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Rocha HNM, Teixeira GF, Batista GMS, Storch AS, Garcia VP, Mentzinger J, Gomes EAC, Campos MO, Nóbrega ACL, Rocha NG. AT1R blocker prevents mental stress induced retrograde blood flow in overweight/obese men. Physiol Rep 2023; 11:e15566. [PMID: 36636769 PMCID: PMC9837474 DOI: 10.14814/phy2.15566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023] Open
Abstract
The main goal was to determine the impact of mental stress (MS) on blood flow regulation in overweight/obese men. Fourteen overweight/obese men (27 ± 7 years; 29.8 ± 2.6 kg/m2 ) participated in two randomized experimental sessions with oral administration of the AT1R blocker Olmesartan (40 mg; AT1RB) or placebo (PL). After 2 h, a 5-min acute MS session (Stroop Color Word Test) was administered. Blood flow was assessed at baseline and during the first 3 min of MS by vascular ultrasound in the brachial artery. Blood was collected before (baseline) and during mental stress (MS) for measurement of nitrite (chemiluminescence) and endothelin-1 (ELISA kit). The AT1R blocker was able to reverse the MS responses observed in the placebo session for retrograde flow (p < 0.01), retrograde SR (p < 0.01) and oscillatory shear index (p = 0.01). Regarding vasoactive substances, no differences were observed in ET-1 (p > 0.05) responses to MS between experimental sessions. However, for nitrite responses, the administration of the AT1R blocker was able to increase circulating levels of NO (p = 0.03) Blockade of AT1R appears to prevent the decrease in endothelial function by reducing low shear stress and maintaining the vasoactive substances balance after MS in overweight/obese men.
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Affiliation(s)
- Helena N. M. Rocha
- Department of Physiology and Pharmacology, Laboratory of Exercise SciencesFluminense Federal UniversityNiteroiBrazil
- Department of Physiology and Pharmacology, Laboratory of Integrative CardiometabologyFluminense Federal UniversityNiteroiBrazil
- National Institute of Science and Technology (INCT) ‐ Physical (In)activity and Exercise, National Council for Scientific and Technological Development (CNPq), Fluminense Federal UniversityNiteroiBrazil
| | - Gabriel F. Teixeira
- Department of Physiology and Pharmacology, Laboratory of Exercise SciencesFluminense Federal UniversityNiteroiBrazil
- Department of Physiology and Pharmacology, Laboratory of Integrative CardiometabologyFluminense Federal UniversityNiteroiBrazil
| | - Gabriel M. S. Batista
- Department of Physiology and Pharmacology, Laboratory of Exercise SciencesFluminense Federal UniversityNiteroiBrazil
- Department of Physiology and Pharmacology, Laboratory of Integrative CardiometabologyFluminense Federal UniversityNiteroiBrazil
- National Institute of Science and Technology (INCT) ‐ Physical (In)activity and Exercise, National Council for Scientific and Technological Development (CNPq), Fluminense Federal UniversityNiteroiBrazil
| | - Amanda S. Storch
- Department of Physiology and Pharmacology, Laboratory of Exercise SciencesFluminense Federal UniversityNiteroiBrazil
- Department of Physiology and Pharmacology, Laboratory of Integrative CardiometabologyFluminense Federal UniversityNiteroiBrazil
- National Institute of Science and Technology (INCT) ‐ Physical (In)activity and Exercise, National Council for Scientific and Technological Development (CNPq), Fluminense Federal UniversityNiteroiBrazil
| | - Vinicius P. Garcia
- Department of Physiology and Pharmacology, Laboratory of Exercise SciencesFluminense Federal UniversityNiteroiBrazil
- Department of Physiology and Pharmacology, Laboratory of Integrative CardiometabologyFluminense Federal UniversityNiteroiBrazil
- National Institute of Science and Technology (INCT) ‐ Physical (In)activity and Exercise, National Council for Scientific and Technological Development (CNPq), Fluminense Federal UniversityNiteroiBrazil
| | - Juliana Mentzinger
- Department of Physiology and Pharmacology, Laboratory of Exercise SciencesFluminense Federal UniversityNiteroiBrazil
- Department of Physiology and Pharmacology, Laboratory of Integrative CardiometabologyFluminense Federal UniversityNiteroiBrazil
| | - Erika A. C. Gomes
- Department of Physiology and Pharmacology, Laboratory of Exercise SciencesFluminense Federal UniversityNiteroiBrazil
- National Institute of Science and Technology (INCT) ‐ Physical (In)activity and Exercise, National Council for Scientific and Technological Development (CNPq), Fluminense Federal UniversityNiteroiBrazil
| | - Monique O. Campos
- Department of Physiology and Pharmacology, Laboratory of Exercise SciencesFluminense Federal UniversityNiteroiBrazil
- National Institute of Science and Technology (INCT) ‐ Physical (In)activity and Exercise, National Council for Scientific and Technological Development (CNPq), Fluminense Federal UniversityNiteroiBrazil
| | - Antonio C. L. Nóbrega
- Department of Physiology and Pharmacology, Laboratory of Exercise SciencesFluminense Federal UniversityNiteroiBrazil
- National Institute of Science and Technology (INCT) ‐ Physical (In)activity and Exercise, National Council for Scientific and Technological Development (CNPq), Fluminense Federal UniversityNiteroiBrazil
| | - Natália G. Rocha
- Department of Physiology and Pharmacology, Laboratory of Exercise SciencesFluminense Federal UniversityNiteroiBrazil
