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Hinton M, Thliveris JA, Hatch GM, Dakshinamurti S. Nitric oxide augments signaling for contraction in hypoxic pulmonary arterial smooth muscle—Implications for hypoxic pulmonary hypertension. Front Physiol 2023; 14:1144574. [PMID: 37064915 PMCID: PMC10090299 DOI: 10.3389/fphys.2023.1144574] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Introduction: Hypoxic persistent pulmonary hypertension in the newborn (PPHN) is usually treated with oxygen and inhaled nitric oxide (NO), both pulmonary arterial relaxants. But treatment failure with NO occurs in 25% of cases. We previously demonstrated that 72 h exposure to hypoxia, modeling PPHN, sensitized pulmonary artery smooth muscle cells (PASMC) to the contractile agonist thromboxane and inhibited relaxant adenylyl cyclase (AC) activity.Methods: In this study, we examined the effects of sodium nitroprusside (SNP), as NO donor, on the thromboxane-mediated contraction and NO-independent relaxation pathways and on reactive oxygen species (ROS) accumulation in PASMC. In addition, we examined the effect of the peroxynitrite scavenger 5,10,15,20-Tetrakis (4-sulfonatophenyl)porphyrinato Iron (III) (FeTPPS) on these processes.Results: Exposure of PASMC to 72 h hypoxia increased total intracellular ROS compared to normoxic control cells and this was mitigated by treatment of cells with either SNP or FeTPPS. Total protein nitrosylation was increased in hypoxic PASMC compared to controls. Both normoxic and hypoxic cells treated with SNP exhibited increased total protein nitrosylation and intracellular nitrite; this was reduced by treatment with FeTPPS. While cell viability and mitochondrial number were unchanged by hypoxia, mitochondrial activity was decreased compared to controls; addition of FeTPPS did not alter this. Basal and maximal mitochondrial metabolism and ATP turnover were reduced in hypoxic PASMC compared to controls. Hypoxic PASMC had higher basal Ca2+, and a heightened peak Ca2+ response to thromboxane challenge compared to controls. Addition of SNP further elevated the peak Ca2+ response, while addition of FeTPPS brought peak Ca2+ response down to control levels. AC mediated relaxation was impaired in hypoxic PASMC compared to controls but was normalized following treatment with FeTPPS. Addition of SNP inhibited adenylyl cyclase activity in both normoxic and hypoxic PASMC. Moreover, addition of the Ca2+ chelator BAPTA improved AC activity, but the effect was minimal.Discussion: We conclude that NO independently augments contraction and inhibits relaxation pathways in hypoxic PASMC, in part by a mechanism involving nitrogen radical formation and protein nitrosylation. These observations may partially explain impaired effectiveness of NO when treating hypoxic pulmonary hypertension.
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Affiliation(s)
- Martha Hinton
- Biology of Breathing Group, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
| | - James A. Thliveris
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, MB, Canada
| | - Grant M. Hatch
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada
| | - Shyamala Dakshinamurti
- Biology of Breathing Group, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
- Department of Pediatrics, Section of Neonatology, Health Sciences Centre, Winnipeg, MB, Canada
- *Correspondence: Shyamala Dakshinamurti,
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Zhang M, Li C, He C, Cui Y, Li Y, Ma Y, Cheng J, Wen J, Li P, Yang Y. Thromboxane-induced contractile response of mesenteric arterioles is diminished in the older rats and the older hypertensive rats. Front Pharmacol 2022; 13:1019511. [PMID: 36313372 PMCID: PMC9602936 DOI: 10.3389/fphar.2022.1019511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 09/30/2022] [Indexed: 11/29/2022] Open
Abstract
Nearly all physiological processes are controlled at some level by G-protein-coupled receptor (GPCR) signaling activity. The thromboxane A2 (TXA2) receptor (TP) is a member of the GPCR family. The ultimate effect of TP receptor activation depends on the availability of specific G proteins, which in turn depend on the cell type, tissue, and disease state. However, the roles of the TXA2-TP signaling pathway executed under disease states are poorly defined. In this study, 16-week-spontaneously hypertensive rats (SHR), the 18-month-SHR (OldSHR), and the age-matched Wistar-Kyoto (WKY) rats were used to study the vasoconstriction of mesenteric resistance artery induced by TP-specific agonist, U-46619. Vasoconstriction induced by U-46619 was significantly attenuated in OldWKY and OldSHR rats, and mesenteric arteries with impaired response to U-46619 responded strongly to the adrenergic receptor agonist, phenylephrine. Similar vascular responses to U-46619 were obtained in endothelium-denuded mesenteric arteries. Accordingly, the expression of TP membrane proteins in mesenteric vessels was decreased, and the endogenous TP competitor, 8, 9-EET, in serum was increased, which was partly responsible for the decreased vascular reactivity of U-46619. Decreased TP membrane expression was associated with TP endocytosis, which involved actin cytoskeletal remodeling, including increased ratio of F-actin/G-actin in OldWKY and OldSHR rats. Hence, we studied the effects of TXA2 and its receptors on blood vessels and found that the TXA2-TP prostaglandin signaling pathway was impaired in older adults, which would facilitate the creation of “precision therapeutics” that possess selective efficacy in diseases.
