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Khan N, Kurnik-Łucka M, Latacz G, Gil K. Systematic-Narrative Hybrid Literature Review: Crosstalk between Gastrointestinal Renin-Angiotensin and Dopaminergic Systems in the Regulation of Intestinal Permeability by Tight Junctions. Int J Mol Sci 2024; 25:5566. [PMID: 38791603 PMCID: PMC11122119 DOI: 10.3390/ijms25105566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/12/2024] [Accepted: 05/18/2024] [Indexed: 05/26/2024] Open
Abstract
In the first part of this article, the role of intestinal epithelial tight junctions (TJs), together with gastrointestinal dopaminergic and renin-angiotensin systems, are narratively reviewed to provide sufficient background. In the second part, the current experimental data on the interplay between gastrointestinal (GI) dopaminergic and renin-angiotensin systems in the regulation of intestinal epithelial permeability are reviewed in a systematic manner using the PRISMA methodology. Experimental data confirmed the copresence of DOPA decarboxylase (DDC) and angiotensin converting enzyme 2 (ACE2) in human and rodent enterocytes. The intestinal barrier structure and integrity can be altered by angiotensin (1-7) and dopamine (DA). Both renin-angiotensin and dopaminergic systems influence intestinal Na+/K+-ATPase activity, thus maintaining electrolyte and nutritional homeostasis. The colocalization of B0AT1 and ACE2 indicates the direct role of the renin-angiotensin system in amino acid absorption. Yet, more studies are needed to thoroughly define the structural and functional interaction between TJ-associated proteins and GI renin-angiotensin and dopaminergic systems.
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Affiliation(s)
- Nadia Khan
- Faculty of Medicine, Department of Pathophysiology, Jagiellonian University Medical College, Czysta 18, 31-121 Krakow, Poland
- Faculty of Pharmacy, Department of Technology and Biotechnology of Drugs, Jagiellonian University Medical College, Medyczna 9, 31-008 Krakow, Poland
| | - Magdalena Kurnik-Łucka
- Faculty of Medicine, Department of Pathophysiology, Jagiellonian University Medical College, Czysta 18, 31-121 Krakow, Poland
| | - Gniewomir Latacz
- Faculty of Pharmacy, Department of Technology and Biotechnology of Drugs, Jagiellonian University Medical College, Medyczna 9, 31-008 Krakow, Poland
| | - Krzysztof Gil
- Faculty of Medicine, Department of Pathophysiology, Jagiellonian University Medical College, Czysta 18, 31-121 Krakow, Poland
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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.
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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
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Forde S, Vozza G, Brayden DJ, Byrne HJ, Frías JM, Ryan SM. Evaluation of Selenomethionine Entrapped in Nanoparticles for Oral Supplementation Using In Vitro, Ex Vivo and In Vivo Models. Molecules 2023; 28:molecules28072941. [PMID: 37049704 PMCID: PMC10095941 DOI: 10.3390/molecules28072941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
Selenium methionine (SeMet) is an essential micronutrient required for normal body function and is associated with additional health benefits. However, oral administration of SeMet can be challenging due to its purported narrow therapeutic index, low oral bioavailability, and high susceptibility to oxidation. To address these issues, SeMet was entrapped in zein-coated nanoparticles made from chitosan using an ionic gelation formulation. The high stability of both the SeMet and selenomethionine nanoparticles (SeMet-NPs) was established using cultured human intestinal and liver epithelial cells, rat liver homogenates, and rat intestinal homogenates and lumen washes. Minimal cytotoxicity to Caco-2 and HepG2 cells was observed for SeMet and SeMet-NPs. Antioxidant properties of SeMet were revealed using a Reactive Oxygen Species (ROS) assay, based on the observation of a concentration-dependent reduction in the build-up of peroxides, hydroxides and hydroxyl radicals in Caco-2 cells exposed to SeMet (6.25–100 μM). The basal apparent permeability coefficient (Papp) of SeMet across isolated rat jejunal mucosae mounted in Ussing chambers was low, but the Papp was increased when presented in NP. SeMet had minimal effects on the electrogenic ion secretion of rat jejunal and colonic mucosae in Ussing chambers. Intra-jejunal injections of SeMet-NPs to rats yielded increased plasma levels of SeMet after 3 h for the SeMet-NPs compared to free SeMet. Overall, there is potential to further develop SeMet-NPs for oral supplementation due to the increased intestinal permeability, versus free SeMet, and the low potential for toxicity.
