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da Silva EF, Bassi M, Menani JV, Colombari DSA, Zoccal DB, Pedrino GR, Colombari E. Carotid bodies contribute to sympathoexcitation induced by acute salt overload. Exp Physiol 2018; 104:15-27. [PMID: 30370945 DOI: 10.1113/ep087110] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/12/2018] [Indexed: 01/24/2023]
Abstract
NEW FINDINGS What is the central question of this study? Does carotid body input contribute to the hyperosmotic responses? What is the main finding and its importance? The response to NaCl overload is sympathorespiratory excitation. Eliminating the carotid body input reduced sympathoexcitation but did not affect the increase in phrenic burst frequency, whereas eliminating the hypothalamus prevented the tachypnoea and sympathoexcitation. We conclude that the carotid body inputs are essential for the full expression of the sympathetic activity during acute NaCl overload, whereas the tachypnoea depends on hypothalamic mechanisms. ABSTRACT Acute salt excess activates central osmoreceptors, which trigger an increase in sympathetic and respiratory activity. The carotid bodies also respond to hyperosmolality of the extracellular compartment, but their contribution to the sympathoexcitatory and ventilatory responses to NaCl overload remains unknown. To evaluate their contribution to acute NaCl overload, we recorded thoracic sympathetic (tSNA), phrenic (PNA) and carotid sinus nerve activities in decorticate in situ preparations of male Holtzman rats (60-100 g) while delivering intra-arterial infusions of hyperosmotic NaCl (0.17, 0.3, 0.7, 1.5 and 2.0 mol l-1 ; 200 μl infusion over 25-30 s, with a 10 min time interval between solutions) or mannitol (0.3, 0.5, 1.0, 2.7 and 3.8 mol l-1 ) progressively. The cumulative infusions of hyperosmotic NaCl increased the perfusate osmolality to 341 ± 5 mosmol (kg water)-1 and elicited an immediate increase in PNA and tSNA (n = 6, P < 0.05) in sham-denervated rats. Carotid body removal attenuated sympathoexcitation (n = 5, P < 0.05) but did not affect the tachypnoeic response. A precollicular transection disconnecting the hypothalamus abolished the sympathoexcitatory and tachypnoeic responses to NaCl overload (n = 6, P < 0.05). Equi-osmolar infusions of mannitol did not alter the PNA and tSNA in sham-denervated rats (n = 5). Sodium chloride infusions increased carotid sinus nerve activity (n = 10, P < 0.05), whereas mannitol produced negligible changes (n = 5). The results indicate that carotid bodies are activated by acute NaCl overload, but not by mannitol. We conclude that the carotid bodies contribute to the increased sympathetic activity during acute NaCl overload, whereas the ventilatory response is mainly mediated by hypothalamic mechanisms.
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Affiliation(s)
- Elaine Fernanda da Silva
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - Mirian Bassi
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - José Vanderlei Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - Débora Simões Almeida Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - Daniel Breseghello Zoccal
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
| | - Gustavo Rodrigues Pedrino
- Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goias, Goiânia, Goias, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, São Paulo, Brazil
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102
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Gong C, Liu X, Ding L, Liu Y, Li T, Wang S, Zhao J, Rao S, Xiong C, Yang Y, Liu C, Liang S, Xu H. A non-synonymous polymorphism in purinergic P2X7 receptor gene confers reduced susceptibility to essential hypertension in Chinese postmenopausal women. Clin Exp Hypertens 2018; 41:558-563. [PMID: 30359160 DOI: 10.1080/10641963.2018.1523914] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Chengxin Gong
- c Department of Science and Education , Chest Hospital of Jiangxi Province , Nanchang , Jiangxi , China
| | - Xingzi Liu
- d Undergraduate student of Clinical Medical College, JiangXi Medical College of Nanchang University , Nanchang , Jiangxi , China
| | - Lu Ding
- d Undergraduate student of Clinical Medical College, JiangXi Medical College of Nanchang University , Nanchang , Jiangxi , China
| | - Yuanyuan Liu
- a Department of Physiology , JiangXi Medical College of Nanchang University , Nanchang , Nanchang, Jiangxi , China.,b Jiangxi Provincial Key Laboratory of Autonomic Nervous Function and Disease , Nanchang , Jiangxi , China
| | - Tao Li
- d Undergraduate student of Clinical Medical College, JiangXi Medical College of Nanchang University , Nanchang , Jiangxi , China
| | - Shuo Wang
- d Undergraduate student of Clinical Medical College, JiangXi Medical College of Nanchang University , Nanchang , Jiangxi , China
| | - Jiani Zhao
- d Undergraduate student of Clinical Medical College, JiangXi Medical College of Nanchang University , Nanchang , Jiangxi , China
| | - Shenqiang Rao
- a Department of Physiology , JiangXi Medical College of Nanchang University , Nanchang , Nanchang, Jiangxi , China.,b Jiangxi Provincial Key Laboratory of Autonomic Nervous Function and Disease , Nanchang , Jiangxi , China
| | - Chaopeng Xiong
- e The Second Affiliated Hospital of Nanchang University , Nanchang , Jiangxi , China
| | - Yuping Yang
- f The Fourth Affiliated Hospital of Nanchang University , Nanchang , Jiangxi , China
| | - Chaxian Liu
- d Undergraduate student of Clinical Medical College, JiangXi Medical College of Nanchang University , Nanchang , Jiangxi , China
| | - Shangdong Liang
- a Department of Physiology , JiangXi Medical College of Nanchang University , Nanchang , Nanchang, Jiangxi , China.,b Jiangxi Provincial Key Laboratory of Autonomic Nervous Function and Disease , Nanchang , Jiangxi , China
| | - Hong Xu
- a Department of Physiology , JiangXi Medical College of Nanchang University , Nanchang , Nanchang, Jiangxi , China.,b Jiangxi Provincial Key Laboratory of Autonomic Nervous Function and Disease , Nanchang , Jiangxi , China
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103
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Schmid R, Evans RJ. ATP-Gated P2X Receptor Channels: Molecular Insights into Functional Roles. Annu Rev Physiol 2018; 81:43-62. [PMID: 30354932 DOI: 10.1146/annurev-physiol-020518-114259] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the nervous system, ATP is co-stored in vesicles with classical transmitters and released in a regulated manner. ATP from the intracellular compartment can also exit the cell through hemichannels and following shear stress or membrane damage. In the past 30 years, the action of ATP as an extracellular transmitter at cell-surface receptors has evolved from somewhat of a novelty that was treated with skepticism to purinergic transmission being accepted as having widespread important functional roles mediated by ATP-gated ionotropic P2X receptors (P2XRs). This review focuses on work published in the last five years and provides an overview of ( a) structural studies, ( b) the molecular basis of channel properties and regulation of P2XRs, and ( c) the physiological and pathophysiological roles of ATP acting at defined P2XR subtypes.
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Affiliation(s)
- Ralf Schmid
- Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, United Kingdom; .,Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, United Kingdom
| | - Richard J Evans
- Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, United Kingdom;
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104
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Carlson DA, Singer MR, Sutherland C, Redondo C, Alexander LT, Hughes PF, Knapp S, Gurley SB, Sparks MA, MacDonald JA, Haystead TAJ. Targeting Pim Kinases and DAPK3 to Control Hypertension. Cell Chem Biol 2018; 25:1195-1207.e32. [PMID: 30033129 PMCID: PMC6863095 DOI: 10.1016/j.chembiol.2018.06.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 03/16/2018] [Accepted: 06/20/2018] [Indexed: 01/19/2023]
Abstract
Sustained vascular smooth muscle hypercontractility promotes hypertension and cardiovascular disease. The etiology of hypercontractility is not completely understood. New therapeutic targets remain vitally important for drug discovery. Here we report that Pim kinases, in combination with DAPK3, regulate contractility and control hypertension. Using a co-crystal structure of lead molecule (HS38) in complex with DAPK3, a dual Pim/DAPK3 inhibitor (HS56) and selective DAPK3 inhibitors (HS94 and HS148) were developed to provide mechanistic insight into the polypharmacology of hypertension. In vitro and ex vivo studies indicated that Pim kinases directly phosphorylate smooth muscle targets and that Pim/DAPK3 inhibition, unlike selective DAPK3 inhibition, significantly reduces contractility. In vivo, HS56 decreased blood pressure in spontaneously hypertensive mice in a dose-dependent manner without affecting heart rate. These findings suggest including Pim kinase inhibition within a multi-target engagement strategy for hypertension management. HS56 represents a significant step in the development of molecularly targeted antihypertensive medications.
