1
|
Vieira-Coelho MA, Martel F. Inhibition of kidney potassium channels by fluoxetine: In vivo and in vitro studies. Fundam Clin Pharmacol 2023; 37:226-234. [PMID: 36103995 DOI: 10.1111/fcp.12833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/09/2022] [Accepted: 09/13/2022] [Indexed: 11/28/2022]
Abstract
In vitro studies have demonstrated that fluoxetine, a commonly used antidepressant drug, can modulate the activity of K+ channels. In the present study, we investigated the in vivo effect of acute and sub-chronic treatment of rats with fluoxetine on K+ renal transport. Furthermore, OK cells, a kidney epithelial cell line, were used in order to evaluate the in vitro effect of fluoxetine on K+ currents. In the sub-chronic study, fluoxetine was administrated daily (10 mg/kg, p.o.) for 15 days to male adult Wistar rats. In the acute study, rats were given increasing doses of fluoxetine (1, 3, 10, 30 and 50 mg/kg, p.o.) for 24 h. Results from the sub-chronic study show that urinary K+ content (in mmol/L) was markedly reduced in the fluoxetine-treated animals (fluoxetine: 83 ± 9; control: 131 ± 10; P < 0.001). K+ fractional renal excretion (in %) was also significantly lower in the fluoxetine group (fluoxetine: 6 ± 1; control: 13 ± 2; P < 0.001). No significant changes was observed in creatinine clearance and on renal tubular Na+ ,K+ -ATPase activity. Results obtained from the acute study demonstrate that, after a 24-h administration, fluoxetine produced a dose-dependent decrease in urinary K+ , with an ED50 (in mg/kg) of 4.2 (2.8; 5.5) and a maximal effect of 62% reduction. In vitro, fluoxetine produced a concentration-dependent inhibition of K+ currents in OK cells, with an EC50 of 107 (84.8; 129.5) μM. In conclusion, fluoxetine produces a marked reduction on urinary K+ excretion; this effect constitutes an in vivo evidence for the inhibitory action of fluoxetine on kidney epithelial K+ channels.
Collapse
Affiliation(s)
- Maria A Vieira-Coelho
- Unit of Pharmacology, Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Fátima Martel
- Unit of Biochemistry, Department of Biomedicine, University of Porto, Porto, Portugal
| |
Collapse
|
2
|
Calcitriol Prevents Cardiovascular Repercussions in Puromycin Aminonucleoside-Induced Nephrotic Syndrome. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3609645. [PMID: 29607318 PMCID: PMC5828333 DOI: 10.1155/2018/3609645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 12/12/2017] [Indexed: 11/18/2022]
Abstract
Puromycin aminonucleoside-induced nephrotic syndrome (PAN-NS) is characterized by cardiac remodeling and increased local inflammatory activity. Patients with NS and animal models of NS have vitamin D3 deficiency. The aim of the present study was to evaluate the influence of calcitriol on cardiac remodeling and local inflammatory state in PAN-NS rat model. Male Sprague-Dawley rats were injected with PAN or vehicle on day 0. PAN and control rats were divided into two subgroups for the administration of calcitriol (PAN-D and Ct-D groups) or the vehicle (PAN-V and Ct-V groups) during 21 days. On day 21, the renal function, metabolic balance, calcitriol and FGF-23 plasma levels, prohypertrophy and proinflammatory markers (ET-1, TGF-β1, TNF-α, and IL-1β), and calcium signaling molecules (PLB and SERCA-2a) were evaluated. Twenty-one days after injection, PAN-V group presented cardiac hypertrophy and a modulation of proinflammatory markers local expression. Calcitriol treatment of PAN rats prevented cardiac hypertrophy and was associated with marked reduction in the cardiac expression levels of proinflammatory markers. Our results suggest that vitamin D3 deficiency in PAN-NS may contribute to cardiac remodeling and to the increase in local inflammatory activity. Calcitriol treatment prevents both cardiac repercussions and local inflammatory processes in PAN-NS.