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Affiliation(s)
- Shane Forde
- UCD School of Veterinary Medicine, UCD Conway Institute, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
| | - Giulianna Vozza
- Environmental Science and Health Institute, Technological University Dublin, Grangegorman, D07 EWV4 Dublin, Ireland
- FOCAS Research Institute, Technological University Dublin, Camden Row, Dublin 8, D08 CKP1 Dublin, Ireland
| | - David J. Brayden
- UCD School of Veterinary Medicine, UCD Conway Institute, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
| | - Hugh J. Byrne
- FOCAS Research Institute, Technological University Dublin, Camden Row, Dublin 8, D08 CKP1 Dublin, Ireland
| | - Jesus M. Frías
- Environmental Science and Health Institute, Technological University Dublin, Grangegorman, D07 EWV4 Dublin, Ireland
| | - Sinéad M. Ryan
- UCD School of Veterinary Medicine, UCD Conway Institute, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
- Correspondence: ; Tel.: +353-1-7166215
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Abstract
PURPOSE OF REVIEW Hypertension, which is present in about one quarter of the world's population, is responsible for about 41% of the number one cause of death - cardiovascular disease. Not included in these statistics is the effect of sodium intake on blood pressure, even though an increase or a marked decrease in sodium intake can increase blood pressure. This review deals with the interaction of gut microbiota and the kidney with genetics and epigenetics in the regulation of blood pressure and salt sensitivity. RECENT FINDINGS The abundance of the gut microbes, Firmicutes and Bacteroidetes, is associated with increased blood pressure in several models of hypertension, including the spontaneously hypertensive and Dahl salt-sensitive rats. Decreasing gut microbiota by antibiotics can increase or decrease blood pressure that is influenced by genotype. The biological function of probiotics may also be a consequence of epigenetic modification, related, in part, to microRNA. Products of the fermentation of nutrients by gut microbiota can influence blood pressure by regulating expenditure of energy, intestinal metabolism of catecholamines, and gastrointestinal and renal ion transport, and thus, salt sensitivity. SUMMARY The beneficial or deleterious effect of gut microbiota on blood pressure is a consequence of several variables, including genetics, epigenetics, lifestyle, and intake of antibiotics. These variables may influence the ultimate level of blood pressure and control of hypertension.
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Zhang LN, Li JX, Hao L, Sun YJ, Xie YH, Wu SM, Liu L, Chen XL, Gao ZB. Crosstalk between dopamine receptors and the Na⁺/K⁺-ATPase (review). Mol Med Rep 2013; 8:1291-9. [PMID: 24065247 DOI: 10.3892/mmr.2013.1697] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 09/05/2013] [Indexed: 11/06/2022] Open
Abstract
Dopamine (DA) receptors, which belong to the G protein-coupled receptor family, are the target of ~50% of all modern medicinal drugs and constitute a large and diverse class of proteins whose primary function is to transduce extracellular stimuli into intracellular signals. Na+/K+-ATPase (NKA) is ubiquitous and crucial for the maintenance of intracellular ion homeostasis and excitability. Furthermore, it plays a critical role in diverse effects, including clinical cardiotonic and cardioprotective effects, ischemic preconditioning in the brain, natriuresis, lung edema clearance and other processes. NKA regulation is of physiological and pharmacological importance and has species- and tissue-specific variations. The activation of DA receptors regulates NKA expression/activity and trafficking in various tissues and cells, for example in the kidney, lung, intestine, brain, non-pigmented ciliary epithelium and the vascular bed. DA receptor-mediated regulation of NKA mediates a diverse range of cellular responses and includes endocytosis/exocytosis, phosphorylation/dephosphorylation of the α subunit of NKA and multiple signaling pathways, including phosphatidylinositol (PI)-phospholipase C/protein kinase (PK) C, cAMP/PKA, PI3K, adaptor protein 2, tyrosine phosphatase and mitogen-activated protein kinase/extracellular signal-regulated protein kinase. Furthermore, in brain and HEK293T cells, D1 and D2 receptors exist in a complex with NKA. Among D1 and D2 receptors and NKA, regulations are reciprocal, which leads to crosstalk between DA receptors and NKA. In the present study, the current understanding of signaling mechanisms responsible for the crosstalk between DA receptors and NKA, as well as with specific consequent functions, is reviewed.