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Hinton M, Eltayeb E, Ghavami S, Dakshinamurti S. Effect of pulsatile stretch on unfolded protein response in a new model of the pulmonary hypertensive vascular wall. Biochem Biophys Rep 2021; 27:101080. [PMID: 34368469 PMCID: PMC8326203 DOI: 10.1016/j.bbrep.2021.101080] [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: 05/18/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 02/07/2023] Open
Abstract
Persistent pulmonary hypertension of the newborn (PPHN) is characterized by hypoxemia and arterial remodeling. Dynamic stretch and recoil of the arterial wall during pulsation (in normal conduit arteries, stretch 20% above diastolic diameter) maintains homeostasis; a static arterial wall is associated with remodeling. PPHN is diagnosed by echocardiography as decreased pulmonary artery wall displacement during systole, causing decreased pulmonary arterial pressure acceleration time in a stiff artery. We hypothesized that a ‘normal’ amplitude of pulsatile stretch is protective against ER stress, while the loss of stretch is a trigger for hypoxia-induced stress responses. Using a novel in vitro model of pulmonary arterial myocytes subject to repetitive stretch-relaxation cycles within a normoxic or hypoxic environment, we examined the relative impact of hypoxia (pulmonary circuit during unresolved PPHN) and cyclic mechanical stretch (diminished in PPHN) on myocyte homeostasis, specifically on signaling proteins for autophagy and endoplasmic reticulum (ER) stress. Stretch induced autophagosome abundance under electron microscopy. Hypoxia, in presence or absence of pulsatile stretch, decreased unfolded protein response (UPR) hallmark BIP (GRP78) in contractile phenotype pulmonary arterial myocytes. Inositol requiring enzyme-1 α (IRE1α) was not activated; but hypoxia induced eif2α phosphorylation, increasing expression of ATF4 (activating transcription factor-4). This was sensitive to inhibition by autophagy inhibitor bafilomycin A1. We conclude that in the pulmonary circuit, hypoxia induces one arm of the UPR pathway and causes ER stress. Pulsatile stretch ameliorates the hypoxic UPR response, and while increasing presence of autophagosomes, does not activate canonical autophagy signaling pathways. We propose that simultaneous application of hypoxia and graded levels of cyclic stretch can be used to distinguish myocyte signaling in the deformable pulmonary artery of early PPHN, versus the inflexible late stage PPHN artery.
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Affiliation(s)
- Martha Hinton
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, 513 - 715 McDermot Avenue, Winnipeg, Canada, R3E 3P4.,Department of Physiology and Pathophysiology, University of Manitoba, 432 Basic Medical Sciences Building, 745 Bannatyne Avenue, Winnipeg, Canada, R3E 0J9
| | - Elwasila Eltayeb
- Section of Neonatology, Department of Pediatrics, University of Manitoba, Health Sciences Centre, 820 Sherbrook Street, Winnipeg, Canada, R3A 1R9
| | - Saeid Ghavami
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, 513 - 715 McDermot Avenue, Winnipeg, Canada, R3E 3P4.,Department of Human Anatomy and Cell Science, University of Manitoba, 130 Basic Medical Sciences Building, 745 Bannatyne Avenue, Winnipeg, Canada, R3E 0J9
| | - Shyamala Dakshinamurti
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, 513 - 715 McDermot Avenue, Winnipeg, Canada, R3E 3P4.,Section of Neonatology, Department of Pediatrics, University of Manitoba, Health Sciences Centre, 820 Sherbrook Street, Winnipeg, Canada, R3A 1R9.,Department of Physiology and Pathophysiology, University of Manitoba, 432 Basic Medical Sciences Building, 745 Bannatyne Avenue, Winnipeg, Canada, R3E 0J9
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Effects of Post-translational Modifications on Membrane Localization and Signaling of Prostanoid GPCR-G Protein Complexes and the Role of Hypoxia. J Membr Biol 2019; 252:509-526. [PMID: 31485700 DOI: 10.1007/s00232-019-00091-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/17/2019] [Indexed: 02/07/2023]
Abstract
G protein-coupled receptors (GPCRs) play a pivotal role in the adaptive responses to cellular stresses such as hypoxia. In addition to influencing cellular gene expression profiles, hypoxic microenvironments can perturb membrane protein localization, altering GPCR effector scaffolding and altering downstream signaling. Studies using proteomics approaches have revealed significant regulation of GPCR and G proteins by their state of post-translational modification. The aim of this review is to examine the effects of post-translational modifications on membrane localization and signaling of GPCR-G protein complexes, with an emphasis on vascular prostanoid receptors, and to highlight what is known about the effect of cellular hypoxia on these mechanisms. Understanding post-translational modifications of protein targets will help to define GPCR targets in treatment of disease, and to inform research into mechanisms of hypoxic cellular responses.