Collapse
|
3
|
Quelhas-Santos J, Serrão MP, Soares-Silva I, Fernandes-Cerqueira C, Simões-Silva L, Pinho MJ, Remião F, Sampaio-Maia B, Desir GV, Pestana M. Renalase regulates peripheral and central dopaminergic activities. Am J Physiol Renal Physiol 2014; 308:F84-91. [PMID: 25411385 DOI: 10.1152/ajprenal.00274.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Renalase is a recently identified FAD/NADH-dependent amine oxidase mainly expressed in kidney that is secreted into blood and urine where it was suggested to metabolize catecholamines. The present study evaluated central and peripheral dopaminergic activities in the renalase knockout (KO) mouse model and examined the changes induced by recombinant renalase (RR) administration on plasma and urine catecholamine levels. Compared with wild-type (WT) mice, KO mice presented increased plasma levels of epinephrine (Epi), norepinephrine (NE), and dopamine (DA) that were accompanied by increases in the urinary excretion of Epi, NE, DA. In addition, the KO mice presented an increase in urinary DA-to-l-3,4-dihydroxyphenylalanine (l-DOPA) ratios without changes in renal tubular aromatic-l-amino acid decarboxylase (AADC) activity. By contrast, the in vivo administration of RR (1.5 mg/kg sc) to KO mice was accompanied by significant decreases in plasma levels of Epi, DA, and l-DOPA as well as in urinary excretion of Epi, DA, and DA-to-l-DOPA ratios notwithstanding the accompanied increase in renal AADC activity. In addition, the increase in renal DA output observed in renalase KO mice was accompanied by an increase in the expression of the L-type amino acid transporter like (LAT) 1 that is reversed by the administration of RR in these animals. These results suggest that the overexpression of LAT1 in the renal cortex of the renalase KO mice might contribute to the enhanced l-DOPA availability/uptake and consequently to the activation of the renal dopaminergic system in the presence of renalase deficiency.
Collapse
Affiliation(s)
- Janete Quelhas-Santos
- Nephrology Research and Development Unit, Faculty of Medicine, University of Porto, Porto, Portugal; Nephrology and Infectious Diseases Research and Development Group, Instituto Nacional de Engenharia Biomédica-(I3S);
| | - Maria Paula Serrão
- Faculdade de Medicina da Universidade do Porto, Department of Pharmacology and Therapeutics, Porto, Portugal
| | - Isabel Soares-Silva
- Nephrology Research and Development Unit, Faculty of Medicine, University of Porto, Porto, Portugal; Nephrology and Infectious Diseases Research and Development Group, Instituto Nacional de Engenharia Biomédica-(I3S)
| | | | - Liliana Simões-Silva
- Nephrology Research and Development Unit, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Maria João Pinho
- Faculdade de Medicina da Universidade do Porto, Department of Pharmacology and Therapeutics, Porto, Portugal
| | - Fernando Remião
- Centro de Química da Universidade do Porto/Serviço de Toxicologia, Faculdade de Farmácia, University of Porto, Porto, Portugal
| | - Benedita Sampaio-Maia
- Nephrology Research and Development Unit, Faculty of Medicine, University of Porto, Porto, Portugal; Faculty of Dental Medicine, University of Porto, Porto, Portugal
| | - Gary V Desir
- Department of Medicine, Veterans Affairs Connecticut Healthcree System, Yale University, New Haven, Connecticut
| | - Manuel Pestana
- Nephrology and Infectious Diseases Research and Development Group, Instituto Nacional de Engenharia Biomédica-(I3S); Faculdade de Medicina da Universidade do Porto, Department of Renal, Urological, and Infectious Diseases, Porto, Portugal; and Department of Nephrology, São João Hospital Center, Entidade Pública Empresarial, Porto, Portugal
| |
Collapse
|
4
|
Abstract
Renalase, a recently discovered flavoprotein, which is strongly expressed in the kidney and heart, effectively metabolizes catecholamines. It was discovered during the search to identify proteins secreted by the kidney that could help explain the high incidence of cardiovascular disease in patients with chronic kidney disease. Recent advances have led to more detailed knowledge of its biology, structure, enzymatic activity, mechanisms of action, associations with human disease states and potential therapeutic value. In this study, we review these advances with a focus on hypertension and kidney disease.
Collapse
Affiliation(s)
- Gary V Desir
- Medical Service, VA Connecticut Healthcare System, West Haven, CT, USA
| | | |
Collapse
|
5
|
Quelhas-Santos J, Sampaio-Maia B, Simões-Silva L, Serrão P, Fernandes-Cerqueira C, Soares-Silva I, Pestana M. Sodium-dependent modulation of systemic and urinary renalase expression and activity in the rat remnant kidney. J Hypertens 2013; 31:543-52; discussion 552-3. [PMID: 23314744 DOI: 10.1097/hjh.0b013e32835d6e34] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE The present study examined the influence of high-sodium intake on systemic and urinary renalase levels and activity in 3/4 nephrectomized (3/4nx) and Sham rats. RESULTS The reduced circulating renalase levels in 3/4nx rats during normal-sodium intake were accompanied by increased plasma renalase activity. The sodium-induced increase of blood pressure in 3/4nx rats was accompanied by significant decreases in circulating renalase levels and activity as well as by a significant decrease in cardiac renalase levels in 3/4nx rats but not in Sham rats. During normal-sodium intake, no significant differences were observed in either urine renalase levels or activity between 3/4nx and Sham rats, not withstanding the ∼75% decrease in daily urine dopamine output observed in the rat remnant kidney. During high-sodium intake, urinary renalase levels increased in both 3/4nx and Sham groups by three-fold whereas urinary renalase activity increased in 3/4nx and Sham rats by greater than twelve-fold and greater than four-fold, respectively. This was accompanied by sodium-induced increases in daily urinary dopamine output in both 3/4nx and Sham rats by ∼2.3-fold and ∼1.6-fold, respectively. CONCLUSION The reduced circulating renalase levels in 3/4nx rats are accompanied by increased plasma renalase activity, which appears to be related with decreased inhibition of the circulating enzyme. Differences in systemic and urinary renalase levels and activity between 3/4nx and Sham rats during high-sodium intake may contribute to activation of the sympathetic nervous system, hypertension and enhanced cardiovascular risk in CKD but do not appear to account for the decrease in renal dopaminergic activity in the rat remnant kidney.
