-K(+) ATPase activity. D(3)/ETB receptor interaction was studied by co-immunoprecipitation. RESULTS In Wistar-Kyoto (WKY) RPT cells, the D(3) receptor agonist, PD128907, increased ETB receptor protein expression, effects that were blocked by removal of calcium in the culture medium. The stimulatory effect of D(3) on ETB receptor mRNA and protein expression was also blocked by nicardipine. In contrast, in SHR RPT cells, PD128907 decreased ETB receptor expression. Basal D(3)/ETB receptor co-immunoprecipitation was three times greater in WKY than in SHRs. The absolute amount of D(3)/ETB receptor co-immunoprecipitation induced by a D(3) receptor agonist was also greater in WKY than in SHRs. Stimulation of ETB receptors decreased Na(+)-K(+) ATPase activity in WKY but not in SHR cells. Pretreatment with PD128907 augmented the inhibitory effect of BQ3020 on Na(+)-K(+) ATPase activity in WKY but not in SHR cells. CONCLUSIONS D(3) receptors regulate ETB receptors by physical receptor interaction and govern receptor expression and function. D(3) receptor regulation of ETB receptors is aberrant in RPT cells from SHRs.
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Effects of long-term ouabain treatment on blood pressure, sodium excretion, and renal dopamine D1 receptor levels in rats. J Comp Physiol B 2009; 180:117-24. [DOI: 10.1007/s00360-009-0391-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 06/25/2009] [Accepted: 06/29/2009] [Indexed: 01/11/2023]
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Zeng C, Villar VAM, Yu P, Zhou L, Jose PA. Reactive oxygen species and dopamine receptor function in essential hypertension. Clin Exp Hypertens 2009; 31:156-78. [PMID: 19330604 DOI: 10.1080/10641960802621283] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Essential hypertension is a major risk factor for stroke, myocardial infarction, and heart and kidney failure. Dopamine plays an important role in the pathogenesis of hypertension by regulating epithelial sodium transport and by interacting with vasoactive hormones and humoral factors. However, the mechanisms leading to impaired dopamine receptor function in hypertension states are not clear. Compelling experimental evidence indicates a role of reactive oxygen species (ROS) in hypertension, and there are increasing pieces of evidence showing that in conditions associated with oxidative stress, which is present in hypertensive states, dopamine receptor effects, such as natriuresis, diuresis, and vasodilation, are impaired. The goal of this review is to present experimental evidence that has led to the conclusion that decreased dopamine receptor function increases ROS activity and vice versa. Decreased dopamine receptor function and increased ROS production, working in concert or independent of each other, contribute to the pathogenesis of essential hypertension.
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Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China.
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Wang X, Villar VAM, Armando I, Eisner GM, Felder RA, Jose PA. Dopamine, kidney, and hypertension: studies in dopamine receptor knockout mice. Pediatr Nephrol 2008; 23:2131-46. [PMID: 18615257 PMCID: PMC3724362 DOI: 10.1007/s00467-008-0901-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 04/18/2008] [Accepted: 05/07/2008] [Indexed: 02/06/2023]
Abstract
Dopamine is important in the pathogenesis of hypertension because of abnormalities in receptor-mediated regulation of renal sodium transport. Dopamine receptors are classified into D(1)-like (D(1), D(5)) and D(2)-like (D(2), D(3), D(4)) subtypes, all of which are expressed in the kidney. Mice deficient in specific dopamine receptors have been generated to provide holistic assessment on the varying physiological roles of each receptor subtype. This review examines recent studies on these mutant mouse models and evaluates the impact of individual dopamine receptor subtypes on blood pressure regulation.