- Department of Physiology and Pharmacology, Laboratory of Integrative CardiometabologyFluminense Federal UniversityNiteroiBrazil
- National Institute of Science and Technology (INCT) ‐ Physical (In)activity and Exercise, National Council for Scientific and Technological Development (CNPq), Fluminense Federal UniversityNiteroiBrazil
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Rocha HNM, Batista GMS, Storch AS, Garcia VP, Teixeira GF, Mentzinger J, Gomes EAC, Campos MO, Nóbrega ACL, Rocha NG. Mental stress induces endothelial dysfunction by AT1R-mediated redox imbalance in overweight/obese men. Braz J Med Biol Res 2023; 56:e12547. [PMID: 36995873 PMCID: PMC10041671 DOI: 10.1590/1414-431x2023e12547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 02/16/2023] [Indexed: 03/31/2023] Open
Abstract
The main goal of this study was to determine whether oxidative imbalance mediated by AT1 receptor (AT1R) is responsible for deleterious endothelial responses to mental stress (MS) in overweight/obese class I men. Fifteen overweight/obese men (27±7 years old; 29.8±2.6 kg/m2) participated in three randomized experimental sessions with oral administration of the AT1R blocker olmesartan (40 mg; AT1R blockade) or ascorbic acid (AA; 3g) infusion or placebo [both intravenously (0.9% NaCl) and orally]. After two hours, endothelial function was determined by flow-mediated dilation (FMD) before (baseline), 30 min (30MS), and 60 min (60MS) after a five-minute acute MS session (Stroop Color Word Test). Blood was collected before (baseline), during MS, and 60 min after MS for redox homeostasis profiling: lipid peroxidation (TBARS; thiobarbituric acid reactive species), protein carbonylation, and catalase activity by colorimetry and superoxide dismutase (SOD) activity by an ELISA kit. At the placebo session, FMD significantly decreased 30MS (P=0.05). When compared to baseline, TBARS (P<0.02), protein carbonylation (P<0.01), catalase (P<0.01), and SOD (P<0.01) increased during the placebo session. During AT1R blockade, FMD increased 30 min after MS (P=0.01 vs baseline; P<0.01 vs placebo), while AA infusion increased FMD only 60 min after MS. No differences were observed during MS with the AT1R blockade and AA regarding TBARS, protein carbonylation, catalase, and SOD. AT1R-mediated redox imbalances played an important role in endothelial dysfunction to mental stress.
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Affiliation(s)
- H N M Rocha
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia - (In)Atividade Física e Exercício, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - G M S Batista
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia - (In)Atividade Física e Exercício, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - A S Storch
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia - (In)Atividade Física e Exercício, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - V P Garcia
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia - (In)Atividade Física e Exercício, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - G F Teixeira
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia - (In)Atividade Física e Exercício, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - J Mentzinger
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia - (In)Atividade Física e Exercício, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - E A C Gomes
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia - (In)Atividade Física e Exercício, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - M O Campos
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - A C L Nóbrega
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia - (In)Atividade Física e Exercício, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - N G Rocha
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia - (In)Atividade Física e Exercício, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidade Federal Fluminense, Niterói, RJ, Brasil
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Garcia VP, Mattos JD, Mentzinger J, Leite PEC, Rocha HNM, Campos MO, Rocha MP, Mansur DE, Secher NH, Nóbrega ACL, Fernandes IA, Rocha NG. Short isocapnic hyperoxia affects indices of vascular remodeling and intercellular adhesion molecules in healthy men. Braz J Med Biol Res 2022; 55:e12110. [PMID: 35703682 PMCID: PMC9200048 DOI: 10.1590/1414-431x2022e12110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 04/11/2022] [Indexed: 11/22/2022] Open
Abstract
In preparation for tracheal intubation during induction of anesthesia, the patient may be ventilated with 100% oxygen. To investigate the impact of acute isocapnic hyperoxia on endothelial activation and vascular remodeling, ten healthy young men (24±3 years) were exposed to 5-min normoxia (21% O2) and 10-min hyperoxia trials (100% O2). During hyperoxia, intercellular adhesion molecules (ICAM-1) (hyperoxia: 4.16±0.85 vs normoxia: 3.51±0.84 ng/mL, P=0.04) and tissue inhibitor matrix metalloproteinase 1 (TIMP-1) (hyperoxia: 8.40±3.84 vs normoxia: 5.73±2.15 pg/mL, P=0.04) increased, whereas matrix metalloproteinase (MMP-9) activity (hyperoxia: 0.53±0.11 vs normoxia: 0.68±0.18 A.U., P=0.03) decreased compared to the normoxia trial. We concluded that even short exposure to 100% oxygen may affect endothelial activation and vascular remodeling.
