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Nilsson D, Chess-Williams R, Sellers D. Phosphodiesterase-5 inhibitors tadalafil and sildenafil potentiate nitrergic-nerve mediated relaxations in the bladder vasculature. Eur J Pharmacol 2023; 960:176152. [PMID: 37925131 DOI: 10.1016/j.ejphar.2023.176152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 10/21/2023] [Accepted: 10/23/2023] [Indexed: 11/06/2023]
Abstract
Recent studies suggest that lower urinary tract dysfunction may arise due to changes in local perfusion. Phosphodiesterase-5 inhibitors can improve urinary bladder blood flow, although the local mechanisms have not been fully elucidated. The aim was to pharmacologically characterise the vascular supply to the bladder and determine the mechanisms underlying the effects of the phosphodiesterase-5 inhibitors tadalafil and sildenafil. Responses of isolated rings of porcine superior vesical arteries to electrical field stimulation (EFS) were measured in the absence and presence of inhibitors of key neurotransmitter systems. Vasodilation responses to nitric oxide (NO) donors were also recorded, and the effects of phosphodiesterase-5 inhibitors on all responses determined. EFS caused biphasic responses with an initial vasoconstriction and a slower developing vasodilation. Vasoconstriction was mediated by ATP (55%) and noradrenaline (45%) release, whilst vasodilation was reduced by L-NNA (100 μM) (80%) and propranolol (1 μM) (20%). The nitrergic component was inhibited (81%) by L-NPA, a selective inhibitor of neuronal nitric oxide synthase (nNOS). Endothelial removal did not affect vasodilation. Tadalafil and sildenafil depressed noradrenaline-evoked vasoconstriction (by 26.8% and 35.5% respectively, P < 0.01), enhanced vasodilation to EFS (by 27.8% and 51.8% respectively, p < 0.01) and enhanced responses to NO donors nitroprusside, SIN-1, and SNAP, increasing pIC50 values (P < 0.01), without affecting maximal responses. In conclusion, neuronal NOS has a predominant role in regulating vascular tone of the porcine superior vesical artery and potentiation of nNO-mediated vasodilation is the primary mechanism underlying effects of phosphodiesterase-5 inhibitors in the bladder vasculature.
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Affiliation(s)
- Damian Nilsson
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, 4226, Australia
| | - Russ Chess-Williams
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, 4226, Australia
| | - Donna Sellers
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, 4226, Australia.
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The Pharmacological Effects of Phenylephrine are Indirect, Mediated by Noradrenaline Release from the Cytoplasm. Neurochem Res 2022; 47:3272-3284. [PMID: 35945308 PMCID: PMC9546997 DOI: 10.1007/s11064-022-03681-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 07/04/2022] [Accepted: 07/06/2022] [Indexed: 10/31/2022]
Abstract
Phenylephrine (PE) is a canonical α1-adrenoceptor-selective agonist. However, unexpected effects of PE have been observed in preclinical and clinical studies, that cannot be easily explained by its actions on α1-adrenoceptors. The probability of the involvement of α2- and β-adrenoceptors in the effect of PE has been raised. In addition, our earlier study observed that PE released noradrenaline (NA) in a [Ca2+]o-independent manner. To elucidate this issue, we have investigated the effects of PE on [3H]NA release and α1-mediated smooth muscle contractions in the mouse vas deferens (MVD) as ex vivo preparation. The release experiments were designed to assess the effects of PE at the presynaptic terminal, whereas smooth muscle isometric contractions in response to electrical field stimulation were used to measure PE effect postsynaptically. Our results show that PE at concentrations between 0.3 and 30 µM significantly enhanced the resting release of [3H]NA in a [Ca2+]o-independent manner. In addition, prazosin did not affect the release of NA evoked by PE. On the contrary, PE-evoked smooth muscle contractions were inhibited by prazosin administration indicating the α1-adrenoceptor-mediated effect. When the function of the NA transporter (NAT) was attenuated with nisoxetine, PE failed to release NA and the contractions were reduced by approximately 88%. The remaining part proved to be prazosin-sensitive. The present work supports the substantial indirect effect of PE which relays on the cytoplasmic release of NA, which might explain the reported side effects for PE.