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Affiliation(s)
- Xiaoyan Wang
- Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
| | | | - Ines Armando
- Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
| | - Gilbert M. Eisner
- Department of Medicine, Georgetown University Medical Center, Washington, DC, USA
| | - Robin A. Felder
- Department of Pathology, University of Virginia Health Sciences Center, Charlottesville, VA, USA
| | - Pedro A. Jose
- Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
- Department of Physiology and Biophysics, Georgetown University Medical Center, Washington, DC, USA
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Zeng C, Asico LD, Yu C, Villar VAM, Shi W, Luo Y, Wang Z, He D, Liu Y, Huang L, Yang C, Wang X, Hopfer U, Eisner GM, Jose PA. Renal D3 dopamine receptor stimulation induces natriuresis by endothelin B receptor interactions. Kidney Int 2008; 74:750-9. [PMID: 18547994 DOI: 10.1038/ki.2008.247] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Dopaminergic and endothelin systems participate in the control blood pressure by regulating sodium transport in the renal proximal tubule. Disruption of either the endothelin B receptor (ETB) or D(3) dopamine receptor gene in mice produces hypertension. To examine whether these two receptors interact we studied the Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats by selectively infusing reagents into the right kidney of anesthetized rats. The D(3) receptor agonist (PD128907) caused natriuresis in WKY rats which was partially blocked by the ETB receptor antagonist. In contrast, PD128907 blunted sodium excretion in the SHRs. We found using laser confocal microscopy that the ETB receptor was mainly located in the cell membrane in control WKY cells. Treatment with the D(3) receptor antagonist caused its internalization into intracellular compartments that contained the D(3) receptors. Combined use of D(3) and ETB antagonists failed to internalize ETB receptors in cells from WKY rats. In contrast in SHR cells, ETB receptors were found mainly in internal compartments under basal condition and thus were likely prevented from interacting with the agonist-stimulated, membrane-bound D(3) receptors. Our studies suggest that D(3) receptors physically interact with proximal tubule ETB receptors and that the blunted natriuretic effect of dopamine in SHRs may be explained, in part, by abnormal D(3)/ETB receptor interactions.
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Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China
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36
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Zeng C, Armando I, Luo Y, Eisner GM, Felder RA, Jose PA. Dysregulation of dopamine-dependent mechanisms as a determinant of hypertension: studies in dopamine receptor knockout mice. Am J Physiol Heart Circ Physiol 2008; 294:H551-69. [PMID: 18083900 PMCID: PMC4029502 DOI: 10.1152/ajpheart.01036.2007] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Dopamine plays an important role in the pathogenesis of hypertension by regulating epithelial sodium transport and by interacting with vasoactive hormones/humoral factors, such as aldosterone, angiotensin, catecholamines, endothelin, oxytocin, prolactin pro-opiomelancortin, reactive oxygen species, renin, and vasopressin. Dopamine receptors are classified into D(1)-like (D(1) and D(5)) and D(2)-like (D(2), D(3), and D(4)) subtypes based on their structure and pharmacology. In recent years, mice deficient in one or more of the five dopamine receptor subtypes have been generated, leading to a better understanding of the physiological role of each of the dopamine receptor subtypes. This review summarizes the results from studies of various dopamine receptor mutant mice on the role of individual dopamine receptor subtypes and their interactions with other G protein-coupled receptors in the regulation of blood pressure.
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MESH Headings
- Animals
- Blood Pressure/genetics
- Blood Pressure/physiology
- Dopamine/physiology
- Hypertension/genetics
- Hypertension/physiopathology
- Mice
- Mice, Knockout
- Receptors, Dopamine/genetics
- Receptors, Dopamine/physiology
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/physiology
- Receptors, Dopamine D3/genetics
- Receptors, Dopamine D3/physiology
- Receptors, Dopamine D4/genetics
- Receptors, Dopamine D4/physiology
- Receptors, Dopamine D5/genetics
- Receptors, Dopamine D5/physiology
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Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing City 400042, People's Republic of China.
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37
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Rodriguez-Iturbe B, Romero F, Johnson RJ. Pathophysiological Mechanisms of Salt-Dependent Hypertension. Am J Kidney Dis 2007; 50:655-72. [PMID: 17900467 DOI: 10.1053/j.ajkd.2007.05.025] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Accepted: 05/18/2007] [Indexed: 12/29/2022]
Abstract
Changes in salt intake are associated in general with corresponding changes in arterial blood pressure. An exaggerated increment in blood pressure driven by a salt load is characteristic of salt-sensitive hypertension, a condition affecting more than two thirds of individuals with essential hypertension who are older than 60 years. In the last decade, significant insight was gained about the role of the kidney in the increment in blood pressure induced by sodium retention. The present review focuses on the pathophysiological characteristics of the blood pressure increase driven by expansion of extracellular fluid and the increment in plasma sodium concentration. In addition, we discuss systemic and renal conditions that result in decreased urinary sodium excretion and were implicated in the development of salt-sensitive hypertension.