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Affiliation(s)
- V P Garcia
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - J D Mattos
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - J Mentzinger
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - P E C Leite
- Laboratório de Bioengenharia e Toxicologia in Vitro, Instituto Nacional de Qualidade e Tecnologia Metrológica, Duque de Caxias, RJ, Brasil
| | - H N M Rocha
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - M O Campos
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - M P Rocha
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - D E Mansur
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - N H Secher
- Department of Anesthesia, Rigshospitalet, Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - A C L Nóbrega
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - I A Fernandes
- NeuroVASQ - Laboratório de Fisiologia Integrativa, Faculdade de Educação Física, Universidade de Brasília, Brasília, DF, Brasil
| | - N G Rocha
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
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Fernandes IA, Mattos JD, Campos MO, Rocha MP, Mansur DE, Rocha HM, Garcia VP, Alvares T, Secher NH, Nóbrega ACL. Reactive oxygen species play a modulatory role in the hyperventilatory response to poikilocapnic hyperoxia in humans. J Physiol 2021; 599:3993-4007. [PMID: 34245024 DOI: 10.1113/jp281635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 07/08/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The proposed mechanism for the increased ventilation in response to hyperoxia includes a reduced brain CO2 -[H+ ] washout-induced central chemoreceptor stimulation that results from a decrease in cerebral perfusion and the weakening of the CO2 affinity for haemoglobin. Nonetheless, hyperoxia also results in excessive brain reactive oxygen species (ROS) formation/accumulation, which hypothetically increases central respiratory drive and causes hyperventilation. We then quantified ventilation, cerebral perfusion/metabolism, arterial/internal jugular vein blood gases and oxidant/antioxidant biomarkers in response to hyperoxia during intravenous infusion of saline or ascorbic acid to determine whether excessive ROS production/accumulation contributes to the hyperoxia-induced hyperventilation in humans. Ascorbic acid infusion augmented the antioxidant defence levels, blunted ROS production/accumulation and minimized both the reduction in cerebral perfusion and the increase in ventilation observed during saline infusion. Hyperoxic hyperventilation seems to be mediated by central chemoreceptor stimulation provoked by the interaction between an excessive ROS production/accumulation and reduced brain CO2 -[H+ ] washout. ABSTRACT The hypothetical mechanism for the increase in ventilation ( V ̇ E ) in response to hyperoxia (HX) includes central chemoreceptor stimulation via reduced CO2 -[H+ ] washout. Nonetheless, hyperoxia disturbs redox homeostasis and raises the hypothesis that excessive brain reactive oxygen species (ROS) production/accumulation may increase the sensitivity to CO2 or even solely activate the central chemoreceptors, resulting in hyperventilation. To determine the mechanism behind the HX-evoked increase in V ̇ E , 10 healthy men (24 ± 4 years) underwent 10 min trials of HX under saline and ascorbic acid infusion. V ̇ E , arterial and right internal right jugular vein (ijv) partial pressure for oxygen (PO2 ) and CO2 (PCO2 ), pH, oxidant (8-isoprostane) and antioxidant (ascorbic acid) markers, as well as cerebral blood flow (CBF) (Duplex ultrasonography), were quantified at each hyperoxic trial. HX evoked an increase in arterial partial pressure for oxygen, followed by a hyperventilatory response, a reduction in CBF, an increase in arterial 8-isoprostane, and unchanged PijvCO2 and ijv pH. Intravenous ascorbic acid infusion augmented the arterial antioxidant marker, blunted the increase in arterial 8-isoprostane and attenuated both the reduction in CBF and the HX-induced hyperventilation. Although ascorbic acid infusion resulted in a slight increase in PijvCO2 and a substantial decrease in ijv pH, when compared with the saline bout, HX evoked a similar reduction and a paired increase in the trans-cerebral exchanges for PCO2 and pH, respectively. These findings indicate that the poikilocapnic hyperoxic hyperventilation is likely mediated via the interaction of the acidic brain interstitial fluid and an increase in central chemoreceptor sensitivity to CO2 , which, in turn, seems to be evoked by the excessive ROS production/accumulation.
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Affiliation(s)
- Igor A Fernandes
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Marcos P Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Helena M Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Vinicius P Garcia
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | | | - Niels H Secher
- Department of Anaesthesia, Rigshospitalet, Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
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Rocha MP, Campos MO, Mattos JD, Mansur DE, Rocha HNM, Secher NH, Nóbrega ACL, Fernandes IA. K ATP channels modulate cerebral blood flow and oxygen delivery during isocapnic hypoxia in humans. J Physiol 2020; 598:3343-3356. [PMID: 32463117 DOI: 10.1113/jp279751] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/11/2020] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS ATP-sensitive K+ (KATP ) channels mediate hypoxia-induced cerebral vasodilatation and hyperperfusion in animals. We tested whether KATP channels blockade affects the increase in human cerebral blood flow (CBF) and the maintenance of oxygen delivery (CDO2 ) during hypoxia. Hypoxia-induced increases in the anterior circulation and total cerebral perfusion were attenuated under KATP channels blockade affecting the relative changes of brain oxygen delivery. Therefore, in humans, KATP channels activation modulates the vascular tone in the anterior circulation of the brain, contributing to CBF and CDO2 responses to hypoxia. ABSTRACT ATP-sensitive K+ (KATP ) channels mediate hypoxia-induced cerebral vasodilatation and hyperperfusion in animals. We tested whether KATP channels blockade affects the increase in cerebral blood flow (CBF) and the maintenance of oxygen delivery (CDO2 ) during hypoxia in humans. Nine healthy men were exposed to 5-min trials of normoxia and isocapnic hypoxia (IHX, 10% O2 ) before (BGB) and 3 h after glibenclamide ingestion (AGB). Mean arterial pressure (MAP), arterial saturation ( S a O 2 ), partial pressure of oxygen ( P a O 2 ) and carbon dioxide ( P aC O 2 ), internal carotid artery blood flow (ICABF), vertebral artery blood flow (VABF), total (t)CBF (Doppler ultrasound) and CDO2 were quantified during the trials. IHX provoked similar reductions in S a O 2 and P a O 2 , while MAP was not affected by oxygen desaturation or KATP blockade. A smaller increase in ICABF (ΔBGB: 36 ± 23 vs. ΔAGB 11 ± 18%, p = 0.019) but not in VABF (∆BGB 26 ± 21 vs. ∆AGB 27 ± 27%, p = 0.893) was observed during the hypoxic trial under KATP channels blockade. Thus, IHX-induced increases in tCBF (∆BGB 32 ± 19 vs. ∆AGB 14 ± 13%, p = 0.012) and CDO2 relative changes (∆BGB 7 ± 13 vs. ∆AGB -6 ± 14%, p = 0.048) were attenuated during the AGB hypoxic trial. In a separate protocol, 6 healthy men (5 from protocol 1) underwent a 5-min exposure to normoxia and IHX before and 3 h after placebo (5 mg of cornstarch) ingestion. IHX reduced S a O 2 and P a O 2 , but placebo did not affect the ICABF, VABF, tCBF, or CDO2 responses. Therefore, in humans, KATP channels activation modulates vascular tone in the anterior rather than the posterior circulation of the brain, contributing to tCBF and CDO2 responses to hypoxia.