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Stolk RF, Reinema F, van der Pasch E, Schouwstra J, Bressers S, van Herwaarden AE, Gerretsen J, Schambergen R, Ruth M, van der Hoeven HG, van Leeuwen HJ, Pickkers P, Kox M. Phenylephrine impairs host defence mechanisms to infection: a combined laboratory study in mice and translational human study. Br J Anaesth 2021; 126:652-664. [PMID: 33483132 DOI: 10.1016/j.bja.2020.11.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Immunosuppression after surgery is associated with postoperative complications, mediated in part by catecholamines that exert anti-inflammatory effects via the β-adrenergic receptor. Phenylephrine, generally regarded as a selective α-adrenergic agonist, is frequently used to treat perioperative hypotension. However, phenylephrine may impair host defence through β-adrenergic affinity. METHODS Human leukocytes were stimulated with lipopolysaccharide (LPS) in the presence or absence of phenylephrine and α- and β-adrenergic antagonists. C57BL/6J male mice received continuous infusion of phenylephrine (30-50 μg kg-1 min-1 i.v.) or saline via micro-osmotic pumps, before LPS administration (5 mg kg-1 i.v.) or caecal ligation and puncture (CLP). Twenty healthy males were randomised to a 5 h infusion of phenylephrine (0.5 μg kg-1 min-1) or saline before receiving LPS (2 ng kg-1 i.v.). RESULTS In vitro, phenylephrine enhanced LPS-induced production of the anti-inflammatory cytokine interleukin (IL)-10 (maximum augmentation of 93%) while attenuating the release of pro-inflammatory mediators. These effects were reversed by pre-incubation with β-antagonists, but not α-antagonists. Plasma IL-10 levels were higher in LPS-challenged mice infused with phenylephrine, whereas pro-inflammatory mediators were reduced. Phenylephrine infusion increased bacterial counts after CLP in peritoneal fluid (+42%, P=0.0069), spleen (+59%, P=0.04), and liver (+35%, P=0.09). In healthy volunteers, phenylephrine enhanced the LPS-induced IL-10 response (+76%, P=0.0008) while attenuating plasma concentrations of pro-inflammatory mediators including IL-8 (-15%, P=0.03). CONCLUSIONS Phenylephrine exerts potent anti-inflammatory effects, possibly involving the β-adrenoreceptor. Phenylephrine promotes bacterial outgrowth after surgical peritonitis. Phenylephrine may therefore compromise host defence in surgical patients and increase susceptibility towards infection. CLINICAL TRIAL REGISTRATION NCT02675868 (Clinicaltrials.gov).
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Affiliation(s)
- Roeland F Stolk
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Intensive Care Medicine, Hospital Rijnstate, Arnhem, The Netherlands
| | - Flavia Reinema
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Eva van der Pasch
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost Schouwstra
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Steffi Bressers
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Jelle Gerretsen
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Roel Schambergen
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mike Ruth
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hans G van der Hoeven
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Henk J van Leeuwen
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Intensive Care Medicine, Hospital Rijnstate, Arnhem, The Netherlands
| | - Peter Pickkers
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Matthijs Kox
- Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands.
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Dissection of heterocellular cross-talk in vascularized cardiac tissue mimetics. J Mol Cell Cardiol 2019; 138:269-282. [PMID: 31866374 DOI: 10.1016/j.yjmcc.2019.12.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 12/07/2019] [Accepted: 12/10/2019] [Indexed: 02/07/2023]
Abstract
Cellular specialization and interaction with other cell types in cardiac tissue is essential for the coordinated function of cell populations in the heart. The complex interplay between cardiomyocytes, endothelial cells and fibroblasts is necessary for adaptation but can also lead to pathophysiological remodeling. To understand this complex interplay, we developed 3D vascularized cardiac tissue mimetics (CTM) to study heterocellular cross-talk in hypertrophic, hypoxic and fibrogenic environments. This 3D platform responds to physiologic and pathologic stressors and mimics the microenvironment of diseased tissue. In combination with endothelial cell fluorescence reporters, these cardiac tissue mimetics can be used to precisely visualize and quantify cellular and functional responses upon stress stimulation. Utilizing this platform, we demonstrate that stimulation of α/β-adrenergic receptors with phenylephrine (PE) promotes cardiomyocyte hypertrophy, metabolic maturation and vascularization of CTMs. Increased vascularization was promoted by conditioned medium of PE-stimulated cardiomyocytes and blocked by inhibiting VEGF or upon β-adrenergic receptor antagonist treatment, demonstrating cardiomyocyte-endothelial cross-talk. Pathophysiological stressors such as severe hypoxia reduced angiogenic sprouting and increased cell death, while TGF β2 stimulation increased collagen deposition concomitant to endothelial-to-mesenchymal transition. In sum, we have developed a cardiac 3D culture system that reflects native cardiac tissue function, metabolism and morphology - and for the first time enables the tracking and analysis of cardiac vascularization dynamics in physiology and pathology.