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Affiliation(s)
- David A Carlson
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Miriam R Singer
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Cindy Sutherland
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada
| | - Clara Redondo
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Leila T Alexander
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Philip F Hughes
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Stefan Knapp
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK; Institute for Pharmaceutical Chemistry, Johann Wolfgang Goethe-University, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany
| | - Susan B Gurley
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, USA
| | - Matthew A Sparks
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, USA
| | - Justin A MacDonald
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada
| | - Timothy A J Haystead
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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105
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Sex differences in the respiratory-sympathetic coupling in rats exposed to chronic intermittent hypoxia. Respir Physiol Neurobiol 2018; 256:109-118. [DOI: 10.1016/j.resp.2017.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 09/02/2017] [Accepted: 09/06/2017] [Indexed: 02/06/2023]
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106
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Sands SA, Edwards BA, Terrill PI, Butler JP, Owens RL, Taranto-Montemurro L, Azarbarzin A, Marques M, Hess LB, Smales ET, de Melo CM, White DP, Malhotra A, Wellman A. Identifying obstructive sleep apnoea patients responsive to supplemental oxygen therapy. Eur Respir J 2018; 52:13993003.00674-2018. [PMID: 30139771 DOI: 10.1183/13993003.00674-2018] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 07/29/2018] [Indexed: 11/05/2022]
Abstract
A possible precision-medicine approach to treating obstructive sleep apnoea (OSA) involves targeting ventilatory instability (elevated loop gain) using supplemental inspired oxygen in selected patients. Here we test whether elevated loop gain and three key endophenotypic traits (collapsibility, compensation and arousability), quantified using clinical polysomnography, can predict the effect of supplemental oxygen on OSA severity.36 patients (apnoea-hypopnoea index (AHI) >20 events·h-1) completed two overnight polysomnographic studies (single-blinded randomised-controlled crossover) on supplemental oxygen (40% inspired) versus sham (air). OSA traits were quantified from the air-night polysomnography. Responders were defined by a ≥50% reduction in AHI (supine non-rapid eye movement). Secondary outcomes included blood pressure and self-reported sleep quality.Nine of 36 patients (25%) responded to supplemental oxygen (ΔAHI=72±5%). Elevated loop gain was not a significant univariate predictor of responder/non-responder status (primary analysis). In post hoc analysis, a logistic regression model based on elevated loop gain and other traits (better collapsibility and compensation; cross-validated) had 83% accuracy (89% before cross-validation); predicted responders exhibited an improvement in OSA severity (ΔAHI 59±6% versus 12±7% in predicted non-responders, p=0.0001) plus lowered morning blood pressure and "better" self-reported sleep.Patients whose OSA responds to supplemental oxygen can be identified by measuring their endophenotypic traits using diagnostic polysomnography.
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Affiliation(s)
- Scott A Sands
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.,Dept of Allergy, Immunology and Respiratory Medicine and Central Clinical School, The Alfred and Monash University, Melbourne, Australia
| | - Bradley A Edwards
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.,Sleep and Circadian Medicine Laboratory, Dept of Physiology, Monash University, Melbourne, Australia.,School of Psychological Sciences, Monash University, Melbourne, Australia.,Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Australia
| | - Philip I Terrill
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia
| | - James P Butler
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Robert L Owens
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.,Division of Pulmonary, Critical Care and Sleep Medicine, University of California San Diego, La Jolla, CA, USA
| | - Luigi Taranto-Montemurro
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Ali Azarbarzin
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Melania Marques
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Lauren B Hess
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Erik T Smales
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Camila M de Melo
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - David P White
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Atul Malhotra
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.,Division of Pulmonary, Critical Care and Sleep Medicine, University of California San Diego, La Jolla, CA, USA
| | - Andrew Wellman
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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107
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Nogueira V, Brito-Alves J, Fontes D, Oliveira L, Lucca W, Tourneur Y, Wanderley A, da Silva GSF, Leandro C, Costa-Silva JH. Carotid body removal normalizes arterial blood pressure and respiratory frequency in offspring of protein-restricted mothers. Hypertens Res 2018; 41:1000-1012. [PMID: 30242293 DOI: 10.1038/s41440-018-0104-7] [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: 03/13/2017] [Revised: 03/12/2018] [Accepted: 03/26/2018] [Indexed: 12/25/2022]
Abstract
The aim of this study is to evaluate the short-term and long-term effects elicited by carotid body removal (CBR) on ventilatory function and the development of hypertension in the offspring of malnourished rats. Wistar rats were fed a normo-protein (NP, 17% casein) or low-protein (LP, 8% casein) diet during pregnancy and lactation. At 29 days of age, the animals were submitted to CBR or a sham surgery, according to the following groups: NP-cbr, LP-cbr, NP-sham, or LP-sham. In the short-term, at 30 days of age, the respiratory frequency (RF) and immunoreactivity for Fos on the retrotrapezoid nucleus (RTN; brainstem site containing CO2 sensitive neurons) after exposure to CO2 were evaluated. In the long term, at 90 days of age, arterial pressure (AP), heart rate (HR), and cardiovascular variability were evaluated. In the short term, an increase in the baseline RF (~6%), response to CO2 (~8%), and Fos in the RTN (~27%) occurred in the LP-sham group compared with the NP-sham group. Interestingly, the CBR in the LP group normalized the RF in response to CO2 as well as RTN cell activation. In the long term, CBR reduced the mean AP by ~20 mmHg in malnourished rats. The normalization of the arterial pressure was associated with a decrease in the low-frequency (LF) oscillatory component of AP (~58%) and in the sympathetic tonus to the cardiovascular system (~29%). In conclusion, carotid body inputs in malnourished offspring may be responsible for the following: (i) enhanced respiratory frequency and CO2 chemosensitivity in early life and (ii) the production of autonomic imbalance and the development of hypertension.
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Affiliation(s)
- Viviane Nogueira
- Department of Physical Education and Sports Sciences, Federal University of Pernambuco, Vitória de Santo Antão, PE, Brazil
| | - Jose Brito-Alves
- Department of Physical Education and Sports Sciences, Federal University of Pernambuco, Vitória de Santo Antão, PE, Brazil
| | - Danilo Fontes
- Department of Physical Education and Sports Sciences, Federal University of Pernambuco, Vitória de Santo Antão, PE, Brazil
| | - Larissa Oliveira
- Department of Morphology, Federal University of Sergipe, Aracajú, SE, Brazil
| | - Waldecy Lucca
- Department of Morphology, Federal University of Sergipe, Aracajú, SE, Brazil
| | - Yves Tourneur
- Department of Physical Education and Sports Sciences, Federal University of Pernambuco, Vitória de Santo Antão, PE, Brazil.,Centre National de la Recherche Scientifique, Université Claude Bernard, Lyon 1, Lyon, France
| | - Almir Wanderley
- Department of Physiology and Pharmacology, Federal University of Pernambuco, Recife, PE, Brazil
| | - Glauber S F da Silva
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Carol Leandro
- Department of Physical Education and Sports Sciences, Federal University of Pernambuco, Vitória de Santo Antão, PE, Brazil
| | - João Henrique Costa-Silva
- Department of Physical Education and Sports Sciences, Federal University of Pernambuco, Vitória de Santo Antão, PE, Brazil.
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108
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Moraes DJA, da Silva MP, Spiller PF, Machado BH, Paton JFR. Purinergic plasticity within petrosal neurons in hypertension. Am J Physiol Regul Integr Comp Physiol 2018; 315:R963-R971. [PMID: 29949411 DOI: 10.1152/ajpregu.00142.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The carotid bodies are peripheral chemoreceptors and contribute to the homeostatic maintenance of arterial levels of O2, CO2, and [H+]. They have attracted much clinical interest recently because of the realization that aberrant signaling in these organs is associated with several pathologies including hypertension. Herein, we describe data suggesting that sympathetic overactivity in neurogenic hypertension is, at least in part, dependent on carotid body tonicity and hyperreflexia that is related to changes in the electrophysiological properties of chemoreceptive petrosal neurons. We present results showing critical roles for both ATP levels in the carotid bodies and expression of P2X3 receptors in petrosal chemoreceptive, but not baroreceptive, terminals in the etiology of carotid body tonicity and hyperreflexia. We discuss mechanisms that may underlie the changes in electrophysiological properties and P2X3 receptor expression in chemoreceptive petrosal neurons, as well as factors affecting ATP release by cells within the carotid bodies. Our findings support the notion of targeting the carotid bodies to reduce sympathetic outflow and arterial pressure, emphasizing the potential clinical importance of modulating purinergic transmission to treat pathologies associated with carotid body dysfunction but, importantly, sparing physiological chemoreflex function.
