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Herring N, Ajijola OA, Foreman RD, Gourine AV, Green AL, Osborn J, Paterson DJ, Paton JFR, Ripplinger CM, Smith C, Vrabec TL, Wang HJ, Zucker IH, Ardell JL. Neurocardiology: translational advancements and potential. J Physiol 2024. [PMID: 39340173 DOI: 10.1113/jp284740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 09/03/2024] [Indexed: 09/30/2024] Open
Abstract
In our original white paper published in the The Journal of Physiology in 2016, we set out our knowledge of the structural and functional organization of cardiac autonomic control, how it remodels during disease, and approaches to exploit such knowledge for autonomic regulation therapy. The aim of this update is to build on this original blueprint, highlighting the significant progress which has been made in the field since and major challenges and opportunities that exist with regard to translation. Imbalances in autonomic responses, while beneficial in the short term, ultimately contribute to the evolution of cardiac pathology. As our understanding emerges of where and how to target in terms of actuators (including the heart and intracardiac nervous system (ICNS), stellate ganglia, dorsal root ganglia (DRG), vagus nerve, brainstem, and even higher centres), there is also a need to develop sensor technology to respond to appropriate biomarkers (electrophysiological, mechanical, and molecular) such that closed-loop autonomic regulation therapies can evolve. The goal is to work with endogenous control systems, rather than in opposition to them, to improve outcomes.
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Affiliation(s)
- N Herring
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - O A Ajijola
- UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
| | - R D Foreman
- Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - A V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, University College London, London, UK
| | - A L Green
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - J Osborn
- Department of Surgery, University of Minnesota, Minneapolis, MN, USA
| | - D J Paterson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - J F R Paton
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - C M Ripplinger
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - C Smith
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - T L Vrabec
- Department of Physical Medicine and Rehabilitation, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - H J Wang
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - I H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - J L Ardell
- UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
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Samora M, Huo Y, Stanhope KL, Havel PJ, Kaufman MP, Harrison ML, Stone AJ. Cyclooxygenase products contribute to the exaggerated exercise pressor reflex evoked by static muscle contraction in male UCD-type 2 diabetes mellitus rats. J Appl Physiol (1985) 2024; 136:1226-1237. [PMID: 38545661 PMCID: PMC11368523 DOI: 10.1152/japplphysiol.00879.2023] [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: 12/08/2023] [Revised: 03/25/2024] [Accepted: 03/25/2024] [Indexed: 05/15/2024] Open
Abstract
Cyclooxygenase (COX) products of arachidonic acid metabolism, specifically prostaglandins, play a role in evoking and transmitting the exercise pressor reflex in health and disease. Individuals with type 2 diabetes mellitus (T2DM) have an exaggerated exercise pressor reflex; however, the mechanisms for this exaggerated reflex are not fully understood. We aimed to determine the role played by COX products in the exaggerated exercise pressor reflex in T2DM rats. The exercise pressor reflex was evoked by static muscle contraction in unanesthetized, decerebrate, male, adult University of California Davis (UCD)-T2DM (n = 8) and healthy Sprague-Dawley (n = 8) rats. Changes (Δ) in peak mean arterial pressure (MAP) and heart rate (HR) during muscle contraction were compared before and after intra-arterial injection of indomethacin (1 mg/kg) into the contracting hindlimb. Data are presented as means ± SD. Inhibition of COX activity attenuated the exaggerated peak MAP (Before: Δ32 ± 13 mmHg and After: Δ18 ± 8 mmHg; P = 0.004) and blood pressor index (BPi) (Before: Δ683 ± 324 mmHg·s and After: Δ361 ± 222 mmHg·s; P = 0.006), but not HR (Before: Δ23 ± 8 beats/min and After Δ19 ± 10 beats/min; P = 0.452) responses to muscle contraction in T2DM rats. In healthy rats, COX activity inhibition did not affect MAP, HR, or BPi responses to muscle contraction. Inhibition of COX activity significantly reduced local production of prostaglandin E2 in T2DM and healthy rats. We conclude that peripheral inhibition of COX activity attenuates the pressor response to muscle contraction in T2DM rats, suggesting that COX products partially contribute to the exaggerated exercise pressor reflex in those with T2DM.NEW & NOTEWORTHY We compared the pressor and cardioaccelerator responses to static muscle contraction before and after inhibition of cyclooxygenase (COX) activity within the contracting hindlimb in decerebrate, unanesthetized type 2 diabetic mellitus (T2DM) and healthy rats. The pressor responses to muscle contraction were attenuated after peripheral inhibition of COX activity in T2DM but not in healthy rats. We concluded that COX products partially contribute to the exaggerated pressor reflex in those with T2DM.
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Affiliation(s)
- Milena Samora
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas, United States
| | - Yu Huo
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas, United States
| | - Kimber L Stanhope
- Department of Molecular Biosciences, School of Veterinary Medicine and Department of Nutrition, University of California Davis, Davis, California, United States
| | - Peter J Havel
- Department of Molecular Biosciences, School of Veterinary Medicine and Department of Nutrition, University of California Davis, Davis, California, United States
| | - Marc P Kaufman
- Heart and Vascular Institute, Penn State College of Medicine, Hershey, Pennsylvania, United States
| | - Michelle L Harrison
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas, United States
| | - Audrey J Stone
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas, United States
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Butenas ALE, Rollins KS, Williams AC, Parr SK, Hammond ST, Ade CJ, Hageman KS, Musch TI, Copp SW. Thromboxane A 2 receptors contribute to the exaggerated exercise pressor reflex in male rats with heart failure. Physiol Rep 2021; 9:e15052. [PMID: 34558221 PMCID: PMC8461035 DOI: 10.14814/phy2.15052] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 08/30/2021] [Accepted: 09/02/2021] [Indexed: 01/31/2023] Open
Abstract
Mechanical and metabolic signals associated with skeletal muscle contraction stimulate the sensory endings of thin fiber muscle afferents and produce reflex increases in sympathetic nerve activity and blood pressure during exercise (i.e., the exercise pressor reflex; EPR). The EPR is exaggerated in patients and animals with heart failure with reduced ejection fraction (HF-rEF) and its activation contributes to reduced exercise capacity within this patient population. Accumulating evidence suggests that the exaggerated EPR in HF-rEF is partially attributable to a sensitization of mechanically activated channels produced by thromboxane A2 receptors (TxA2 -Rs) on those sensory endings; however, this has not been investigated. Accordingly, the purpose of this investigation was to determine the role played by TxA2 -Rs on the sensory endings of thin fiber muscle afferents in the exaggerated EPR in rats with HF-rEF induced by coronary artery ligation. In decerebrate, unanesthetized rats, we found that injection of the TxA2 -R antagonist daltroban (80 μg) into the arterial supply of the hindlimb reduced the pressor response to 30 s of electrically induced 1 Hz dynamic hindlimb muscle contraction in HF-rEF (n = 8, peak ∆MAP pre: 22 ± 3; post: 14 ± 2 mmHg; p = 0.01) but not sham (n = 10, peak ∆MAP pre: 13 ± 3; post: 11 ± 2 mmHg; p = 0.68) rats. In a separate group of HF-rEF rats (n = 4), we found that the systemic (intravenous) injection of daltroban had no effect on the EPR (peak ΔMAP pre: 26 ± 7; post: 25 ± 7 mmHg; p = 0.50). Our data suggest that TxA2 -Rs on thin fiber muscle afferents contribute to the exaggerated EPR evoked in response to dynamic muscle contraction in HF-rEF.