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Zhang Y, Poler SM, Li J, Abedi V, Pendergrass SA, Williams MS, Lee MTM. Dissecting genetic factors affecting phenylephrine infusion rates during anesthesia: a genome-wide association study employing EHR data. BMC Med 2019; 17:168. [PMID: 31455332 PMCID: PMC6712853 DOI: 10.1186/s12916-019-1405-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 08/07/2019] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The alpha-adrenergic agonist phenylephrine is often used to treat hypotension during anesthesia. In clinical situations, low blood pressure may require prompt intervention by intravenous bolus or infusion. Differences in responsiveness to phenylephrine treatment are commonly observed in clinical practice. Candidate gene studies indicate genetic variants may contribute to this variable response. METHODS Pharmacological and physiological data were retrospectively extracted from routine clinical anesthetic records. Response to phenylephrine boluses could not be reliably assessed, so infusion rates were used for analysis. Unsupervised k-means clustering was conducted on clean data containing 4130 patients based on phenylephrine infusion rate and blood pressure parameters, to identify potential phenotypic subtypes. Genome-wide association studies (GWAS) were performed against average infusion rates in two cohorts: phase I (n = 1205) and phase II (n = 329). Top genetic variants identified from the meta-analysis were further examined to see if they could differentiate subgroups identified by k-means clustering. RESULTS Three subgroups of patients with different response to phenylephrine were clustered and characterized: resistant (high infusion rate yet low mean systolic blood pressure (SBP)), intermediate (low infusion rate and low SBP), and sensitive (low infusion rate with high SBP). Differences among clusters were tabulated to assess for possible confounding influences. Comorbidity hierarchical clustering showed the resistant group had a higher prevalence of confounding factors than the intermediate and sensitive groups although overall prevalence is below 6%. Three loci with P < 1 × 10-6 were associated with phenylephrine infusion rate. Only rs11572377 with P = 6.09 × 10-7, a 3'UTR variant of EDN2, encoding a secretory vasoconstricting peptide, could significantly differentiate resistant from sensitive groups (P = 0.015 and 0.018 for phase I and phase II) or resistant from pooled sensitive and intermediate groups (P = 0.047 and 0.018). CONCLUSIONS Retrospective analysis of electronic anesthetic records data coupled with the genetic data identified genetic variants contributing to variable sensitivity to phenylephrine infusion during anesthesia. Although the identified top gene, EDN2, has robust biological relevance to vasoconstriction by binding to endothelin type A (ETA) receptors on arterial smooth muscle cells, further functional as well as replication studies are necessary to confirm this association.
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Affiliation(s)
- Yanfei Zhang
- Genomic Medicine Institute, Geisinger, Danville, PA, 17822, USA
| | - S Mark Poler
- Department of Anesthesiology, Geisinger, Danville, PA, 17822, USA
| | - Jiang Li
- Biomedical Translational Informatics Institute, Geisinger, Danville, PA, 17822, USA
| | - Vida Abedi
- Biomedical Translational Informatics Institute, Geisinger, Danville, PA, 17822, USA
| | - Sarah A Pendergrass
- Biomedical Translational Informatics Institute, Geisinger, Bethesda, MD, USA
| | - Marc S Williams
- Genomic Medicine Institute, Geisinger, Danville, PA, 17822, USA
| | - Ming Ta Michael Lee
- Genomic Medicine Institute, Geisinger, Danville, PA, 17822, USA. .,Lab 218, Weis Center for Research, Geisinger, 100 North Academy Ave, Danville, 17822-2620, PA, USA.
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Zhang S, Takahashi R, Yamashita N, Teraoka H, Kitazawa T. Αlpha 1B-adrenoceptor-mediated positive inotropic and positive chronotropic actions in the mouse atrium. Eur J Pharmacol 2018; 839:82-88. [PMID: 30172786 DOI: 10.1016/j.ejphar.2018.08.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 08/21/2018] [Accepted: 08/29/2018] [Indexed: 11/15/2022]
Abstract
Modulation of cardiac contractility by α-adrenoceptor is well known in several mammals. Mice are useful experimental animals, but α-adrenoceptor-mediated responses have been examined only in the ventricles. To determine function of α-adrenoceptors in the atrium, effects of α-adrenoceptor agonists on spontaneous contraction and electrical-field stimulation (EFS)-induced contraction were examined. In addition, expression of α1A, α1B, α1D and β1-adrenoceptor mRNAs were examined. In the right atrium, noradrenaline and phenylephrine caused positive inotropic and positive chronotropic actions. However, methoxamine, clonidine and xylazine caused positive inotropic actions, but contractile frequency was decreased at high concentrations. Phenylephrine-induced positive inotropic and chronotropic actions were partially decreased by propranolol, and both actions remained in the presence of propranolol were inhibited by phentolamine or prazosin. A low concentration of silodosin (<100 nM) did not but a high concentration (1 μM) decreased the phenylephrine-induced chronotropic actions. Negative chronotropic actions of clonidine and xylazine were insensitive to propranolol and phentolamine. The EFS-induced contraction of the left atrium was potentiated by noradrenaline, phenylephrine and methoxamine but was not changed by clonidine or xylazine. Propranolol partially decreased the actions of phenylephrine, and prazosin caused additional inhibition. Expression of β1-, α1A-, α1B- and α1D-adrenoceptor mRNAs was found in the atrium, and the expression level of β1-adrenoceptor was the highest. Of α1-adrenoceptors, the expression level of α1B was higher than that of α1A and α1D. In conclusion, α1B-adrenoceptors are expressed in the mouse atrium and mediate both positive chronotropic and inotropic actions. In contrast, the α2-adrenoceptor is not functional in the isolated atrium.