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Affiliation(s)
- Davi J A Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo , Ribeirão Preto, São Paulo , Brazil
| | - Melina P da Silva
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo , Ribeirão Preto, São Paulo , Brazil
| | - Pedro F Spiller
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo , Ribeirão Preto, São Paulo , Brazil
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo , Ribeirão Preto, São Paulo , Brazil
| | - Julian F R Paton
- Cardiovascular Autonomic Research Cluster, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland , Auckland , New Zealand
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109
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ATP-Gated P2X3 Receptors Are Specialised Sensors of the Extracellular Environment. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018. [PMID: 28639246 DOI: 10.1007/5584_2017_56] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
P2X3 receptors are ion channels expressed by autonomic and sensory nerves and specialised in transducing extracellular ATP signals. Structural data, together with functional and biochemical studies, suggest that conformational changes of P2X3 receptors upon agonist binding influence downstream intracellular molecular mechanisms relevant for neuronal responses. Activity of P2X3 receptors is implicated in pain, itch, asthma, cardiovascular dysfunction and other pathologies. The study of these receptors has therefore a large potential in the field of drug development and interdisciplinary efforts could clarify molecular mechanisms controlling P2X3 receptor function in different physiological or pathological contexts.
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110
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Abstract
PURPOSE OF REVIEW An abnormal heightened carotid body (CB) chemoreflex, which produces autonomic dysfunction and sympathetic overactivation, is the common hallmark of obstructive sleep apnea (OSA), resistant hypertension, systolic heart failure (HF), and cardiometabolic diseases. Accordingly, it has been proposed that the elimination of the CB chemosensory input to the brainstem may reduce the autonomic and cardiorespiratory alterations in sympathetic-associated diseases in humans. RECENT FINDINGS A growing body of evidence obtained in preclinical animal models support that an enhanced CB discharge produces sympathetic hyperactivity, baroreflex sensitivity and heart rate variability impairment, breathing instability, hypertension, and insulin resistance. The elimination CB chemosensory input reduces the sympathetic hyperactivity, the elevated arterial blood pressure in OSA and hypertensive models, abolishes breathing instability and improves animal survival in HF models, and restores insulin tolerance in metabolic models. These results highlight the role played by the enhanced CB drive in the progression of sympathetic-related diseases and support the proposal that the surgical ablation of the CB is useful to restore the autonomic balance and normal cardiorespiratory function in humans. Accordingly, the CB ablation has been used in pilot human studies as a therapeutic treatment for resistant hypertension and HF-induced sympathetic hyperactivity. In this review, I will discuss the supporting evidence for a crucial contribution of the CB in the central autonomic dysfunction and the pros and cons of the CB ablation as a therapy to revert autonomic overactivation. The CB ablation could be a useful method to reverse the enhanced chemoreflex in HF and severe hypertension, but caution is required before extensive use of bilateral CB ablation, which abolished ventilatory responses to hypoxia and may impair baroreceptor function.
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111
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Jaźwiec P, Gać P, Poręba M, Sobieszczańska M, Mazur G, Poręba R. The cardiovascular health score and the volume of carotid body in computed tomography angiography in patients with arterial hypertension. ACTA ACUST UNITED AC 2018; 12:551-560. [PMID: 29784505 DOI: 10.1016/j.jash.2018.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 04/07/2018] [Accepted: 04/19/2018] [Indexed: 10/17/2022]
Abstract
The cardiovascular health (CVH) score constitutes a reliable and measurable indicator of CVH proposed by the American Heart Association (AHA) calculated based on seven fundamental parameters, that is, smoking, body mass index, physical activity, healthy diet score, blood pressure, blood cholesterol, and fasting plasma glucose. The size and activity of carotid body (CB) play an important role in the pathogenesis of the cardiovascular system. The objective of this study was to define the relationship between the AHA CVH score and the volume of CB (VrCB+lCB) estimated based on computed tomography angiography (CTA) in patients with arterial hypertension. Studies were conducted on a group of 57 patients with arterial hypertension (age: 70.74 ± 8.21 years). The CVH score was calculated, and CTA of carotid arteries was carried out for all patients. The CB analysis was performed based on delayed phase imaging obtained from CTA of carotid arteries. Based on the CVH score value, CVH was determined as optimal (CVH score between 10 and 14 points), average (5 and 9 points), or inadequate (0 and 4 points). CVH score in the studied group of patients was 6.53 ± 1.81, whereas VrCB+lCB value was 38.58 ± 18.43 mm3. Patients with an inadequate CVH score (0-4 points) have statistically significantly higher VrCB+lCB, and they are fraught with VrCB+lCB ≥ median much more often than patients with an optimal CVH score (10-14 points). The receiver operating characteristic curve indicated a CVH score value of 6 as an optimal cutoff point to predict VrCB+lCB ≥ median. The CVH score ≤6 criterion indicates VrCB+lCB ≥ median with sensitivity of 58.6% and specificity of 71.4%. In the regression analysis, it was indicated that lower partial scores for physical activity, healthy diet score, and blood pressure in the AHA CVH evaluation constitute independent risk factors for higher VrCB+lCB. In the studied group of patients with arterial hypertension, an inversely proportional dependence between the CVH score and the size of CB is observed in CTA of carotid arteries.
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Affiliation(s)
- Przemysław Jaźwiec
- Department of Radiology and Diagnostic Imaging, 4th Military Hospital, Wroclaw, Poland
| | - Paweł Gać
- Department of Radiology and Diagnostic Imaging, 4th Military Hospital, Wroclaw, Poland; Department of Hygiene, Wroclaw Medical University, Wroclaw, Poland.
| | - Małgorzata Poręba
- Department of Pathophysiology, Wroclaw Medical University, Wroclaw, Poland
| | | | - Grzegorz Mazur
- Department of Internal Medicine, Occupational Diseases and Hypertension, Wroclaw Medical University, Wroclaw, Poland
| | - Rafał Poręba
- Department of Internal Medicine, Occupational Diseases and Hypertension, Wroclaw Medical University, Wroclaw, Poland
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112
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The therapeutic potential of purinergic signalling. Biochem Pharmacol 2018; 151:157-165. [DOI: 10.1016/j.bcp.2017.07.016] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/18/2017] [Indexed: 01/05/2023]
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113
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Abstract
Allosteric modulation provides exciting opportunities for drug discovery of enzymes, ion channels, and G protein-coupled receptors. As cation channels gated by extracellular ATP, P2X receptors have attracted wide attention as new drug targets. Although small molecules targeting P2X receptors have entered into clinical trials for rheumatoid arthritis, cough, and pain, negative allosteric modulation of these receptors remains largely unexplored. Here, combining X-ray crystallography, computational modeling, and functional studies of channel mutants, we identified a negative allosteric site on P2X3 receptors, fostered by the left flipper (LF), lower body (LB), and dorsal fin (DF) domains. Using two structurally analogous subtype-specific allosteric inhibitors of P2X3, AF-353 and AF-219, the latter being a drug candidate under phase II clinical trials for refractory chronic cough and idiopathic pulmonary fibrosis, we defined the molecular interactions between the drugs and receptors and the mechanism by which allosteric changes in the LF, DF, and LB domains modulate ATP activation of P2X3. Our detailed characterization of this druggable allosteric site should inspire new strategies to develop P2X3-specific allosteric modulators for clinical use.
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114
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Macias D, Cowburn AS, Torres-Torrelo H, Ortega-Sáenz P, López-Barneo J, Johnson RS. HIF-2α is essential for carotid body development and function. eLife 2018; 7:34681. [PMID: 29671738 PMCID: PMC5916566 DOI: 10.7554/elife.34681] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 04/18/2018] [Indexed: 02/06/2023] Open
Abstract
Mammalian adaptation to oxygen flux occurs at many levels, from shifts in cellular metabolism to physiological adaptations facilitated by the sympathetic nervous system and carotid body (CB). Interactions between differing forms of adaptive response to hypoxia, including transcriptional responses orchestrated by the Hypoxia Inducible transcription Factors (HIFs), are complex and clearly synergistic. We show here that there is an absolute developmental requirement for HIF-2α, one of the HIF isoforms, for growth and survival of oxygen sensitive glomus cells of the carotid body. The loss of these cells renders mice incapable of ventilatory responses to hypoxia, and this has striking effects on processes as diverse as arterial pressure regulation, exercise performance, and glucose homeostasis. We show that the expansion of the glomus cells is correlated with mTORC1 activation, and is functionally inhibited by rapamycin treatment. These findings demonstrate the central role played by HIF-2α in carotid body development, growth and function.