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Darwiche T, Collum SD, Bi W, Reynolds JO, Wilson C, Wareing N, Hernandez AM, Mertens TCJ, Zhou Z, Pandit LM, Karmouty-Quintana H. Alterations in cardiovascular function in an experimental model of lung fibrosis and pulmonary hypertension. Exp Physiol 2019; 104:568-579. [PMID: 30663834 DOI: 10.1113/ep087321] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 01/18/2019] [Indexed: 01/02/2023]
Abstract
NEW FINDINGS What is the central question of this study? We have evaluated changes in cardiovascular physiology using echocardiography in an experimental model of lung fibrosis. What is the main finding and its importance? Remarkably, we report changes in cardiovascular function as early as day 7, concomitant with evidence of vascular remodelling. We also report that isolated pulmonary arteries were hypercontractile in response to a thromboxane A2 agonist. These findings are significant because the development of pulmonary hypertension is one of the most significant predictors of mortality in patients with lung fibrosis, where there are no available therapies and a lack of animal models. ABSTRACT Group III pulmonary hypertension is observed in patients with chronic lung diseases such as chronic obstructive pulmonary disease or idiopathic pulmonary fibrosis. Pulmonary hypertension (PH) develops as a result of extensive pulmonary vascular remodelling and resultant changes in vascular tone that can lead to right ventricle hypertrophy. This eventually leads to right heart failure, which is the leading indicator of mortality in patients with idiopathic pulmonary fibrosis. Treatments for group III PH are not available, in part owing to a lack of viable animal models. Here, we have evaluated the cardiovascular changes in a model of lung fibrosis and PH. Data obtained from this study indicated that structural alterations in the right heart, such as right ventricular wall hypertrophy, occurred as early as day 14, and similar increases in right ventricle chamber size were seen between days 21 and 28. These structural changes were correlated with decreases in the systolic function of the right ventricle and right ventricular cardiac output, which also occurred between the same time points. Characterization of pulmonary artery dynamics also highlighted that PH might be occurring as early as day 21, indicated by reductions in the velocity-time integral; however, evidence for PH is apparent as early as day 7, indicated by the significant reduction in pulmonary acceleration time values. These changes are consistent with evidence of vascular remodelling observed histologically starting on day 7. In addition, we report hyperactivity of bleomycin-exposed pulmonary arteries to a thromboxane A2 receptor (Tbxa2r) agonist.
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Affiliation(s)
- Tamara Darwiche
- Department of Pharmacology, School of Biomedical Sciences, King's College London, London, UK.,Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Scott D Collum
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Weizhen Bi
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Julia O Reynolds
- Department of Medicine, Pulmonary, Critical Care and Sleep Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Cory Wilson
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Nancy Wareing
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Adriana M Hernandez
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Tinne C J Mertens
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Zhen Zhou
- Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Lavannya M Pandit
- Department of Medicine, Pulmonary, Critical Care and Sleep Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Harry Karmouty-Quintana
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
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Chakraborty R, Sikarwar AS, Hinton M, Dakshinamurti S, Chelikani P. Characterization of GPCR signaling in hypoxia. Methods Cell Biol 2018; 142:101-110. [PMID: 28964329 DOI: 10.1016/bs.mcb.2017.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
G protein-coupled receptors (GPCRs) signal in response to various external stimuli including stress. GPCR signaling has been shown to play a critical role in the adaptation of cell response to limited oxygen supply. Hypoxia has been implicated in cardiovascular diseases, human pulmonary arterial responses, and persistent pulmonary hypertension in newborns. One of the key GPCRs implicated in hypoxia is the prostanoid receptor, thromboxane A2 receptor (TP). Hypoxia can affect TP localization, stability, and activity both in vivo and in vitro. To elucidate hypoxia-mediated GPCR signaling in vitro, we lay out a general strategy to perform hypoxic experiments using both primary pulmonary artery smooth muscle cells and TP expressed in HEK293T cells. We describe assay for measuring moderate tissue hypoxia using static cell cultures, monitoring pericellular media oxygen content, and signaling of TP.