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Affiliation(s)
| | | | - Auni C. Williams
- Department of KinesiologyKansas State UniversityManhattanKansasUSA
| | - Shannon K. Parr
- Department of KinesiologyKansas State UniversityManhattanKansasUSA
| | | | - Carl J. Ade
- Department of KinesiologyKansas State UniversityManhattanKansasUSA
| | - K. Sue Hageman
- Department of Anatomy and PhysiologyKansas State UniversityManhattanKansasUSA
| | - Timothy I. Musch
- Department of KinesiologyKansas State UniversityManhattanKansasUSA
- Department of Anatomy and PhysiologyKansas State UniversityManhattanKansasUSA
| | - Steven W. Copp
- Department of KinesiologyKansas State UniversityManhattanKansasUSA
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Butenas ALE, Rollins KS, Williams AC, Parr SK, Hammond ST, Ade CJ, Hageman KS, Musch TI, Copp SW. Exaggerated sympathetic and cardiovascular responses to dynamic mechanoreflex activation in rats with heart failure: Role of endoperoxide 4 and thromboxane A 2 receptors. Auton Neurosci 2021; 232:102784. [PMID: 33610008 DOI: 10.1016/j.autneu.2021.102784] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/18/2021] [Accepted: 02/10/2021] [Indexed: 12/15/2022]
Abstract
The primary purpose of this investigation was to determine the role played by endoperoxide 4 receptors (EP4-R) and thromboxane A2 receptors (TxA2-R) during isolated dynamic muscle mechanoreflex activation in rats with heart failure with reduced ejection fraction (HF-rEF) and sham-operated healthy controls. We found that injection of the EP4-R antagonist L-161,982 (1 μg) into the arterial supply of the hindlimb had no effect on the peak pressor response to dynamic hindlimb muscle stretch in HF-rEF (n = 6, peak ∆MAP pre: 27 ± 7; post: 27 ± 4 mm Hg; P = 0.99) or sham (n = 6, peak ∆MAP pre: 15 ± 3; post: 13 ± 3 mm Hg; P = 0.67) rats. In contrast, injection of the TxA2-R antagonist daltroban (80 μg) into the arterial supply of the hindlimb reduced the pressor response to dynamic hindlimb muscle stretch in HF-rEF (n = 11, peak ∆MAP pre: 28 ± 4; post: 16 ± 2 mm Hg; P = 0.02) but not sham (n = 8, peak ∆MAP pre: 17 ± 3; post: 16 ± 3; P = 0.84) rats. Our data suggest that TxA2-Rs on thin fibre muscle afferents contribute to the exaggerated mechanoreflex in HF-rEF.
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Affiliation(s)
- Alec L E Butenas
- Department of Kinesiology, Kansas State University, Manhattan, KS, United States of America
| | - Korynne S Rollins
- Department of Kinesiology, Kansas State University, Manhattan, KS, United States of America
| | - Auni C Williams
- Department of Kinesiology, Kansas State University, Manhattan, KS, United States of America
| | - Shannon K Parr
- Department of Kinesiology, Kansas State University, Manhattan, KS, United States of America
| | - Stephen T Hammond
- Department of Kinesiology, Kansas State University, Manhattan, KS, United States of America
| | - Carl J Ade
- Department of Kinesiology, Kansas State University, Manhattan, KS, United States of America
| | - K Sue Hageman
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, United States of America
| | - Timothy I Musch
- Department of Kinesiology, Kansas State University, Manhattan, KS, United States of America; Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, United States of America
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, KS, United States of America.