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Affiliation(s)
- Marcos P Rocha
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Helena N M Rocha
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Niels H Secher
- Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Igor A Fernandes
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brazil
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Mattos JD, Campos MO, Rocha MP, Mansur DE, Rocha HNM, Garcia VP, Rocha NG, Alvares TS, Secher NH, Nóbrega ACL, Fernandes IA. Differential vasomotor responses to isocapnic hyperoxia: cerebral versus peripheral circulation. Am J Physiol Regul Integr Comp Physiol 2020; 318:R182-R187. [DOI: 10.1152/ajpregu.00248.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isocapnic hyperoxia (IH) evokes cerebral and peripheral hypoperfusion via both disturbance of redox homeostasis and reduction in nitric oxide (NO) bioavailability. However, it is not clear whether the magnitude of the vasomotor responses depends on the vessel network exposed to IH. To test the hypothesis that the magnitude of IH-induced reduction in peripheral blood flow (BF) may differ from the hypoperfusion response observed in the cerebral vascular network under oxygen-enriched conditions, nine healthy men (25 ± 3 yr, mean ± SD) underwent 10 min of IH during either saline or vitamin C (3 g) infusion, separately. Femoral artery (FA), internal carotid artery (ICA), and vertebral artery (VA) BF (Doppler ultrasound), as well as arterial oxidant (8-isoprostane), antioxidant [ascorbic acid (AA)], and NO bioavailability (nitrite) markers were simultaneously measured. IH increased 8-isoprostane levels and reduced nitrite levels; these responses were followed by a reduction in both FA BF and ICA BF, whereas VA BF did not change. Absolute and relative reductions in FA BF were greater than IH-induced changes in ICA and VA perfusion. Vitamin C infusion increased arterial AA levels and abolished the IH-induced increase in 8-isoprostane levels and reduction in nitrite levels. Whereas ICA and VA BF did not change during the vitamin C-IH trial, FA perfusion increased and reached similar levels to those observed during normoxia with saline infusion. Therefore, the magnitude of IH-induced reduction in femoral blood flow is greater than that observed in the vessel network of the brain, which might involve the determinant contribution that NO has in the regulation of peripheral vascular perfusion.
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Affiliation(s)
- João D. Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Monique O. Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Marcos P. Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Daniel E. Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Helena N. M. Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Vinicius P. Garcia
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Natalia G. Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Thiago S. Alvares
- Nutrition Institute, Federal University of Rio de Janeiro, Macaé, Brazil
| | - Niels H. Secher
- Department of Anesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | | | - Igor A. Fernandes
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
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Campos MO, Mansur DE, Mattos JD, Paiva ACS, Videira RLR, Macefield VG, da Nóbrega ACL, Fernandes IA. Acid-sensing ion channels blockade attenuates pressor and sympathetic responses to skeletal muscle metaboreflex activation in humans. J Appl Physiol (1985) 2019; 127:1491-1501. [PMID: 31545154 DOI: 10.1152/japplphysiol.00401.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In animals, the blockade of acid-sensing ion channels (ASICs), cation pore-forming membrane proteins located in the free nerve endings of group IV afferent fibers, attenuates increases in arterial pressure (AP) and sympathetic nerve activity (SNA) during muscle contraction. Therefore, ASICs play a role in mediating the metabolic component (skeletal muscle metaboreflex) of the exercise pressor reflex in animal models. Here we tested the hypothesis that ASICs also play a role in evoking the skeletal muscle metaboreflex in humans, quantifying beat-by-beat mean AP (MAP; finger photoplethysmography) and muscle SNA (MSNA; microneurography) in 11 men at rest and during static handgrip exercise (SHG; 35% of the maximal voluntary contraction) and postexercise muscle ischemia (PEMI) before (B) and after (A) local venous infusion of either saline or amiloride (AM), an ASIC antagonist, via the Bier block technique. MAP (BAM +30 ± 6 vs. AAM +25 ± 7 mmHg, P = 0.001) and MSNA (BAM +14 ± 9 vs. AAM +10 ± 6 bursts/min, P = 0.004) responses to SHG were attenuated under ASIC blockade. Amiloride also attenuated the PEMI-induced increases in MAP (BAM +25 ± 6 vs. AAM +16 ± 6 mmHg, P = 0.0001) and MSNA (BAM +16 ± 9 vs. AAM +8 ± 8 bursts/min, P = 0.0001). MAP and MSNA responses to SHG and PEMI were similar before and after saline infusion. We conclude that ASICs play a role in evoking pressor and sympathetic responses to SHG and the isolated activation of the skeletal muscle metaboreflex in humans. NEW & NOTEWORTHY We showed that regional blockade of the acid-sensing ion channels (ASICs), induced by venous infusion of the antagonist amiloride via the Bier block anesthetic technique, attenuated increases in arterial pressure and muscle sympathetic nerve activity during both static handgrip exercise and postexercise muscle ischemia. These findings indicate that ASICs contribute to both pressor and sympathetic responses to the activation of the skeletal muscle metaboreflex in humans.