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38
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Abstract
Dopamine plays an important role in the pathogenesis of hypertension by regulating epithelial sodium transport, vascular smooth muscle contractility and production of reactive oxygen species and by interacting with the renin–angiotensin and sympathetic nervous systems. Dopamine receptors are classified into D1-like (D1 and D5) and D2-like (D2, D3 and D4) subtypes based on their structure and pharmacology. Each of the dopamine receptor subtypes participates in the regulation of blood pressure by mechanisms specific for the subtype. Some receptors regulate blood pressure by influencing the central and/or peripheral nervous system; others influence epithelial transport and regulate the secretion and receptors of several humoral agents. This review summarizes the physiology of the different dopamine receptors in the regulation of blood pressure, and the relationship between dopamine receptor subtypes and hypertension.
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MESH Headings
- Blood Pressure/physiology
- Dopamine/metabolism
- Gastrointestinal Tract/metabolism
- Gastrointestinal Tract/physiopathology
- Humans
- Hypertension/metabolism
- Hypertension/physiopathology
- Kidney/metabolism
- Kidney/physiopathology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Receptors, Dopamine/metabolism
- Receptors, Dopamine/physiology
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/metabolism
- Receptors, Dopamine D2/physiology
- Receptors, Dopamine D3/metabolism
- Receptors, Dopamine D3/physiology
- Receptors, Dopamine D4/metabolism
- Receptors, Dopamine D4/physiology
- Receptors, Dopamine D5/metabolism
- Receptors, Dopamine D5/physiology
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Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing City, People's Republic of China.
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39
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Felder RA, Jose PA. Mechanisms of disease: the role of GRK4 in the etiology of essential hypertension and salt sensitivity. ACTA ACUST UNITED AC 2006; 2:637-50. [PMID: 17066056 DOI: 10.1038/ncpneph0301] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Accepted: 07/03/2006] [Indexed: 12/15/2022]
Abstract
Hypertension and salt sensitivity of blood pressure are two conditions the etiologies of which are still elusive because of the complex influences of genes, environment, and behavior. Recent understanding of the molecular mechanisms that govern sodium homeostasis is shedding new light on how genes, their protein products, and interacting metabolic pathways contribute to disease. Sodium transport is increased in the proximal tubule and thick ascending limb of Henle of the kidney in human essential hypertension. This Review focuses on the counter-regulation between the dopaminergic and renin-angiotensin systems in the renal proximal tubule, which is the site of about 70% of total renal sodium reabsorption. The inhibitory effect of dopamine is most evident under conditions of moderate sodium excess, whereas the stimulatory effect of angiotensin II is most evident under conditions of sodium deficit. Dopamine and angiotensin II exert their actions via G protein-coupled receptors, which are in turn regulated by G protein-coupled receptor kinases (GRKs). Polymorphisms that lead to aberrant action of GRKs cause a number of conditions, including hypertension and salt sensitivity. Polymorphisms in one particular member of this family-GRK4-have been shown to cause hyperphosphorylation, desensitization and internalization of a member of the dopamine receptor family, the dopamine 1 receptor, while increasing the expression of a key receptor of the renin-angiotensin system, the angiotensin II type 1 receptor. Novel diagnostic and therapeutic approaches for identifying at-risk subjects, followed by selective treatment of hypertension and salt sensitivity, might center on restoring normal receptor function through blocking the effects of GRK4 polymorphisms.
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Affiliation(s)
- Robin A Felder
- Department of Pathology, Post Office Box 800403, University of Virginia Health Sciences Center, Charlottesville, VA 22908, USA.
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40
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Zeng C, Liu Y, Wang Z, He D, Huang L, Yu P, Zheng S, Jones JE, Asico LD, Hopfer U, Eisner GM, Felder RA, Jose PA. Activation of D
3
Dopamine Receptor Decreases Angiotensin II Type 1 Receptor Expression in Rat Renal Proximal Tubule Cells. Circ Res 2006; 99:494-500. [PMID: 16902178 DOI: 10.1161/01.res.0000240500.96746.ec] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The dopaminergic and renin angiotensin systems interact to regulate blood pressure. Disruption of the D
3
dopamine receptor gene in mice produces renin-dependent hypertension. In rats, D
2
-like receptors reduce angiotensin II binding sites in renal proximal tubules (RPTs). Because the major D
2
-like receptor in RPTs is the D
3
receptor, we examined whether D
3
receptors regulate angiotensin II type 1 (AT
1
) receptors in rat RPT cells. The effect of D
3
receptors on AT
1
receptors was studied in vitro and in vivo. The D
3
receptor agonist PD128907 decreased AT
1
receptor protein and mRNA in WKY RPT cells and increased it in SHR cells. PD128907 increased D
3
receptors in WKY cells but had no effect in SHR cells. D
3
/AT
1
receptors colocalized in RPT cells; D
3
receptor stimulation decreased the percent amount of D
3
receptors that coimmunoprecipitated with AT
1
receptors to a greater extent in WKY than in SHR cells. However, D
3
receptor stimulation did not change the percent amount of AT
1
receptors that coimmunoprecipitated with D
3
receptors in WKY cells and markedly decreased the coimmunoprecipitation in SHR cells. The D
3
receptor also regulated the AT
1
receptor in vivo because AT
1
receptor expression was increased in kidneys of D
3
receptor–null mice compared with wild type littermates. D
3
receptors may regulate AT
1
receptor function by direct interaction with and regulation of AT
1
receptor expression. One mechanism of hypertension may be related to increased renal expression of AT
1
receptors due decreased D
3
receptor regulation.