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Affiliation(s)
- David Macias
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Andrew S Cowburn
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | | | | | - Randall S Johnson
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
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115
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Conde SV. Ablation of the carotid bodies in disease: meeting its adverse effects. J Physiol 2018; 596:2955. [PMID: 29388224 DOI: 10.1113/jp275796] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Silvia V Conde
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
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116
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Neuroreflex control of cardiovascular function is impaired after acute poisoning with chlorpyrifos, an organophosphorus insecticide: Possible short and long term clinical implications. Toxicology 2018; 398-399:13-22. [PMID: 29471072 DOI: 10.1016/j.tox.2018.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/29/2018] [Accepted: 02/15/2018] [Indexed: 02/07/2023]
Abstract
Although it is well-established that severe poisoning by organophosphorus (OP) compounds strongly affects the cardiorespiratory system, the effects of sub-lethal exposure to these compounds on the neural control of cardiovascular function are poorly explored. The aim of this study was to evaluate the effects of acute sub-lethal exposure to chlorpyrifos (CPF), a commonly used OP insecticide, on three basic reflex mechanisms involved in blood pressure regulation, the peripheral chemoreflex, the baroreflex and the Bezold-Jarisch reflex. Adult male Wistar rats were injected intraperitoneally with a single dose of CPF (30 mg/kg) or saline (0.9%). 24 h after injections, cardiovascular reflexes were tested in awake rats. Potassium cyanide (KCN) and phenylbiguanide (PBG) were injected intravenously to activate the chemoreflex and the Bezold-Jarisch reflex, respectively. The baroreflex was activated by phenylephrine and sodium nitroprusside infusions. Blood samples were taken for measurements of butyrylcholinesterase (BChE) activity while acetylcholinesterase (AChE) activity was measured in brainstem samples. Animals treated with CPF presented signs of intoxication such as ataxia, tremor, lacrimation, salivation, tetany, urination and defecation. The hypertensive and the bradycardic responses of the chemoreflex as well as the hypotensive and bradycardic responses of the Bezold-Jarisch reflex were attenuated in CPF treated animals (P < 0.05). Concerning the baroreflex responses, CPF treatment reduced the bradycardia plateau, the range and the gain of the reflex (P < 0.05). Plasma BChE and brainstem AChE were both reduced significantly after CPF treatment (P < 0.05). Our results showed that acute sub-lethal exposure to CPF impairs the cardiovascular responses of homeostatic and defensive cardiovascular reflexes. These effects are associated with a marked inhibition of plasma BChE and brainstem AChE.
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117
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Pijacka W, Katayama PL, Salgado HC, Lincevicius GS, Campos RR, McBryde FD, Paton JFR. Variable role of carotid bodies in cardiovascular responses to exercise, hypoxia and hypercapnia in spontaneously hypertensive rats. J Physiol 2018; 596:3201-3216. [PMID: 29313987 DOI: 10.1113/jp275487] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 12/29/2017] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Carotid bodies play a critical role in maintaining arterial pressure during hypoxia and this has important implications when considering resection therapy of the carotid body in disease states such as hypertension. Curbing hypertension in patients whether resting or under stress remains a major global health challenge. We demonstrated previously the benefits of removing carotid body afferent input into the brain for both alleviating sympathetic overdrive and reducing blood pressure in neurogenic hypertension. We describe a new approach in rats for selective ablation of the carotid bodies that spares the functional integrity of the carotid sinus baroreceptors, and demonstrate the importance of the carotid bodies in the haemodynamic response to forced exercise, hypoxia and hypercapnia in conditions of hypertension. Selective ablation reduced blood pressure in hypertensive rats and re-set baroreceptor reflex function accordingly; the increases in blood pressure seen during exercise, hypoxia and hypercapnia were unaffected, abolished and augmented, respectively, after selective carotid body removal. The data suggest that carotid body ablation may trigger potential cardiovascular risks particularly during hypoxia and hypercapnia and that suppression rather than obliteration of their activity may be a more effective and safer route to pursue. ABSTRACT The carotid body has recently emerged as a promising therapeutic target for treating cardiovascular disease, but the potential impact of carotid body removal on the dynamic cardiovascular responses to acute stressors such as exercise, hypoxia and hypercapnia in hypertension is an important safety consideration that has not been studied. We first validated a novel surgical approach to selectively resect the carotid bodies bilaterally (CBR) sparing the carotid sinus baroreflex. Second, we evaluated the impact of CBR on the cardiovascular responses to exercise, hypoxia and hypercapnia in conscious, chronically instrumented spontaneously hypertensive (SH) rats. The results confirm that our CBR technique successfully and selectively abolished the chemoreflex, whilst preserving carotid baroreflex function. CBR produced a sustained fall in arterial pressure in the SH rat of ∼20 mmHg that persisted across both dark and light phases (P < 0.001), with baroreflex function curves resetting around lower arterial pressure levels. The cardiovascular and respiratory responses to moderate forced exercise were similar between CBR and Sham rats. In contrast, CBR abolished the pressor response to hypoxia seen in Sham animals, although the increases in heart rate and respiration were similar between Sham and CBR groups. Both the pressor and the respiratory responses to 7% hypercapnia were augmented after CBR (P < 0.05) compared to sham. Our finding that the carotid bodies play a critical role in maintaining arterial pressure during hypoxia has important implications when considering resection therapy of the carotid body in disease states such as hypertension as well as heart failure with sleep apnoea.
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Affiliation(s)
- Wioletta Pijacka
- Bristol CardioNomics Group, School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Pedro L Katayama
- Bristol CardioNomics Group, School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.,Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Helio C Salgado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Gisele S Lincevicius
- Bristol CardioNomics Group, School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.,Cardiovascular Division - Department of Physiology, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, Brazil
| | - Ruy R Campos
- Cardiovascular Division - Department of Physiology, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, Brazil
| | - Fiona D McBryde
- Cardiovascular Autonomic Research Cluster, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Julian F R Paton
- Bristol CardioNomics Group, School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.,Cardiovascular Autonomic Research Cluster, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
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118
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Sobrino V, González-Rodríguez P, Annese V, López-Barneo J, Pardal R. Fast neurogenesis from carotid body quiescent neuroblasts accelerates adaptation to hypoxia. EMBO Rep 2018; 19:embr.201744598. [PMID: 29335248 DOI: 10.15252/embr.201744598] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 11/30/2017] [Accepted: 12/13/2017] [Indexed: 01/01/2023] Open
Abstract
Unlike other neural peripheral organs, the adult carotid body (CB) has a remarkable structural plasticity, as it grows during acclimatization to hypoxia. The CB contains neural stem cells that can differentiate into oxygen-sensitive glomus cells. However, an extended view is that, unlike other catecholaminergic cells of the same lineage (sympathetic neurons or chromaffin cells), glomus cells can divide and thus contribute to CB hypertrophy. Here, we show that O2-sensitive mature glomus cells are post-mitotic. However, we describe an unexpected population of pre-differentiated, immature neuroblasts that express catecholaminergic markers and contain voltage-dependent ion channels, but are unresponsive to hypoxia. Neuroblasts are quiescent in normoxic conditions, but rapidly proliferate and differentiate into mature glomus cells during hypoxia. This unprecedented "fast neurogenesis" is stimulated by ATP and acetylcholine released from mature glomus cells. CB neuroblasts, which may have evolved to facilitate acclimatization to hypoxia, could contribute to the CB oversensitivity observed in highly prevalent human diseases.