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Butenas ALE, Rollins KS, Matney JE, Williams AC, Kleweno TE, Parr SK, Hammond ST, Ade CJ, Hageman KS, Musch TI, Copp SW. No effect of endoperoxide 4 or thromboxane A 2 receptor blockade on static mechanoreflex activation in rats with heart failure. Exp Physiol 2020; 105:1840-1854. [PMID: 32954541 DOI: 10.1113/ep088835] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/18/2020] [Indexed: 12/30/2022]
Abstract
NEW FINDINGS What is the central question of this study? Do endoperoxide 4 and thromboxane A2 receptors, which are receptors for cyclooxygenase products of arachidonic metabolism, on thin fibre muscle afferents play a role in the chronic mechanoreflex sensitization present in rats with heart failure with reduced ejection fraction (HF-rEF)? What is the main finding and its importance? The data do not support a role for endoperoxide 4 receptors or thromboxane A2 receptors in the chronic mechanoreflex sensitization in HF-rEF rats. ABSTRACT We investigated the role of cyclooxygenase metabolite-associated endoperoxide 4 receptors (EP4-R) and thromboxane A2 receptors (TxA2 -R) on thin fibre muscle afferents in the chronic mechanoreflex sensitization in rats with myocardial infarction-induced heart failure with reduced ejection fraction (HF-rEF). We hypothesized that injection of either the EP4-R antagonist L-161,982 (1 µg) or the TxA2 -R antagonist daltroban (80 µg) into the arterial supply of the hindlimb would reduce the increase in blood pressure and renal sympathetic nerve activity (RSNA) evoked in response to 30 s of static hindlimb skeletal muscle stretch (a model of isolated mechanoreflex activation) in decerebrate, unanaesthetized HF-rEF rats but not sham-operated control rats (SHAM). Ejection fraction was significantly reduced in HF-rEF (45 ± 11%) compared to SHAM (83 ± 6%; P < 0.01) rats. In SHAM and HF-rEF rats, we found that the EP4-R antagonist had no effect on the peak increase in mean arterial pressure (peak ΔMAP SHAM n = 6, pre: 15 ± 7, post: 15 ± 9, P = 0.99; HF-rEF n = 9, pre: 30 ± 11, post: 32 ± 15 mmHg, P = 0.84) or peak increase in RSNA (peak ΔRSNA SHAM pre: 33 ± 14, post: 47 ± 31%, P = 0.94; HF-rEF, pre: 109 ± 47, post: 139 ± 150%, P = 0.76) response to stretch. Similarly, in SHAM and HF-rEF rats, we found that the TxA2 -R antagonist had no effect on the peak ΔMAP (SHAM n = 7, pre: 13 ± 7, post: 19 ± 14, P = 0.15; HF-rEF n = 14, pre: 24 ± 13, post: 21 ± 13 mmHg, P = 0.47) or peak ΔRSNA (SHAM pre: 52 ± 43, post: 57 ± 67%, P = 0.94; HF-rEF, pre: 108 ± 93, post: 88 ± 72%, P = 0.30) response to stretch. The data do not support a role for EP4-Rs or TxA2 -Rs in the chronic mechanoreflex sensitization in HF-rEF.
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Affiliation(s)
- Alec L E Butenas
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Korynne S Rollins
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Jacob E Matney
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Auni C Williams
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Talyn E Kleweno
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Shannon K Parr
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Stephen T Hammond
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Carl J Ade
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Karen S Hageman
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, USA
| | - Timothy I Musch
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA.,Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, USA
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
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Smith JR, Hart CR, Ramos PA, Akinsanya JG, Lanza IR, Joyner MJ, Curry TB, Olson TP. Metabo- and mechanoreceptor expression in human heart failure: Relationships with the locomotor muscle afferent influence on exercise responses. Exp Physiol 2020; 105:809-818. [PMID: 32105387 DOI: 10.1113/ep088353] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/20/2020] [Indexed: 12/17/2022]
Abstract
NEW FINDINGS What is the central question of this study? How do locomotor muscle metabo- and mechanoreceptor expression compare in heart failure patients and controls? Do relationships exist between the protein expression and cardiopulmonary responses during exercise with locomotor muscle neural afferent feedback inhibition? What is the main finding and its importance? Heart failure patients exhibited greater protein expression of transient receptor potential vanilloid type 1 and cyclooxygenase-2 than controls. These findings are important as they identify receptors that may underlie the augmented locomotor muscle neural afferent feedback in heart failure. ABSTRACT Heart failure patients with reduced ejection fraction (HFrEF) exhibit abnormal locomotor group III/IV afferent feedback during exercise; however, the underlying mechanisms are unclear. Therefore, the purpose of this study was to determine (1) metabo- and mechanoreceptor expression in HFrEF and controls and (2) relationships between receptor expression and changes in cardiopulmonary responses with afferent inhibition. Ten controls and six HFrEF performed 5 min of cycling exercise at 65% peak workload with lumbar intrathecal fentanyl (FENT) or placebo (PLA). Arterial blood pressure and catecholamines were measured via radial artery catheter. A vastus lateralis muscle biopsy was performed to quantify cyclooxygenase-2 (COX-2), purinergic 2X3 (P2X3 ), transient receptor potential vanilloid type 1 (TRPV 1), acid-sensing ion channel 3 (ASIC3 ), Piezo 1 and Piezo 2 protein expression. TRPV 1 and COX-2 protein expression was greater in HFrEF than controls (both P < 0.04), while P2X3 , ASIC3 , and Piezo 1 and 2 were not different between groups (all P > 0.16). In all participants, COX-2 protein expression was related to the percentage change in ventilation (r = -0.66) and mean arterial pressure (MAP) (r = -0.82) (both P < 0.01) with FENT (relative to PLA) during exercise. In controls, TRPV 1 protein expression was related to the percentage change in systolic blood pressure (r = -0.77, P = 0.02) and MAP (r = -0.72, P = 0.03) with FENT (relative to PLA) during exercise. TRPV 1 and COX-2 protein levels are elevated in HFrEF compared to controls. These findings suggest that the elevated TRPV 1 and COX-2 expression may contribute to the exaggerated locomotor muscle afferent feedback during cycling exercise in HFrEF.
