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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 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, Ishizawa R, Rollins KS, Mizuno M, Copp SW. Sex-dependent attenuating effects of capsaicin administration on the mechanoreflex in healthy rats. Am J Physiol Heart Circ Physiol 2023; 325:H372-H384. [PMID: 37389947 PMCID: PMC10396229 DOI: 10.1152/ajpheart.00237.2023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 07/02/2023]
Abstract
Stimulation of mechanically sensitive channels on the sensory endings of group III and IV thin fiber muscle afferents activates the mechanoreflex, which contributes to reflex increases in sympathetic nerve activity (SNA) and blood pressure during exercise. Accumulating evidence suggests that activation of the nonselective cation channel transient receptor potential vanilloid-1 (TRPV1) on the sensory endings of thin fiber afferents with capsaicin may attenuate mechanosensation. However, no study has investigated the effect of capsaicin on the mechanoreflex. We tested the hypothesis that in male and female decerebrate, unanesthetized rats, the injection of capsaicin (0.05 µg) into the arterial supply of the hindlimb reduces the pressor and renal SNA (RSNA) response to 30 s of 1 Hz rhythmic hindlimb muscle stretch (a model of isolated mechanoreflex activation). In male rats (n = 8), capsaicin injection significantly reduced the integrated blood pressure (blood pressure index or BPI: pre, 363 ± 78; post, 211 ± 88 mmHg·s; P = 0.023) and RSNA [∫ΔRSNA; pre, 687 ± 206; post, 216 ± 80 arbitrary units (au), P = 0.049] response to hindlimb muscle stretch. In female rats (n = 8), capsaicin injection had no significant effect on the pressor (BPI; pre: 277 ± 67; post: 207 ± 77 mmHg·s; P = 0.343) or RSNA (∫ΔRSNA: pre, 697 ± 123; post, 440 ± 183 au; P = 0.307) response to hindlimb muscle stretch. The data suggest that the injection of capsaicin into the hindlimb arterial supply to stimulate TRPV1 on the sensory endings of thin fiber muscle afferents attenuates the mechanoreflex in healthy male, but not female, rats. The findings may carry important implications for chronic conditions in which an exaggerated mechanoreflex contributes to aberrant sympathoexcitation during exercise.NEW & NOTEWORTHY Recent evidence in isolated sensory neurons indicates that capsaicin-induced stimulation of TRPV1 attenuates mechanosensitivity. Here we demonstrate for the first time that capsaicin exposure/administration reduces the reflex pressor and renal sympathetic nerve response to mechanoreflex activation in male rats, but not female rats, in vivo. Our data may carry important clinical implications for chronic diseases which have been linked to an exaggerated mechanoreflex, at least in males.
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Affiliation(s)
- Alec L E Butenas
- Department of Kinesiology, Kansas State University, Manhattan, Kansas, United States
| | - Rie Ishizawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Korynne S Rollins
- Department of Kinesiology, Kansas State University, Manhattan, Kansas, United States
| | - Masaki Mizuno
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, Kansas, United States
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Aranda LC, Ribeiro IC, Freitas TO, Degani-Costa LH, Dias DS, DE Angelis K, Paixão AO, Brum PC, Oliveira ASB, Vianna LC, Nery LE, Silva BM. Enhanced Respiratory Frequency Response to Lower Limb Mechanoreceptors Activation in Patients with Chronic Obstructive Pulmonary Disease. Med Sci Sports Exerc 2023; 55:418-429. [PMID: 36730960 DOI: 10.1249/mss.0000000000003065] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE To investigate the mechanoreflex control of respiration and circulation in patients with chronic obstructive pulmonary disease (COPD). METHODS Twenty-eight patients with moderate-to-severe COPD (mean ± SD: 67.0 ± 7.9 yr, 10 women) and 14 age- and sex-matched controls (67.9 ± 2.6 yr, 7 women) participated in the study. Their dominant knee was passively moved to stimulate mechanoreceptors, whereas vastus lateralis surface electrical activity checked active contractions. A differential pressure flowmeter, an electrocardiogram, and a servo-controlled finger photoplethysmograph acquired cardiorespiratory data. To gain insight into the mechanoreflex arc, we further analyzed reduced/oxidized glutathione ratio and mechanoreceptor-related gene expression in a vastus lateralis biopsy of additional nine patients (63.9 ± 8.1 yr, 33% women) and eight controls (62.9 ± 9.1 yr, 38% women). RESULTS Patients with COPD had a greater peak respiratory frequency response (COPD: Δ = 3.2 ± 2.3 vs Controls: 1.8 ± 1.2 cycles per minute, P = 0.036) and a smaller peak tidal volume response to passive knee movement than controls. Ventilation, heart rate, stroke volume, and cardiac output peak responses, and total peripheral resistance nadir response, were unaltered by COPD. In addition, patients had a diminished glutathione ratio (COPD: 13.3 ± 3.8 vs controls: 20.0 ± 5.5 a.u., P = 0.015) and an augmented brain-derived neurotrophic factor expression (COPD: 2.0 ± 0.7 vs controls: 1.1 ± 0.4 a.u., P = 0.002) than controls. Prostaglandin E receptor 4, cyclooxygenase 2, and Piezo1 expression were similar between groups. CONCLUSIONS Respiratory frequency response to mechanoreceptors activation is increased in patients with COPD. This abnormality is possibly linked to glutathione redox imbalance and augmented brain-derived neurotrophic factor expression within locomotor muscles, which could increase mechanically sensitive afferents' stimulation and sensitivity.