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Affiliation(s)
- Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Adrielle C S Paiva
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | | | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, Australia.,Baker Heart and Diabetes Institute, Melbourne, Australia
| | | | - Igor A Fernandes
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
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Storch AS, Rocha HNM, Garcia VP, Batista GMS, Mattos JD, Campos MO, Nóbrega ACL, Fernandes IA, Rocha NG. Inflammatory and oxidative responses to disturbed blood flow in hypertensive men. Hypertens Res 2019; 42:1832-1835. [PMID: 31253943 DOI: 10.1038/s41440-019-0296-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/07/2019] [Accepted: 06/09/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Amanda S Storch
- Laboratory of Exercise Sciences (LACE), Department of Physiology and Pharmacology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil
| | - Helena N M Rocha
- Laboratory of Exercise Sciences (LACE), Department of Physiology and Pharmacology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil
| | - Vinicius P Garcia
- Laboratory of Exercise Sciences (LACE), Department of Physiology and Pharmacology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil
| | - Gabriel M S Batista
- Laboratory of Exercise Sciences (LACE), Department of Physiology and Pharmacology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil
| | - João Dario Mattos
- Laboratory of Exercise Sciences (LACE), Department of Physiology and Pharmacology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences (LACE), Department of Physiology and Pharmacology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil
| | - Antonio Claudio L Nóbrega
- Laboratory of Exercise Sciences (LACE), Department of Physiology and Pharmacology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil.,National Institute of Science and Technology (INCT)- Physical (In)activity and Exercise, National Council for Scientific and Technological Development (CNPq), Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil
| | - Igor A Fernandes
- Laboratory of Exercise Sciences (LACE), Department of Physiology and Pharmacology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil
| | - Natalia G Rocha
- Laboratory of Exercise Sciences (LACE), Department of Physiology and Pharmacology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil. .,National Institute of Science and Technology (INCT)- Physical (In)activity and Exercise, National Council for Scientific and Technological Development (CNPq), Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil.
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Campos MO, Nóbrega ACL, Miranda SM, Ribeiro ML, Guerra TRB, Braghirolli AMS, Mesquita CT, Fernandes IA. Transcutaneous electrical nerve stimulation attenuates cardiac sympathetic drive in heart failure: a 123MIBG myocardial scintigraphy randomized controlled trial. Am J Physiol Heart Circ Physiol 2019; 317:H226-H233. [PMID: 31149841 DOI: 10.1152/ajpheart.00091.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cardiac sympathetic overdrive provides inotropic support to the failing heart. However, as myocardial insult evolves, this compensatory response impairs contractile function and constitutes an independent mortality predictor and a primary target in the treatment of heart failure (HF). In this prospective, randomized, double-blind, controlled crossover trial, we proposed cervicothoracic transcutaneous electrical nerve stimulation (CTENS) as a nonpharmacological therapy on cardiac sympathetic activity in patients with HF. Seventeen patients with HF were randomly assigned to an in-home CTENS (30 min twice daily, 80-Hz frequency, and 150-μs pulse duration) or a control intervention (Sham) for 14 consecutive days. Following a 60-day washout phase, patients were crossed over to the opposite intervention. The heart-to-mediastinum ratio (HMR) and washout rate (WR) (indexes of sympathetic innervation density and activity from planar 123iodo-metaiodobenzylguanidine myocardial scintigraphy images, respectively), as well as blood pressure (BP) and heart rate (HR), were quantified before and after each intervention. HMR, BP, and HR did not change throughout the study. Nonetheless, CTENS reduced WR (CTENS -4 ± 10 vs. Sham +5 ± 15%, P = 0.03) when compared with Sham. When allocated in two independent groups, preserved (PCSI, HMR > 1.6, n = 10) and impaired cardiac sympathetic innervation (ICSI, HRM ≤1.6, n = 7), PCSI patients showed an important attenuation of WR (-11 ± 9 vs. Sham +8 ± 19%, P = 0.007) after CTENS. Nonetheless, neither Sham nor CTENS evoked changes in WR of the ICSI patients (P > 0.05). These findings indicate that CTENS attenuates the cardiac sympathetic overdrive in patients with HF and a preserved innervation constitutes an essential factor for this beneficial neuromodulatory impact. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Identifier: NCT03354689. NEW & NOTEWORTHY We found that short-term cervicothoracic transcutaneous electrical nerve stimulation (CTENS) attenuates cardiac sympathetic overdrive in patients with heart failure and a preserved autonomic innervation may constitute an essential factor to maximize this beneficial neuromodulatory effect. CTENS then emerges as an alternative noninvasive and nonpharmacological strategy to attenuate exaggerated cardiac sympathetic drive in patients with heart failure.