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MESH Headings
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Animals
- Benzopyrans/pharmacology
- Cells, Cultured
- Dopamine Agonists/pharmacology
- Kidney Tubules, Proximal/metabolism
- Kidney Tubules, Proximal/pathology
- Mice
- Mice, Knockout
- Oxazines/pharmacology
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Receptor, Angiotensin, Type 1/metabolism
- Receptors, Dopamine D3/agonists
- Receptors, Dopamine D3/deficiency
- Receptors, Dopamine D3/metabolism
- Tissue Distribution
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Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing 400042, People's Republic of China.
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41
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Zeng C, Sanada H, Watanabe H, Eisner GM, Felder RA, Jose PA. Functional genomics of the dopaminergic system in hypertension. Physiol Genomics 2005; 19:233-46. [PMID: 15548830 DOI: 10.1152/physiolgenomics.00127.2004] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Abnormalities in dopamine production and receptor function have been described in human essential hypertension and rodent models of genetic hypertension. Under normal conditions, D(1)-like receptors (D(1) and D(5)) inhibit sodium transport in the kidney and intestine. However, in the Dahl salt-sensitive and spontaneously hypertensive rats (SHRs) and in humans with essential hypertension, the D(1)-like receptor-mediated inhibition of epithelial sodium transport is impaired because of an uncoupling of the D(1)-like receptor from its G protein/effector complex. The uncoupling is receptor specific, organ selective, nephron-segment specific, precedes the onset of hypertension, and cosegregates with the hypertensive phenotype. The defective transduction of the renal dopaminergic signal is caused by activating variants of G protein-coupled receptor kinase type 4 (GRK4: R65L, A142V, A486V). The GRK4 locus is linked to and GRK4 gene variants are associated with human essential hypertension, especially in salt-sensitive hypertensive subjects. Indeed, the presence of three or more GRK4 variants impairs the natriuretic response to dopaminergic stimulation in humans. In genetically hypertensive rats, renal inhibition of GRK4 expression ameliorates the hypertension. In mice, overexpression of GRK4 variants causes hypertension either with or without salt sensitivity according to the variant. GRK4 gene variants, by preventing the natriuretic function of the dopaminergic system and by allowing the antinatriuretic factors (e.g., angiotensin II type 1 receptor) to predominate, may be responsible for salt sensitivity. Subclasses of hypertension may occur because of additional perturbations caused by variants of other genes, the quantitative interaction of which may vary depending upon the genetic background.
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Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
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42
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Banday AA, Marwaha A, Tallam LS, Lokhandwala MF. Tempol reduces oxidative stress, improves insulin sensitivity, decreases renal dopamine D1 receptor hyperphosphorylation, and restores D1 receptor-G-protein coupling and function in obese Zucker rats. Diabetes 2005; 54:2219-26. [PMID: 15983225 DOI: 10.2337/diabetes.54.7.2219] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Oxidative stress plays a pathogenic role in hypertension, particularly the one associated with diabetes and obesity. Here, we test the hypothesis that renal dopamine D1 receptor dysfunction in obese Zucker rats is caused by oxidative stress. One group each from lean and obese Zucker rats received tempol, a superoxide dismutase mimetic in drinking water for 2 weeks. Obese animals were hypertensive, hyperglycemic, and hyperinsulinemic, exhibited renal oxidative stress, and increased protein kinase C activity. Also, there was hyperphosphorylation of D1 receptor, defective receptor-G-protein coupling, blunted dopamine-induced Na+-K+-ATPase inhibition, and diminished natriuretic response to D1 receptor agonist, SKF-38393. However, obese animals had elevated levels of plasma nitric oxide and urinary cGMP. In addition, L-N-nitroarginine and sodium nitroprusside showed similar effect on blood pressure in lean and obese rats. In obese animals, tempol reduced blood pressure, blood glucose, insulin, renal oxidative stress, and protein kinase C activity. Tempol also decreased D1 receptor phosphorylation and restored receptor G-protein coupling. Dopamine inhibited Na+-K+-ATPase activity, and SKF-38393 elicited a natriuretic response in tempol-treated obese rats. Thus in obese Zucker rats, tempol ameliorates oxidative stress and improves insulin sensitivity. Consequently, hyperphosphorylation of D1 receptor is reduced, leading to restoration of receptor-G-protein coupling and the natriuretic response to SKF-38393.