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Affiliation(s)
- Joshua R Smith
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Corey R Hart
- Division of Endocrinology, Mayo Clinic, Rochester, MN, USA
| | - Paola A Ramos
- Division of Endocrinology, Mayo Clinic, Rochester, MN, USA
| | | | - Ian R Lanza
- Division of Endocrinology, Mayo Clinic, Rochester, MN, USA
| | | | - Timothy B Curry
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
| | - Thomas P Olson
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
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Butenas ALE, Hopkins TD, Rollins KS, Felice KP, Copp SW. Investigation of the mechanisms of cyclooxygenase-mediated mechanoreflex sensitization in a rat model of simulated peripheral artery disease. Am J Physiol Heart Circ Physiol 2019; 317:H1050-H1061. [PMID: 31469294 DOI: 10.1152/ajpheart.00399.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mechanical and metabolic stimuli within contracting skeletal muscles reflexly increase sympathetic nervous system activity and blood pressure. That reflex, termed the exercise pressor reflex, is exaggerated in patients with peripheral artery disease (PAD) and in a rat PAD model with a chronically ligated femoral artery. The cyclooxygenase (COX) pathway contributes to the exaggerated pressor response during rhythmic skeletal muscle contractions in patients with PAD, but the specific mechanism(s) of the COX-mediated exaggeration are not known. In decerebrate, unanesthetized rats with a chronically ligated femoral artery ("ligated" rats), we hypothesized that hindlimb arterial injection of the COX inhibitor indomethacin would reduce the pressor response during 1-Hz dynamic hindlimb skeletal muscle stretch; a model of the activation of the mechanical component of the exercise pressor reflex (i.e., the mechanoreflex). In ligated rats (n = 7), indomethacin reduced the pressor response during stretch (control: 30 ± 4; indomethacin: 12 ± 3 mmHg; P < 0.01), whereas there was no effect in rats with "freely perfused" femoral arteries (n = 6, control: 18 ± 5; indomethacin: 17 ± 5 mmHg; P = 0.87). In ligated rats (n = 4), systemic indomethacin injection had no effect on the pressor response during stretch. Femoral artery ligation had no effect on skeletal muscle COX protein expression or activity or concentration of the COX metabolite prostaglandin E2. Conversely, femoral artery ligation increased expression of the COX metabolite receptors endoperoxide 4 and thromboxane A2-R in dorsal root ganglia tissue. We conclude that, in ligated rats, the COX pathway sensitizes the peripheral endings of mechanoreflex afferents, which occurs principally as a result of increased expression of COX metabolite receptors.NEW & NOTEWORTHY We demonstrate that the mechanoreflex is sensitized by the cyclooxygenase (COX) pathway within hindlimb skeletal muscles in the rat chronic femoral artery ligation model of simulated peripheral artery disease (PAD). The mechanism of sensitization appears attributable to increased receptors for COX metabolites on sensory neurons and not increased concentration of COX metabolites. Our data may carry important clinical implications for patients with PAD who demonstrate exaggerated increases in blood pressure during exercise compared with healthy counterparts.
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Affiliation(s)
- Alec L E Butenas
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Tyler D Hopkins
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Korynne S Rollins
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Kennedy P Felice
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
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Rollins KS, Hopkins TD, Butenas AL, Felice KP, Ade CJ, Copp SW. Cyclooxygenase inhibition does not impact the pressor response during static or dynamic mechanoreflex activation in healthy decerebrate rats. Am J Physiol Regul Integr Comp Physiol 2019; 317:R369-R378. [PMID: 31241976 DOI: 10.1152/ajpregu.00080.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Passive limb movement and limb muscle stretch in humans and animals are common experimental strategies used to investigate activation of the muscle mechanoreflex independent of contraction-induced metabolite production. Cyclooxygenase (COX) metabolites, however, are produced by skeletal muscle stretch in vitro and have been found to impact various models of mechanoreflex activation. Whether COX metabolites influence the decerebrate rat triceps surae muscle stretch mechanoreflex model remains unknown. We examined the effect of rat triceps surae muscle stretch on the interstitial concentration of the COX metabolite prostaglandin E2 (PGE2). Interstitial PGE2 concentration was increased above baseline values by 4 min of both static (38% increase, P = 0.01) and dynamic (56% increase, P < 0.01) triceps surae muscle stretch (n = 10). The 4-min protocol was required to collect enough microdialysis fluid for PGE2 detection. The finding that skeletal muscle stretch in vivo was capable of producing COX metabolites prompted the hypothesis that intra-arterial administration of the COX inhibitor indomethacin (1 mg/kg) would reduce the pressor and cardioaccelerator responses evoked during 30 s (the duration most commonly used in the rat mechanoreflex model) of static and dynamic rat triceps surae muscle stretch. We found that indomethacin had no effect (P > 0.05, n = 9) on the pressor or cardioaccelerator response during 30 s of either static or dynamic stretch. We conclude that, despite the possibility of increased COX metabolite concentration, COX metabolites do not activate or sensitize thin-fiber muscle afferents stimulated during 30 s of static or dynamic hindlimb skeletal muscle stretch in healthy rats.
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Affiliation(s)
- Korynne S Rollins
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Tyler D Hopkins
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Alec L Butenas
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Kennedy P Felice
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Carl J Ade
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
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Kim JS, Kaufman MP. Stimulation of spinal δ-opioid receptors attenuates the exercise pressor reflex in decerebrate rats. Am J Physiol Regul Integr Comp Physiol 2019; 316:R727-R734. [PMID: 30943058 DOI: 10.1152/ajpregu.00013.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A reflex arising from contracting hindlimb muscle is responsible in part for the increases in arterial pressure and heart rate evoked by exercise. The afferent arm of this reflex comprises group III and IV afferents. δ-Opioid receptors are expressed predominately on the spinal endings of group III afferents, whereas μ-opioid receptors are expressed predominately on the spinal endings of group IV afferents. Using stimuli that activated group III afferents, namely static contraction, calcaneal tendon stretch, and lactic acid injection into the superficial epigastric artery, we tested the hypothesis that, in rats with either patent or ligated femoral arteries, activation of pre- and postsynaptic δ-opioid receptors in the dorsal horn attenuated pressor reflex responses to these stimuli. In rats with patent arteries or ligated femoral arteries, [d-Pen2,5]enkephalin (DPDPE), a δ-opioid agonist injected intrathecally (10 μg in 10 μl), significantly attenuated the pressor responses to contraction, stretch, and lactic acid (all P < 0.05). Naltrindole, a δ-opioid receptor antagonist, prevented the attenuation. In contrast, DPDPE did not attenuate the pressor response to capsaicin injection into the superficial epigastric artery in either group of rats (both P > 0.05). Intrathecal injection of saline (10 μl), the vehicle for DPDPE, had no effect on the pressor responses in either group of rats. We conclude that activation of spinal δ-opioid receptors attenuates reflexes evoked by group III afferents in both freely perfused and ligated rats.