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Affiliation(s)
- Verónica Sobrino
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain
| | - Patricia González-Rodríguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain
| | - Valentina Annese
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain .,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Seville, Spain
| | - Ricardo Pardal
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain .,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain
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119
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Guyenet PG, Bayliss DA, Stornetta RL, Kanbar R, Shi Y, Holloway BB, Souza GMPR, Basting TM, Abbott SBG, Wenker IC. Interdependent feedback regulation of breathing by the carotid bodies and the retrotrapezoid nucleus. J Physiol 2017; 596:3029-3042. [PMID: 29168167 DOI: 10.1113/jp274357] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/02/2017] [Indexed: 12/13/2022] Open
Abstract
The retrotrapezoid nucleus (RTN) regulates breathing in a CO2 - and state-dependent manner. RTN neurons are glutamatergic and innervate principally the respiratory pattern generator; they regulate multiple aspects of breathing, including active expiration, and maintain breathing automaticity during non-REM sleep. RTN neurons encode arterial PCO2 /pH via cell-autonomous and paracrine mechanisms, and via input from other CO2 -responsive neurons. In short, RTN neurons are a pivotal structure for breathing automaticity and arterial PCO2 homeostasis. The carotid bodies stimulate the respiratory pattern generator directly and indirectly by activating RTN via a neuronal projection originating within the solitary tract nucleus. The indirect pathway operates under normo- or hypercapnic conditions; under respiratory alkalosis (e.g. hypoxia) RTN neurons are silent and the excitatory input from the carotid bodies is suppressed. Also, silencing RTN neurons optogenetically quickly triggers a compensatory increase in carotid body activity. Thus, in conscious mammals, breathing is subject to a dual and interdependent feedback regulation by chemoreceptors. Depending on the circumstance, the activity of the carotid bodies and that of RTN vary in the same or the opposite directions, producing additive or countervailing effects on breathing. These interactions are mediated either via changes in blood gases or by brainstem neuronal connections, but their ultimate effect is invariably to minimize arterial PCO2 fluctuations. We discuss the potential relevance of this dual chemoreceptor feedback to cardiorespiratory abnormalities present in diseases in which the carotid bodies are hyperactive at rest, e.g. essential hypertension, obstructive sleep apnoea and heart failure.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Roy Kanbar
- Department of Pharmaceutical Sciences, Lebanese American University, Beyrouth, Lebanon
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Benjamin B Holloway
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Tyler M Basting
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University, New Orleans, Louisiana 70112, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ian C Wenker
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
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120
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Antipurinergic therapy for autism-An in-depth review. Mitochondrion 2017; 43:1-15. [PMID: 29253638 DOI: 10.1016/j.mito.2017.12.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/11/2017] [Accepted: 12/14/2017] [Indexed: 12/13/2022]
Abstract
Are the symptoms of autism caused by a treatable metabolic syndrome that traces to the abnormal persistence of a normal, alternative functional state of mitochondria? A small clinical trial published in 2017 suggests this is possible. Based on a new unifying theory of pathogenesis for autism called the cell danger response (CDR) hypothesis, this study of 10 boys, ages 5-14years, showed that all 5 boys who received antipurinergic therapy (APT) with a single intravenous dose of suramin experienced improvements in all the core symptoms of autism that lasted for 5-8weeks. Language, social interaction, restricted interests, and repetitive movements all improved. Two children who were non-verbal spoke their first sentences. None of these improvements were observed in the placebo group. Larger and longer studies are needed to confirm this promising discovery. This review introduces the concept of M2 (anti-inflammatory) and M1 (pro-inflammatory) mitochondria that are polarized along a functional continuum according to cell stress. The pathophysiology of the CDR, the complementary functions of M1 and M2 mitochondria, relevant gene-environment interactions, and the metabolic underpinnings of behavior are discussed as foundation stones for understanding the improvements in ASD behaviors produced by antipurinergic therapy in this small clinical trial.
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121
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Conde SV, Monteiro EC, Sacramento JF. Purines and Carotid Body: New Roles in Pathological Conditions. Front Pharmacol 2017; 8:913. [PMID: 29311923 PMCID: PMC5733106 DOI: 10.3389/fphar.2017.00913] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/29/2017] [Indexed: 01/28/2023] Open
Abstract
It is known that adenosine and adenosine-5′-triphosphate (ATP) are excitatory mediators involved in carotid body (CB) hypoxic signaling. The CBs are peripheral chemoreceptors classically defined by O2, CO2, and pH sensors. When hypoxia activates the CB, it induces the release of neurotransmitters from chemoreceptor cells leading to an increase in the action potentials frequency at the carotid sinus nerve (CSN). This increase in the firing frequency of the CSN is integrated in the brainstem to induce cardiorespiratory compensatory responses. In the last decade several pathologies, as, hypertension, diabetes, obstructive sleep apnea and heart failure have been associated with CB overactivation. In the first section of the present manuscript we review in a concise manner fundamental aspects of purine metabolism. The second section is devoted to the role of purines on the hypoxic response of the CB, providing the state-of-the art for the presence of adenosine and ATP receptors in the CB; for the role of purines at presynaptic level in CB chemoreceptor cells, as well as, its metabolism and regulation; at postsynaptic level in the CSN activity; and on the ventilatory responses to hypoxia. Recently, we have showed that adenosine is involved in CB hypersensitization during chronic intermittent hypoxia (CIH), which mimics obstructive sleep apnea, since caffeine, a non-selective adenosine receptor antagonist that inhibits A2A and A2B adenosine receptors, decreased CSN chemosensory activity in animals subjected to CIH. Apart from this involvement of adenosine in CB sensitization in sleep apnea, it was recently found that P2X3 ATP receptor in the CB contributes to increased chemoreflex hypersensitivity and hypertension in spontaneously hypertension rats. Therefore the last section of this manuscript is devoted to review the recent findings on the role of purines in CB-mediated pathologies as hypertension, diabetes and sleep apnea emphasizing the potential clinical importance of modulating purines levels and action to treat pathologies associated with CB dysfunction.
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Affiliation(s)
- Silvia V Conde
- Centro de Estudos de Doenças Crónicas, NOVA Medical School - Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Emilia C Monteiro
- Centro de Estudos de Doenças Crónicas, NOVA Medical School - Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Joana F Sacramento
- Centro de Estudos de Doenças Crónicas, NOVA Medical School - Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
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122
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Iturriaga R. Translating carotid body function into clinical medicine. J Physiol 2017; 596:3067-3077. [PMID: 29114876 DOI: 10.1113/jp275335] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 10/18/2017] [Indexed: 12/12/2022] Open
Abstract
The carotid body (CB) is considered the main O2 chemoreceptor, which contributes to cardiorespiratory homeostasis and ventilatory acclimatization. In clinical medicine, the most common pathologies associated with the CB are tumours. However, a growing body of evidence supports the novel idea that an enhanced CB chemosensory discharge contributes to the autonomic dysfunction and pathological consequences in obstructive sleep apnoea (OSA), hypertension, systolic heart failure (HF) and cardiometabolic diseases. Heightened CB chemosensory reactivity elicited by oxidative stress has been involved in sympathetic hyperactivity, cardiorespiratory instability, hypertension and insulin resistance. CB ablation, which reduces sympathetic hyperactivity, decreases hypertension in animal models of OSA and hypertension, eliminates breathing instability and improves animal survival in HF, and restores insulin tolerance in cardiometabolic models. Thus, data obtained from preclinical studies highlight the importance of the CB in the progression of sympathetic-related diseases, supporting the idea that appeasing the enhanced CB chemosensory drive may be useful in improving cardiovascular, respiratory and endocrine alterations. Accordingly, CB ablation has been proposed and used as a treatment for moderating resistant hypertension and HF-induced sympathetic hyperactivity in humans. First-in-human studies have shown that CB ablation reduces sympathetic overactivity, transiently reduces severe hypertension and improves quality of life in HF patients. Thus, CB ablation would be a useful therapy to reverse sympathetic overactivation in HF and severe hypertension, but caution is required before it is widely used due to the crucial physiological function played by the CB. Further studies in preclinical models are required to assess side-effects of CB ablation.
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Affiliation(s)
- Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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123
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Patinha D, Pijacka W, Paton JFR, Koeners MP. Cooperative Oxygen Sensing by the Kidney and Carotid Body in Blood Pressure Control. Front Physiol 2017; 8:752. [PMID: 29046642 PMCID: PMC5632678 DOI: 10.3389/fphys.2017.00752] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 09/15/2017] [Indexed: 12/13/2022] Open
Abstract
Oxygen sensing mechanisms are vital for homeostasis and survival. When oxygen levels are too low (hypoxia), blood flow has to be increased, metabolism reduced, or a combination of both, to counteract tissue damage. These adjustments are regulated by local, humoral, or neural reflex mechanisms. The kidney and the carotid body are both directly sensitive to falls in the partial pressure of oxygen and trigger reflex adjustments and thus act as oxygen sensors. We hypothesize a cooperative oxygen sensing function by both the kidney and carotid body to ensure maintenance of whole body blood flow and tissue oxygen homeostasis. Under pathological conditions of severe or prolonged tissue hypoxia, these sensors may become continuously excessively activated and increase perfusion pressure chronically. Consequently, persistence of their activity could become a driver for the development of hypertension and cardiovascular disease. Hypoxia-mediated renal and carotid body afferent signaling triggers unrestrained activation of the renin angiotensin-aldosterone system (RAAS). Renal and carotid body mediated responses in arterial pressure appear to be synergistic as interruption of either afferent source has a summative effect of reducing blood pressure in renovascular hypertension. We discuss that this cooperative oxygen sensing system can activate/sensitize their own afferent transduction mechanisms via interactions between the RAAS, hypoxia inducible factor and erythropoiesis pathways. This joint mechanism supports our view point that the development of cardiovascular disease involves afferent nerve activation.