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Affiliation(s)
- Anees Ahmad Banday
- Heart and Kidney Institute, University of Houston, Houston, Texas 77204, USA
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43
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Zeng C, Yang Z, Wang Z, Jones J, Wang X, Altea J, Mangrum AJ, Hopfer U, Sibley DR, Eisner GM, Felder RA, Jose PA. Interaction of Angiotensin II Type 1 and D
5
Dopamine Receptors in Renal Proximal Tubule Cells. Hypertension 2005; 45:804-10. [PMID: 15699451 DOI: 10.1161/01.hyp.0000155212.33212.99] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Angiotensin II type 1 (AT
1
) receptor and D
1
and D
3
dopamine receptors directly interact in renal proximal tubule (RPT) cells from normotensive Wistar-Kyoto rats (WKY). There is indirect evidence for a D
5
and AT
1
receptor interaction in WKY and spontaneously hypertensive rats (SHR). Therefore, we sought direct evidence of an interaction between AT
1
and D
5
receptors in RPT cells. D
5
and AT
1
receptors colocalized in WKY cells. Angiotensin II decreased D
5
receptors in WKY cells in a time- and concentration-dependent manner (EC
50
=2.7×10
−9
M; t
1/2
=4.9 hours), effects that were blocked by an AT
1
receptor antagonist (losartan). In SHR, angiotensin II (10
−8
M/24 hours) also decreased D
5
receptors (0.96±0.08 versus 0.72±0.08; n=12) and to the same degree as in WKY cells (1.44±0.07 versus 0.92±0.08). However, basal D
5
receptors were decreased in SHR RPT cells (SHR 0.96±0.08; WKY 1.44±0.07; n=12 per strain;
P
<0.05) and renal brush border membranes of SHR compared with WKY (SHR 0.54±0.16 versus WKY 1.46±0.10; n=5 per strain;
P
<0.05). Angiotensin II decreased AT
1
receptor expression in WKY (1.00±0.04 versus 0.72±0.08; n=8;
P
<0.05) but increased it in SHR (0.96±0.04 versus 1.32±0.08; n=8;
P
<0.05). AT
1
and D
5
receptors also interacted in vivo; renal D
5
receptor protein was higher in mice lacking the AT
1A
receptor (AT
1A
−/−; 1.61±0.31; n=6) than in wild-type littermates used as controls (AT
1A
+/+; 0.81±0.08; n=6;
P
<0.05), and renal cortical AT
1
receptor protein was higher in D
5
receptor null mice than in wild-type littermates (1.18±0.08 versus 0.84±0.07; n=4;
P
<0.05). We conclude that D
5
and AT
1
receptors interact with each other. Altered interactions between AT
1
and dopamine receptors may play a role in the pathogenesis of hypertension.
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MESH Headings
- Angiotensin II/pharmacology
- Animals
- Cells, Cultured
- Drug Interactions
- Kidney Tubules, Proximal/cytology
- Kidney Tubules, Proximal/metabolism
- Mice
- Mice, Inbred Strains
- Mice, Knockout
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Receptor, Angiotensin, Type 1/deficiency
- Receptor, Angiotensin, Type 1/drug effects
- Receptor, Angiotensin, Type 1/metabolism
- Receptors, Dopamine D1/antagonists & inhibitors
- Receptors, Dopamine D1/deficiency
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D5
- Tissue Distribution
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Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing, P.R. China.