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Affiliation(s)
- Joyce S Kim
- Pennsylvania State Heart and Vascular Institute and Department of Internal Medicine, Pennsylvania State College of Medicine , Hershey, Pennsylvania
| | - Marc P Kaufman
- Pennsylvania State Heart and Vascular Institute and Department of Internal Medicine, Pennsylvania State College of Medicine , Hershey, Pennsylvania
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Rollins KS, Smith JR, Esau PJ, Kempf EA, Hopkins TD, Copp SW. Bradykinin does not acutely sensitize the reflex pressor response during hindlimb skeletal muscle stretch in decerebrate rats. Am J Physiol Regul Integr Comp Physiol 2017; 313:R463-R472. [PMID: 28724548 DOI: 10.1152/ajpregu.00187.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/18/2017] [Accepted: 07/18/2017] [Indexed: 01/03/2023]
Abstract
Hindlimb skeletal muscle stretch (i.e., selective activation of the muscle mechanoreflex) in decerebrate rats evokes reflex increases in blood pressure and sympathetic nerve activity. Bradykinin has been found to sensitize mechanogated channels through a bradykinin B2 receptor-dependent mechanism. Moreover, bradykinin B2 receptor expression on sensory neurons is increased following chronic femoral artery ligation in the rat (a model of simulated peripheral artery disease). We tested the hypothesis that injection of bradykinin into the arterial supply of a hindlimb in decerebrate, unanesthetized rats would acutely augment (i.e., sensitize) the increase in blood pressure and renal sympathetic nerve activity during hindlimb muscle stretch to a greater extent in rats with a ligated femoral artery than in rats with a freely perfused femoral artery. The pressor response during static hindlimb muscle stretch was compared before and after hindlimb arterial injection of 0.5 µg of bradykinin. Injection of bradykinin increased blood pressure to a greater extent in "ligated" (n = 10) than "freely perfused" (n = 10) rats. The increase in blood pressure during hindlimb muscle stretch, however, was not different before vs. after bradykinin injection in freely perfused (14 ± 2 and 15 ± 2 mmHg for pre- and post-bradykinin, respectively, P = 0.62) or ligated (15 ± 3 and 14 ± 2 mmHg for pre- and post-bradykinin, respectively, P = 0.80) rats. Likewise, the increase in renal sympathetic nerve activity during stretch was not different before vs. after bradykinin injection in either group of rats. We conclude that bradykinin did not acutely sensitize the pressor response during hindlimb skeletal muscle stretch in freely perfused or ligated decerebrate rats.
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Affiliation(s)
- Korynne S Rollins
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Joshua R Smith
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Peter J Esau
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Evan A Kempf
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Tyler D Hopkins
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
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11
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Santos MRD, Sayegh ALC, Groehs RVR, Fonseca G, Trombetta IC, Barretto ACP, Arap MA, Negrão CE, Middlekauff HR, Alves MJDNN. Testosterone deficiency increases hospital readmission and mortality rates in male patients with heart failure. Arq Bras Cardiol 2015. [PMID: 26200897 PMCID: PMC4592174 DOI: 10.5935/abc.20150078] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Background Testosterone deficiency in patients with heart failure (HF) is associated with
decreased exercise capacity and mortality; however, its impact on hospital
readmission rate is uncertain. Furthermore, the relationship between testosterone
deficiency and sympathetic activation is unknown. Objective We investigated the role of testosterone level on hospital readmission and
mortality rates as well as sympathetic nerve activity in patients with HF. Methods Total testosterone (TT) and free testosterone (FT) were measured in 110
hospitalized male patients with a left ventricular ejection fraction < 45% and
New York Heart Association classification IV. The patients were placed into low
testosterone (LT; n = 66) and normal testosterone (NT; n = 44) groups.
Hypogonadism was defined as TT < 300 ng/dL and FT < 131 pmol/L. Muscle
sympathetic nerve activity (MSNA) was recorded by microneurography in a
subpopulation of 27 patients. Results Length of hospital stay was longer in the LT group compared to in the NT group (37
± 4 vs. 25 ± 4 days; p = 0.008). Similarly, the cumulative hazard of readmission
within 1 year was greater in the LT group compared to in the NT group (44% vs.
22%, p = 0.001). In the single-predictor analysis, TT (hazard ratio [HR], 2.77;
95% confidence interval [CI], 1.58–4.85; p = 0.02) predicted hospital readmission
within 90 days. In addition, TT (HR, 4.65; 95% CI, 2.67–8.10; p = 0.009) and
readmission within 90 days (HR, 3.27; 95% CI, 1.23–8.69; p = 0.02) predicted
increased mortality. Neurohumoral activation, as estimated by MSNA, was
significantly higher in the LT group compared to in the NT group (65 ± 3 vs. 51 ±
4 bursts/100 heart beats; p < 0.001). Conclusion These results support the concept that LT is an independent risk factor for
hospital readmission within 90 days and increased mortality in patients with HF.
Furthermore, increased MSNA was observed in patients with LT.
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Affiliation(s)
| | | | | | - Guilherme Fonseca
- Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, BR
| | | | | | | | | | - Holly R Middlekauff
- Division of Cardiology, David Geffen School of Medicine, University of California, US
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12
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Muller MD, Drew RC, Ross AJ, Blaha CA, Cauffman AE, Kaufman MP, Sinoway LI. Inhibition of cyclooxygenase attenuates the blood pressure response to plantar flexion exercise in peripheral arterial disease. Am J Physiol Heart Circ Physiol 2015; 309:H523-8. [PMID: 26055794 DOI: 10.1152/ajpheart.00267.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 05/29/2015] [Indexed: 11/22/2022]
Abstract
Prostanoids are produced during skeletal muscle contraction and subsequently stimulate muscle afferent nerves, thereby contributing to the exercise pressor reflex. Humans with peripheral arterial disease (PAD) have an augmented exercise pressor reflex, but the metabolite(s) responsible for this augmented response is not known. We tested the hypothesis that intravenous injection of ketorolac, which blocks the activity of cyclooxygenase, would attenuate the rise in mean arterial blood pressure (MAP) and heart rate (HR) evoked by plantar flexion exercise. Seven PAD patients underwent 4 min of single-leg dynamic plantar flexion (30 contractions/min) in the supine posture (workload: 0.5-2.0 kg). MAP and HR were measured on a beat-by-beat basis; changes from baseline in response to exercise were determined. Ketorolac did not affect MAP or HR at rest. During the first 20 s of exercise with the most symptomatic leg, ΔMAP was significantly attenuated by ketorolac (2 ± 2 mmHg) compared with control (8 ± 2 mmHg, P = 0.005), but ΔHR was similar (6 ± 2 vs. 5 ± 1 beats/min). Importantly, patients rated the exercise bout as "very light" to "fairly light," and average pain ratings were 1 of 10. Ketorolac had no effect on perceived exertion or pain ratings. Ketorolac also had no effect on MAP or HR in seven age- and sex-matched healthy subjects who performed a similar but longer plantar flexion protocol (workload: 0.5-7.0 kg). These data suggest that prostanoids contribute to the augmented exercise pressor reflex in patients with PAD.