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Affiliation(s)
- Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University , Brazil
| | | | - Sandra M Miranda
- Antonio Pedro University Hospital, Fluminense Federal University , Brazil
| | - Mario L Ribeiro
- Antonio Pedro University Hospital, Fluminense Federal University , Brazil
| | - Thais R B Guerra
- Antonio Pedro University Hospital, Fluminense Federal University , Brazil
| | - Ana M S Braghirolli
- Institute of Nuclear Engineering, Federal University of Rio de Janeiro , Brazil
| | - Claudio T Mesquita
- Antonio Pedro University Hospital, Fluminense Federal University , Brazil
| | - Igor A Fernandes
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília , Brazil
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Fernandes IA, Campos MO, Mansur DE, Mattos J, Paiva A, Videira R, Macefield V, Nóbrega ACL. Acid‐Sensing Ion Channels Blockade Attenuates Pressor and Sympathetic Responses to Skeletal Muscle Metaboreflex Activation in Humans. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.860.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Igor Alexandre Fernandes
- NeuroVASQ ‐ Integrative Physiology LabFaculty of Physical EducationUniversity of BrasíliaBrasíliaBrazil
| | - Monique O Campos
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | - Daniel E Mansur
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | - João Mattos
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | - Adrielle Paiva
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | - Rogerio Videira
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | | | - Antonio CL Nóbrega
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
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11
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Mansur D, Campos MO, Mattos JD, Paiva ACS, Videira R, Macefield V, Nóbrega ACL, Fernandes IA. Muscle Sympathetic Nerve Activity and Hemodynamic Responses to Venous Distension: Does Sex Play a Role? FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.561.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Daniel Mansur
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | - Monique O Campos
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | - João D Mattos
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | - Adrielle CS Paiva
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | - Rogério Videira
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | | | - Antonio CL Nóbrega
- LACE ‐ Laboratory of Exercise SciencesFluminense Federal UniversityNiteróiBrazil
| | - Igor Alexandre Fernandes
- NeuroVASQ ‐ Integrative Physiology LaboratoryFaculty of Physical EducationUniversity of BrasíliaBrasíliaBrazil
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12
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Mansur DE, Campos MO, Mattos JD, Paiva ACS, Rocha MP, Videira RLR, Macefield VG, Nóbrega ACL, Fernandes IA. Muscle sympathetic nerve activity and hemodynamic responses to venous distension: does sex play a role? Am J Physiol Heart Circ Physiol 2018; 316:H734-H742. [PMID: 30592900 DOI: 10.1152/ajpheart.00702.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peripheral venous distension mechanically stimulates type III/IV sensory fibers in veins and evokes pressor and sympathoexcitatory reflex responses in humans. As young women have reduced venous compliance and impaired sympathetic transduction, we tested the hypothesis that pressor and sympathoexcitatory responses to venous distension may be attenuated in women compared with men. Mean arterial pressure (photoplethysmography), heart rate (HR), stroke volume (SV; Modelflow), cardiac output (CO = HR × SV), muscle sympathetic nerve activity (MSNA), femoral artery blood flow, and femoral artery conductance (Doppler ultrasound) were quantified in eight men (27 ± 4 yr) and nine women (28 ± 4 yr) before [control (CON)], during (INF), and immediately after (post-INF) a local infusion of saline [5% of the total forearm volume (30 ml/min); the infusion time was 2 ± 1 and 1 ± 1 min ( P = 0.0001) for men and women, respectively] through a retrograde catheter inserted into an antecubital vein, to which venous drainage and arterial supply had been occluded. Mean arterial pressure increased during and after infusion in both groups (vs. the CON group, P < 0.05), but women showed a smaller pressor response in the post-INF period (Δ+7.2 ± 2.0 vs. Δ+18.3 ± 3.9 mmHg in men, P = 0.019). MSNA increased and femoral artery conductance decreased similarly in both groups (vs. the CON group, P < 0.05) at post-INF. Although HR changes were similar, increases in SV (Δ+20.4 ± 8.6 vs. Δ+2.6 ± 2.7 ml, P = 0.05) and CO (Δ+0.84 ± 0.17 vs. Δ+0.34 ± 0.10 l/min, P = 0.024) were greater in men compared with women. Therefore, venous distension evokes a smaller pressor response in young women due to attenuated cardiac adjustments rather than reduced venous compliance or sympathetic transduction. NEW & NOTEWORTHY We found that the pressor response to venous distension was attenuated in young women compared with age-matched men. This was due to attenuated cardiac adjustments rather than reduced venous compliance, sympathetic activation, or impaired transduction and vascular control. Collectively, these findings suggest that an attenuated venous distension reflex could be involved in orthostatic intolerance in young women.