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Affiliation(s)
| | | | | | - Luiza H Degani-Costa
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Division of Respiratory Medicine, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, SP, BRAZIL
| | | | | | - Ailma O Paixão
- School of Physical Education and Sport, University of São Paulo, São Paulo, SP, BRAZIL
| | - Patricia C Brum
- School of Physical Education and Sport, University of São Paulo, São Paulo, SP, BRAZIL
| | - Acary S B Oliveira
- Department of Neurology and Neurosurgery, UNIFESP, São Paulo, SP, BRAZIL
| | - Lauro C Vianna
- NeuroV̇ASQ˙-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasilia, Brasilia, Federal District, BRAZIL
| | - Luiz E Nery
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Division of Respiratory Medicine, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, SP, BRAZIL
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Rollins KS, Butenas ALE, Williams AC, Copp SW. Sensory neuron inositol 1,4,5-trisphosphate receptors contribute to chronic mechanoreflex sensitization in rats with simulated peripheral artery disease. Am J Physiol Regul Integr Comp Physiol 2021; 321:R768-R780. [PMID: 34494467 PMCID: PMC8616625 DOI: 10.1152/ajpregu.00165.2021] [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: 06/30/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 11/22/2022]
Abstract
The mechanoreflex is exaggerated in patients with peripheral artery disease (PAD) and in a rat model of simulated PAD in which a femoral artery is chronically (∼72 h) ligated. We found recently that, in rats with a ligated femoral artery, blockade of thromboxane A2 (TxA2) receptors on the sensory endings of thin fiber muscle afferents reduced the pressor response to 1 Hz repetitive/dynamic hindlimb skeletal muscle stretch (a model of mechanoreflex activation isolated from contraction-induced metabolite production). Conversely, we found no effect of TxA2 receptor blockade in rats with freely perfused femoral arteries. Here, we extended the isolated mechanoreflex findings in "ligated" rats to experiments evoking dynamic hindlimb skeletal muscle contractions. We also investigated the role played by inositol 1,4,5-trisphosphate (IP3) receptors, receptors associated with intracellular signaling linked to TxA2 receptors, in the exaggerated response to dynamic mechanoreflex and exercise pressor reflex activation in ligated rats. Injection of the TxA2 receptor antagonist daltroban into the arterial supply of the hindlimb reduced the pressor response to 1 Hz dynamic contraction in ligated but not "freely perfused" rats. Moreover, injection of the IP3 receptor antagonist xestospongin C into the arterial supply of the hindlimb reduced the pressor response to 1 Hz dynamic stretch and contraction in ligated but not freely perfused rats. These findings demonstrate that, in rats with a ligated femoral artery, sensory neuron TxA2 receptor and IP3 receptor-mediated signaling contributes to a chronic sensitization of the mechanically activated channels associated with the mechanoreflex and the exercise pressor reflex.