Collapse
Affiliation(s)
- Janete Quelhas-Santos
- Nephrology Research and Development Unit, Faculty of Medicine, University of Porto, Porto, Portugal
| | | | | | | | | | | | | |
Collapse
|
6
|
Sizova D, Velazquez H, Sampaio-Maia B, Quelhas-Santos J, Pestana M, Desir GV. Renalase regulates renal dopamine and phosphate metabolism. Am J Physiol Renal Physiol 2013; 305:F839-44. [PMID: 23863468 DOI: 10.1152/ajprenal.00616.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Renalase is a kidney-secreted catecholamines-degrading enzyme whose expression and activity are downregulated by increased dietary phosphate. A renalase knockout (KO) mouse model was used to explore the mechanisms mediating renalase's effect on phosphate excretion. Compared with wild-type (WT) mice maintained on a regular diet, KO mice show decreased serum PO4(-) (KO = 5.3 ± 0.2 vs. WT = 6.0 ± 0.1, n = 6; P < 0.04) and increased urinary PO4(-) excretion (urine PO4(-)/creatinine: KO = 7.7 ± 0.3 vs. WT = 6.1 ± 0.3, n = 6; P < 0.02). However, both WT and KO mice respond similarly to PO4(-) restriction by increasing renal COMT-1 activity and markedly decreasing PO4(-) excretion, which excludes an intrinsic renal defect in the KO. Renal sodium-phosphate cotransporter Npt2a, sodium proton exchanger NHE3 expression, and MAO-A and B activity did not differ between WT and KO. Only catechol-O-methyl transferase (COMT) expression and activity were significantly increased in KO mice. Despite that, urinary dopamine increased by twofold, whereas urinary l-DOPA excretion decreased by twofold in the KO mouse, indicating an upregulation of renal dopamine (DA) synthesis. These data indicate that renalase deficiency is associated with increased renal DA synthesis, stimulated PO4(-) excretion, and moderately severe hypophosphatemia. The signal to increase renal DA synthesis is strong since it overcomes a compensatory increase in COMT activity.
Collapse
Affiliation(s)
- Daria Sizova
- Section of Nephrology, Dept. of Medicine, Yale School of Medicine, P.O. Box 208029, New Haven, CT 06520-8029.
| | | | | | | | | | | |
Collapse
|
7
|
Simões-Silva L, Moreira-Rodrigues M, Quelhas-Santos J, Fernandes-Cerqueira C, Pestana M, Soares-Silva I, Sampaio-Maia B. Intestinal and renal guanylin peptides system in hypertensive obese mice. Exp Biol Med (Maywood) 2013; 238:90-7. [PMID: 23479768 DOI: 10.1258/ebm.2012.012232] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Guanylin (GN), uroguanylin (UGN) and the GC-C receptor have been associated with two endocrine axes: the salt and water homeostasis regulating enterorenal axis and the recently described appetite-regulating UGN/GC-C extraintestinal axis. The present work assessed the mRNA expression levels of GN peptides system (GPS) in a model of diet-induced obesity. Male C57BL/6J mice were submitted to either a high-fat high-simple carbohydrate diet (obese) or a normal diet (control). The renal and intestinal GN, UGN and GC-C receptor mRNA expression were evaluated by reverse transcriptase quantitative polymerase chain reaction in both groups, during normo-saline (NS) and high-saline (HS) diet. The diet-induced obesity was accompanied by glucose intolerance and insulin resistance as well as by a significant increase in blood pressure. During NS diet, obese mice presented reduced mRNA expression of GN in ileum and colon, UGN in duodenum, ileum and colon and GC-C in duodenum, jejunum, ileum and colon. This was accompanied by increased UGN mRNA expression in renal cortex. During HS diet, obese mice presented reduced mRNA expression of GN in jejunum as well as reduced mRNA expression of UGN and GC-C in duodenum, jejunum and colon. The data obtained suggest that, in a mouse model of diet-induced obesity, a down-regulation of intestinal mRNA expression of GN, UGN and its GC-C receptor is accompanied by a compensatory increase of renal UGN mRNA expression. We hypothesize that the decrease in gene expression levels of intestinal GPS may contribute to the development of hypertension and obesity during hypercaloric diet intake.