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Affiliation(s)
- Li-Nan Zhang
- Department of Pharmacy, College of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018, P.R. China
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Villar VAM, Jones JE, Armando I, Asico LD, Escano CS, Lee H, Wang X, Yang Y, Pascua-Crusan AM, Palmes-Saloma CP, Felder RA, Jose PA. Sorting nexin 1 loss results in D5 dopamine receptor dysfunction in human renal proximal tubule cells and hypertension in mice. J Biol Chem 2012; 288:152-63. [PMID: 23152498 DOI: 10.1074/jbc.m112.428458] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The peripheral dopaminergic system plays a crucial role in blood pressure regulation through its actions on renal hemodynamics and epithelial ion transport. The dopamine D5 receptor (D(5)R) interacts with sorting nexin 1 (SNX1), a protein involved in receptor retrieval from the trans-Golgi network. In this report, we elucidated the spatial, temporal, and functional significance of this interaction in human renal proximal tubule cells and HEK293 cells stably expressing human D(5)R and in mice. Silencing of SNX1 expression via RNAi resulted in the failure of D(5)R to internalize and bind GTP, blunting of the agonist-induced increase in cAMP production and decrease in sodium transport, and up-regulation of angiotensin II receptor expression, of which expression was previously shown to be negatively regulated by D(5)R. Moreover, siRNA-mediated depletion of renal SNX1 in C57BL/6J and BALB/cJ mice resulted in increased blood pressure and blunted natriuretic response to agonist in salt-loaded BALB/cJ mice. These data demonstrate a crucial role for SNX1 in D(5)R trafficking and that SNX1 depletion results in D(5)R dysfunction and thus may represent a novel mechanism for the pathogenesis of essential hypertension.
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Affiliation(s)
- Van Anthony M Villar
- Center for Molecular Physiology Research, Children's Research Institute, Children's National Medical Center, Washington DC 20010, USA.
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Zeng C, Villar VAM, Eisner GM, Williams SM, Felder RA, Jose PA. G protein-coupled receptor kinase 4: role in blood pressure regulation. Hypertension 2008; 51:1449-55. [PMID: 18347232 DOI: 10.1161/hypertensionaha.107.096487] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing City, People's Republic of China.
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8
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Cheung THC, Bezzina G, Hampson CL, Body S, Fone KCF, Bradshaw CM, Szabadi E. Evidence for the sensitivity of operant timing behaviour to stimulation of D1 dopamine receptors. Psychopharmacology (Berl) 2007; 195:213-22. [PMID: 17668188 DOI: 10.1007/s00213-007-0892-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Accepted: 07/05/2007] [Indexed: 10/23/2022]
Abstract
RATIONALE Temporal differentiation of operant behaviour is sensitive to dopaminergic manipulations. Previous studies using the fixed-interval peak procedure implicated D(2)-like dopamine receptors in these effects. However, recent findings suggest that d-amphetamine alters timing performance on the free-operant psychophysical procedure via D(1)-like receptors. It is not known whether this effect of d-amphetamine is mimicked by direct D(1)-like receptor stimulation. OBJECTIVE The effects of a D(1)-like receptor agonist 6-chloro-2,3,4,5-tetrahydro-1-phenyl-1H-3-benzazepine (SKF-81297) on performance on the free-operant psychophysical procedure and the interaction between SKF-81297 and a D(1)-like receptor antagonist 8-bromo-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin-7-ol (SKF-83566) and a D(2)-like receptor antagonist haloperidol, were examined. MATERIALS AND METHODS Rats were trained to respond on two levers (A and B) under a free-operant psychophysical schedule, in which sucrose reinforcement was provided intermittently for responding on A during the first half and on B during the second half of 50-s trials. Logistic psychometric functions were fitted to the relative response rate data (percent responding on B [%B] vs time from trial onset [t]) under each treatment condition, and quantitative indices of timing (T(50) [value of t corresponding to %B = 50] and the Weber fraction [(T(75)-T(25))/2T(50); T(25) and T(75) are values of t corresponding to %B = 25 and %B = 75] were compared among treatments. RESULTS SKF-81297 (0.8 mg kg(-1)) reduced T(50); this effect was antagonized by SKF-83566 (0.03 mg kg(-1)) but not by haloperidol (0.05, 0.1 mg kg(-1)). CONCLUSIONS Stimulation of D(1)-like dopamine receptors affects performance in the free-operant psychophysical procedure.