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Affiliation(s)
- Raja Chakraborty
- College of Dentistry, Winnipeg, MB, Canada; Manitoba Chemosensory Biology (MCSB) Research Group, University of Manitoba, Winnipeg, MB, Canada; Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Anurag Singh Sikarwar
- College of Dentistry, Winnipeg, MB, Canada; Manitoba Chemosensory Biology (MCSB) Research Group, University of Manitoba, Winnipeg, MB, Canada; Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Martha Hinton
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada; College of Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - Shyamala Dakshinamurti
- Manitoba Chemosensory Biology (MCSB) Research Group, University of Manitoba, Winnipeg, MB, Canada; Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada; College of Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - Prashen Chelikani
- College of Dentistry, Winnipeg, MB, Canada; Manitoba Chemosensory Biology (MCSB) Research Group, University of Manitoba, Winnipeg, MB, Canada; Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada.
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Musharaf I, Hinton M, Yi M, Dakshinamurti S. Hypoxic challenge of hyperoxic pulmonary artery myocytes increases oxidative stress due to impaired mitochondrial superoxide dismutase activity. Pulm Pharmacol Ther 2018; 48:195-202. [DOI: 10.1016/j.pupt.2017.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 12/06/2017] [Accepted: 12/11/2017] [Indexed: 01/14/2023]
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Sheak JR, Weise-Cross L, deKay RJ, Walker BR, Jernigan NL, Resta TC. Enhanced NO-dependent pulmonary vasodilation limits increased vasoconstrictor sensitivity in neonatal chronic hypoxia. Am J Physiol Heart Circ Physiol 2017; 313:H828-H838. [PMID: 28733445 DOI: 10.1152/ajpheart.00123.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 02/03/2023]
Abstract
Augmented vasoconstrictor reactivity is thought to play an important role in the development of chronic hypoxia (CH)-induced neonatal pulmonary hypertension. However, whether this response to CH results from pulmonary endothelial dysfunction and reduced nitric oxide (NO)-mediated vasodilation is not well understood. We hypothesized that neonatal CH enhances basal tone and pulmonary vasoconstrictor sensitivity by limiting NO-dependent pulmonary vasodilation. To test this hypothesis, we assessed the effects of the NO synthase (NOS) inhibitor Nω-nitro-l-arginine (l-NNA) on baseline pulmonary vascular resistance (PVR) and vasoconstrictor sensitivity to the thromboxane mimetic U-46619 in saline-perfused lungs (in situ) from 2-wk-old control and CH (12-day exposure, 0.5 atm) Sprague-Dawley rats. Basal tone was defined as that reversed by exogenous NO (spermine NONOate). CH neonates displayed elevated right ventricular systolic pressure (in vivo) and right ventricular hypertrophy, indicative of pulmonary hypertension. Perfused lungs from CH rats demonstrated greater baseline PVR, basal tone, and U-46619-mediated vasoconstriction compared with control rats in the absence of l-NNA. l-NNA markedly increased baseline PVR and reactivity to U-46619 in lungs from CH neonates, further augmenting vasoconstrictor sensitivity compared with control lungs. Exposure to CH also enhanced NO-dependent vasodilation to arginine vasopressin, pulmonary expression of NOS III [endothelial NOS (eNOS)], and eNOS phosphorylation at activation residue Ser1177 However, CH did not alter lung nitrotyrosine levels, a posttranslational modification reflecting [Formula: see text] scavenging of NO. We conclude that, in contrast to our hypothesis, enhanced basal tone and agonist-induced vasoconstriction after neonatal CH is limited by increased NO-dependent pulmonary vasodilation resulting from greater eNOS expression and phosphorylation at activation residue Ser1177NEW & NOTEWORTHY This research is the first to demonstrate enhanced nitric oxide-dependent vasodilation that limits increased vasoconstrictor reactivity in neonatal pulmonary hypertension. These results suggest that augmented vasoconstriction in this setting reflects changes in smooth muscle reactivity rather than a reduction in nitric oxide-dependent pulmonary vasodilation.
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Affiliation(s)
- Joshua R Sheak
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Laura Weise-Cross
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Ray J deKay
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Benjimen R Walker
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Nikki L Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Thomas C Resta
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
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Fediuk J, Sikarwar A, Lizotte P, Hinton M, Nolette N, Dakshinamurti S. Hypoxia increases pulmonary arterial thromboxane receptor internalization independent of receptor sensitization. Pulm Pharmacol Ther 2015; 30:1-10. [DOI: 10.1016/j.pupt.2014.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 09/05/2014] [Accepted: 10/03/2014] [Indexed: 01/07/2023]
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