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Affiliation(s)
- Shuangyi Zhang
- Veterinary Pharmacology, Department of Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Rena Takahashi
- Comparative Animal Pharmacology, Department of Veterinary Science, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Natsumi Yamashita
- Veterinary Pharmacology, Department of Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Hiroki Teraoka
- Veterinary Pharmacology, Department of Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Takio Kitazawa
- Veterinary Pharmacology, Department of Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan; Comparative Animal Pharmacology, Department of Veterinary Science, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
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Harris DA, Park JM, Lee KS, Xu C, Stella N, Hague C. Label-Free Dynamic Mass Redistribution Reveals Low-Density, Prosurvival α1B-Adrenergic Receptors in Human SW480 Colon Carcinoma Cells. J Pharmacol Exp Ther 2017; 361:219-228. [PMID: 28196836 DOI: 10.1124/jpet.116.237255] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 02/10/2017] [Indexed: 12/11/2022] Open
Abstract
Small molecules that target the adrenergic family of G protein-coupled receptors (GPCRs) show promising therapeutic efficacy for the treatment of various cancers. In this study, we report that human colon cancer cell line SW480 expresses low-density functional α1B-adrenergic receptors (ARs) as revealed by label-free dynamic mass redistribution (DMR) signaling technology and confirmed by quantitative reverse-transcriptase polymerase chain reaction analysis. Remarkably, although endogenous α1B-ARs are not detectable via either [3H]-prazosin-binding analysis or phosphoinositol hydrolysis assays, their activation leads to robust DMR and enhanced cell viability. We provide pharmacological evidence that stimulation of α1B-ARs enhances SW480 cell viability without affecting proliferation, whereas stimulating β-ARs diminishes both viability and proliferation of SW480 cells. Our study illustrates the power of label-free DMR technology for identifying and characterizing low-density GPCRs in cells and suggests that drugs targeting both α1B- and β-ARs may represent valuable small-molecule therapeutics for the treatment of colon cancer.
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Affiliation(s)
- Dorathy-Ann Harris
- Departments of Pharmacology (D.-A.H., J.-M.P., K.-S.L., C.X., N.S., C.H.) and Psychiatry and Behavioral Sciences (C.X., N.S.), University of Washington School of Medicine, Seattle, Washington
| | - Ji-Min Park
- Departments of Pharmacology (D.-A.H., J.-M.P., K.-S.L., C.X., N.S., C.H.) and Psychiatry and Behavioral Sciences (C.X., N.S.), University of Washington School of Medicine, Seattle, Washington
| | - Kyung-Soon Lee
- Departments of Pharmacology (D.-A.H., J.-M.P., K.-S.L., C.X., N.S., C.H.) and Psychiatry and Behavioral Sciences (C.X., N.S.), University of Washington School of Medicine, Seattle, Washington
| | - Cong Xu
- Departments of Pharmacology (D.-A.H., J.-M.P., K.-S.L., C.X., N.S., C.H.) and Psychiatry and Behavioral Sciences (C.X., N.S.), University of Washington School of Medicine, Seattle, Washington
| | - Nephi Stella
- Departments of Pharmacology (D.-A.H., J.-M.P., K.-S.L., C.X., N.S., C.H.) and Psychiatry and Behavioral Sciences (C.X., N.S.), University of Washington School of Medicine, Seattle, Washington
| | - Chris Hague
- Departments of Pharmacology (D.-A.H., J.-M.P., K.-S.L., C.X., N.S., C.H.) and Psychiatry and Behavioral Sciences (C.X., N.S.), University of Washington School of Medicine, Seattle, Washington
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Charrua A, Pinto R, Taylor A, Canelas A, Ribeiro-da-Silva A, Cruz CD, Birder LA, Cruz F. Can the adrenergic system be implicated in the pathophysiology of bladder pain syndrome/interstitial cystitis? A clinical and experimental study. Neurourol Urodyn 2013; 34:489-96. [PMID: 24375689 DOI: 10.1002/nau.22542] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 11/29/2013] [Indexed: 12/20/2022]
Abstract
AIMS To evaluate sympathetic system activity in bladder pain syndrome/interstitial cystitis (BPS/IC) patients and to investigate if chronic adrenergic stimulation in intact rats induces BPS/IC-like bladder modifications. METHODS Clinical study--In BPS/IC patients and aged and body mass index matched volunteers TILT test was undertaken and catecholamines were measured in plasma and 24 hr urine samples. Experimental study--Phenylephrine was injected subcutaneously (14 days) to female Wistar rats. Pain behavior, spinal Fos expression, urinary spotting, number of fecal pellets expelled, frequency of reflex bladder contractions, and urothelial height were analyzed. Urothelium permeability was investigated by trypan blue staining. Immunoreactivity against caspase 3 and bax were studied in the urothelium and against alpha-1-adrenoreceptor and TRPV1 in suburothelial nerves. Mast cell number was determined in the sub-urothelium. In rats with lipopolysaccharide-induced cystitis, urinary catecholamines, and Vesicular Monoamine Transporter 2 (VMAT2) expression in bladder nerves were analyzed. RESULTS The TILT test showed an increase of sympathetic activity. Noradrenaline levels in blood at resting conditions and in 24-hr urine samples were higher in BPS/IC patients. Phenylephrine administration increased visceral pain, spinal Fos expression, bladder reflex activity, urinary spotting and the number of expelled fecal pellets. The mucosa showed urothelial thinning and increased immunoreactivity for caspase 3 and bax. Trypan blue staining was only observed in phenylephrine treated animals. Suburothelial nerves co-expressed alpha1 and TRPV1. Mastocytosis was present in the suburothelium. Cystitis increased sympathetic nerve density and urinary noradrenaline levels. CONCLUSIONS Excessive adrenergic stimulation of the bladder may contribute to the pathophysiological mechanisms of BPS/IC.