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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
- Behavior, Animal/drug effects
- Benzazepines/pharmacology
- Conditioning, Operant/drug effects
- Dopamine Agonists/pharmacology
- Dopamine Antagonists/pharmacology
- Dopamine D2 Receptor Antagonists
- Dose-Response Relationship, Drug
- Female
- Haloperidol/pharmacology
- Psychometrics
- Rats
- Rats, Wistar
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/antagonists & inhibitors
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/physiology
- Time Perception/drug effects
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Affiliation(s)
- T H C Cheung
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, Room B109, Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
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9
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Fraga S, Luo Y, Jose P, Zandi-Nejad K, Mount DB, Soares-da-Silva P. Dopamine D1-like receptor-mediated inhibition of Cl/HCO3- exchanger activity in rat intestinal epithelial IEC-6 cells is regulated by G protein-coupled receptor kinase 6 (GRK 6). Cell Physiol Biochem 2007; 18:347-60. [PMID: 17170521 DOI: 10.1159/000097612] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2006] [Indexed: 01/11/2023] Open
Abstract
The present study investigated the effect of dopamine D1-like receptor stimulation on the Cl-/HCO3- exchange activity in rat intestinal epithelial IEC-6 cells. The Cl-/HCO3- exchange activity was found to be a chloride-dependent, DIDS-sensitive and niflumate-insensitive process. The presence of the SLC26A6 anion exchanger was detected by both RT-PCR and immunoblotting analysis in IEC-6 cells, in which three different small interfering RNAs (siRNAs) targeting SLC26A6 markedly inhibited Cl-/HCO3- exchange. Activation of dopamine D1-like receptors with SKF 38393 inhibited Cl-/HCO3- exchanger activity, this being antagonized by the D1 selective antagonist SKF 83566. However, effects of SKF 38393 were maximal at 5 min of exposure to the agonist and rapidly diminished with no effect at 15 min, suggestive of agonist-induced desensitization of D1-like receptors. Pretreatment of cells with heparin, a non-selective inhibitor of G protein-coupled receptor kinases (GRKs), prevented the observed attenuation of SKF 38393-induced inhibition of Cl-/HCO3- exchange. Overnight pretreatment with anti-GRK6A and anti-GRK6B, but not with anti-GRK4 antibodies, prevented the loss of SKF 38393-mediated effects. Both PKA and PKC signaling pathways participate in SKF 38393-mediated inhibition of Cl-/HCO3- exchange. These findings suggest that SLC26A6 is at least one of the anion exchanger's family members responsible for Cl-/HCO3- exchange in IEC-6 cells. Dopamine D1 receptors in IEC-6 rapidly desensitize to D1-like agonist stimulation and GRK 6, but not GRK 4, appear to be involved in agonist-mediated responsiveness and desensitization.
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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
- Cells, Cultured
- Chloride-Bicarbonate Antiporters/antagonists & inhibitors
- Chloride-Bicarbonate Antiporters/genetics
- Chloride-Bicarbonate Antiporters/metabolism
- Chloride-Bicarbonate Antiporters/physiology
- Dopamine Agonists/pharmacology
- Dopamine Antagonists/pharmacology
- G-Protein-Coupled Receptor Kinase 4
- G-Protein-Coupled Receptor Kinases
- Gene Expression
- Heparin/pharmacology
- Heparin Antagonists/pharmacology
- Immunohistochemistry
- Intestinal Mucosa/drug effects
- Intestinal Mucosa/enzymology
- Intestinal Mucosa/metabolism
- Intestines/chemistry
- Intestines/cytology
- Protein Serine-Threonine Kinases/analysis
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/metabolism
- RNA, Messenger/analysis
- Rats
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/metabolism
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Affiliation(s)
- Sónia Fraga
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal
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Body S, Cheung THC, Bezzina G, Asgari K, Fone KCF, Glennon JC, Bradshaw CM, Szabadi E. Effects of d-amphetamine and DOI (2,5-dimethoxy-4-iodoamphetamine) on timing behavior: interaction between D1 and 5-HT2A receptors. Psychopharmacology (Berl) 2006; 189:331-43. [PMID: 17051415 DOI: 10.1007/s00213-006-0575-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Accepted: 08/17/2006] [Indexed: 12/25/2022]
Abstract
RATIONALE The dopamine-releasing agent d-amphetamine and the 5-HT(2) receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) have similar effects on free-operant timing behavior. The selective D(1) dopamine receptor antagonist 8-bromo-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin-7-ol (SKF-83566), but not the D(2) dopamine receptor antagonist haloperidol, can antagonize the effect of d-amphetamine, and the selective 5-HT(2A) receptor antagonist (+/-)2,3-dimethoxyphenyl-1-(2-(4-piperidine)-methanol (MDL-100907) can antagonize the effect of DOI. However, it is not known whether the effect of d-amphetamine can be reversed by MDL-100907 and the effect of DOI by dopamine receptor antagonists. OBJECTIVE The objective of this work is to examine the interactions of d-amphetamine and DOI with MDL-100907, SKF-83566, and haloperidol on timing performance. MATERIALS AND METHODS Rats (n = 12-15 per experiment) were trained under the free-operant psychophysical procedure to press two levers (A and B) in 50-s trials in which reinforcement was provided intermittently for responding on A in the first half, and B in the second half of the trial. Percent responding on B (%B) was recorded in successive 5-s epochs of the trials; logistic functions were fitted to the data from each rat for the derivation of timing indices [T (50) (time corresponding to %B = 50); Weber fraction]. Rats were treated systemically with d-amphetamine or DOI, alone and in combination with haloperidol, SKF-83566, or MDL-100907. RESULTS d-Amphetamine (0.4 mg kg(-1)) reduced T (50) compared to vehicle; this effect was antagonized by SKF-83566 (0.03 mg kg(-1)) and MDL-100907 (0.5 mg kg(-1)), but not by haloperidol (0.05, 0.1 mg kg(-1)). DOI (0.25 mg kg(-1)) also reduced T (50); this effect was reversed by MDL-100907 (0.5 mg kg(-1)), but not by SKF-83566 (0.03 mg kg(-1)) or haloperidol (0.05 mg kg(-1)). CONCLUSIONS The results suggest that both 5-HT(2A) and D(1) receptors, but not D(2) receptors, are involved in d-amphetamine's effect on timing behavior in the free-operant psychophysical procedure. DOI's effect on timing is mediated by 5-HT(2A) receptors, but neither D(1) nor D(2) receptors are involved in this effect.