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Affiliation(s)
- Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Adrielle C S Paiva
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Marcos P Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | | | - Vaughan G Macefield
- College of Medicine, Mohammed Bin Rashid University of Health and Medicine , Dubai , United Arab Emirates.,Baker Heart and Diabetes Institute , Melbourne, Victoria , Australia
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Igor A Fernandes
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil.,NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília , Brasília , Brazil
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13
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Mattos JD, Campos MO, Rocha MP, Mansur DE, Rocha HNM, Garcia VP, Batista G, Alvares TS, Oliveira GV, Souza MV, Videira RLR, Rocha NG, Secher NH, Nóbrega ACL, Fernandes IA. Human brain blood flow and metabolism during isocapnic hyperoxia: the role of reactive oxygen species. J Physiol 2018; 597:741-755. [PMID: 30506968 DOI: 10.1113/jp277122] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/16/2018] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS It is unknown whether excessive reactive oxygen species (ROS) production drives the isocapnic hyperoxia (IH)-induced decline in human cerebral blood flow (CBF) via reduced nitric oxide (NO) bioavailability and leads to disruption of the blood-brain barrier (BBB) or neural-parenchymal damage. Cerebral metabolic rate for oxygen (CMR O 2 ) and transcerebral exchanges of NO end-products, oxidants, antioxidants and neural-parenchymal damage markers were simultaneously quantified under IH with intravenous saline and ascorbic acid infusion. CBF and CMR O 2 were reduced during IH, responses that were followed by increased oxidative stress and reduced NO bioavailability when saline was infused. No indication of neural-parenchymal damage or disruption of the BBB was observed during IH. Antioxidant defences were increased during ascorbic acid infusion, while CBF, CMR O 2 , oxidant and NO bioavailability markers remained unchanged. ROS play a role in the regulation of CBF and metabolism during IH without evidence of BBB disruption or neural-parenchymal damage. ABSTRACT To test the hypothesis that isocapnic hyperoxia (IH) affects cerebral blood flow (CBF) and metabolism through exaggerated reactive oxygen species (ROS) production, reduced nitric oxide (NO) bioavailability, disturbances in the blood-brain barrier (BBB) and neural-parenchymal homeostasis, 10 men (24 ± 1 years) were exposed to a 10 min IH trial (100% O2 ) while receiving intravenous saline and ascorbic acid (AA, 3 g) infusion. Internal carotid artery blood flow (ICABF), vertebral artery blood flow (VABF) and total CBF (tCBF, Doppler ultrasound) were determined. Arterial and right internal jugular venous blood was sampled to quantify the cerebral metabolic rate of oxygen (CMR O 2 ), transcerebral exchanges (TCE) of NO end-products (plasma nitrite), antioxidants (AA and AA plus dehydroascorbic acid (AA+DA)) and oxidant biomarkers (thiobarbituric acid-reactive substances (TBARS) and 8-isoprostane), and an index of BBB disruption and neuronal-parenchymal damage (neuron-specific enolase; NSE). IH reduced ICABF, tCBF and CMR O 2 , while VABF remained unchanged. Arterial 8-isoprostane and nitrite TCE increased, indicating that CBF decline was related to ROS production and reduced NO bioavailability. AA, AA+DA and NSE TCE did not change during IH. AA infusion did not change the resting haemodynamic and metabolic parameters but raised antioxidant defences, as indicated by increased AA/AA+DA concentrations. Negative AA+DA TCE, unchanged nitrite, reductions in arterial and venous 8-isoprostane, and TBARS TCE indicated that AA infusion effectively inhibited ROS production and preserved NO bioavailability. Similarly, AA infusion prevented IH-induced decline in regional and total CBF and re-established CMR O 2 . These findings indicate that ROS play a role in CBF regulation and metabolism during IH without evidence of BBB disruption or neural-parenchymal damage.
