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Khalilpour J, Zangbar HS, Alipour MR, Pakdel FQ, Zavari Z, Shahabi P. Chronic Sustained Hypoxia Leads to Brainstem Tauopathy and Declines the Power of Rhythms in the Ventrolateral Medulla: Shedding Light on a Possible Mechanism. Mol Neurobiol 2024; 61:3121-3143. [PMID: 37976025 DOI: 10.1007/s12035-023-03763-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Abstract
Hypoxia, especially the chronic type, leads to disruptive results in the brain that may contribute to the pathogenesis of some neurodegenerative diseases such as Alzheimer's disease (AD). The ventrolateral medulla (VLM) contains clusters of interneurons, such as the pre-Bötzinger complex (preBötC), that generate the main respiratory rhythm drive. We hypothesized that exposing animals to chronic sustained hypoxia (CSH) might develop tauopathy in the brainstem, consequently changing the rhythmic manifestations of respiratory neurons. In this study, old (20-22 months) and young (2-3 months) male rats were subjected to CSH (10 ± 0.5% O2) for ten consecutive days. Western blotting and immunofluorescence (IF) staining were used to evaluate phosphorylated tau. Mitochondrial membrane potential (MMP or ∆ψm) and reactive oxygen species (ROS) production were measured to assess mitochondrial function. In vivo diaphragm's electromyography (dEMG) and local field potential (LFP) recordings from preBötC were employed to assess the respiratory factors and rhythmic representation of preBötC, respectively. Findings showed that ROS production increased significantly in hypoxic groups, associated with a significant decline in ∆ψm. In addition, tau phosphorylation elevated in the brainstem of hypoxic groups. On the other hand, the power of rhythms declined significantly in the preBötC of hypoxic rats, parallel with changes in the respiratory rate, total respiration time, and expiration time. Moreover, there was a positive and statistically significant correlation between LFP rhythm's power and inspiration time. Our data showed that besides CSH, aging also contributed to mitochondrial dysfunction, tau hyperphosphorylation, LFP rhythms' power decline, and changes in respiratory factors.
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Affiliation(s)
- Jamal Khalilpour
- Drug Applied Research Center, Tabriz University of Medical Sciences, Golgasht Street, Tabriz, East Azerbaijan, Iran
| | - Hamid Soltani Zangbar
- Department of Neuroscience, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Golgasht Street, Tabriz, East Azerbaijan, Iran.
| | - Mohammad Reza Alipour
- Drug Applied Research Center, Tabriz University of Medical Sciences, Golgasht Street, Tabriz, East Azerbaijan, Iran
| | - Firouz Qaderi Pakdel
- Department of Physiology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Zohre Zavari
- Drug Applied Research Center, Tabriz University of Medical Sciences, Golgasht Street, Tabriz, East Azerbaijan, Iran
| | - Parviz Shahabi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Golgasht Street, Tabriz, East Azerbaijan, Iran.
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2
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Simpson LL, Stembridge M, Siebenmann C, Moore JP, Lawley JS. Mechanisms underpinning sympathoexcitation in hypoxia. J Physiol 2024. [PMID: 38533641 DOI: 10.1113/jp284579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 02/28/2024] [Indexed: 03/28/2024] Open
Abstract
Sympathoexcitation is a hallmark of hypoxic exposure, occurring acutely, as well as persisting in acclimatised lowland populations and with generational exposure in highland native populations of the Andean and Tibetan plateaus. The mechanisms mediating altitude sympathoexcitation are multifactorial, involving alterations in both peripheral autonomic reflexes and central neural pathways, and are dependent on the duration of exposure. Initially, hypoxia-induced sympathoexcitation appears to be an adaptive response, primarily mediated by regulatory reflex mechanisms concerned with preserving systemic and cerebral tissue O2 delivery and maintaining arterial blood pressure. However, as exposure continues, sympathoexcitation is further augmented above that observed with acute exposure, despite acclimatisation processes that restore arterial oxygen content (C a O 2 ${C_{{\mathrm{a}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ). Under these conditions, sympathoexcitation may become maladaptive, giving rise to reduced vascular reactivity and mildly elevated blood pressure. Importantly, current evidence indicates the peripheral chemoreflex does not play a significant role in the augmentation of sympathoexcitation during altitude acclimatisation, although methodological limitations may underestimate its true contribution. Instead, processes that provide no obvious survival benefit in hypoxia appear to contribute, including elevated pulmonary arterial pressure. Nocturnal periodic breathing is also a potential mechanism contributing to altitude sympathoexcitation, although experimental studies are required. Despite recent advancements within the field, several areas remain unexplored, including the mechanisms responsible for the apparent normalisation of muscle sympathetic nerve activity during intermediate hypoxic exposures, the mechanisms accounting for persistent sympathoexcitation following descent from altitude and consideration of whether there are sex-based differences in sympathetic regulation at altitude.