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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
- Amphetamine/pharmacology
- Amphetamines/pharmacology
- Animals
- Conditioning, Operant
- Drug Interactions
- Female
- Fluorobenzenes/pharmacology
- Piperidines/pharmacology
- Rats
- Rats, Wistar
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptors, Dopamine D2/metabolism
- Serotonin Antagonists/pharmacology
- Serotonin Receptor Agonists/pharmacology
- Time Perception/drug effects
- Time Perception/physiology
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Affiliation(s)
- S Body
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, Room B109, Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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Cheung THC, Bezzina G, Asgari K, Body S, Fone KCF, Bradshaw CM, Szabadi E. Evidence for a role of D1 dopamine receptors in d-amphetamine's effect on timing behaviour in the free-operant psychophysical procedure. Psychopharmacology (Berl) 2006; 185:378-88. [PMID: 16538470 DOI: 10.1007/s00213-006-0339-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Accepted: 01/31/2006] [Indexed: 10/24/2022]
Abstract
RATIONALE Temporal differentiation of operant behaviour is sensitive to dopaminergic manipulations. Studies using the fixed-interval peak procedure implicated D2 dopamine receptors in these effects. Less is known about the effects of dopaminergic manipulations on temporal differentiation in other timing schedules. OBJECTIVE To examine the effects of a D1 antagonist,8-bromo-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin-7-ol (SKF-83566), and a D2 antagonist, haloperidol, on performance on the free-operant psychophysical procedure, and the ability of these antagonists to reverse the effects of the catecholamine-releasing agent, d-amphetamine on performance. The antagonists' ability to reverse d-amphetamine-induced hyperlocomotion was also examined. MATERIALS AND METHODS Rats responded on two levers (A and B) under a free-operant psychophysical schedule, in which reinforcement was provided intermittently for responding on A during the first half, and B during the second half, of 50-s trials. Logistic functions were fitted to the relative response rate data (percent responding on B [%B] vs time [t]) in each treatment condition, and quantitative timing indices [T50 (value of t corresponding to %B=50) and Weber fraction] were compared among treatments. Effects of the treatments on locomotion were measured in a separate experiment. RESULTS SKF-83566 (0.015, 0.03, 0.06 mg kg(-1)) did not affect timing performance. Haloperidol (0.025, 0.05 mg kg(-1)) had no effect; a higher dose (0.1 mg kg(-1)) reduced T (50). d-Amphetamine (0.4 mg kg(-1)) reduced T50; this effect was antagonised by SKF-83566 but not by haloperidol. Both antagonists reduced d-amphetamine-induced hyperlocomotion. CONCLUSIONS The results suggest that d-amphetamine's effect on performance in the free-operant psychophysical procedure is mediated by D1 rather than D2 receptors.