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44
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Pedrosa R, Gomes P, Zeng C, Hopfer U, Jose PA, Soares-da-Silva P. Dopamine D3 receptor-mediated inhibition of Na+/H+ exchanger activity in normotensive and spontaneously hypertensive rat proximal tubular epithelial cells. Br J Pharmacol 2004; 142:1343-53. [PMID: 15265811 PMCID: PMC1575199 DOI: 10.1038/sj.bjp.0705893] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This study evaluated the response of the Na(+)/H(+) exchanger (NHE) to dopamine D(1)- and D(2)-like receptor stimulation in immortalized renal proximal tubular epithelial cells and freshly isolated renal proximal tubules from the spontaneously hypertensive rat (SHR) and their normotensive controls (Wistar Kyoto rats; WKY). Stimulation of D(1)-like receptors with SKF 38393 attenuated NHE activity in WKY cells (IC(50)=151 nM), but not in SHR cells. Stimulation of D(2)-like receptors with quinerolane (IC(50)=120 nM) attenuated NHE activity in SHR cells, but not in WKY cells. Forskolin was equipotent in SHR and WKY cells in inhibiting NHE activity. The effect of SKF 38393 was abolished by overnight treatment of WKY cells with cholera toxin (CTX, 500 ng ml(-1)), but not with pertussis toxin (PTX, 100 ng ml(-1)). The effect of quinerolane (1 microm) was abolished by overnight treatment of SHR cells with PTX, but not with CTX. The D(3) receptor agonist 7-OH-DPAT (IC(50)=0.8 microM) attenuated NHE activity in SHR cells only. This effect was abolished by S-sulpiride and by overnight treatment with PTX. The D(4) receptor agonist RBI 257 did not affect NHE activity. The 7-OH-DPAT inhibited NHE activity in freshly isolated renal proximal tubules from 4- and 12-week-old SHR and 12-week-old WKY, but not in freshly isolated renal proximal tubules from 4-week-old WKY. It is concluded that D(3) receptors coupled to a G(i/o) protein play a role in the handling of tubular Na(+), namely through inhibition of the NHE activity, this being of particular relevance in the SHR, which fail to respond to D(1)-like dopamine receptor stimulation.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/analogs & derivatives
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Blood Pressure/drug effects
- Blood Pressure/physiology
- Cell Line, Transformed
- Cells, Cultured
- Dopamine/pharmacology
- Dopamine D2 Receptor Antagonists
- Dose-Response Relationship, Drug
- Epithelial Cells/drug effects
- Epithelial Cells/metabolism
- Hypertension/metabolism
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Male
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Receptors, Dopamine D2/agonists
- Receptors, Dopamine D2/physiology
- Receptors, Dopamine D3
- Sodium-Hydrogen Exchangers/antagonists & inhibitors
- Sodium-Hydrogen Exchangers/metabolism
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Affiliation(s)
- Rui Pedrosa
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, Porto 4200-319, Portugal
| | - Pedro Gomes
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, Porto 4200-319, Portugal
| | - Chunyu Zeng
- Departments of Pediatrics and Physiology and Biophysics, Georgetown University Medical Center, Washington, DC, U.S.A
| | - Ulrich Hopfer
- Department of Physiology, Case Western Reserve Medical School, Cleveland, OH, U.S.A
| | - Pedro A Jose
- Departments of Pediatrics and Physiology and Biophysics, Georgetown University Medical Center, Washington, DC, U.S.A
| | - Patrício Soares-da-Silva
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, Porto 4200-319, Portugal
- Author for correspondence:
| |
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45
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Zeng C, Luo Y, Asico LD, Hopfer U, Eisner GM, Felder RA, Jose PA. Perturbation of D1 dopamine and AT1 receptor interaction in spontaneously hypertensive rats. Hypertension 2003; 42:787-92. [PMID: 12900438 DOI: 10.1161/01.hyp.0000085334.34963.4e] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The dopaminergic and renin-angiotensin systems interact to regulate blood pressure. Because this interaction may be perturbed in genetic hypertension, we studied D1 dopamine and AT1 angiotensin receptors in immortalized renal proximal tubule (RPT) and A10 aortic vascular smooth muscle cells. In normotensive Wistar-Kyoto (WKY) rats, the D1-like agonist fenoldopam increased D1 receptors but decreased AT1 receptors. These effects were blocked by the D1-like antagonist SCH 23390 (10(-7) mol/L per 24 hours). In spontaneously hypertensive rat (SHR) RPT cells, fenoldopam also decreased AT1 receptors but no longer stimulated D1 receptor expression. Basal levels of AT1/D1 receptor coimmunoprecipitation were greater in WKY RPT cells (29+/-2 density units, DU) than in SHR RPT cells (21+/-2 DU, n=7 per group, P<0.05). The coimmunoprecipitation of D1 and AT1 receptors was increased by fenoldopam (10(-7) mol/L per 24 hours) in WKY RPT cells but decreased in SHR RPT cells. The effects of fenoldopam in RPT cells from WKY rats were similar in aortic vascular smooth muscle cells from normotensive BD IX rats, that is, fenoldopam decreased AT1 receptors and increased D1 receptors. Our studies show differential regulation of the expression of D1 and AT1 receptors in RPT cells from WKY and SHR. This regulation and D1/AT1 receptor interaction are different in RPT cells of WKY and SHR. An altered interaction of D1 and AT1 receptors may play a role in the impaired sodium excretion and enhanced vasoconstriction in hypertension.