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Affiliation(s)
- Lydia L Simpson
- Department of Sport Science, Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | | | - Jonathan P Moore
- School of Psychology and Sport Science, Institute of Applied Human Physiology, Bangor University, Bangor, UK
| | - Justin S Lawley
- Department of Sport Science, Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
- Institute of Mountain Emergency Medicine, EURAC Research, Bolzano, Italy
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3
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Simpson LL, Hansen AB, Moralez G, Amin SB, Hofstaetter F, Gasho C, Stembridge M, Dawkins TG, Tymko MM, Ainslie PN, Lawley JS, Hearon CM. Adrenergic control of skeletal muscle blood flow during chronic hypoxia in healthy males. Am J Physiol Regul Integr Comp Physiol 2023; 324:R457-R469. [PMID: 36717165 PMCID: PMC10026988 DOI: 10.1152/ajpregu.00230.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/24/2023] [Accepted: 01/24/2023] [Indexed: 02/01/2023]
Abstract
Sympathetic transduction is reduced following chronic high-altitude (HA) exposure; however, vascular α-adrenergic signaling, the primary mechanism mediating sympathetic vasoconstriction at sea level (SL), has not been examined at HA. In nine male lowlanders, we measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (ΔFVC) during 1) incremental intra-arterial infusion of phenylephrine to assess α1-adrenergic receptor responsiveness and 2) combined intra-arterial infusion of β-adrenergic and α-adrenergic antagonists propranolol and phentolamine (α-β-blockade) to assess adrenergic vascular restraint at rest and during exercise-induced sympathoexcitation (cycling; 60% peak power). Experiments were performed near SL (344 m) and after 3 wk at HA (4,383 m). HA abolished the vasoconstrictor response to low-dose phenylephrine (ΔFVC: SL: -34 ± 15%, vs. HA; +3 ± 18%; P < 0.0001) and markedly attenuated the response to medium (ΔFVC: SL: -45 ± 18% vs. HA: -28 ± 11%; P = 0.009) and high (ΔFVC: SL: -47 ± 20%, vs. HA: -35 ± 20%; P = 0.041) doses. Blockade of β-adrenergic receptors alone had no effect on resting FVC (P = 0.500) and combined α-β-blockade induced a similar vasodilatory response at SL and HA (P = 0.580). Forearm vasoconstriction during cycling was not different at SL and HA (P = 0.999). Interestingly, cycling-induced forearm vasoconstriction was attenuated by α-β-blockade at SL (ΔFVC: Control: -27 ± 128 vs. α-β-blockade: +19 ± 23%; P = 0.0004), but unaffected at HA (ΔFVC: Control: -20 ± 22 vs. α-β-blockade: -23 ± 11%; P = 0.999). Our results indicate that in healthy males, altitude acclimatization attenuates α1-adrenergic receptor responsiveness; however, resting α-adrenergic restraint remains intact, due to concurrent resting sympathoexcitation. Furthermore, forearm vasoconstrictor responses to cycling are preserved, although the contribution of adrenergic receptors is diminished, indicating a reliance on alternative vasoconstrictor mechanisms.
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Affiliation(s)
- Lydia L Simpson
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Alexander B Hansen
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Sachin B Amin
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Florian Hofstaetter
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Christopher Gasho
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University, Loma Linda, California, United States
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, Wales, United Kingdom
| | - Tony G Dawkins
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Michael M Tymko
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
- Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Philip N Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Justin S Lawley
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Christopher M Hearon
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, United States
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4
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Spiroski AM, Niu Y, Nicholas LM, Austin-Williams S, Camm EJ, Sutherland MR, Ashmore TJ, Skeffington KL, Logan A, Ozanne SE, Murphy MP, Giussani DA. Mitochondria antioxidant protection against cardiovascular dysfunction programmed by early-onset gestational hypoxia. FASEB J 2021; 35:e21446. [PMID: 33788974 PMCID: PMC7612077 DOI: 10.1096/fj.202002705r] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/19/2021] [Accepted: 02/01/2021] [Indexed: 02/02/2023]
Abstract
Mitochondria-derived oxidative stress during fetal development increases cardiovascular risk in adult offspring of pregnancies complicated by chronic fetal hypoxia. We investigated the efficacy of the mitochondria-targeted antioxidant MitoQ in preventing cardiovascular dysfunction in adult rat offspring exposed to gestational hypoxia, integrating functional experiments in vivo, with those at the isolated organ and molecular levels. Rats were randomized to normoxic or hypoxic (13%-14% O2 ) pregnancy ± MitoQ (500 μM day-1 ) in the maternal drinking water. At 4 months of age, one cohort of male offspring was chronically instrumented with vascular catheters and flow probes to test in vivo cardiovascular function. In a second cohort, the heart was isolated and mounted onto a Langendorff preparation. To establish mechanisms linking gestational hypoxia with cardiovascular dysfunction and protection by MitoQ, we quantified the expression of antioxidant system, β-adrenergic signaling, and calcium handling genes in the fetus and adult, in frozen tissues from a third cohort. Maternal MitoQ in hypoxic pregnancy protected offspring against increased α1 -adrenergic reactivity of the cardiovascular system, enhanced reactive hyperemia in peripheral vascular beds, and sympathetic dominance, hypercontractility and diastolic dysfunction in the heart. Inhibition of Nfe2l2-mediated oxidative stress in the fetal heart and preservation of calcium regulatory responses in the hearts of fetal and adult offspring link molecular mechanisms to the protective actions of MitoQ treatment of hypoxic pregnancy. Therefore, these data show the efficacy of MitoQ in buffering mitochondrial stress through NADPH-induced oxidative damage and the prevention of programmed cardiovascular disease in adult offspring of hypoxic pregnancy.