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Affiliation(s)
- Ana Charrua
- Department of Experimental Biology, Faculty of Medicine, University of Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, University of Porto, Porto, Portugal.,Department of Renal, Urologic and Infectious Disease, Faculty of Medicine, University of Porto, Porto, Portugal.,Department of Urology, S. João Hospital, Porto, Portugal
| | - Rui Pinto
- IBMC - Instituto de Biologia Molecular e Celular, University of Porto, Porto, Portugal.,Department of Renal, Urologic and Infectious Disease, Faculty of Medicine, University of Porto, Porto, Portugal.,Department of Urology, S. João Hospital, Porto, Portugal
| | - Anna Taylor
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - André Canelas
- Department of Experimental Biology, Faculty of Medicine, University of Porto, Porto, Portugal
| | | | - Célia D Cruz
- Department of Experimental Biology, Faculty of Medicine, University of Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, University of Porto, Porto, Portugal
| | - Lori Ann Birder
- Departments of Medicine and Pharmacology-Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Francisco Cruz
- IBMC - Instituto de Biologia Molecular e Celular, University of Porto, Porto, Portugal.,Department of Renal, Urologic and Infectious Disease, Faculty of Medicine, University of Porto, Porto, Portugal.,Department of Urology, S. João Hospital, Porto, Portugal
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Sermsappasuk P, Weiss M. Modelling of alpha1-adrenoceptor-mediated temporal dynamics of inotropic response in rat heart to assess ligand binding and signal transduction parameters. Br J Pharmacol 2009; 156:764-73. [PMID: 19220295 DOI: 10.1111/j.1476-5381.2008.00013.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE In order to use the transient response to an antagonist (prazosin) to evaluate properties of agonist interactions with the alpha(1)-adrenoceptor system, an integrative mechanistic model of cardiac uptake of prazosin and its competitive interaction with phenylephrine at the receptor site was developed. Based on the operational model of agonism, the aim was to evaluate both the receptor binding and signal transduction process as determinants of the inotropic effect of phenylephrine. EXPERIMENTAL APPROACH In Langendorff-perfused rat hearts, prazosin outflow concentration and left ventricular developed pressure were measured, first in the presence of 12.3 micromol x L(-1) phenylephrine following a 1 min infusion of 1.27 nmol [(3)H]-prazosin, and second, when after 30 min the phenylephrine concentration in perfusate was reduced to 6.1 micromol x L(-1), the 1 min infusion of 1.27 nmol [(3)H]-prazosin was repeated. KEY RESULTS The kinetic model accounted for cardiac uptake and receptor binding kinetics of prazosin (dissociation constant, mean +/- SD: 0.057 +/- 0.012 nmol.L(-1)), assuming that the competitive displacement of phenylephrine (dissociation constant: 101 +/- 13 nmol x L(-1)) reduced the receptor occupation by the agonist and, consequently, contractility. This competitive binding process appeared to be the rate-determining step in response generation. The relationship between receptor occupancy and inotropic response was described by an efficacy parameter (tau, ratio of receptor density and coupling efficiency) of 4.9. CONCLUSIONS AND IMPLICATIONS Mechanistic pharmacodynamic modelling of the kinetics of antagonism by prazosin allows quantitative assessment of the alpha(1)-adrenoceptor system both at the receptor and post-receptor levels.