Collapse
Affiliation(s)
- Liliana Simões-Silva
- Nephrology Research and Development Unit, Faculty of Medicine, University of Porto, Alameda Prof. Hernaˆ ni Monteiro, 4200–319 Porto, Portugal
| | | | | | | | | | | | | |
Collapse
|
8
|
Desir GV, Wang L, Peixoto AJ. Human renalase: a review of its biology, function, and implications for hypertension. ACTA ACUST UNITED AC 2012; 6:417-26. [DOI: 10.1016/j.jash.2012.09.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 09/18/2012] [Indexed: 02/04/2023]
|
9
|
Malyszko J, Malyszko JS, Rysz J, Mysliwiec M, Tesar V, Levin-Iaina N, Banach M. Renalase, hypertension, and kidney - the discussion continues. Angiology 2012; 64:181-7. [PMID: 22969162 DOI: 10.1177/0003319712459212] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Hypertension and cardiovascular complications are very common in chronic kidney disease (CKD). Overactivation of sympathetic nervous system is also widely recognized in CKD. Renalase may play an important role in the control of blood pressure (BP) by its regulatory function of catecholamine metabolism. Renalase could be synthesized not only by the kidney but also by cardiomyocytes, liver, and adipose tissue. It probably exerts a hypotensive action, at least in animal models. Whether it metabolizes catecholamines remains to be proved. Another issue that remains to be resolved is the relationship between renalase and renal natriuresis and phosphaturia. In this review, the updated experimental and clinical data on renalase are presented and possible interactions with the endothelium are discussed. Renalase is "a new postulated therapeutic target." Proof of concept studies are needed to define the pathophysiological link between the kidney, sympathetic tone, BP, and cardiovascular complications.
Collapse
Affiliation(s)
- Jolanta Malyszko
- Department of Nephrology and Transplantology, Medical University in Bialystok, Bialystok, Poland.
| | | | | | | | | | | | | |
Collapse
|
10
|
Moreira-Rodrigues M, Quelhas-Santos J, Roncon-Albuquerque R, Serrão P, Leite-Moreira A, Sampaio-Maia B, Pestana M. Blunted renal dopaminergic system in a mouse model of diet-induced obesity. Exp Biol Med (Maywood) 2012; 237:949-55. [DOI: 10.1258/ebm.2012.012077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Obesity has reached epidemic proportions in the Western world and is implicated in the pathophysiology of essential hypertension. The aim of the present study was to evaluate sodium handling, blood pressure and renal dopaminergic system activity in a mouse model of obesity induced by exposure to a hypercaloric diet. From six to 18 weeks of age, animals were fed with a control diet or a high-fat high-simple-carbohydrate (HFHSC) diet. Renal function, blood pressure and urinary and plasmatic catecholamines and biochemical parameters were evaluated in both groups. In parallel, the effects of high sodium intake (HS, 1.0% NaCl, 3 days) on natriuresis, urinary catecholamine excretion and aromatic l-amino acid decarboxylase (AADC) activity were evaluated in control and obese mice. Mice exposed to the HFHSC diet presented obesity, hyperglycemia, glucose intolerance, insulin resistance, hyperinsulinemia and increased blood pressure. This was accompanied, in obese mice, by decreases in urinary excretion of dopamine and metabolites as well as reduced AADC activity in renal tissues. During HS intake, absolute urinary dopamine excretion increased in control, but not in obese mice. This was accompanied in obese mice by a natriuretic resistance on day 1 of the HS diet. In addition, obese mice presented increased urinary and plasmatic noradrenaline levels, as well as an increased heart rate when compared with control mice. In conclusion, in this model of diet-induced obesity hyperinsulinemia, insulin resistance and increased sympathetic tone are associated with blunted renal dopaminergic activity. It is suggested that this may contribute to compromised sodium excretion and increased blood pressure in obesity.