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Affiliation(s)
- Ana-Mishel Spiroski
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.,Cambridge Cardiovascular Strategic Research Initiative, Cambridge, UK
| | - Youguo Niu
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.,Cambridge Cardiovascular Strategic Research Initiative, Cambridge, UK
| | - Lisa M Nicholas
- Institute of Metabolic Science-Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - Shani Austin-Williams
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Emily J Camm
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Megan R Sutherland
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Thomas J Ashmore
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Katie L Skeffington
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Angela Logan
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Susan E Ozanne
- Cambridge Cardiovascular Strategic Research Initiative, Cambridge, UK.,Institute of Metabolic Science-Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.,Strategic Research Initiative in Reproduction, Cambridge, UK
| | - Michael P Murphy
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.,Department of Medicine, University of Cambridge, Cambridge, UK
| | - Dino A Giussani
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.,Cambridge Cardiovascular Strategic Research Initiative, Cambridge, UK.,Strategic Research Initiative in Reproduction, Cambridge, UK
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5
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Zhao YC, Guo W, Gao BH. Hypoxic training upregulates mitochondrial turnover and angiogenesis of skeletal muscle in mice. Life Sci 2021; 291:119340. [PMID: 33716067 DOI: 10.1016/j.lfs.2021.119340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/23/2021] [Accepted: 03/01/2021] [Indexed: 11/18/2022]
Abstract
AIMS Hypoxic training promotes human cardiopulmonary function and exercise performance efficiently, but the myocellular mechanism has been less studied. We aimed to examine the effects of hypoxic trainings on mitochondrial turnover and vascular remodeling of skeletal muscle. MAIN METHODS C57BL/6 J mice were divided into control, hypoxic exposure, exercise training, "live high-train low" (LHTL), and "live low-train high" (LLTH) groups (n = 8/group). Western blot and immunohistochemistry were used to evaluate mitochondrial turnover of gastrocnemius and angiogenesis of quadriceps after six weeks interventions. KEY FINDINGS Compared with control group, both LHTL and LLTH increased phosphorylation levels of p38 MAPK markedly (p < 0.05). LLTH also elevated PGC-1α protein expression significantly (p < 0.05). All interventions did not influence Bnip3 and Drp-1 proteins levels (p > 0.05), while LLTH enhanced Parkin and Mff protein contents significantly (p < 0.05). Immunohistochemical analysis showed both LHTL and LLTH promoted CD31 and VEGF expressions (p < 0.05). ATP content, citrate synthase activities of gastrocnemius were robustly elevated in LHTL and LLTH groups (p < 0.01). The exercise training increased Mff protein and ATP content in gastrocnemius as well as VEGF expression in quadriceps (p < 0.05). The hypoxic exposure also increased ATP content, citrate synthase, and ATP synthase activities in gastrocnemius as well as VEGF expression in quadriceps (p < 0.01). SIGNIFICANCE Our results suggested that hypoxic trainings, especially LLTH, promoted mitochondrial turnover and angiogenesis of skeletal muscle, which may be an underlying mechanism of hypoxic training-induced exercise capacity.
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Affiliation(s)
- Yong-Cai Zhao
- Graduate Department of Shanghai University of Sport, Shanghai University of Sport, Changhai road 399, Yangpu District, Shanghai 200438, China; College of Social Sport and Health Sciences, Tianjin University of Sport, Donghai Road 16, Jinghai District, Tianjin, 301617, China
| | - Wei Guo
- Graduate Department of Shanghai University of Sport, Shanghai University of Sport, Changhai road 399, Yangpu District, Shanghai 200438, China.
| | - Bing-Hong Gao
- School of Physical Education and Sport Training, Shanghai University of Sport, Changhai road 399, Yangpu District, Shanghai 200438, China.
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6
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Hypoxia and its preconditioning on cardiac and vascular remodelling in experimental animals. Respir Physiol Neurobiol 2020; 285:103588. [PMID: 33253893 DOI: 10.1016/j.resp.2020.103588] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 09/28/2020] [Accepted: 11/12/2020] [Indexed: 11/21/2022]
Abstract
Since oxygen (O2) is indispensable for mammalian life, every cell in the body is endowed with mechanisms to detect and to respond to changes in the O2 levels in the microenvironment. The heart and the brain are the two most vital, life-supporting organs requiring a continuous supply of O2 to sustain their high metabolic rate. On being challenged with hypoxia, maintenance of O2 supply to these organs even at the cost of others becomes a priority. This review describes the cardiovascular, skeletal muscle vascular, pulmonary vascular and cerebrovascular remodelling in face of chronic mild hypoxia exposure and the underlying mechanisms, with special reference to the role of oxidative stress, hypoxia signalling, autonomic nervous mechanisms. The significance of the normalized wall index (NWI) in assessing the remodelling of the vessels particularly of the intramyocardial coronary artery has been underscored. The review also highlights the basic concepts of hypoxic preconditioning and the subsequent protection of the brain against an acute ischemic insult in preclinical studies hinting towards its possible therapeutic potential in the management of ischemic stroke.