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Affiliation(s)
- P Sermsappasuk
- Section of Pharmacokinetics, Department of Pharmacology, Martin Luther University Halle-Wittenberg, Halle, Germany
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Michael G, Kane KA, Coker SJ. Adrenaline reveals the torsadogenic effect of combined blockade of potassium channels in anaesthetized guinea pigs. Br J Pharmacol 2008; 154:1414-26. [PMID: 18493252 DOI: 10.1038/bjp.2008.169] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Torsade de pointes (TdP) can be induced in several species by a reduction in cardiac repolarizing capacity. The aim of this study was to assess whether combined I(Kr) and I(Ks) blockade could induce TdP in anaesthetized guinea pigs and whether short-term variability (STV) or triangulation of action potentials could predict TdP. EXPERIMENTAL APPROACH Experiments were performed in open-chest, pentobarbital-anaesthetized, adrenaline-stimulated male Dunkin Hartley guinea pigs, which received three consecutive i.v. infusions of either vehicle, the I(Kr) blocker E-4031 (3, 10 and 30 nmol kg(-1) min(-1)), the I(Ks) blocker HMR1556 (75, 250, 750 nmol kg(-1) min(-1)) or E-4031 and HMR1556 combined. Phenylephrine-stimulated guinea pigs were also treated with the K(+) channel blockers in combination. Arterial blood pressure, ECGs and epicardial monophasic action potential (MAP) were recorded. KEY RESULTS TdP was observed in 75% of adrenaline-stimulated guinea pigs given the K(+) channel blockers in combination, but was not observed in guinea pigs treated with either I(K) blocker alone, or in phenylephrine-stimulated guinea pigs. Salvos and ventricular tachycardia occurred with adrenaline but not with phenylephrine. No changes in STV or triangulation of the MAP signals were observed before TdP. CONCLUSIONS AND IMPLICATIONS Combined blockade of both I(Kr) and I(Ks) plus the addition of adrenaline were required to induce TdP in anaesthetized guinea pigs. This suggests that there must be sufficient depletion of repolarization reserve and an appropriate trigger for TdP to occur.
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Affiliation(s)
- G Michael
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
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Nisar PJ, Gruss HJ, Bush D, Acheson AG, Scholefield JH. Intra-anal application of l-erythro methoxamine gel increases anal resting pressure in patients with incontinence. Br J Surg 2007; 94:1155-61. [PMID: 17542041 DOI: 10.1002/bjs.5821] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Abstract
Background
This study examined the effects of a single dose of intra-anal l-erythro methoxamine on mean anal resting pressure (MARP) and cardiovascular variables in patients with faecal incontinence.
Methods
Patients had anorectal physiology tests and ultrasonography before participating. Six patients received 0·3 and 1 per cent gels on separate days, two patients received 0·3 per cent gel, and two patients received 1 per cent gel. MARP, blood pressure, pulse rate and plasma drug concentrations were measured for 6 h after application.
Results
Intra-anal 0·3 per cent gel caused a rapid, significant rise in MARP lasting 2 h (P = 0·036). In four of these patients, the response was sufficient to increase MARP to within the normal range at 2 h. Application of 1 per cent gel caused a significant rise in MARP for 4 h after application (P = 0·028). There was a significant decrease in pulse at 2 and 1 h respectively after application of 0·3 and 1 per cent gels.
Conclusion
Intra-anal application of l-erythro methoxamine can be used to increase MARP in patients with faecal incontinence. Application of 1 per cent l-erythro methoxamine gel produced a rapid, sustained rise in MARP, which raises the possibility of therapeutic application.
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Affiliation(s)
- P J Nisar
- Section of Surgery, University Hospital, Queen's Medical Centre, Nottingham, UK.
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Broadley KJ, Williamson KL, Roach AG. In vivo demonstration of alpha-adrenoceptor-mediated positive inotropy in pithed rats: evidence that noradrenaline does not stimulate myocardial alpha-adrenoceptors. JOURNAL OF AUTONOMIC PHARMACOLOGY 1999; 19:55-63. [PMID: 10385270 DOI: 10.1046/j.1365-2680.1999.00115.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. This study examines whether positive inotropy via alpha-adrenoceptors could be observed in vivo in pithed rats. Cardiac contractility was measured as the maximum rate of rise of left ventricular pressure (dP/dt(max)). Heart rate and aortic blood pressure were also recorded. 2. The selective alpha1-adrenoceptor agonists, methoxamine, cirazoline, amidephrine and phenylephrine caused dose-related increases in dP/dt(max). This response was progressively reduced by increasing doses of the alpha1-adrenoceptor antagonist prazosin. However, since the concomitant increase in diastolic blood pressure (DBP) was also blocked, the changes in dP/dt(max) may have been a consequence of increased after load. 3. Adrenaline and noradrenaline also increased dP/dt(max), accompanied by pressor responses. Propranolol (1 mg kg(-1)) antagonized the increase in dP/dt(max) in response to noradrenaline, suggesting beta-adrenoceptor involvement, but not that to adrenaline. The additional presence of prazosin (1 mg kg(-1)) further shifted the dose-response curves for both noradrenaline and adrenaline to the right. 4. Analysis of the increases in dP/dt(max) at predetermined increases in DBP by each agonist revealed three groups of regression lines. Adrenaline in the presence of propranolol and the four selective alpha1-adrenoceptor agonists occupied a common central position. Above this group were adrenaline and noradrenaline in the absence of antagonists; their additional effects on contractility were beta-adrenoceptor-mediated since the regression lines were lowered by propranolol. Clearly below the main group of agonists was noradrenaline in the presence of propranolol. 5. Thus, for a given increase in DBP, adrenaline (in the presence of beta-blockade) and the alpha1-adrenoceptor agonists exert an additional inotropic effect to noradrenaline (also in the presence of beta-blockade). This is concluded to be an alpha-adrenoceptor-mediated increase in cardiac contractility which is not shared by noradrenaline.