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Affiliation(s)
- Daniela Patinha
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom.,Institute of Biomedical and Clinical Science, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - Wioletta Pijacka
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Julian F R Paton
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Maarten P Koeners
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom.,Institute of Biomedical and Clinical Science, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
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124
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Burnstock G. Purinergic Signalling: Therapeutic Developments. Front Pharmacol 2017; 8:661. [PMID: 28993732 PMCID: PMC5622197 DOI: 10.3389/fphar.2017.00661] [Citation(s) in RCA: 263] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/05/2017] [Indexed: 12/15/2022] Open
Abstract
Purinergic signalling, i.e., the role of nucleotides as extracellular signalling molecules, was proposed in 1972. However, this concept was not well accepted until the early 1990's when receptor subtypes for purines and pyrimidines were cloned and characterised, which includes four subtypes of the P1 (adenosine) receptor, seven subtypes of P2X ion channel receptors and 8 subtypes of the P2Y G protein-coupled receptor. Early studies were largely concerned with the physiology, pharmacology and biochemistry of purinergic signalling. More recently, the focus has been on the pathophysiology and therapeutic potential. There was early recognition of the use of P1 receptor agonists for the treatment of supraventricular tachycardia and A2A receptor antagonists are promising for the treatment of Parkinson's disease. Clopidogrel, a P2Y12 antagonist, is widely used for the treatment of thrombosis and stroke, blocking P2Y12 receptor-mediated platelet aggregation. Diquafosol, a long acting P2Y2 receptor agonist, is being used for the treatment of dry eye. P2X3 receptor antagonists have been developed that are orally bioavailable and stable in vivo and are currently in clinical trials for the treatment of chronic cough, bladder incontinence, visceral pain and hypertension. Antagonists to P2X7 receptors are being investigated for the treatment of inflammatory disorders, including neurodegenerative diseases. Other investigations are in progress for the use of purinergic agents for the treatment of osteoporosis, myocardial infarction, irritable bowel syndrome, epilepsy, atherosclerosis, depression, autism, diabetes, and cancer.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical SchoolLondon, United Kingdom
- Department of Pharmacology and Therapeutics, The University of Melbourne, MelbourneVIC, Australia
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125
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Franco M, Bautista-Pérez R, Cano-Martínez A, Pacheco U, Santamaría J, del Valle Mondragón L, Pérez-Méndez O, Navar LG. Physiopathological implications of P2X1and P2X7receptors in regulation of glomerular hemodynamics in angiotensin II-induced hypertension. Am J Physiol Renal Physiol 2017; 313:F9-F19. [DOI: 10.1152/ajprenal.00663.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 04/04/2017] [Accepted: 04/07/2017] [Indexed: 11/22/2022] Open
Abstract
Deleterious effects of purinergic P2X1and P2X7receptors (P2XRs) in ANG II-dependent hypertension include increased renal vascular resistance, and impaired autoregulation and pressure natriuresis. However, their specific effects on the determinants of glomerular hemodynamics remain incompletely delineated. To investigate the P2XR contributions to altered glomerular hemodynamics in hypertension, the effects of acute blockade of P2X1R, P2X7R, and P2X4R with NF449, A438079, and PSB12054, respectively, were evaluated in ANG II-infused rats (435 ng·kg−1·min−1). P2X1R or P2X7R blockade reduced afferent (6.85 ± 1.05 vs. 2.37 ± 0.20 dyn·s−1·cm−5) and efferent (2.85 ± 0.38 vs. 0.99 ± 0.07 dyn·s−1·cm−5) arteriolar resistances, leading to increases in glomerular plasma flow (75.82 ± 5.58 vs. 206.7 ± 16.38 nl/min), ultrafiltration coefficient (0.0198 ± 0.0024 vs. 0.0512 ± 0.0046 nl·min−1·mmHg−1), and single-nephron glomerular filtration rate (22.73 ± 2.02 vs. 51.56 ± 3.87 nl/min) to near normal values. Blockade of P2X4R did not elicit effects in hypertensive rats. In normotensive sham-operated rats, only the P2X1R antagonist caused an increase plasma flow and single-nephron glomerular filtration rate, whereas the P2X4R antagonist induced glomerular vasoconstriction that was consistent with evidence that P2X4R stimulation increases release of nitric oxide from endothelial cells. Mean arterial pressure remained unchanged in both hypertensive and normotensive groups. Western blot analysis showed overexpression of P2X1R, P2X7R, and P2X4R proteins in hypertensive rats. Whereas it has been generally assumed that the altered glomerular vascular resistances in ANG II hypertension are due to AT1receptor-mediated vasoconstriction, these data indicate a predominant P2X1R and P2X7R control of glomerular hemodynamics in ANG II hypertension.
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Affiliation(s)
- Martha Franco
- Renal Pathophysiology Laboratory, Department of Nephrology, Instituto Nacional de Cardiología “Ignacio Chávez,” México City, México
| | - Rocío Bautista-Pérez
- Department of Molecular Biology, Instituto Nacional de Cardiología “Ignacio Chávez,” México City, México
| | - Agustina Cano-Martínez
- Department of Physiology, Instituto Nacional de Cardiología “Ignacio Chávez,” México City, México
| | - Ursino Pacheco
- Renal Pathophysiology Laboratory, Department of Nephrology, Instituto Nacional de Cardiología “Ignacio Chávez,” México City, México
| | - José Santamaría
- Renal Pathophysiology Laboratory, Department of Nephrology, Instituto Nacional de Cardiología “Ignacio Chávez,” México City, México
| | | | - Oscar Pérez-Méndez
- Department of Molecular Biology, Instituto Nacional de Cardiología “Ignacio Chávez,” México City, México
| | - L. Gabriel Navar
- Department of Physiology and Hypertension and Renal Center, Tulane University School of Medicine, New Orleans, Louisiana
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127
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Ayas NT, Drager LF, Morrell MJ, Polotsky VY. Update in Sleep-disordered Breathing 2016. Am J Respir Crit Care Med 2017; 195:1561-1566. [PMID: 28530119 PMCID: PMC5955019 DOI: 10.1164/rccm.201701-0048up] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Accepted: 03/20/2017] [Indexed: 12/17/2022] Open
Affiliation(s)
- Najib T. Ayas
- Sleep Disorders Program and
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Luciano F. Drager
- Hypertension Unit, Heart Institute (InCor) and
- Hypertension Unit, Renal Division, University of Sao Paulo Medical School, Sao Paulo, Brazil
| | - Mary J. Morrell
- Sleep and Ventilation Unit, National Heart and Lung Institute, Imperial College London, London, United Kingdom
- National Institute for Health Research Respiratory Disease Biomedical Research Unit at the Royal Brompton and Harefield National Health Service Foundation Trust and Imperial College London, London, United Kingdom; and
| | - Vsevolod Y. Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
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128
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Burnstock G. Purinergic Signaling in the Cardiovascular System. Circ Res 2017; 120:207-228. [PMID: 28057794 DOI: 10.1161/circresaha.116.309726] [Citation(s) in RCA: 259] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/21/2016] [Accepted: 11/23/2016] [Indexed: 02/07/2023]
Abstract
There is nervous control of the heart by ATP as a cotransmitter in sympathetic, parasympathetic, and sensory-motor nerves, as well as in intracardiac neurons. Centers in the brain control heart activities and vagal cardiovascular reflexes involve purines. Adenine nucleotides and nucleosides act on purinoceptors on cardiomyocytes, AV and SA nodes, cardiac fibroblasts, and coronary blood vessels. Vascular tone is controlled by a dual mechanism. ATP, released from perivascular sympathetic nerves, causes vasoconstriction largely via P2X1 receptors. Endothelial cells release ATP in response to changes in blood flow (via shear stress) or hypoxia, to act on P2 receptors on endothelial cells to produce nitric oxide, endothelium-derived hyperpolarizing factor, or prostaglandins to cause vasodilation. ATP is also released from sensory-motor nerves during antidromic reflex activity, to produce relaxation of some blood vessels. Purinergic signaling is involved in the physiology of erythrocytes, platelets, and leukocytes. ATP is released from erythrocytes and platelets, and purinoceptors and ectonucleotidases are expressed by these cells. P1, P2Y1, P2Y12, and P2X1 receptors are expressed on platelets, which mediate platelet aggregation and shape change. Long-term (trophic) actions of purine and pyrimidine nucleosides and nucleotides promote migration and proliferation of vascular smooth muscle and endothelial cells via P1 and P2Y receptors during angiogenesis, vessel remodeling during restenosis after angioplasty and atherosclerosis. The involvement of purinergic signaling in cardiovascular pathophysiology and its therapeutic potential are discussed, including heart failure, infarction, arrhythmias, syncope, cardiomyopathy, angina, heart transplantation and coronary bypass grafts, coronary artery disease, diabetic cardiomyopathy, hypertension, ischemia, thrombosis, diabetes mellitus, and migraine.