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7
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Bagali S, Nerune SM, Reddy RC, Yendigeri SM, Patil BS, Naikwadi AA, Kulkarni RV, Das KK. Low oxygen microenvironment and cardiovascular remodeling: Role of dual L/N.type Ca 2+ channel blocker. Indian J Pharmacol 2020; 52:383-391. [PMID: 33283770 PMCID: PMC8025765 DOI: 10.4103/ijp.ijp_136_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE Patients exposed to chronic sustained hypoxia frequently develop cardiovascular disease risk factors to ultimately succumb to adverse cardiovascular events. In this context, the present study intends to assess the role of cilnidipine (Cil), a unique calcium channel blocker that blocks both L-type and N-type calcium channels, on cardiovascular pathophysiology in face of chronic sustained hypoxia exposure. MATERIALS AND METHODS The study involved Wistar strain albino rats. The group-wise allocation of the experimental animals is as follows - Group 1, control (21% O2); Group 2, chronic hypoxia (CH) (10% O2, 90% N); Group 3, Cil + 21% O2; and Group 4, CH (10% O2, 90% N) + Cil (CH + Cil). Cardiovascular hemodynamics, heart rate variability, and endothelial functions (serum nitric oxide [NO], serum endothelial nitric oxide synthase [NOS3], and serum vascular endothelial growth factor [VEGF]) were assessed. Cardiovascular remodeling was studied by histopathological examination of the ventricular tissues, coronary artery (intramyocardial), and elastic and muscular arteries. Normalized wall index of the coronary artery was also calculated. RESULTS AND CONCLUSION The results demonstrated altered cardiovascular hemodynamics, disturbed cardiovascular autonomic balance, increased levels of VEGF and NOS3, and decreased bioavailability of NO on exposure to chronic sustained hypoxia. The histopathological examination further pointed toward cardiovascular remodeling. Treatment with Cil ameliorated the cardiovascular remodeling and endothelial dysfunction induced by CH exposure, which may be due to its blocking actions on L/N-type of calcium channels, indicating the possible therapeutic role of Cil against CH-induced cardiovascular pathophysiology.
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Affiliation(s)
- Shrilaxmi Bagali
- Laboratory of Vascular Physiology and Medicine, Department of Physiology, Shri B. M. Patil Medical College, Hospital and Research Centre, BLDE (Deemed to be University), Vijayapura, Karnataka, India
| | - Savitri M Nerune
- Department of Pathology, Shri B. M. Patil Medical College, Hospital and Research Centre, BLDE (Deemed to be University), Vijayapura, Karnataka, India
| | - R Chandramouli Reddy
- Department of Biochemistry, Shri B. M. Patil Medical College, Hospital and Research Centre, BLDE (Deemed to be University), Vijayapura, Karnataka, India
| | - Saeed M Yendigeri
- Department of Pathology, Al-Ameen Medical College, Vijayapura, Karnataka, India
| | - Bheemshetty S Patil
- Department of Anatomy, Shri B. M. Patil Medical College, Hospital and Research Centre, BLDE (Deemed to be University), Vijayapura, Karnataka, India
| | - Akram A Naikwadi
- Department of Pharmacology, Shri B. M. Patil Medical College, Hospital and Research Centre, BLDE (Deemed to be University), Vijayapura, Karnataka, India
| | - Raghavendra V Kulkarni
- Department of Pharmaceutics and Pharmaceutical Technology, BLDEA's SSM College of Pharmacy and Research Centre, Vijayapura, Karnataka, India
| | - Kusal K Das
- Laboratory of Vascular Physiology and Medicine, Department of Physiology, Shri B. M. Patil Medical College, Hospital and Research Centre, BLDE (Deemed to be University), Vijayapura, Karnataka, India
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8
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Davison G, Vinaixa M, McGovern R, Beltran A, Novials A, Correig X, McClean C. Metabolomic Response to Acute Hypoxic Exercise and Recovery in Adult Males. Front Physiol 2018; 9:1682. [PMID: 30534085 PMCID: PMC6275205 DOI: 10.3389/fphys.2018.01682] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 11/08/2018] [Indexed: 12/28/2022] Open
Abstract
Metabolomics is a relatively new “omics” approach used to characterize metabolites in a biological system at baseline and following a diversity of stimuli. However, the metabolomic response to exercise in hypoxia currently remains unknown. To examine this, 24 male participants completed 1 h of exercise at a workload corresponding to 75% of pre-determined O2max in hypoxia (Fio2 = 0.16%), and repeated in normoxia (Fio2 = 0.21%), while pre- and post-exercise and 3 h post-exercise metabolites were analyzed using a LC ESI-qTOF-MS untargeted metabolomics approach in serum samples. Exercise in hypoxia and in normoxia independently increased metabolism as shown by a change in a combination of twenty-two metabolites associated with lipid metabolism (p < 0.05, pre vs. post-exercise), though hypoxia per se did not induce a greater metabolic change when compared with normoxia (p > 0.05). Recovery from exercise in hypoxia independently decreased seventeen metabolites associated with lipid metabolism (p < 0.05, post vs. 3 h post-exercise), compared with twenty-two metabolites in normoxia (p < 0.05, post vs. 3 h post-exercise). Twenty-six metabolites were identified as responders to exercise and recovery (pooled hypoxia and normoxia pre vs. recovery, p < 0.05), including metabolites associated with purine metabolism (adenine, adenosine and hypoxanthine), the amino acid phenylalanine, and several acylcarnitine molecules. Our novel data provides preliminary evidence of subtle metabolic differences to exercise and recovery in hypoxia and normoxia. Specifically, exercise in hypoxia activates metabolic pathways aligned to purine and lipid metabolism, but this effect is not selectively different from exercise in normoxia. We also show that exercise per se can activate pathways associated with lipid, protein and purine nucleotide metabolism.