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Affiliation(s)
- Matthew D Muller
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Rachel C Drew
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Amanda J Ross
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Cheryl A Blaha
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Aimee E Cauffman
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Marc P Kaufman
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Lawrence I Sinoway
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
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13
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Laurin J, Pertici V, Dousset E, Marqueste T, Decherchi P. Group III and IV muscle afferents: Role on central motor drive and clinical implications. Neuroscience 2015; 290:543-51. [DOI: 10.1016/j.neuroscience.2015.01.065] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 01/27/2015] [Accepted: 01/28/2015] [Indexed: 12/12/2022]
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14
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Abnormal neurocirculatory control during exercise in humans with chronic renal failure. Auton Neurosci 2014; 188:74-81. [PMID: 25458430 DOI: 10.1016/j.autneu.2014.10.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 09/13/2014] [Accepted: 10/13/2014] [Indexed: 02/07/2023]
Abstract
Abnormal neurocirculatory control during exercise is one important mechanism leading to exercise intolerance in patients with both end-stage renal disease (ESRD) and earlier stages of chronic kidney disease (CKD). This review will provide an overview of mechanisms underlying abnormal neurocirculatory and hemodynamic responses to exercise in patients with kidney disease. Recent studies have shown that ESRD and CKD patients have an exaggerated increase in blood pressure (BP) during both isometric and rhythmic exercise. Subsequent studies examining the role of the exercise pressor reflex in the augmented pressor response revealed that muscle sympathetic nerve activity (MSNA) was not augmented during exercise in these patients, and metaboreflex-mediated increases in MSNA were blunted, while mechanoreflex-mediated increases were preserved under basal conditions. However, normalizing the augmented BP response during exercise via infusion of nitroprusside (NTP), and thereby equalizing baroreflex-mediated suppression of MSNA, an important modulator of the final hemodynamic response to exercise, revealed that CKD patients had an exaggerated increase in MSNA during isometric and rhythmic exercise. In addition, mechanoreflex-mediated control was augmented, and metaboreceptor blunting was no longer apparent in CKD patients with baroreflex normalization. Factors leading to mechanoreceptor sensitization, and other mechanisms underlying the exaggerated exercise pressor response, such as impaired functional sympatholysis, should be investigated in future studies.
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15
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Antunes-Correa LM, Nobre TS, Groehs RV, Alves MJNN, Fernandes T, Couto GK, Rondon MUPB, Oliveira P, Lima M, Mathias W, Brum PC, Mady C, Almeida DR, Rossoni LV, Oliveira EM, Middlekauff HR, Negrao CE. Molecular basis for the improvement in muscle metaboreflex and mechanoreflex control in exercise-trained humans with chronic heart failure. Am J Physiol Heart Circ Physiol 2014; 307:H1655-66. [PMID: 25305179 DOI: 10.1152/ajpheart.00136.2014] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Previous studies have demonstrated that muscle mechanoreflex and metaboreflex controls are altered in heart failure (HF), which seems to be due to changes in cyclooxygenase (COX) pathway and changes in receptors on afferent neurons, including transient receptor potential vanilloid type-1 (TRPV1) and cannabinoid receptor type-1 (CB1). The purpose of the present study was to test the hypotheses: 1) exercise training (ET) alters the muscle metaboreflex and mechanoreflex control of muscle sympathetic nerve activity (MSNA) in HF patients. 2) The alteration in metaboreflex control is accompanied by increased expression of TRPV1 and CB1 receptors in skeletal muscle. 3) The alteration in mechanoreflex control is accompanied by COX-2 pathway in skeletal muscle. Thirty-four consecutive HF patients with ejection fractions <40% were randomized to untrained (n = 17; 54 ± 2 yr) or exercise-trained (n = 17; 56 ± 2 yr) groups. MSNA was recorded by microneurography. Mechanoreceptors were activated by passive exercise and metaboreceptors by postexercise circulatory arrest (PECA). COX-2 pathway, TRPV1, and CB1 receptors were measured in muscle biopsies. Following ET, resting MSNA was decreased compared with untrained group. During PECA (metaboreflex), MSNA responses were increased, which was accompanied by the expression of TRPV1 and CB1 receptors. During passive exercise (mechanoreflex), MSNA responses were decreased, which was accompanied by decreased expression of COX-2, prostaglandin-E2 receptor-4, and thromboxane-A2 receptor and by decreased in muscle inflammation, as indicated by increased miRNA-146 levels and the stable NF-κB/IκB-α ratio. In conclusion, ET alters muscle metaboreflex and mechanoreflex control of MSNA in HF patients. This alteration with ET is accompanied by alteration in TRPV1 and CB1 expression and COX-2 pathway and inflammation in skeletal muscle.