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Affiliation(s)
- K J Broadley
- Department of Pharmacology, Welsh School of Pharmacy, Cardiff University, UK
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Chess-Williams R, Aston N, Couldwell C. Alpha 1A-adrenoceptor subtype mediates contraction of the rat urethra. JOURNAL OF AUTONOMIC PHARMACOLOGY 1994; 14:375-81. [PMID: 7876271 DOI: 10.1111/j.1474-8673.1994.tb00618.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
1. The alpha 1-adrenoceptor-mediated responses of the rat urethra to phenylephrine have been examined in vitro. Phenylephrine caused concentration-dependent contractions of the isolated urethra which were antagonized by WB4101 (3-30 nM) and prazosin (10-100 nM) but not idazoxan (1.5 microM). Schild plot analysis of the antagonism by prazosin and WB4101 yielded straight lines with slopes not significantly different from unity. The pA2 value of 9.0 for WB4101 was significantly greater than the value previously obtained at the alpha 1B-adrenoceptor of the rat spleen. 2. 5-Methylurapidil (30 nM) and abanoquil (1 nM) caused dextral shifts of concentration-response curves yielding pKB values of 8.3 and 9.4 respectively. Maximal responses to phenylephrine were also reduced by this concentration of abanoquil. 3. Preincubation with chloroethylclonidine (25 microM for 40 min) failed to alter responses, but removing extracellular calcium or the presence of nifedipine (1 microM) almost abolished contractions to phenylephrine. 4. These results indicate that the responses of the rat urethra to phenylephrine are mediated via the alpha 1A-adrenoceptor subtype and are dependent on the influx of extracellular calcium.
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14
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Doggrell SA. Negative inotropic effect of pinacidil on the rat left atria. J Pharm Pharmacol 1993; 45:1000-2. [PMID: 7908028 DOI: 10.1111/j.2042-7158.1993.tb05647.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cromakalim at 50 microM and pinacidil at 0.1-10 microM had no effect, but pinacidil at 0.1 mM had a negative inotropic effect on the rat electrically-driven left atria without altering the positive inotropic responses to isoprenaline or phenylephrine alone. Glibenclamide had no effect but 4-aminopyridine, procaine (30 microM) and tetraethylammonium (3 mM) augmented the cardiac stimulation response. The ability of pinacidil to attenuate the cardiac stimulation response was not altered by glibenclamide, 4-aminopyridine or procaine but was prevented by pretreatment with tetraethylammonium. Thus, on the rat left atria, pinacidil has a negative inotropic effect which is unrelated to the opening of ATP-sensitive potassium channels, but may be due to opening the inward rectifying potassium channels.
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Affiliation(s)
- S A Doggrell
- Department of Pharmacology, School of Medicine, University of Auckland, New Zealand
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15
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Couldwell C, Jackson A, O'Brien H, Chess-Williams R. Characterization of the alpha 1-adrenoceptors of the rat prostate gland. J Pharm Pharmacol 1993; 45:922-4. [PMID: 7904635 DOI: 10.1111/j.2042-7158.1993.tb05623.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The alpha 1-adrenoceptor-mediated responses of the rat prostate to phenylephrine have been examined in-vitro. Phenylephrine induced concentration-dependent contractions of the isolated prostate gland which were antagonized by WB4101 (1-30 nM). Schild plot analysis of the antagonism yielded a straight line with a slope not significantly different from unity. The pKB value of 9.2 was similar to that obtained for WB4101 on the rat vas deferens (9.4) but was greater than that obtained on the rat spleen (8.4). Chloroethylclonidine depressed responses to phenylephrine of the rat spleen but not the prostate or the vas deferens. These results indicate that the rat prostate gland possesses a typical alpha 1A-adrenoceptor similar to that found in the vas deferens.