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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
- Conditioning, Operant/drug effects
- Dextroamphetamine/pharmacology
- Dopamine D2 Receptor Antagonists
- Dose-Response Relationship, Drug
- Female
- Haloperidol/pharmacology
- Motor Activity/drug effects
- Rats
- Rats, Wistar
- Receptors, Dopamine D1/antagonists & inhibitors
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/physiology
- Time Perception/drug effects
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Affiliation(s)
- T H C Cheung
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, Room B109, Medical School, Queen's Medical Centre Nottingham, Nottingham, NG7 2UH, UK
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Al-Jahmany AA, Schultheiss G, Diener M. Effects of dopamine on ion transport across the rat distal colon. Pflugers Arch 2004; 448:605-12. [PMID: 15235915 DOI: 10.1007/s00424-004-1299-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 04/02/2004] [Accepted: 05/13/2004] [Indexed: 11/29/2022]
Abstract
Dopamine (5.10(-6)-5.10(-4) M) induced a concentration-dependent decrease in short-circuit current (I(sc)) across the rat distal colon. This response was preceded by a transient and inconsistent increase in I(sc). The alpha-adrenoceptor blocker phentolamine and the inhibitors of dopamine-2-like (D(2)-like) receptors L-741,626 and L-745,870 inhibited the dopamine response, suggesting a contribution of adrenergic and dopaminergic receptors. The decrease in I(sc) evoked by dopamine was inhibited by bumetanide, an inhibitor of the basolateral Na(+)-K(+)-2 Cl(-) cotransporter responsible for the uptake of K(+), and by quinine, a blocker of apical K(+) channels, indicating that stimulation of K(+) secretion contributes to the measured change in I(sc). In patch-clamp experiments dopamine hyperpolarized the membrane and increased cellular K(+) current. This response was not concomitant with a change in the intracellular [Ca(2+)] as demonstrated in parallel fura-2 experiments. These results demonstrate that dopamine, like other catecholamines, stimulates colonic K(+) secretion.
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Affiliation(s)
- Abed A Al-Jahmany
- Institut für Veterinär-Physiologie, Justus-Liebig-Universität Giessen, Frankfurter Strasse 100, 35392 Giessen, Germany
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Magro F, Fraga S, Ribeiro T, Soares-da-Silva P. Decreased availability of intestinal dopamine in transmural colitis may relate to inhibitory effects of interferon-gamma upon L-DOPA uptake. ACTA ACUST UNITED AC 2004; 180:379-86. [PMID: 15030379 DOI: 10.1111/j.1365-201x.2004.01260.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS The present study aimed to evaluate the relationship between intestinal inflammation, interferon-gamma (IFN-gamma) levels and intestinal levels of dopamine, its precursor l-3,4-dihydroxyphenylalanine (L-DOPA), and the activity of aromatic L-amino acid decarboxylase (AADC) activity along the digestive tract in a rat experimental model of colitis. METHODS Colitis was induced by rectal administration of 2,4,6-trinitrobenzene sulphonic acid (TNBS). Catechol derivatives were assayed by means of HPLC-EC. RESULTS It is shown that dopamine and noradrenaline levels in the distal colon (inflamed mucosa), but not in the ileum (non-inflamed mucosa), of TNBS-treated rats were markedly lower than in control animals. A slight decrease in L-DOPA tissue levels, no changes in AADC activity and an increase in plasma IFN-gamma levels accompanied this decrease in dopamine levels. Exposure of Caco-2 cells, a human intestinal epithelial cell line, to human IFN-gamma resulted in a concentration-dependent and long-lasting inhibition of L-DOPA uptake, which most likely explains the decrease in dopamine levels in the inflamed mucosa. CONCLUSION Changes in tissue levels of noradrenaline and dopamine in experimental colitis in the rat follow a similar pattern to that observed in patients with Crohn's disease and ulcerative colitis. In this model of experimental colitis, the decrease in dopamine levels is most likely explained by the inhibitory effect of IFN-gamma on L-DOPA uptake by intestinal epithelial cells.
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Affiliation(s)
- F Magro
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal
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14
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Fraga S, Jose PA, Soares-da-Silva P. Involvement of G protein-coupled receptor kinase 4 and 6 in rapid desensitization of dopamine D1 receptor in rat IEC-6 intestinal epithelial cells. Am J Physiol Regul Integr Comp Physiol 2004; 287:R772-9. [PMID: 15166006 DOI: 10.1152/ajpregu.00208.2004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dopamine-induced inhibition of Na(+)-K(+)-ATPase has been suggested to play a role in the regulation of Na(+) absorption at the intestinal level, and these effects were mediated by dopamine D(1)-like receptors. The aim of this work was to evaluate the effect of the activation of the D(1)-like receptors on the activity of the Na(+)/H(+) exchanger (NHE) in the rat intestinal epithelial cell line IEC-6. The presence of D(1) receptors was confirmed by immunoblotting. The dopamine D(1)-like receptor agonist SKF-38393 produced a concentration-dependent inhibition of NHE activity and stimulation of adenylyl cyclase (AC), this being antagonized by the D(1) selective antagonist SKF-83566. Effects of SKF-38393 on NHE and AC activities were maximal at 5 min of exposure to the agonist and rapidly diminished with no effect at 25 min. Exposure of cells for 25 min to dibutyryl-cAMP (0.5 mM) or to the AC activator forskolin (3 microM) effectively inhibited NHE activity. Pretreatment of cells with heparin (1 microM), a nonselective G protein-coupled receptor kinase (GRK) inhibitor, prevented the loss of effects on NHE activity after 25 min exposure to SKF-38393. The presence of GRK4, GRK6A, and GRK6B was confirmed by immunoblotting. Overnight treatment with the anti-GRK4-6 antibody complexed with Lipofectin was also effective in preventing loss of the effects of SKF-38393 on NHE and AC activities. It is concluded that dopamine D(1) receptors in IEC-6 rapidly desensitize to D(1)-like agonist stimulation and GRK4 and 6 appear to be involved in agonist-mediated responsiveness and desensitization.