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MESH Headings
- Animals
- Cell Line
- Cells, Cultured
- Dopamine Agonists/pharmacology
- Fenoldopam/pharmacology
- Hypertension/metabolism
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Precipitin Tests
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Receptor, Angiotensin, Type 1
- Receptors, Angiotensin/metabolism
- Receptors, Dopamine D1/metabolism
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Affiliation(s)
- Chunyu Zeng
- Department of Pediatrics, Georgetown University Medical Center, 3800 Reservoir Road, NW, Washington, DC 20007, USA.
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46
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Haegeman A, Williams JL, Law A, Van Zeveren A, Peelman LJ. Characterization and mapping of bovine dopamine receptors 1 and 5. Anim Genet 2003; 34:290-3. [PMID: 12873217 DOI: 10.1046/j.1365-2052.2003.00994.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A cDNA encoding the bovine dopamine receptor 1 (DRD1) was isolated from a bovine cDNA library, cloned and completely sequenced. The coding region showed 93 and 91% sequence identity on DNA level and 96 and 94% on protein level with its respective porcine and human orthologs. The bovine DRD1 and dopamine receptor 5 (DRD5) were mapped, respectively, to BTA10 and 6 by radiation hybrid mapping. One SNP was found in DRD1 and four in DRD5. Using polymerase chain reaction-restriction fragment length polymorphism, 11 different European cattle breeds were screened for the presence of the DRD1 and DRD5 substitutions. Allele frequencies for DRD1 and DRD5 alleles were very similar across all the breeds examined. Allele frequency discrepancies were found between Belgian Blue beef breed and the other breeds.
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Affiliation(s)
- A Haegeman
- Department of Animal Nutrition, Genetics, Breeding and Ethology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | | | | | | | | |
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47
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Zeng C, Asico LD, Wang X, Hopfer U, Eisner GM, Felder RA, Jose PA. Angiotensin II regulation of AT1 and D3 dopamine receptors in renal proximal tubule cells of SHR. Hypertension 2003; 41:724-9. [PMID: 12623987 DOI: 10.1161/01.hyp.0000047880.78462.0e] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Dopamine and angiotensin II negatively interact to regulate sodium excretion and blood pressure. D3 dopamine receptors downregulate angiotensin type 1 (AT1) receptors in renal proximal tubule cells from normotensive Wistar-Kyoto rats. We determined whether AT1 receptors regulate D3 receptors and whether the regulation is different in cultured renal proximal tubule cells from normotensive and spontaneously hypertensive rats. Angiotensin II (10(-8)M/24 hours) decreased D3 receptors in both normotensive (control, 36+/-3; angiotensin II, 24+/-3 U) and hypertensive (control, 30+/-3; angiotensin II, 11+/-3 U; n=9 per group) rats; effects that were blocked by the AT1 receptor antagonist, losartan (10(-8)M/24 hours). However, the reduction in D3 expression was greater in hypertensive (60+/-10%) than in normotensive rats (32+/-9%). In normotensive rats, angiotensin II (10(-8)M/24hr) also decreased AT1 receptors. In contrast, in cells from hypertensive rats, angiotensin II increased AT1 receptors. AT1 and D3 receptors co-immunoprecipitated in renal proximal tubule cells from both strains. Angiotensin II decreased D3/AT1 receptor co-immunoprecipitation similarly in both rat strains, but basal D3/AT1 co-immunoprecipitation was 6 times higher in normotensive than in hypertensive rats. Therefore, AT1 and D3 receptor interaction is qualitatively and quantitatively different between normotensive and hypertensive rats; angiotensin II decreases AT1 expression in normotensive but increases it in hypertensive rats. In addition, angiotensin II decreases D3 expression to a greater extent in hypertensive than in normotensive rats. Aberrant interactions between D3 and AT1 receptors may play a role in the pathogenesis of hypertension.