Collapse
Affiliation(s)
- Mónica Moreira-Rodrigues
- Nephrology Research and Development Unit, Faculty of Medicine
- Neuropharmacology, IBMC
- Department of Pharmacology and Therapeutics, Faculty of Medicine
| | | | | | - Paula Serrão
- Department of Pharmacology and Therapeutics, Faculty of Medicine
| | | | - Benedita Sampaio-Maia
- Nephrology Research and Development Unit, Faculty of Medicine
- Faculty of Dental Medicine, University of Porto, 4200 Porto
| | - Manuel Pestana
- Nephrology Research and Development Unit, Faculty of Medicine
- Department of Nephrology, Hospital S. João, 4200–319 Porto, Portugal
| |
Collapse
|
11
|
Novel insights into the physiology of renalase and its role in hypertension and heart disease. Pediatr Nephrol 2012; 27:719-25. [PMID: 21424526 DOI: 10.1007/s00467-011-1828-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 01/05/2011] [Accepted: 01/07/2011] [Indexed: 01/11/2023]
Abstract
Renalase is an amine oxidase expressed in kidney, heart, liver, and brain that metabolizes catecholamines. Tissue and plasma levels are decreased in models of hypertension and chronic kidney disease. Its expression is modulated by salt intake, and urinary renalase may regulate catecholamines levels and effect renal sodium and phosphate transport. The renalase knockout mouse is hypertensive in the absence of significant changes in renal function. Sympathetic tone is increased as evidenced by elevated plasma and urine catecholamines. Studies in humans with resistant hypertension indicate that plasma renalase levels are inversely associated with systolic blood pressure. Additionally, a functional mutation in renalase (Glu37Asp), known to be associated with essential hypertension, also predicts more severe cardiac hypertrophy and dysfunction. Lastly, a single dose of recombinant renalase administered subcutaneously to rats with chronic kidney disease or to Spontaneously Hypertensive Stroke Prone rats significantly decreases blood pressure for more than 24 h. Available data suggest that renalase deficiency is associated with increased sympathetic tone and resistant hypertension, and recombinant renalase is a potent antihypertensive agent that may provide a valuable option for treating hypertension in chronic kidney disease.
Collapse
|
12
|
Role of renalase in the regulation of blood pressure and the renal dopamine system. Curr Opin Nephrol Hypertens 2011; 20:31-6. [PMID: 21099685 DOI: 10.1097/mnh.0b013e3283412721] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE OF REVIEW Renalase is a secreted amine oxidase that is synthesized in the kidney, and that metabolizes circulating catecholamines. Tissue and plasma renalase levels are decreased in models of chronic kidney disease. Recent data indicate that renalase deficiency is associated with increased blood pressure and elevated circulating catecholamines. The mechanisms of hypertension in renalase deficiency and the possibility that renalase regulates the renal dopamine system are discussed. RECENT FINDINGS Characterization of the renalase knockout mouse model revealed that renalase deficiency increases SBP and DBP. Renal and cardiac functions are unaffected, but there is evidence of sympathetic activation, with elevation of plasma and urine catecholamines. Renalase is continually excreted in urine, and is enzymatically active and could modulate catecholamines levels in tubular fluid. Renalase expression is modulated by salt intake, and recombinant renalase has a potent and prolonged hypotensive effect on blood pressure in Dahl salt-sensitive rats and rats with chronic kidney disease. Plasma renalase levels are inversely associated with SBP in patients with resistant hypertension. A functional mutation in renalase (Glu37Asp) associated with essential hypertension also predicts more severe cardiac hypertrophy, dysfunction, and ischemia in individuals with stable coronary artery disease, comparable blood pressure and normal renal function. SUMMARY Urinary renalase metabolizes urinary catecholamines, and perhaps regulates dopamine concentration in luminal fluid, and modulate proximal tubular sodium transport. Renalase deficiency is associated with increased sympathetic tone and resistant hypertension. Recombinant renalase is a potent antihypertensive agent in Dahl salt-sensitive rats and in rats with chronic kidney disease.