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Affiliation(s)
| | - Thais S Nobre
- Heart Institute (InCor), University of Sao Paulo Medical School, Sao Paulo, Brazil
| | - Raphaela V Groehs
- Heart Institute (InCor), University of Sao Paulo Medical School, Sao Paulo, Brazil
| | | | - Tiago Fernandes
- School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil
| | - Gisele K Couto
- Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, Brazil
| | | | - Patricia Oliveira
- Heart Institute (InCor), University of Sao Paulo Medical School, Sao Paulo, Brazil
| | - Marta Lima
- Heart Institute (InCor), University of Sao Paulo Medical School, Sao Paulo, Brazil
| | - Wilson Mathias
- Heart Institute (InCor), University of Sao Paulo Medical School, Sao Paulo, Brazil
| | - Patricia C Brum
- School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil
| | - Charles Mady
- Heart Institute (InCor), University of Sao Paulo Medical School, Sao Paulo, Brazil
| | - Dirceu R Almeida
- Department of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil; and
| | - Luciana V Rossoni
- Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, Brazil
| | - Edilamar M Oliveira
- School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil
| | - Holly R Middlekauff
- Departament of Medicine (Cardiology) and Physiology, Geffen School of Medicine at University of California, Los Angeles, California
| | - Carlos E Negrao
- Heart Institute (InCor), University of Sao Paulo Medical School, Sao Paulo, Brazil; School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil;
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16
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Smith SA, Downey RM, Williamson JW, Mizuno M. Autonomic dysfunction in muscular dystrophy: a theoretical framework for muscle reflex involvement. Front Physiol 2014; 5:47. [PMID: 24600397 PMCID: PMC3927082 DOI: 10.3389/fphys.2014.00047] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 01/24/2014] [Indexed: 01/16/2023] Open
Abstract
Muscular dystrophies are a heterogeneous group of genetically inherited disorders whose most prominent clinical feature is progressive degeneration of skeletal muscle. In several forms of the disease, the function of cardiac muscle is likewise affected. The primary defect in this group of diseases is caused by mutations in myocyte proteins important to cellular structure and/or performance. That being stated, a growing body of evidence suggests that the development of autonomic dysfunction may secondarily contribute to the generation of skeletal and cardio-myopathy in muscular dystrophy. Indeed, abnormalities in the regulation of both sympathetic and parasympathetic nerve activity have been reported in a number of muscular dystrophy variants. However, the mechanisms mediating this autonomic dysfunction remain relatively unknown. An autonomic reflex originating in skeletal muscle, the exercise pressor reflex, is known to contribute significantly to the control of sympathetic and parasympathetic activity when stimulated. Given the skeletal myopathy that develops with muscular dystrophy, it is logical to suggest that the function of this reflex might also be abnormal with the pathogenesis of disease. As such, it may contribute to or exacerbate the autonomic dysfunction that manifests. This possibility along with a basic description of exercise pressor reflex function in health and disease are reviewed. A better understanding of the mechanisms that possibly underlie autonomic dysfunction in muscular dystrophy may not only facilitate further research but could also lead to the identification of new therapeutic targets for the treatment of muscular dystrophy.
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Affiliation(s)
- Scott A Smith
- Department of Health Care Sciences, University of Texas Southwestern Medical Center Dallas, TX, USA ; Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Ryan M Downey
- Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Jon W Williamson
- Department of Health Care Sciences, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Masaki Mizuno
- Department of Health Care Sciences, University of Texas Southwestern Medical Center Dallas, TX, USA
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17
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Olson TP, Joyner MJ, Eisenach JH, Curry TB, Johnson BD. Influence of locomotor muscle afferent inhibition on the ventilatory response to exercise in heart failure. Exp Physiol 2013; 99:414-26. [DOI: 10.1113/expphysiol.2013.075937] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Thomas P. Olson
- Departments of Internal Medicine; Division of Cardiovascular Diseases
| | | | | | | | - Bruce D. Johnson
- Departments of Internal Medicine; Division of Cardiovascular Diseases
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18
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Drew RC, Muller MD, Blaha CA, Mast JL, Herr MD, Stocker SD, Sinoway LI. Aspirin augments carotid-cardiac baroreflex sensitivity during muscle mechanoreflex and metaboreflex activation in humans. J Appl Physiol (1985) 2013; 115:1183-90. [PMID: 23970529 DOI: 10.1152/japplphysiol.00100.2013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Muscle mechanoreflex activation decreases the sensitivity of carotid baroreflex (CBR)-heart rate (HR) control during local metabolite accumulation in humans. However, the contribution of thromboxane A2 (TXA2) toward this response is unknown. Therefore, the effect of inhibiting TXA2 production via low-dose aspirin on CBR-HR sensitivity during muscle mechanoreflex and metaboreflex activation in humans was examined. Twelve young subjects performed two trials during two visits, preceded by 7 days' low-dose aspirin (81 mg) or placebo. One trial involved 3-min passive calf stretch (mechanoreflex) during 7.5-min limb circulatory occlusion (CO). In another trial, CO was preceded by 1.5 min of 70% maximal voluntary contraction isometric calf exercise to accumulate metabolites during CO and stretch (mechanoreflex and metaboreflex). HR (ECG) and mean arterial pressure (Finometer) were recorded. CBR function was assessed using rapid neck pressures ranging from +40 to -80 mmHg. Aspirin significantly decreased baseline thromboxane B2 production by 84 ± 4% (P < 0.05) but did not affect 6-keto prostaglandin F1α. Following aspirin, stretch with metabolite accumulation significantly augmented maximal gain (GMAX) and operating point gain (GOP) of CBR-HR (GMAX; -0.71 ± 0.14 vs. -0.37 ± 0.08 and GOP; -0.69 ± 0.13 vs. -0.35 ± 0.12 beats·min(-1)·mmHg(-1) for aspirin and placebo, respectively; P < 0.05). CBR-HR function curves were reset similarly with aspirin and placebo during stretch with metabolite accumulation. In conclusion, these findings suggest that low-dose aspirin augments CBR-HR sensitivity during concurrent muscle mechanoreflex and metaboreflex activation in humans. This increased sensitivity appears linked to reduced TXA2 production, which likely plays a role in metabolite sensitization of muscle mechanoreceptors.