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MESH Headings
- Angiotensin II/pharmacology
- Animals
- Antibody Specificity
- Cells, Cultured
- Hypertension/metabolism
- Immunoblotting
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Precipitin Tests
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Receptor, Angiotensin, Type 1
- Receptors, Angiotensin/immunology
- Receptors, Angiotensin/metabolism
- Receptors, Dopamine D2/immunology
- Receptors, Dopamine D2/metabolism
- Receptors, Dopamine D3
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Affiliation(s)
- Chunyu Zeng
- Department of Pediatrics, Georgetown University Medical Center, Washington, DC 20007, USA.
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Abstract
PURPOSE OF REVIEW Defective transduction of the dopamine receptor signal in the kidney has been shown to be important in the pathogenesis of hypertension This review will discuss the genetic mechanism for the defective renal dopaminergic function and the interaction with other gene variant products in the pathogenesis of salt sensitivity and essential hypertension. RECENT FINDINGS Single nucleotide polymorphisms of G protein-coupled receptor kinase type 4 (GRK4) phosphorylate, desensitize, and diminish the inhibitory action of D receptors on sodium transport in the kidney. Inhibition of GRK4 expression normalizes renal proximal tubule D receptor function in humans and rodents and ameliorates the hypertension in genetically hypertensive rats. Expression of the GRK4 variant, GRK4gammaA142V, produces hypertension and impairs the natriuretic effect of D receptor stimulation in mice. In humans, GRK4 single nucleotide polymorphisms are associated with essential hypertension, particularly salt sensitive hypertension. The prediction of the hypertensive phenotype is most accurate when elements of the renin-angiotensin system and GRK4 are included in the analysis. SUMMARY GRK4 single nucleotide polymorphisms, by preventing the natriuretic function of the dopaminergic system and by allowing the antinatriuretic function of angiotensin II type 1 receptors to predominate, may be responsible for salt sensitivity. Hypertension develops with additional perturbations caused by the variants of other genes (e.g., alpha-adducin, angiotensin converting enzyme, angiotensinogen, angiotensin II type 1 receptor, aldosterone synthase, 11beta-hydroxysteroid dehydrogenase type 2), the quantitative interaction of which may vary depending upon the genetic background.
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Affiliation(s)
- Pedro A Jose
- Georgetown University Medical Center, Washington, DC 20007, USA.
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Shin Y, Kumar U, Patel Y, Patel SC, Sidhu A. Differential expression of D2-like dopamine receptors in the kidney of the spontaneously hypertensive rat. J Hypertens 2003; 21:199-207. [PMID: 12544452 DOI: 10.1097/00004872-200301000-00030] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To compare the expression and cellular distribution of D(2)-like dopamine receptors in the kidney of the spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) rat. DESIGN Renal D(2)-like receptor protein expression and distribution has not been studied in the SHR. Since changes in D(2)-like receptor expression and/or distribution may contribute to the dysregulation of renal dopamine and D(1A) receptor function, we examined the expression of the three subtypes of D(2)-like receptors (D(2), D(3) and D(4)) in SHR and WKY rat kidneys. METHODS Western blot analysis and confocal immunocytochemistry with specific polyclonal antipeptide antibodies directed against the receptor subtypes, were used to assess protein expression. RESULTS There were no differences in protein expression and cellular immunolocalization of the D(2) receptor subtypes between SHR and WKY rats. Expression of the 50 kDa D(3) receptor was reduced in the cortex of the SHR; no differences in D(3) receptor levels were seen in the inner medulla of SHR and WKY rats. The D(4) receptor polypeptides were overexpressed in the cortex of SHR, while in the inner medulla no difference in expression of the D(4) receptor proteins was observed between SHR and WKY rats. Immunocytochemistry also showed increased immunostaining of D(4) receptors in tubular structures in the cortex, but diminished staining in the SHR inner medulla. CONCLUSION The observed differences in expression and distribution of D(3) and D(4) dopamine receptors between cortex and inner medulla of the kidneys of SHR and WKY rats may contribute to the aberrant state of dopaminergic-mediated natriuresis in SHR.
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Affiliation(s)
- Yangmee Shin
- Department of Pediatrics, Georgetown University Medical Center, 3970 Reservoir Road NW, Washington, DC 20007, USA
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