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Affiliation(s)
- Gareth Davison
- Sport and Exercise Science Research Institute, Ulster University, Antrim, United Kingdom
| | - Maria Vinaixa
- Metabolomics Platform of the Spanish Biomedical Research Center in Diabetes and Associated Metabolic Disorders, IISPV - Rovira i Virgili University, Tarragona, Spain
| | - Rose McGovern
- Sport and Exercise Science Research Institute, Ulster University, Antrim, United Kingdom
| | - Antoni Beltran
- Metabolomics Platform of the Spanish Biomedical Research Center in Diabetes and Associated Metabolic Disorders, IISPV - Rovira i Virgili University, Tarragona, Spain
| | - Anna Novials
- Department of Endocrinology, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, Barcelona, Spain
| | - Xavier Correig
- Metabolomics Platform of the Spanish Biomedical Research Center in Diabetes and Associated Metabolic Disorders, IISPV - Rovira i Virgili University, Tarragona, Spain
| | - Conor McClean
- Sport and Exercise Science Research Institute, Ulster University, Antrim, United Kingdom
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9
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Cowburn AS, Macias D, Summers C, Chilvers ER, Johnson RS. Cardiovascular adaptation to hypoxia and the role of peripheral resistance. eLife 2017; 6. [PMID: 29049022 PMCID: PMC5648530 DOI: 10.7554/elife.28755] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 10/03/2017] [Indexed: 12/21/2022] Open
Abstract
Systemic vascular pressure in vertebrates is regulated by a range of factors: one key element of control is peripheral resistance in tissue capillary beds. Many aspects of the relationship between central control of vascular flow and peripheral resistance are unclear. An important example of this is the relationship between hypoxic response in individual tissues, and the effect that response has on systemic cardiovascular adaptation to oxygen deprivation. We show here how hypoxic response via the HIF transcription factors in one large vascular bed, that underlying the skin, influences cardiovascular response to hypoxia in mice. We show that the response of the skin to hypoxia feeds back on a wide range of cardiovascular parameters, including heart rate, arterial pressures, and body temperature. These data represent the first demonstration of a dynamic role for oxygen sensing in a peripheral tissue directly modifying cardiovascular response to the challenge of hypoxia.
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Affiliation(s)
- Andrew S Cowburn
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - David Macias
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Charlotte Summers
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Edwin R Chilvers
- 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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10
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Impact of mitochondrial nitrite reductase on hemodynamics and myocardial contractility. Sci Rep 2017; 7:12092. [PMID: 28935964 PMCID: PMC5608763 DOI: 10.1038/s41598-017-11531-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 08/22/2017] [Indexed: 01/11/2023] Open
Abstract
Inorganic nitrite (NO2−) can be reduced back to nitric oxide (NO) by several heme proteins called nitrite reductases (NR) which affect both the vascular tonus and hemodynamics. The objective of this study was to clarify the impact of several NRs on the regulation of hemodynamics, for which hemodynamic parameters such as heart rate, blood pressure, arterial stiffness, peripheral resistance and myocardial contractility were characterized by pulse wave analysis. We have demonstrated that NO2− reduced to NO in RBCs predominantly influences the heart rate, while myoglobin (Mb) and mitochondria-derived NO regulates arterial stiffness, peripheral resistance and myocardial contractility. Using ex vivo on-line NO-detection, we showed that Mb is the strongest NR occurring in heart, which operates sufficiently only at very low oxygen levels. In contrast, mitochondrial NR operates under both hypoxia and normoxia. Additional experiments with cardiomyocytes suggested that only mitochondria-derived generation of NO regulates cGMP levels mediating the contractility of cardiomyocytes. Our data suggest that a network of NRs is involved in NO2− mediated regulation of hemodynamics. Oxygen tension and hematocrit define the activity of specific NRs.