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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
- Adenylyl Cyclases/metabolism
- Animals
- Antibodies, Blocking/pharmacology
- Blotting, Western
- Cell Line
- Cyclic AMP/physiology
- Cyclic AMP-Dependent Protein Kinases/physiology
- Dopamine Agonists/pharmacology
- Enzyme Inhibitors/pharmacology
- Epithelial Cells/physiology
- G-Protein-Coupled Receptor Kinase 4
- G-Protein-Coupled Receptor Kinases
- Heparin/pharmacology
- Intestines/cytology
- Intestines/physiology
- Isoenzymes/antagonists & inhibitors
- Isoenzymes/metabolism
- Isoenzymes/physiology
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/physiology
- Rats
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/physiology
- Sodium-Hydrogen Exchangers/antagonists & inhibitors
- Sodium-Hydrogen Exchangers/metabolism
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Affiliation(s)
- Sónia Fraga
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, 4200 Porto, Portugal
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Gomes P, Soares-Da-Silva P. D2-like receptor-mediated inhibition of Na+-K+-ATPase activity is dependent on the opening of K+ channels. Am J Physiol Renal Physiol 2002; 283:F114-23. [PMID: 12060593 DOI: 10.1152/ajprenal.00244.2001] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study examined the effects of D2-like dopamine receptor activation on Na+-K+-ATPase activity while apical-to-basal, ouabain-sensitive, amphotericin B-induced increases in short-circuit current and basolateral K+ (I(K)) currents in opossum kidney cells were measured. The inhibitory effect of dopamin on Na+-K+-ATPase activity was completely abolished by either D1- or D2-like receptor antagonists and mimicked by D1- and D2-like receptor agonists SKF-38393 and quinerolane, respectively. Blockade of basolateral K+ channels with BaCl2 (1 mM) or glibenclamide (10 microM), but not apamin (1 microM), totally prevented the inhibitory effects of quinerolane. The K+ channel opener pinacidil decreased Na+-K+-ATPase activity. The inhibitory effect of quinerolane on Na+-K+- ATPase activity was abolished by pretreatment of opossum kidney cells with pertussis toxin (PTX). Quinerolane increased I(K) across the basolateral membrane in a concentration-dependent manner; this effect was abolished by pretreatment with PTX, S-sulpiride, and glibenclamide. SKF-38393 did not change I(K). Both H-89 (protein kinase A inhibitor) and chelerythrine (protein kinase C inhibitor) failed to prevent the stimulatory effect of quinerolane on I(K). The stimulation of the D2-like receptor was associated with a rapid hyperpolarizing effect, whereas D1-like receptor activation was accompanied by increases in cell membrane potential. It is concluded that stimulation of D2-like receptors leads to inhibition of Na+-K+-ATPase activity and hyperpolarization; both effects are associated with the opening of K+ channels.