Collapse
|
13
|
Moreira-Rodrigues M, Quelhas-Santos J, Serrão P, Fernandes-Cerqueira C, Sampaio-Maia B, Pestana M. Glycaemic control with insulin prevents the reduced renal dopamine D1 receptor expression and function in streptozotocin-induced diabetes. Nephrol Dial Transplant 2010; 25:2945-53. [PMID: 20339101 DOI: 10.1093/ndt/gfq150] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND It was demonstrated in streptozotocin (STZ)-induced diabetic rats that the D(1) receptor agonist failed to promote sodium excretion as a result of reduced renal D(1) receptor expression and decreased receptor G protein coupling. The present study examined the influence of glycaemic control with insulin on the renal D(1) receptor dysfunction in STZ-induced type 1 diabetes. METHODS Renal function, blood pressure, the natriuretic response to 5% volume expansion (VE) and the effects of the D(1) receptor agonist fenoldopam on natriuresis and on Na(+)/K(+)-ATPase activity in renal tubules were evaluated in uninephrectomized and sham-operated Wistar rats treated with STZ and compared with controls and STZ-treated rats made euglycaemic with insulin. D(1) receptor immunohistochemistry and protein abundance by western blot were also determined in all groups. RESULTS Treatment of sham and uninephrectomized rats with STZ caused a 4-fold increase in glucose plasma levels compared to controls and euglycaemic diabetic rats. A blunted natriuretic response to VE was observed in both sham and uninephrectomized hyperglycaemic diabetic rats, and this was accompanied by failure of fenoldopam to increase natriuresis and to inhibit renal Na(+)/K(+)-ATPase activity. In contrast, in both sham and uninephrectomized euglycaemic diabetic rats, the natriuretic response to VE, the fenoldopam-induced natriuresis and the accompanied inhibition of Na(+)/K(+)-ATPase activity were similar to those of the corresponding controls. D(1) receptor immunodetection and protein abundance were reduced in hyperglycaemic diabetic rats, but not in euglycaemic diabetic animals. CONCLUSIONS We conclude that the renal expression and natriuretic response to D(1) receptor activation is compromised in both sham and uninephrectomized rats with STZ-induced diabetes. These abnormalities were prevented by lowering glucose blood levels with insulin, thus providing evidence for the involvement of hyperglycaemia in the disturbances that underlie the compromised dopamine-sensitive natriuresis and increase of blood pressure in type 1 diabetes.
Collapse
Affiliation(s)
- Mónica Moreira-Rodrigues
- Nephrology Research and Development Unit, Faculty of Medicine & Hospital S. João EPE, Porto, Portugal
| | | | | | | | | | | |
Collapse
|
14
|
Katayama R, Yamaguchi N, Yamashita T, Watanabe S, Satoh H, Yamagishi N, Furuhama K. Calculation of glomerular filtration rate in conscious rats by the use of a bolus injection of iodixanol and a single blood sample. J Pharmacol Toxicol Methods 2010; 61:59-64. [DOI: 10.1016/j.vascn.2009.10.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 10/06/2009] [Accepted: 10/06/2009] [Indexed: 10/20/2022]
|
15
|
Amaral JS, Pinho MJ, Soares-da-Silva P. Regulation of amino acid transporters in the rat remnant kidney. Nephrol Dial Transplant 2009; 24:2058-67. [PMID: 19155532 DOI: 10.1093/ndt/gfn752] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Partial renal ablation is associated with compensatory renal growth, significant azotaemia, a significant increase in fractional excretion of sodium and changes in solute transport. The present study evaluated the occurrence of adaptations in the remnant kidney, especially in renal amino acid transporters and sodium transporters and their putative role in sodium handling in the early stages (24 h and 1 week) after uninephrectomy. METHODS Wistar rats aged 8 weeks old were submitted to renal ablation of the right kidney--Unx rats (n = 10). 24 hours (n = 5) and 1 week (n = 5) after surgery, rats were anesthetized and the left kidney was removed. Urinary and plasmatic levels of catecholamines, sodium, urea and creatinine were measured. Gene expression of the amino acid and sodium transporters was determined by Real-time reverse transcription PCR. Protein expression was evaluated by Western blot using specific antibodies for the amino acid and sodium transporters. RESULTS Uninephrectomized (Unx) rats for 24 h showed a lower urinary excretion of L-DOPA, dopamine and DOPAC than the corresponding Sham rats, accompanied by an increase in the expression of the Na(+)-K(+)-ATPase protein (64% increase). Unx rats for 1 week presented a hypertrophied remnant kidney, higher urine outflow and a approximately 2-fold increase in the fractional excretion of sodium. The NHE3 mRNA expression was significantly decreased in Unx rats throughout the study (approximately 20% decrease). LAT1 transcript and protein were consistently overexpressed at both 24 h and 1 week after uninephrectomy. In contrast, 4F2hc and LAT2 transcript abundance was lower in 24-h Unx rats than in Sham rats (a 36% decrease in both cases). CONCLUSIONS These results provide evidence that the renal expression of the amino acid transporters LAT1, LAT2 and 4F2hc and the sodium transporters Na(+)-K(+)-ATPase and NHE3 is differently regulated following unilateral nephrectomy. In conclusion, this study allowed us to characterize the renal adaptations in the early stages after uninephrectomy, which showed a combined interaction of multiple mechanisms regulating sodium homeostasis including the renal dopaminergic system, and the abundance of amino acid transporters and sodium transporters.