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Affiliation(s)
- João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Marcos P Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Helena N M Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Vinicius P Garcia
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Gabriel Batista
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | | | | | | | | | - Natalia G Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Niels H Secher
- Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Igor A Fernandes
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil.,NeuroVASQ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brazil
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14
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Fernandes IA, Rocha MP, Campos MO, Mattos JD, Mansur DE, Rocha HNM, Terra PAC, Garcia VP, Rocha NG, Secher NH, Nóbrega ACL. Reduced arterial vasodilatation in response to hypoxia impairs cerebral and peripheral oxygen delivery in hypertensive men. J Physiol 2018; 596:1167-1179. [PMID: 29462837 DOI: 10.1113/jp275545] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 01/16/2018] [Indexed: 01/31/2023] Open
Abstract
KEY POINTS Hypoxaemia evokes a repertoire of homeostatic adjustments that maintain oxygen supply to organs and tissues including the brain and skeletal muscles. Because hypertensive patients have impaired endothelial-dependent vasodilatation and an increased sympathetic response to arterial oxygen desaturation, we investigated whether hypertension impairs isocapnic hypoxia-induced cerebral and skeletal muscle hyperaemia to an extent that limits oxygen supply. In middle-aged hypertensive men, vertebral and femoral artery blood flow do not increase in response to isocapnic hypoxia, limiting brain and peripheral hyperaemia and oxygen supply. Increased chemoreflex-induced sympathetic activation impairs skeletal muscle perfusion and oxygen supply, whereas an attenuation of local vasodilatory signalling in the posterior cerebrovasculature reduced brain hyperperfusion of hypertensive middle-aged men in response to isocapnic hypoxia. ABSTRACT The present study investigated whether hypertension impairs isocapnic hypoxia (IH)-induced cerebral and skeletal muscle hyperaemia to an extent that limits oxygen supply. Oxygen saturation (oxymetry), mean arterial pressure (photoplethysmography) and muscle sympathetic nerve activity (MSNA; microneugraphy), as well as femoral artery (FA), internal carotid artery and vertebral artery (VA) blood flow (BF; Doppler ultrasound), were quantified in nine normotensive (NT) (aged 40 ± 11 years, systolic pressure 119 ± 7 mmHg and diastolic pressure 73 ± 6 mmHg) and nine hypertensive men (HT) (aged 44 ± 12 years, systolic pressure 152 ± 11 mmHg and diastolic pressure 90 ± 9 mmHg) during 5 min of normoxia (21% O2 ) and IH (10% O2 ). Total cerebral blood flow (tCBF), brain (CDO2 ) and leg (LDO2 ) oxygen delivery were estimated. IH provoked similar oxygen desaturation without changing mean arterial pressure. Internal carotid artery perfusion increased in both groups during IH. However, VA and FA BF only increased in NT. Thus, IH-induced increase in tCBF was smaller in HT. CDO2 only increased in NT and LDO2 decreased in HT. Furthermore, IH evoked a greater increase in HT MSNA. Changes in MSNA were inversely related to FA BF, LDO2 and end-tidal oxygen tension. In conclusion, hypertension disturbs regional and total cerebrovascular and peripheral responses to IH and consequently limits oxygen supply to the brain and skeletal muscle. Although increased chemoreflex-induced sympathetic activation may explain impaired peripheral perfusion, attenuated vasodilatory signalling in the posterior cerebrovasculature appears to be responsible for the small increase in tCBF when HT were exposed to IH.
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Affiliation(s)
- Igor A Fernandes
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Marcos P Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Helena N M Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Paulo A C Terra
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Vinícius P Garcia
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Natália G Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Niels H Secher
- Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
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15
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Fernandes IA, Mattos JD, Campos MO, Machado AC, Rocha MP, Rocha NG, Vianna LC, Nobrega ACL. Selective α1-adrenergic blockade disturbs the regional distribution of cerebral blood flow during static handgrip exercise. Am J Physiol Heart Circ Physiol 2016; 310:H1541-8. [DOI: 10.1152/ajpheart.00125.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 03/23/2016] [Indexed: 11/22/2022]
Abstract
Handgrip-induced increases in blood flow through the contralateral artery that supplies the cortical representation of the arm have been hypothesized as a consequence of neurovascular coupling and a resultant metabolic attenuation of sympathetic cerebral vasoconstriction. In contrast, sympathetic restraint, in theory, inhibits changes in perfusion of the cerebral ipsilateral blood vessels. To confirm whether sympathetic nerve activity modulates cerebral blood flow distribution during static handgrip (SHG) exercise, beat-to-beat contra- and ipsilateral internal carotid artery blood flow (ICA; Doppler) and mean arterial pressure (MAP; Finometer) were simultaneously assessed in nine healthy men (27 ± 5 yr), both at rest and during a 2-min SHG bout (30% maximal voluntary contraction), under two experimental conditions: 1) control and 2) α1-adrenergic receptor blockade. End-tidal carbon dioxide (rebreathing system) was clamped throughout the study. SHG induced increases in MAP (+31.4 ± 10.7 mmHg, P < 0.05) and contralateral ICA blood flow (+80.9 ± 62.5 ml/min, P < 0.05), while no changes were observed in the ipsilateral vessel (−9.8 ± 39.3 ml/min, P > 0.05). The reduction in ipsilateral ICA vascular conductance (VC) was greater compared with contralateral ICA (contralateral: −0.8 ± 0.8 vs. ipsilateral: −2.6 ± 1.3 ml·min−1·mmHg−1, P < 0.05). Prazosin was effective to induce α1-blockade since phenylephrine-induced increases in MAP were greatly reduced ( P < 0.05). Under α1-adrenergic receptor blockade, SHG evoked smaller MAP responses (+19.4 ± 9.2, P < 0.05) but similar increases in ICAs blood flow (contralateral: +58.4 ± 21.5 vs. ipsilateral: +54.3 ± 46.2 ml/min, P > 0.05) and decreases in VC (contralateral: −0.4 ± 0.7 vs. ipsilateral: −0.4 ± 1.0 ml·min−1·mmHg−1, P > 0.05). These findings indicate a role of sympathetic nerve activity in the regulation of cerebral blood flow distribution during SHG.
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Affiliation(s)
- Igor A. Fernandes
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Rio de Janeiro, Brazil; and
| | - João D. Mattos
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Rio de Janeiro, Brazil; and
| | - Monique O. Campos
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Rio de Janeiro, Brazil; and
| | - Alessandro C. Machado
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Rio de Janeiro, Brazil; and
| | - Marcos P. Rocha
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Rio de Janeiro, Brazil; and
| | - Natalia G. Rocha
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Rio de Janeiro, Brazil; and
| | - Lauro C. Vianna
- Faculty of Physical Education, University of Brasilia, Distrito Federal, Brazil
| | - Antonio C. L. Nobrega
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Rio de Janeiro, Brazil; and
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