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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
- Amphotericin B/pharmacology
- Animals
- Antifungal Agents/pharmacology
- Cardiotonic Agents/pharmacology
- Cell Line
- Dopamine/pharmacology
- Dopamine Agonists/pharmacology
- Dopamine Antagonists/pharmacology
- Female
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Glyburide/pharmacology
- Hypoglycemic Agents/pharmacology
- Ion Channel Gating/physiology
- Kidney/cytology
- Kidney/metabolism
- Opossums
- Pertussis Toxin
- Pinacidil/pharmacology
- Potassium Channels/metabolism
- Quinolines/pharmacology
- Receptors, Dopamine D2/metabolism
- Sodium/pharmacokinetics
- Sodium-Potassium-Exchanging ATPase/antagonists & inhibitors
- Sodium-Potassium-Exchanging ATPase/metabolism
- Sulpiride/pharmacology
- Vasodilator Agents/pharmacology
- Virulence Factors, Bordetella/pharmacology
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Affiliation(s)
- Pedro Gomes
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, 4200 Porto, Portugal
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Gomes P, Soares-da-Silva P. Dopamine-induced inhibition of Na+-K+-ATPase activity requires integrity of actin cytoskeleton in opossum kidney cells. ACTA PHYSIOLOGICA SCANDINAVICA 2002; 175:93-101. [PMID: 12028129 DOI: 10.1046/j.1365-201x.2002.00972.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study evaluated the importance of the association between Na+-K+-ATPase and the actin cytoskeleton on dopamine-induced inhibition of Na+-K+-ATPase activity. The approach used measures the transepithelial transport of Na+ in monolayers of opossum kidney (OK) cells, when the Na+ delivered to Na+-K+-ATPase was increased at the saturating level by amphotericin B. The maximal amphotericin B (1.0 microg mL-1) induced increase in short-circuit current (Isc) was prevented by ouabain (100 microM) or removal of apical Na+. Dopamine (1 microM) applied from the apical side significantly decreased (29 +/- 5% reduction) the amphotericin B-induced increase in Isc, this being prevented by the D1-like receptor antagonist SKF 83566 (1 microM) and the protein kinase C (PKC) inhibitor chelerythrine (1 microM). Exposure of OK cells to cytochalasin B (1 microM) or cytochalasin D (1 microM), inhibitors of actin polymerization, from both cell sides reduced by 31 +/- 4% and 36 +/- 3% the amphotericin B-induced increase in Isc and abolished the inhibitory effect of apical dopamine (1 microM), but not that of the PKC activator phorbol-12,13-dibutyrate (PDBu; 100 nM). Colchicine (1 microM) failed to alter the inhibitory effects of dopamine. The relationship between Na+-K+-ATPase and the concentration of extracellular Na+ showed a Michaelis-Menten constant (Km) of 44.1 +/- 13.7 mM and a Vmax of 49.6 +/- 4.8 microA cm-2 in control monolayers. In the presence of apical dopamine (1 microM) or cytochalasin B (1 microM) Vmax values were significantly (P < 0.05) reduced without changes in Km values. These results are the first, obtained in live cells, showing that the PKC-dependent inhibition of Na+-K+-ATPase activity by dopamine requires the integrity of the association between actin cytoskeleton and Na+-K+-ATPase.
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Affiliation(s)
- P Gomes
- Institute of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal
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Fraga S, Serrão MP, Soares-da-Silva P. The L-3,4-dihydroxyphenylalanine transporter in human and rat epithelial intestinal cells is a type 2 hetero amino acid exchanger. Eur J Pharmacol 2002; 441:127-35. [PMID: 12063083 DOI: 10.1016/s0014-2999(02)01416-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Information on the intestinal transport of L-3,4-dihydroxyphenylalanine (L-DOPA) is scarce. We present here the functional characteristics and regulation of the apical inward L-DOPA transport in two intestinal epithelial cell lines (human Caco-2 and rat IEC-6). The inward transfer of L-DOPA and L-leucine was promoted through an energy-driven system but with different sensitivity to extracellular Na(+) concentration: a minor component of L-leucine uptake (approximately 25%) was found to require extracellular Na(+) in comparison with L-DOPA transport which was Na(+)-independent. L-DOPA and L-leucine uptake was insensitive to N-(methylamino)-isobutyric acid, but competitively inhibited by 2-aminobicyclo(2,2,1)-heptane-2-carboxylic acid (BCH). L- and D-neutral amino acids, but not acidic and basic amino acids, markedly inhibited L-DOPA and [(14)C]L-leucine accumulation in both cell lines. The [(14)C]L-DOPA and [14C]L-leucine outward were markedly increased by L-leucine and BCH present in extracellular medium, but not by L-arginine. In both cell lines, L-DOPA transport was stimulated by acidic pH in comparison with [(14)C]L-leucine inward which was pH-independent. In conclusion, it is likely that system B(0) might be responsible for the Na(+)-dependent uptake of L-leucine in Caco-2 and IEC-6 cells, whereas sodium-independent uptake of L-leucine and L-DOPA may include system type 1 and type 2 L-amino acid transporter (LAT1 and LAT2), the activation of which results in trans-stimulation of substrates outward transfer.
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Affiliation(s)
- Sónia Fraga
- Faculty of Medicine, Institute of Pharmacology and Therapeutics, 4200-319 Porto, Portugal
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