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11
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Salman S, Vollmer C, McClelland GB, Nurse CA. Characterization of ectonucleotidase expression in the rat carotid body: regulation by chronic hypoxia. Am J Physiol Cell Physiol 2017. [PMID: 28637679 DOI: 10.1152/ajpcell.00328.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The carotid body (CB) chemoreflex maintains blood Po2 and Pco2/H+ homeostasis and displays sensory plasticity during exposure to chronic hypoxia. Purinergic signaling via P1 and P2 receptors plays a pivotal role in shaping the afferent discharge at the sensory synapse containing catecholaminergic chemoreceptor (type I) cells, glial-like type II cells, and sensory (petrosal) nerve endings. However, little is known about the family of ectonucleotidases that control synaptic nucleotide levels. Using quantitative PCR (qPCR), we first compared expression levels of ectonucleoside triphosphate diphosphohydrolases (NTPDases1,2,3,5,6) and ecto-5'-nucleotidase (E5'Nt/CD73) mRNAs in juvenile rat CB vs. brain, petrosal ganglia, sympathetic (superior cervical) ganglia, and a sympathoadrenal chromaffin (MAH) cell line. In whole CB extracts, qPCR revealed a high relative expression of surface-located members NTPDase1,2 and E5'Nt/CD73, compared with low NTPDase3 expression. Immunofluorescence staining of CB sections or dissociated CB cultures localized NTPDase2,3 and E5'Nt/CD73 protein to the periphery of type I clusters, and in association with sensory nerve fibers and/or isolated type II cells. Interestingly, in CBs obtained from rats reared under chronic hypobaric hypoxia (~60 kPa, equivalent to 4,300 m) for 5-7 days, in addition to the expected upregulation of tyrosine hydroxylase and VEGF mRNAs, there was a significant upregulation of NTPDase3 and E5'Nt/CD73 mRNA, but a downregulation of NTPDase1 and NTPDase2 relative to normoxic controls. We conclude that NTPDase1,2,3 and E5'Nt/CD73 are the predominant surface-located ectonucleotidases in the rat CB and suggest that their differential regulation during chronic hypoxia may contribute to CB plasticity via control of synaptic ATP, ADP, and adenosine pools.
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Affiliation(s)
- Shaima Salman
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Cathy Vollmer
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | | | - Colin A Nurse
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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Minnella AM, Federici M, Falsini B, Barbano L, Gambini G, Lanza A, Caporossi A, Savastano MC. Choroidal Thickness Changes After Intravitreal Ranibizumab for Exudative Age-Related Macular Degeneration. BioDrugs 2017; 30:353-9. [PMID: 27189458 DOI: 10.1007/s40259-016-0179-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND The results regarding changes of choroidal thickness following intravitreal ranibizumab injections in the literature are controversial. Vascular endothelial growth factor A is implicated in pathogenesis of neovascular age-related macular degeneration (AMD). The suspected unchanged choroidal layer thickness after intravitreal injections of ranibizumab suggests a possible protection of the outer blood-retinal barrier in the human eye. OBJECTIVE The aim was to evaluate choroidal thickness following the first administration of the study drug ranibizumab into the eyes of naïve wet AMD patients (nAMD). METHODS In this open label, 3-month, prospective, single-center, interventional, single-arm pilot study, 20 nAMD eyes were included and underwent three consecutive monthly injections of ranibizumab (0.5 mg/0.05 ml). Vital signs (i.e., blood pressure and pulse), ophthalmic examinations, intraocular pressure, best correct visual acuity and subfoveal choroidal thickness as examined with optical coherence tomography using enhanced depth imaging (OCT-EDI) were assessed at each visit. All patients were evaluated at baseline and at 15, 30 60 and 90 days after intravitreal injection. Ten eyes with fibrotic AMD lesions were evaluated as the control group. RESULTS In all eyes, the choroidal thicknesses (µm) exhibited no significant changes from the baseline visit to the visits at 15, 30, 60 and 90 days post-injection (P > 0.05). The intravitreal treatment with ranibizumab was well tolerated, and no adverse events were registered. CONCLUSION Choroidal thickness appeared to be unmodified following the intravitreal injection of ranibizumab into nAMD eyes. Intravitreal ranibizumab injections probably elicit a pharmacologic effect only in the choroidal neovascularization and not in the choroid circulation under neovascular lesions. Clinical Trials Eudract Registration #: 2013-005091-17.
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Affiliation(s)
- Angelo Maria Minnella
- Catholic University of Sacred Heart, "A. Gemelli" Foundation, Largo A. Gemelli, 00168, Rome, Italy.