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Affiliation(s)
- Rachel C Drew
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania
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19
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Morales A, Gao W, Lu J, Xing J, Li J. Muscle cyclo-oxygenase-2 pathway contributes to the exaggerated muscle mechanoreflex in rats with congestive heart failure. Exp Physiol 2012; 97:943-54. [PMID: 22523381 DOI: 10.1113/expphysiol.2012.065425] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cyclo-oxygenase (COX) enzymes are responsible for the formation from arachidonic acid of prostaglandins, among other metabolites. Prior studies have suggested that inhibition of the COX pathway attenuates the responses of sympathetic nerve activity and blood pressure during static muscle contraction. Static muscle contraction activates the exercise pressor reflex, which in turn increases sympathetic nerve activity and blood pressure. Also, COX products contribute to exaggeration of the exercise pressor reflex in heart failure (HF). This dysfunction of the exercise pressor reflex has previously been shown to be mediated primarily by muscle mechanoreflex overactivity. It is well known that COX-1 and COX-2 are two isoforms of the enzyme that lead to formation of these important biological mediators involved in the muscle reflex. Thus, in the present study, we determined whether the COX-1 and/or COX-2 pathway contribute(s) to the augmented mechanoreflex activity in HF. First, Western blot analysis was employed to examine protein expression of COX-1 and COX-2 in skeletal muscle tissue of control rats and rats with HF induced by myocardial infarction. Our data show that there is no significant difference in COX-1 expression in both experimental groups. However, COX-2 displays significant overexpression in rats with HF compared with control rats (optical density 1.06 ± 0.05 in control and 1.6 ± 0.05 in HF, P < 0.05 versus control). Second, the mechanoreflex was evoked by passive tendon stretch, and the reflex sympathetic and pressor responses to muscle stretch were examined after COX-1 and COX-2 inhibitors (FR-122047 and SC-236) were individually injected into the arterial blood supply of the hindlimb muscles. The results demonstrate that the stretch-evoked reflex responses in rats with HF were significantly attenuated by administration of SC-236, but not by FR-122047, i.e. renal sympathetic nerve activity and mean arterial pressure responses evoked by 0.5 kg of muscle tension were 52.3 ± 8.9% and 19 ± 1.4 mmHg, respectively, in control conditions and 26.4 ± 5.6% and 5.7 ± 1.6 mmHg (P < 0.05 versus control group) after 0.25 mg kg(-1) of SC-236. Muscle stretch-evoked renal sympathetic nerve activity and mean arterial pressure responses were 51.8 ± 8.2% and 18.7 ± 1.2 mmHg, respectively, in control conditions and 48.3 ± 5.3% and 17.5 ± 1.9 mmHg (P > 0.05 versus control group) after 1.0 mg kg(-1) of FR-122047. Accordingly, the results obtained from this study support our hypothesis that heightened COX-2 expression within the hindlimb muscles contributes to the exaggerated muscle mechanoreflex in congestive HF.
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Affiliation(s)
- Ariel Morales
- Heart & Vascular Institute, The Pennsylvania State University College of Medicine, Hershey, PA, USA
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20
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Abstract
The temporal relationship between the development of heart failure and activation of the neurohumoral systems involved in chronic heart failure (CHF) has not been precisely defined. When a compensatory mechanism switches to a deleterious contributing factor in the progression of the disease is unclear. This article addresses these issues through evaluating the contribution of various cardiovascular reflexes and cellular mechanisms to the sympathoexcitation in CHF. It also sheds light on some of the important central mechanisms that contribute to the increase in sympathetic nerve activity in CHF.
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Affiliation(s)
- Irving H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, USA.
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21
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Cui J, Leuenberger UA, Blaha C, Yoder J, Gao Z, Sinoway LI. Local adenosine receptor blockade accentuates the sympathetic responses to fatiguing exercise. Am J Physiol Heart Circ Physiol 2010; 298:H2130-7. [PMID: 20400689 DOI: 10.1152/ajpheart.00083.2010] [Citation(s) in RCA: 11] [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
The role adenosine plays in evoking the exercise pressor reflex in humans remains controversial. We hypothesized that localized forearm adenosine receptor blockade would attenuate muscle sympathetic nerve activity (MSNA) responses to fatiguing handgrip exercise in humans. Blood pressure (Finometer), heart rate, and MSNA from the peroneal nerve were assessed in 11 healthy young volunteers during fatiguing isometric handgrip, postexercise circulatory occlusion (PECO), and passive muscle stretch during PECO. The protocol was performed before and after adenosine receptor blockade by local infusion of 40 mg aminophylline in saline via forearm Bier block (regional intravenous anesthesia). In the second experiment, the same amount of saline was infused via the Bier block. After aminophylline, the MSNA and blood pressure responses to fatiguing handgrip, PECO, and passive stretch (all P < 0.05) were significantly greater than during the control condition. Saline Bier block had no similar effects on the MSNA and blood pressure responses. These data suggest that adenosine receptor antagonism in the exercising muscles may accentuate sympathetic activation during fatiguing exercise.
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Affiliation(s)
- Jian Cui
- Penn State Heart & Vascular Institute, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA
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22
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Koba S, Xing J, Sinoway LI, Li J. Bradykinin receptor blockade reduces sympathetic nerve response to muscle contraction in rats with ischemic heart failure. Am J Physiol Heart Circ Physiol 2010; 298:H1438-44. [PMID: 20207818 DOI: 10.1152/ajpheart.00558.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Previous animal and human studies have suggested that a muscle reflex engaged during contraction leads to heightened levels of sympathetic activity in congestive heart failure (CHF). The present experiment was designed to test the role for bradykinin, which is produced within contracting skeletal muscle and contributes to the muscle reflex through its action on kinin B(2) receptors located on the endings of thin fiber muscle afferents. CHF was induced in rats by myocardial infarction (MI) after coronary artery ligation. Echocardiography was performed to determine fractional shortening (FS), an index of the left ventricular function. In the decerebrate rats, we examined renal sympathetic nerve activity (RSNA) during 1 min intermittent (1 to 4 s stimulation to relaxation) contraction of left triceps surae muscles. RSNA responded synchronously as tension was developed, and the response was significantly (P < 0.05) greater in MI rats [+39 +/- 9% s(-1) (integrated RSNA over time); n = 16] with 20 +/- 2% of FS than that in control healthy rats (+19 +/- 2% s(-1); n = 16) with 49 +/- 2% of FS. Tension development did not differ significantly between the two groups of rats. Thirty minutes after intra-arterial injection into the hindlimb circulation of the kinin B(2) receptor antagonist, HOE-140 (2 microg/kg), the RSNA response to contraction was significantly reduced in the MI rats (+26 +/- 7% s(-1)) but not in the control rats (+17 +/- 2% s(-1)). These data suggest that bradykinin within contracting muscle is part of the exaggerated muscle reflex seen in CHF.
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Affiliation(s)
- Satoshi Koba
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, 500 University Drive, Hershey, PA 17033, USA
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