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Affiliation(s)
- Geoffrey Burnstock
- From the Autonomic Neuroscience Institute, Royal Free and University College Medical School, London, United Kingdom.
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129
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McBryde FD, Hart EC, Ramchandra R, Paton JF. Evaluating the carotid bodies and renal nerves as therapeutic targets for hypertension. Auton Neurosci 2017; 204:126-130. [DOI: 10.1016/j.autneu.2016.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 07/28/2016] [Accepted: 08/01/2016] [Indexed: 11/30/2022]
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130
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Taxini CL, Moreira TS, Takakura AC, Bícego KC, Gargaglioni LH, Zoccal DB. Role of A5 noradrenergic neurons in the chemoreflex control of respiratory and sympathetic activities in unanesthetized conditions. Neuroscience 2017; 354:146-157. [PMID: 28461215 DOI: 10.1016/j.neuroscience.2017.04.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/21/2017] [Accepted: 04/21/2017] [Indexed: 01/04/2023]
Abstract
The A5 area at the ventrolateral pons contains noradrenergic neurons connected with other medullary areas involved in the cardiorespiratory control. Its contribution to the cardiorespiratory regulation was previously evidenced in anesthetized conditions. In the present study, we investigated the involvement of the A5 noradrenergic neurons to the basal and chemoreflex control of the sympathetic and respiratory activities in unanesthetized conditions. A5 noradrenergic neurons were lesioned using microinjections of anti-dopamine β-hydroxylase saporin (anti-DβH-SAP). After 7-8days, we evaluated the arterial pressure levels, heart rate and minute ventilation in freely moving adult rats (280-350g) as well as recorded from thoracic sympathetic (tSN) and phrenic nerves (PN) using the arterially perfused in situ preparation of juvenile rats (80-90g). Baseline cardiovascular, sympathetic and respiratory parameters were similar between control (n=7-8) and A5-lesioned rats (n=5-6) in both experimental preparations. In adult rats, lesions of A5 noradrenergic neurons did not modify the reflex cardiorespiratory adjustments to hypoxia (7% O2) and hypercapnia (7% CO2). In the in situ preparations, the sympatho-excitation, but not the PN reflex response, elicited by either the stimulation of peripheral chemoreceptors (ΔtSN: 110±12% vs 58±8%, P<0.01) or hypercapnia (ΔtSN: 9.5±1.4% vs 3.9±1.7%, P<0.05) was attenuated in A5-lesioned rats compared to controls. Our data demonstrated that A5 noradrenergic neurons are part of the circuitry recruited for the processing of sympathetic response to hypoxia and hypercapnia in unanesthetized conditions.
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Affiliation(s)
- Camila L Taxini
- Department of Morphology and Animal Physiology, São Paulo State University (UNESP), Jaboticabal, SP, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, SP, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, SP, Brazil
| | - Kênia C Bícego
- Department of Morphology and Animal Physiology, São Paulo State University (UNESP), Jaboticabal, SP, Brazil
| | - Luciane H Gargaglioni
- Department of Morphology and Animal Physiology, São Paulo State University (UNESP), Jaboticabal, SP, Brazil.
| | - Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil.
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131
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Age-related changes in immunoreactivity for dopamine β-hydroxylase in carotid body glomus cells in spontaneously hypertensive rats. Auton Neurosci 2017; 205:50-56. [PMID: 28473232 DOI: 10.1016/j.autneu.2017.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/18/2017] [Accepted: 04/27/2017] [Indexed: 12/17/2022]
Abstract
The purpose of this study was to investigate immunoreactivity for dopamine β-hydroxylase (DBH) and tyrosine hydroxylase (TH) in carotid body (CB) glomus cells in spontaneously hypertensive rats (SHR/Izm) at 4 (prehypertensive stage), 8 (early stage of developmental hypertension), 12 (later stage of developmental hypertension), and 16weeks of age (established hypertensive stage). Age-matched Wistar Kyoto rats (WKY/Izm) were used as controls. Staining properties for TH were similar between both strains at each age. Regarding DBH immunostaining, although some glomus cells showed intense DBH immunoreactivity at 4weeks of age, these cells were rarely observed at 8, 12, and 16weeks of age in WKY/Izm. In SHR/Izm, intense DBH immunoreactivity was observed in some glomus cells at 4weeks of age, these cells were also observed at 8 and 12weeks of age, and their number increased at 16weeks of age. An image analysis showed that the percentage of DBH-immunopositive glomus cells in WKY/Izm was approximately 30% at 4weeks of age and significantly decreased to approximately 10% at 8, 12, and 16weeks of age (p<0.05). This percentage in SHR/Izm was approximately 40% at each age. The gray scale intensity for DBH immunoreactivity in DBH-immunopositive glomus cells was similar in both strains at 4weeks of age, but became significantly lower in WKY/Izm and higher in SHR/Izm with increase in age (p<0.05). These results suggest that noradrenaline in glomus cells plays an important role in the regulation of neurotransmission between CB and afferent nerves during developmental hypertension.
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132
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On the permeation of large organic cations through the pore of ATP-gated P2X receptors. Proc Natl Acad Sci U S A 2017; 114:E3786-E3795. [PMID: 28442564 DOI: 10.1073/pnas.1701379114] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Pore dilation is thought to be a hallmark of purinergic P2X receptors. The most commonly held view of this unusual process posits that under prolonged ATP exposure the ion pore expands in a striking manner from an initial small-cation conductive state to a dilated state, which allows the passage of larger synthetic cations, such as N-methyl-d-glucamine (NMDG+). However, this mechanism is controversial, and the identity of the natural large permeating cations remains elusive. Here, we provide evidence that, contrary to the time-dependent pore dilation model, ATP binding opens an NMDG+-permeable channel within milliseconds, with a conductance that remains stable over time. We show that the time course of NMDG+ permeability superimposes that of Na+ and demonstrate that the molecular motions leading to the permeation of NMDG+ are very similar to those that drive Na+ flow. We found, however, that NMDG+ "percolates" 10 times slower than Na+ in the open state, likely due to a conformational and orientational selection of permeating molecules. We further uncover that several P2X receptors, including those able to desensitize, are permeable not only to NMDG+ but also to spermidine, a large natural cation involved in ion channel modulation, revealing a previously unrecognized P2X-mediated signaling. Altogether, our data do not support a time-dependent dilation of the pore on its own but rather reveal that the open pore of P2X receptors is wide enough to allow the permeation of large organic cations, including natural ones. This permeation mechanism has considerable physiological significance.
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133
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Machado BH, Zoccal DB, Moraes DJA. Neurogenic hypertension and the secrets of respiration. Am J Physiol Regul Integr Comp Physiol 2017; 312:R864-R872. [PMID: 28438764 DOI: 10.1152/ajpregu.00505.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 04/12/2017] [Accepted: 04/13/2017] [Indexed: 11/22/2022]
Abstract
Despite recent advances in the knowledge of the neural control of cardiovascular function, the cause of sympathetic overactivity in neurogenic hypertension remains unknown. Studies from our laboratory point out that rats submitted to chronic intermittent hypoxia (CIH), an experimental model of neurogenic hypertension, present changes in the central respiratory network that impact the pattern of sympathetic discharge and the levels of arterial pressure. In addition to the fine coordination of respiratory muscle contraction and relaxation, which is essential for O2 and CO2 pulmonary exchanges, neurons of the respiratory network are connected precisely to the neurons controlling the sympathetic activity in the brain stem. This respiratory-sympathetic neuronal interaction provides adjustments in the sympathetic outflow to the heart and vasculature during each respiratory phase according to the metabolic demands. Herein, we report that CIH-induced sympathetic over activity and mild hypertension are associated with increased frequency discharge of ventral medullary presympathetic neurons. We also describe that their increased frequency discharge is dependent on synaptic inputs, mostly from neurons of the brain stem respiratory network, rather than changes in their intrinsic electrophysiological properties. In perspective, we are taking into consideration the possibility that changes in the central respiratory rhythm/pattern generator contribute to increased sympathetic outflow and the development of neurogenic hypertension. Our experimental evidence provides support for the hypothesis that changes in the coupling of respiratory and sympathetic networks might be one of the unrevealed secrets of neurogenic hypertension in rats.