| | - Matteo Federici
- Catholic University of Sacred Heart, "A. Gemelli" Foundation, Largo A. Gemelli, 00168, Rome, Italy
| | - Benedetto Falsini
- Catholic University of Sacred Heart, "A. Gemelli" Foundation, Largo A. Gemelli, 00168, Rome, Italy
| | - Lucilla Barbano
- Catholic University of Sacred Heart, "A. Gemelli" Foundation, Largo A. Gemelli, 00168, Rome, Italy
| | - Gloria Gambini
- Catholic University of Sacred Heart, "A. Gemelli" Foundation, Largo A. Gemelli, 00168, Rome, Italy
| | - Angela Lanza
- Catholic University of Sacred Heart, "A. Gemelli" Foundation, Largo A. Gemelli, 00168, Rome, Italy
| | - Aldo Caporossi
- Catholic University of Sacred Heart, "A. Gemelli" Foundation, Largo A. Gemelli, 00168, Rome, Italy
| | - Maria Cristina Savastano
- Catholic University of Sacred Heart, "A. Gemelli" Foundation, Largo A. Gemelli, 00168, Rome, Italy
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Marshall JM. Interactions between local dilator and sympathetic vasoconstrictor influences in skeletal muscle in acute and chronic hypoxia. Exp Physiol 2015; 100:1400-11. [DOI: 10.1113/ep085139] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 12/14/2022]
Affiliation(s)
- Janice M. Marshall
- School of Clinical & Experimental Medicine; Centre for Cardiovascular Science, University of Birmingham; B15 2TT UK
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14
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Karsten M, Contini M, Cefalù C, Cattadori G, Palermo P, Apostolo A, Bussotti M, Magrì D, Salvioni E, Farina S, Sciomer S, Catai AM, Agostoni P. Effects of carvedilol on oxygen uptake and heart rate kinetics in patients with chronic heart failure at simulated altitude. Eur J Prev Cardiol 2011; 19:444-51. [DOI: 10.1177/1741826711402736] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background: The response to moderate exercise at altitude in heart failure (HF) is unknown. Methods and results: We evaluated 30 HF patients, (NYHA I-III, 25 M/5 F; 59 ± 10 years; LVEF = 39.6 ± 7.1%), in stable clinical conditions, treated with carvedilol at the maximal tolerated dose. We performed a maximal cardiopulmonary exercise test (CPET) with ramp protocol at sea level to evaluate patients’ performance and two moderate intensity constant workload CPETs (50% of peak workload) at sea level (normoxia) and simulated altitude (hypoxia). Oxygen uptake ([Formula: see text]) and heart rate (HR) on-kinetics at constant workload were assessed calculating the time constant (τ) with a monoexponential equation. [Formula: see text] and HR were higher in hypoxia (0.944 ± 0.233 vs 1.031 ± 0.264 l/min; 100 ± 23 vs 108 ± 22 bpm; p < 0.001). On-kinetics showed a different behavior of τ being [Formula: see text] faster in hypoxia (67.1 ± 23.0 vs. 56.3 ± 19.7 s; p = 0.026) and HR faster in normoxia (49.3 ± 19.4 vs. 62.2 ± 22.5 s; p = 0.018). Ten patients, who lowered oxygen kinetics in hypoxia, had greater HR increase during maximal CPET suggesting lower functional betablockade. The higher τ of [Formula: see text] in hypoxia is likely to be due to a peripheral effect of carvedilol mediated either by β- or α-receptor. Conclusion: HF patients performing moderate exercise at 2000 m simulated altitude have 20% [Formula: see text] increase without trouble at the beginning of exercise when treated with carvedilol.
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Affiliation(s)
- Marlus Karsten
- Centro Cardiologico Monzino, IRCCS, Milan, Italy
- Laboratório de Fisioterapia Cardiovascular, Núcleo de Pesquisa em Exercício Físico, Departamento de Fisioterapia, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | | | | | | | | | | | - Maurizio Bussotti
- Cardiologia Riabilitativa, Fondazione S Maugeri, IRCCS, Milan, Italy
| | - Damiano Magrì
- U.O. Cardiologia, S. Andrea Hospital, “Sapienza”, Rome University, Rome, Italy
| | | | | | - Susanna Sciomer
- Dipartimento di Scienze Cardiovascolari, Respiratorie, Nefrologiche e Geriatriche, ‘Sapienza’, Rome University, Rome, Italy
| | - Aparecida Maria Catai
- Laboratório de Fisioterapia Cardiovascular, Núcleo de Pesquisa em Exercício Físico, Departamento de Fisioterapia, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | - Piergiuseppe Agostoni
- Centro Cardiologico Monzino, IRCCS, Milan, Italy
- Division of Critical Care and Respiratory Medicine, University of Washington, Seattle, USA
- Dipartimento di Scienze Cardiovascolari, Università di Milano, Milan, Italy
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Aggarwal NT, Pfister SL, Gauthier KM, Chawengsub Y, Baker JE, Campbell WB. Chronic hypoxia enhances 15-lipoxygenase-mediated vasorelaxation in rabbit arteries. Am J Physiol Heart Circ Physiol 2008; 296:H678-88. [PMID: 19112096 DOI: 10.1152/ajpheart.00777.2008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
15-Lipoxygenase (15-LO-1) metabolizes arachidonic acid (AA) to 11,12,15-trihydroxyeicosatrienoic acids (THETAs) and 15-hydroxy-11,12-epoxyeicosatrienoic acids (HEETA) that dilate rabbit arteries. Increased endothelial 15-LO-1 expression enhances arterial relaxations to agonists. We tested the effect of hypoxia on 15-LO-1 expression, THETA and HEETA synthesis, and relaxations in rabbit arteries. The incubation of rabbit aortic endothelial cells and isolated aortas in 0.7% O(2) increased 15-LO-1 expression. Rabbits were housed in a hypoxic atmosphere of 12% O(2) for 5 days. 15-LO-1 expression increased in the endothelium of the arteries of rabbits in 12% O(2) compared with room air. THETA and HEETA synthesis was also enhanced in aortas and mesenteric arteries. AA hyperpolarized the smooth muscle cells in indomethacin- and phenylephrine-treated mesenteric arteries of hypoxic rabbits from -29.4 +/- 1 to -50.1 +/- 3 mV. The hyperpolarization to AA was less in arteries of normoxic rabbits (from -26.0 +/- 2 to -37 +/- 2 mV). This AA-induced hyperpolarization was inhibited by the 15-LO inhibitor BW-755C. Nitric oxide and prostaglandin-independent maximum relaxations to acetylcholine (79.7 +/- 2%) and AA (38.3 +/- 4%) were enhanced in mesenteric arteries from hypoxic rabbits compared with the normoxic rabbits (49.7 +/- 6% and 19.9 +/- 2%, respectively). These relaxations were inhibited by BW-755C and nordihydroguaiaretic acid. Therefore, hypoxia increased the relaxations to agonists in the rabbit mesenteric arteries by enhancing endothelial 15-LO-1 expression and synthesis of the hyperpolarizing factors THETA and HEETA.