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Affiliation(s)
- Korynne S Rollins
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Alec L E Butenas
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Auni C Williams
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
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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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6
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Aimo A, Saccaro LF, Borrelli C, Fabiani I, Gentile F, Passino C, Emdin M, Piepoli MF, Coats AJS, Giannoni A. The ergoreflex: how the skeletal muscle modulates ventilation and cardiovascular function in health and disease. Eur J Heart Fail 2021; 23:1458-1467. [PMID: 34268843 PMCID: PMC9292527 DOI: 10.1002/ejhf.2298] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/16/2021] [Accepted: 07/13/2021] [Indexed: 11/28/2022] Open
Abstract
The control of ventilation and cardiovascular function during physical activity is partially regulated by the ergoreflex, a cardiorespiratory reflex activated by physical activity. Two components of the ergoreflex have been identified: the mechanoreflex, which is activated early by muscle contraction and tendon stretch, and the metaboreflex, which responds to the accumulation of metabolites in the exercising muscles. Patients with heart failure (HF) often develop a skeletal myopathy with varying degrees of severity, from a subclinical disease to cardiac cachexia. HF‐related myopathy has been associated with increased ergoreflex sensitivity, which is believed to contribute to dyspnoea on effort, fatigue and sympatho‐vagal imbalance, which are hallmarks of HF. Ergoreflex sensitivity increases significantly also in patients with neuromuscular disorders. Exercise training is a valuable therapeutic option for both HF and neuromuscular disorders to blunt ergoreflex sensitivity, restore the sympatho‐vagal balance, and increase tolerance to physical exercise. A deeper knowledge of the mechanisms mediating ergoreflex sensitivity might enable a drug or device modulation of this reflex when patients cannot exercise because of advanced skeletal myopathy.
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Affiliation(s)
- Alberto Aimo
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.,Cardiology Department, Fondazione Toscana Gabriele Monasterio, Pisa, Italy
| | | | - Chiara Borrelli
- Emergency Medicine Division, University Hospital of Pisa, Pisa, Italy
| | - Iacopo Fabiani
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.,Cardiology Department, Fondazione Toscana Gabriele Monasterio, Pisa, Italy
| | | | - Claudio Passino
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.,Cardiology Department, Fondazione Toscana Gabriele Monasterio, Pisa, Italy
| | - Michele Emdin
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.,Cardiology Department, Fondazione Toscana Gabriele Monasterio, Pisa, Italy
| | | | - Andrew J S Coats
- Monash University, Melbourne, Australia.,University of Warwick, Coventry, UK
| | - Alberto Giannoni
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.,Cardiology Department, Fondazione Toscana Gabriele Monasterio, Pisa, Italy
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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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8
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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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9
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Rollins KS, Butenas ALE, Felice KP, Matney JE, Williams AC, Kleweno TE, Copp SW. Thromboxane A 2 receptors mediate chronic mechanoreflex sensitization in a rat model of simulated peripheral artery disease. Am J Physiol Heart Circ Physiol 2020; 319:H320-H330. [PMID: 32530751 DOI: 10.1152/ajpheart.00255.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The exercise pressor reflex is a feedback autonomic and cardiovascular control mechanism evoked by mechanical and metabolic signals within contracting skeletal muscles. The mechanically sensitive component of the reflex (the mechanoreflex) is exaggerated in patients with peripheral artery disease (PAD) and in a rat model of simulated PAD in which a femoral artery is chronically ligated. Products of cyclooxygenase enzyme activity have been shown to chronically sensitize the mechanoreflex in PAD, but the identity of the muscle afferent receptors that mediate the sensitization is unclear. We hypothesized that injection of the endoperoxide 4 receptor (EP4-R) antagonist L161982 or the thromboxane A2 receptor (TxA2-R) antagonist daltroban into the arterial supply of the hindlimb would reduce the pressor response to repetitive, dynamic hindlimb skeletal muscle stretch (a model of isolated mechanoreflex activation) in rats with a femoral artery that was ligated ~72 h before the experiment but not in rats with freely perfused femoral arteries. We found that EP4-R blockade had no effect on the pressor response (peak Δmean arterial pressure) to stretch in freely perfused (n = 6, pre: 14 ± 2, post: 15 ± 2 mmHg, P = 0.97) or ligated (n = 8, pre: 29 ± 4, post: 29 ± 6 mmHg, P = 0.98) rats. In contrast, TxA2-R blockade had no effect on the pressor response to stretch in freely perfused rats (n = 6, pre: 16 ± 3, post: 17 ± 4 mmHg, P = 0.99) but significantly reduced the response in ligated rats (n = 11, pre: 29 ± 4, post: 17 ± 5 mmHg, P < 0.01). We conclude that TxA2-Rs contribute to chronic mechanoreflex sensitization in the chronic femoral artery-ligated rat model of simulated PAD.NEW & NOTEWORTHY We demonstrate that thromboxane A2 receptors, but not endoperoxide 4 receptors, on the sensory endings of thin fiber muscle afferents contribute to the chronic sensitization of the muscle mechanoreflex in rats with a ligated femoral artery (a model of simulated peripheral artery disease). The data may have important implications for our understanding of blood pressure control during exercise in patients with peripheral artery disease.
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Affiliation(s)
- Korynne S Rollins
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Alec L E Butenas
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Kennedy P Felice
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Jacob E Matney
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Auni C Williams
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Talyn E Kleweno
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
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