Collapse
Affiliation(s)
- João S Amaral
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, 4200-319 Porto, Portugal
| | | | | |
Collapse
|
16
|
Renal dopaminergic system activity in rat remnant kidney up to twenty-six weeks after surgery. Life Sci 2009; 84:409-14. [PMID: 19167406 DOI: 10.1016/j.lfs.2008.12.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 12/02/2008] [Accepted: 12/31/2008] [Indexed: 12/15/2022]
Abstract
AIMS In 3/4 nephrectomized (3/4nx) rats the renal dopaminergic system was suggested to be involved in the adaptive increase of sodium excretion two weeks after renal mass ablation. The aim of the present study was to evaluate the renal adaptations in sodium handling and renal dopaminergic system activity in 3/4nx rats up to twenty-six weeks after surgery. MAIN METHODS The rats were placed in metabolic cages for the collection of 24 h urine for evaluation of sodium, dopamine, dopamine precursor and metabolites. Blood pressure, aromatic L-amino acid decarboxylase (AADC) activity in proximal tubules and the effect of dopamine D(1) receptor selective antagonist (Sch-23390) on natriuresis was evaluated. KEY FINDINGS A time-dependent increase in both systolic and diastolic blood pressure was observed in 3/4nx rats, and this was accompanied by a decrease in urinary levels of dopamine and in renal AADC activity at twenty-six weeks after renal mass ablation. In contrast to what has been found two weeks after renal mass ablation, the natriuretic response to volume expansion was progressively reduced in 3/4nx rats at ten and twenty-six weeks after surgery and this was accompanied by insensitivity of natriuresis to Sch-23390. SIGNIFICANCE In conclusion the renal dopaminergic system activity is compromised in 3/4nx rats in a time-dependent manner after renal mass ablation. It is suggested that this may contribute to compromise sodium excretion and increase blood pressure, in chronic renal insufficiency.
Collapse
|
17
|
Moreira-Rodrigues M, Sampaio-Maia B, Moura M, Pestana M. Renal dopaminergic system activity in uninephrectomized rats up to 26 weeks after surgery. Am J Nephrol 2007; 27:232-9. [PMID: 17389783 DOI: 10.1159/000101368] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Accepted: 02/26/2007] [Indexed: 01/11/2023]
Abstract
BACKGROUND Dopamine of renal origin exerts natriuretic and diuretic effects by activating D1-like receptors located at various regions in the nephron. Two weeks after uninephrectomy the renal dopaminergic system was suggested to be involved in the adaptative increase of sodium excretion. AIM The aim of the present study was to evaluate the renal adaptations in sodium handling and renal dopaminergic system activity in uninephrectomized (Unx) rats up to 26 weeks after the surgery. RESULTS A time-dependent increase in both systolic and diastolic blood pressure was observed in Unx rats up to 26 weeks after uninephrectomy. This was accompanied by a compensatory increase in aromatic L-amino acid decarboxylase at 2 weeks but not 10 and 26 weeks after uninephrectomy. In contrast to what has been found 2 weeks after uninephrectomy, at 10 and 26 weeks after surgery the natriuretic response to volume expansion was reduced in Unx rats and this was accompanied by insensitivity of natriuresis to dopamine D1 receptor selective antagonist (Sch23390). CONCLUSION A time-dependent decrease in dopamine sensitive natriuresis is observed in Unx rats throughout the 26 weeks after uninephectomy. It is suggested that this may contribute to compromise sodium excretion and increase blood pressure.
Collapse
Affiliation(s)
- M Moreira-Rodrigues
- Unit of Research and Development of Nephrology, Faculty of Medicine, University of Porto, Portugal
| | | | | | | |
Collapse
|
18
|
Sampaio-Maia B, Serrao P, Moura M, Pestana M. Jejunal dopamine and Na,K-ATPase activity in early chronic renal insufficiency. Nephrology (Carlton) 2006; 11:63-7. [PMID: 16509935 DOI: 10.1111/j.1440-1797.2006.00533.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM The uninephrectomised and three-quarter nephrectomised (3/4nx) rats present dopamine-sensitive enhanced natriuresis. This is accompanied in uninephrectomised rats by a reduced jejunal Na(+),K(+)-ATPase activity with recovered sensitivity to inhibition by dopamine. The present study examined the jejunal Na(+),K(+)-ATPase activity and the role of dopamine in 3/4nx animals. METHODS Fourteen days after surgery, the L-amino acid decarboxylase activity (AADC) activity, the enzyme responsible for the synthesis of dopamine, and the Na(+),K(+)-ATPase activity, were determined in jejunal epithelial cells from 3/4nx and Sham rats. In addition, the effect of dopamine (1 micromol/L) on jejunal Na(+),K(+)-ATPase activity was evaluated in both groups. RESULTS The 3/4nx rats presented a reduced AADC activity in jejunal epithelial cells (V(max) in nmol/mg prot/15 min, 142 +/- 6 vs 190 +/- 10, P < 0.05). In addition, the jejunal Na(+),K(+)-ATPase activity was increased in 3/4nx rats (Pi release in nmol/mg prot/min, 137 +/- 1 vs 122 +/- 2, P < 0.05). However, dopamine was unable to inhibit the Na(+),K(+)-ATPase activity in jejunal epithelial cells from both 3/4nx and Sham animals. CONCLUSIONS In contrast to uninephrectomy, the jejunal Na(+),K(+)-ATPase activity is increased in 3/4nx rats and is not sensitive to inhibition by dopamine.