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Affiliation(s)
- C Couldwell
- Department of Biomedical Science, University of Sheffield, UK
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16
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Northover BJ. Phorbol 12,13-dibutyrate produces negative inotropism and selective antagonism of responses to adrenoceptor agonists in rat atria. Biochem Pharmacol 1993; 45:1183-9. [PMID: 8096695 DOI: 10.1016/0006-2952(93)90269-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Rat atria loaded in vitro with the dye INDO-1 produced fluorescence signals indicative of changes in cytoplasmic calcium ion concentration ([Ca2+]c). Such atria showed systolic/diastolic fluctuations indicative of a systolic rise and a diastolic fall in both tension and [Ca2+]c. Positively inotropic responses of the atria to isoprenaline, phenylephrine, ouabain or 4-aminopyridine were associated with fluorescence changes indicative of increased systolic increments in [Ca2+]c. Treatment of atria with phorbol dibutyrate, on the other hand, produced negative inotropism and fluorescence changes indicative of declining systolic increments in [Ca2+]c. Pretreating atria with phorbol dibutyrate diminished both the inotropic and fluorescence responses to subsequent treatment with phenylephrine or isoprenaline, although responses to ouabain or 4-aminopyridine were unchanged. Exposure of atria to a selective inhibitor of protein kinase C mitigated the effects of pretreatment with phorbol dibutyrate, but failed to modify responses to phenylephrine or isoprenaline that were produced in the absence of phorbol dibutyrate.
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Affiliation(s)
- B J Northover
- School of Applied Sciences, De Montfort University, Gateway, Leicester, U.K
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Austin CE, Chess-Williams R. Transient elevation of cardiac beta-adrenoceptor responsiveness and receptor number in the streptozotocin-diabetic rat. JOURNAL OF AUTONOMIC PHARMACOLOGY 1992; 12:205-14. [PMID: 1324940 DOI: 10.1111/j.1474-8673.1992.tb00334.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
1. The effects on cardiac responsiveness of diabetes of up to 12 weeks duration has been examined in streptozotocin-pretreated rats. 2. Two weeks of diabetes resulted in a supersensitivity of isolated left atria and papillary muscles to isoprenaline, which was associated with an increase in the density of ventricular [3H]-dihydroalprenolol binding sites. 3. The beta-adrenoceptor supersensitivity was still evident in both tissues after 4 weeks of diabetes, but in left atria the supersensitivity was reduced compared with that observed at 2 weeks, while for papillary muscles it was greater than at 2 weeks. 4. Following 12 weeks of diabetes, responses of papillary muscles to isoprenaline were similar to controls, while beta-mediated responses of left atria were significantly depressed. 5. The alpha-adrenoceptor-mediated responses of cardiac tissues to phenylephrine were similar to controls following diabetes of 2 or 4 weeks duration. At 12 weeks, however, papillary muscle alpha-adrenoceptor-mediated responses were enhanced. The change in ventricular responsiveness to phenylephrine was not accompanied by any change in [3H]-prazosin binding to ventricular membranes. 6. The results demonstrate a transient elevation of cardiac beta-adrenoceptor sensitivity and receptor density during acute diabetes and illustrate the time- and tissue-dependence of diabetes-induced changes in cardiac adrenoceptor sensitivity.
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Affiliation(s)
- C E Austin
- Department of Pharmacology and Therapeutics, University of Liverpool, UK
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Butterfield MC, Chess-Williams R. Enhanced alpha-adrenoceptor responsiveness and receptor number during global ischaemia in the Langendorff perfused rat heart. Br J Pharmacol 1990; 100:641-5. [PMID: 2167740 PMCID: PMC1917773 DOI: 10.1111/j.1476-5381.1990.tb15860.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
1. Idioventricular rate responses and adrenoceptor number have been examined in normal Langendorff hearts perfused at 70 cmH2O and in 'ischaemic' hearts perfused at 10 cmH2O. 2. In hearts perfused at normal pressure, ventricular rate responses to phenylephrine in the presence of propranolol were biphasic with low concentrations of phenylephrine reducing, and high concentrations increasing, ventricular rate. Both responses were abolished in the presence of prazosin (100 nM). In hearts perfused at low pressure, the negative chronotropic responses to phenylephrine were no longer present and positive chronotropic responses were enhanced compared with those of control tissues. The number of ventricular [3H]-prazosin binding sites was also significantly increased during ischaemia. 3. Idioventricular rate responses to isoprenaline were depressed in ischaemic tissues compared with controls, but [3H]-dihydroalprenolol binding was not altered in these hearts. 4. The incidence and duration of arrhythmias which occurred during 30 min of global ischaemia and reperfusion were not significantly altered in the presence of 100 nM prazosin. 5. These results demonstrate that reducing the perfusion pressure of rat isolated hearts enhances alpha-adrenoceptor-mediated responses and increases alpha-adrenoceptor density. Whether the increase in alpha-adrenoceptor responsiveness during ischaemia is involved in arrhythmogenesis requires further investigation.
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Affiliation(s)
- M C Butterfield
- Department of Pharmacology and Therapeutics, University of Liverpool
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