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Affiliation(s)
- Nitin T Aggarwal
- Dept. of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA
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Irwin DC, Foreman B, Morris K, White M, Sullivan T, Jacobs R, Monnet E, Hackett T, TissotvanPatot MC, Hamilton KL, Gotshall RW. Polymerized bovine hemoglobin decreases oxygen delivery during normoxia and acute hypoxia in the rat. Am J Physiol Heart Circ Physiol 2008; 295:H1090-H1099. [PMID: 18567708 DOI: 10.1152/ajpheart.00303.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hemoglobin-based oxygen carriers (HBOC) have been primarily studied for blood loss treatment. More recently infusions of HBOC in euvolemic subjects have been proposed for a wide variety of potential therapies in which increased tissue oxygenation would be beneficial. However, compared with the exchange transfusion models to study blood loss, less is known about HBOC oxygen delivery and vasoacitvity when it is infused in euvolemic subjects. We hypothesized that HBOC [polymerized bovine hemoglobin (PBvHb)] infusion creating hypervolemia would increase oxygen delivery to tissues during acute global hypoxia. Vascular oxygen content and hemodynamics were determined after euvolemic rats were infused with 3 ml of either lactated Ringer or PBvHb solution (13 g/dl, 1.3 g/kg) during acute hypoxia (FIO2 = 10%, 4 h) or normoxia (FIO2 = 21%) exposure. Our data demonstrated that compared with Ringer-infused animals, in hypoxia and normoxia, PBvHb treatment improved oxygen content but raised mean arterial pressure, lowered stroke volume, heart rate, and cardiac index, which resulted in a net reduction in blood flow and oxygen delivery to the tissues. The PBvHb vasoactive effect was similar in magnitude and direction as to the Ringer-infused animals treated with a nitric oxide synthase inhibitor nitro-l-arginine, suggesting the PBvHb effect is mediated via nitric oxide scavenging. We conclude that infusion of PBvHb is not likely to be useful in treating global hypoxia under these conditions.
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Affiliation(s)
- David C Irwin
- Cardiovascular Pulmonary Research Group, School of Medicine, University of Colorado Health Science Center, 4200 E 9Ave., Denver, CO 80262, USA.
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Calcium Movements in CGRP-treated Cultured Skeletal Muscle Cells: Is There a Role for CGRP in Tension Headaches? Int J Pept Res Ther 2008. [DOI: 10.1007/s10989-008-9130-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Walsh MP, Marshall JM. The role of adenosine in the early respiratory and cardiovascular changes evoked by chronic hypoxia in the rat. J Physiol 2006; 575:277-89. [PMID: 16690710 PMCID: PMC1819418 DOI: 10.1113/jphysiol.2006.108779] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Experiments were performed on anaesthetized normoxic (N) rats and chronically hypoxic rats that had been exposed to 12% O2 for 1, 3 or 7 days (1, 3 or 7CH rats). The adenosine A1 receptor antagonist DPCPX did not affect the resting hyperventilation of 1-7CH rats breathing 12% O2 and increased resting heart rate (HR) in 1CH rats only. DPCPX partially restored the decreased baseline arterial pressure (ABP) and increased femoral vascular conductance (FVC) of 1 and 3CH rats, but had no effect in N or 7CH rats. DPCPX also attenuated the decrease in arterial blood pressure (ABP) and increase in FVC evoked by acute hypoxia in N and 1-7CH rats. The non-selective adenosine receptor antagonist 8-SPT had no further effect on baselines or cardiovascular responses to acute hypoxia, but attenuated the hypoxia-evoked increase in respiratory frequency in 1-7CH rats. In N, and 1 and 3CH rats, the inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine had no effect on baselines or increases in FVC evoked by acetylcholine. We propose: (i) that tonically released adenosine acting on A1 receptors reduces HR in 1CH rats and stimulates endothelial NOS in 1 and 3CH rats to decrease ABP and increase FVC, the remaining NO-dependent tonic vasodilatation being independent of iNOS activity; (ii) that in 7CH rats, tonic adenosine release has waned; (iii) that in 1-7CH rats, adenosine released by acute hypoxia stimulates A1 but not A2 receptors to produce muscle vasodilatation, and stimulates carotid body A2 receptors to increase respiration.
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Affiliation(s)
- Martin P Walsh
- Department of Physiology, The Medical School, Birmingham B15 2TT, UK
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