Collapse
|
19
|
Sampaio-Maia B, Moreira-Rodrigues M, Serrão P, Pestana M. Blunted renal dopaminergic system activity in HgCl2-induced membranous nephropathy. Life Sci 2006; 78:1246-55. [PMID: 16182313 DOI: 10.1016/j.lfs.2005.06.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Accepted: 06/27/2005] [Indexed: 01/11/2023]
Abstract
The present study evaluated the possible role of the renal dopaminergic system in the sodium retention of HgCl2-induced nephrotic syndrome. The time courses of urinary excretion of sodium, protein, dopamine and the precursor l-3,4-dihydroxyphenylalanine (L-Dopa) were evaluated in HgCl2-treated and control rats up to day 21. The renal aromatic l-amino acid decarboxylase (AADC) activity, the enzyme responsible for the synthesis of renal dopamine, was evaluated during negligible proteinuria accompanied with enhanced sodium retention (day 7), increased proteinuria accompanied with greatest sodium retention (day 14) as well as during increased proteinuria accompanied with negative sodium balance (day 21). Also, the influence of volume expansion (VE, 5% bw) and the effects of the D1-like agonist fenoldopam (10 microg kg bw(-1) min(-1)) on natriuresis and on proximal tubular Na+,K+-ATPase activity were examined on day 14. The daily urinary dopamine output and urinary dopamine/L-Dopa ratios were reduced in HgCl2-treated rats from day 2 and beyond. This was accompanied by a marked decrease in renal AADC throughout the study. During VE, the fenoldopam-induced inhibition of proximal tubular Na+,K+-ATPase activity was similar between HgCl2-treated and control rats. However, the urinary sodium excretion during fenoldopam infusion was markedly increased by 60% to 120% in control rats but was not altered in HgCl2-treated rats. It is concluded that HgCl2 nephrosis is associated with a blunted renal dopaminergic system activity. However, the lack of renal dopamine in HgCl2 nephrosis does not appear to be related with the overall renal sodium retention in a state of proteinuria.
Collapse
Affiliation(s)
- B Sampaio-Maia
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Alameda Prof. Hernani Monteiro, 4200-319, Porto, Portugal
| | | | | | | |
Collapse
|
20
|
Sampaio-Maia B, Moreira-Rodrigues M, Serrão P, Pestana M. Blunted renal dopaminergic system activity in puromycin aminonucleoside-induced nephrotic syndrome. Nephrol Dial Transplant 2005; 21:314-23. [PMID: 16204272 DOI: 10.1093/ndt/gfi171] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND A primary tubular sodium handling abnormality has been implicated in the edema formation of nephrotic syndrome. Dopamine synthesized by renal proximal tubules behaves as an endogenous natriuretic hormone by activating D(1)-like receptors as a paracrine/autocrine substance. METHODS We examined the time courses of the urinary excretion of sodium, protein and dopamine in puromycin aminonucleoside (PAN)-treated and control rats. The rats were sacrificed during greatest sodium retention (day 7) as well as during negative sodium balance (day 14) for the evaluation of renal aromatic l-amino acid decarboxylase (AADC) activity, the enzyme responsible for the synthesis of renal dopamine. Also, the influence of volume expansion (VE) and the effects of the D(1)-like agonist fenoldopam (10 microg/kg bw/min) on natriuresis and on proximal tubular Na(+),K(+)-ATPase activity were examined on day 7. RESULTS The daily urinary excretion of dopamine was decreased in PAN-treated rats, from day 5 and beyond. This was accompanied by a marked decrease in the renal AADC activity, on days 7 and 14. During VE, the fenoldopam-induced decrease in proximal tubular Na(+),K(+)-ATPase activity was more pronounced in PAN-treated rats than in controls. However, the urinary sodium excretion during fenoldopam infusion was markedly increased in control rats but was not altered in PAN-treated animals. CONCLUSION PAN nephrosis is associated with a blunted renal dopaminergic system activity which may contribute to enhance the proximal tubular Na(+),K(+)-ATPase activity. However, the lack of renal dopamine appears not to be related with the overall renal sodium retention in a state of proteinuria.
Collapse
|