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Affiliation(s)
- Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; and
| | - Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University, Araraquara, São Paulo, Brazil
| | - Davi J A Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; and
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134
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Sunggip C, Nishimura A, Shimoda K, Numaga-Tomita T, Tsuda M, Nishida M. Purinergic P2Y 6 receptors: A new therapeutic target of age-dependent hypertension. Pharmacol Res 2017; 120:51-59. [PMID: 28336370 DOI: 10.1016/j.phrs.2017.03.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 03/13/2017] [Accepted: 03/13/2017] [Indexed: 01/04/2023]
Abstract
Aging has a remarkable effect on cardiovascular homeostasis and it is known as the major non-modifiable risk factor in the development of hypertension. Medications targeting sympathetic nerve system and/or renin-angiotensin-aldosterone system are widely accepted as a powerful therapeutic strategy to improve hypertension, although the control rates remain unsatisfactory especially in the elder patients with hypertension. Purinergic receptors, activated by adenine, uridine nucleotides and nucleotide sugars, play pivotal roles in many biological processes, including platelet aggregation, neurotransmission and hormone release, and regulation of cardiovascular contractility. Since clopidogrel, a selective inhibitor of G protein-coupled purinergic P2Y12 receptor (P2Y12R), achieved clinical success as an anti-platelet drug, P2YRs has been attracted more attention as new therapeutic targets of cardiovascular diseases. We have revealed that UDP-responsive P2Y6R promoted angiotensin type 1 receptor (AT1R)-stimulated vascular remodeling in mice, in an age-dependent manner. Moreover, the age-related formation of heterodimer between AT1R and P2Y6R was disrupted by MRS2578, a P2Y6R-selective inhibitor. These findings suggest that P2Y6R is a therapeutic target to prevent age-related hypertension.
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Affiliation(s)
- Caroline Sunggip
- Division of Cardiocirculatory Signaling, National Institute for Physiological Sciences (Okazaki Institute for Integrative Bioscience), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan; Department of Biomedical Science & Therapeutic, Faculty of Medicine and Health Sciences, University Malaysia Sabah, 88400 Kota Kinabalu Sabah, Malaysia
| | - Akiyuki Nishimura
- Division of Cardiocirculatory Signaling, National Institute for Physiological Sciences (Okazaki Institute for Integrative Bioscience), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan; Department of Physiological Sciences, SOKENDAI (School of Life Science, The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan
| | - Kakeru Shimoda
- Division of Cardiocirculatory Signaling, National Institute for Physiological Sciences (Okazaki Institute for Integrative Bioscience), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan; Department of Physiological Sciences, SOKENDAI (School of Life Science, The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan; Department of Translational Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Takuro Numaga-Tomita
- Division of Cardiocirculatory Signaling, National Institute for Physiological Sciences (Okazaki Institute for Integrative Bioscience), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan; Department of Physiological Sciences, SOKENDAI (School of Life Science, The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan
| | - Makoto Tsuda
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Motohiro Nishida
- Division of Cardiocirculatory Signaling, National Institute for Physiological Sciences (Okazaki Institute for Integrative Bioscience), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan; Department of Physiological Sciences, SOKENDAI (School of Life Science, The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan; Department of Translational Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
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135
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Menuet C, Le S, Dempsey B, Connelly AA, Kamar JL, Jancovski N, Bassi JK, Walters K, Simms AE, Hammond A, Fong AY, Goodchild AK, McMullan S, Allen AM. Excessive Respiratory Modulation of Blood Pressure Triggers Hypertension. Cell Metab 2017; 25:739-748. [PMID: 28215844 DOI: 10.1016/j.cmet.2017.01.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 12/09/2016] [Accepted: 01/28/2017] [Indexed: 02/07/2023]
Abstract
The etiology of hypertension, the world's biggest killer, remains poorly understood, with treatments targeting the established symptom, not the cause. The development of hypertension involves increased sympathetic nerve activity that, in experimental hypertension, may be driven by excessive respiratory modulation. Using selective viral and cell lesion techniques, we identify adrenergic C1 neurons in the medulla oblongata as critical for respiratory-sympathetic entrainment and the development of experimental hypertension. We also show that a cohort of young, normotensive humans, selected for an exaggerated blood pressure response to exercise and thus increased hypertension risk, has enhanced respiratory-related blood pressure fluctuations. These studies pinpoint a specific neuronal target for ameliorating excessive sympathetic activity during the developmental phase of hypertension and identify a group of pre-hypertensive subjects that would benefit from targeting these cells.
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Affiliation(s)
- Clément Menuet
- Department of Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Sheng Le
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Bowen Dempsey
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Angela A Connelly
- Department of Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jessica L Kamar
- Department of Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Nikola Jancovski
- Department of Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jaspreet K Bassi
- Department of Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Keryn Walters
- Department of Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Annabel E Simms
- Department of Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Andrew Hammond
- Department of Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Angelina Y Fong
- Department of Physiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Ann K Goodchild
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Simon McMullan
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Andrew M Allen
- Department of Physiology, University of Melbourne, Parkville, VIC 3010, Australia; Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3010, Australia.
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136
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Cutsforth-Gregory JK, Benarroch EE. Nucleus of the solitary tract, medullary reflexes, and clinical implications. Neurology 2017; 88:1187-1196. [PMID: 28202704 DOI: 10.1212/wnl.0000000000003751] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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137
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Crunkhorn S. Hypertension: Purinergic receptor inhibition lowers blood pressure. Nat Rev Drug Discov 2016; 15:748-749. [PMID: 27807365 DOI: 10.1038/nrd.2016.217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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138
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Pijacka W, McBryde FD, Marvar PJ, Lincevicius GS, Abdala APL, Woodward L, Li D, Paterson DJ, Paton JFR. Carotid sinus denervation ameliorates renovascular hypertension in adult Wistar rats. J Physiol 2016; 594:6255-6266. [PMID: 27510951 DOI: 10.1113/jp272708] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 08/03/2016] [Indexed: 01/24/2023] Open
Abstract
KEY POINTS Peripheral chemoreflex sensitization is a feature of renovascular hypertension. Carotid sinus nerve denervation (CSD) has recently been shown to relieve hypertension and reduce sympathetic activity in other rat models of hypertension. We show that CSD in renovascular hypertension halts further increases in blood pressure. Possible mechanisms include improvements in baroreceptor reflex sensitivity and renal function, restoration of cardiac calcium signalling towards control levels, and reduced neural inflammation. Our data suggest that the peripheral chemoreflex may be a viable therapeutic target for renovascular hypertension. ABSTRACT The peripheral chemoreflex is known to be hyper-responsive in both spontaneously hypertensive (SHR) and Goldblatt hypertensive (two kidney one clip; 2K1C) rats. We have previously shown that carotid sinus nerve denervation (CSD) reduces arterial blood pressure (ABP) in SHR. In the present study, we show that CSD ameliorates 2K1C hypertension and reveal the potential underlying mechanisms. Adult Wistar rats were instrumented to record ABP via telemetry, and then underwent CSD (n = 9) or sham CSD (n = 9) 5 weeks after renal artery clipping, in comparison with normal Wistar rats (n = 5). After 21 days, renal function was assessed, and tissue was collected to assess sympathetic postganglionic intracellular calcium transients ([Ca2+ ]i ) and immune cell infiltrates. Hypertensive 2K1C rats showed a profound elevation in ABP (Wistar: 98 ± 4 mmHg vs. 2K1C: 147 ± 8 mmHg; P < 0.001), coupled with impairments in renal function and baroreflex sensitivity, increased neuroinflammatory markers and enhanced [Ca2+ ]I in stellate neurons (P < 0.05). CSD reduced ABP in 2K1C+CSD rats and prevented the further progressive increase in ABP seen in 2K1C+sham CSD rats, with a between-group difference of 14 ± 2 mmHg by week 3 (P < 0.01), which was accompanied by improvements in both baroreflex control and spectral indicators of cardiac sympatho-vagal balance. Furthermore, CSD improved protein and albuminuria, decreased [Ca2+ ]i evoked responses from stellate neurons, and also reduced indicators of brainstem inflammation. In summary, CSD in 2K1C rats reduces the hypertensive burden and improves renal function. This may be mediated by improvements in autonomic balance, functional remodelling of post-ganglionic neurons and reduced inflammation. Our results suggest that the peripheral chemoreflex may be considered as a potential therapeutic target for controlling renovascular hypertension.
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Affiliation(s)
- Wioletta Pijacka
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Fiona D McBryde
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK.,Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Paul J Marvar
- Department of Pharmacology and Physiology, The George Washington University School of Medical and Health Sciences, Washington, DC, USA
| | - Gisele S Lincevicius
- Cardiovascular Division - Department of Physiology, Escola Paulista de Medicina, Universidade Federal de, Sao Paulo, Brazil
| | - Ana P L Abdala
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Lavinia Woodward
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, UK
| | - Dan Li
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, UK
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, UK
| | - Julian F R Paton
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK.
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