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Ferreira Miranda MT, Lemos MP, Sasaki JE, Mota GR, Marocolo M, Sordi CCD, Almeida TR, Dias da Silva VJ, Neto OB. Exercise training ameliorates adrenergic control in spontaneously hypertensive rats. Clin Exp Hypertens 2021; 43:101-111. [PMID: 32924628 DOI: 10.1080/10641963.2020.1817474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The goal of this study was to examine vascular control after sympathetic stimulation by tyramine infusion in hypertensive rats submitted to swimming training. To this end, male rats were assigned to the following groups: sedentary (SN) and trained normotensive (TN), sedentary (SH) and trained hypertensive (TH). Arterial pressure (AP), heart rate (HR), HR variability (HRV), AP variability (APV), and cardiac autonomic function were recorded. Following, infusion of tyramine was administrated. The TN and TH showed a lower resting HR compared with their respective sedentary groups (p < .05). Pressure levels were less in TH than SH (p < .05). The TH showed a higher HRV together with a lower APV in comparison to SH (p < .05). The sympathetic modulation of HRV and APV was lower in TH than in SH (p < .05). Both trained groups presented an increased parasympathetic modulation of HRV compared with their respective sedentary groups (p < .05). The TN and TH groups had a higher vagal effect in comparison with their respective sedentary groups (p < .001). The sympathetic effect was lower in TH than in SH (p < .001). Pressor and HR responses to tyramine in different doses were attenuated in TH (p < .001). Further analysis showed a significant association between infusion of tyramine and normalized LF component of HRV (r = 0.84, p < .001), systolic APV (r = 0.58, p < .001) and diastolic APV (r = 0.49, p < .001). In conclusion, exercise training provokes less pressor response variation by tyramine infusion in hypertensive animals suggesting sympathetic nerve endings adjustments and decrease of the vasoconstrictor effect attenuates injury caused by hypertension improving cardiovascular autonomic dysfunction, which can be associated with sympathetic attenuation.
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Affiliation(s)
- Munique Tostes Ferreira Miranda
- Exercise Science, Health and Human Performance Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro , Uberaba, Brazil.,Department of Medicine, Federal University of São Paulo , São Paulo, Brazil
| | - Marina Paiva Lemos
- Exercise Science, Health and Human Performance Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro , Uberaba, Brazil
| | - Jeffer Eidi Sasaki
- Exercise Science, Health and Human Performance Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro , Uberaba, Brazil
| | - Gustavo R Mota
- Exercise Science, Health and Human Performance Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro , Uberaba, Brazil
| | - Moacir Marocolo
- Department of Physiology, Federal University of Juiz de Fora , Juiz de Fora, Brazil
| | - Carla Cristina de Sordi
- Department of Endocrinology and Metabolism, Postgraduate Course on Health Science, Federal University of Triângulo Mineiro , Uberaba, Brazil
| | | | | | - Octávio Barbosa Neto
- Exercise Science, Health and Human Performance Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro , Uberaba, Brazil.,Department of Physiology, Federal University of Triângulo Mineiro , Uberaba, Brazil
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Lakin R, Guzman C, Izaddoustdar F, Polidovitch N, Goodman JM, Backx PH. Changes in Heart Rate and Its Regulation by the Autonomic Nervous System Do Not Differ Between Forced and Voluntary Exercise in Mice. Front Physiol 2018; 9:841. [PMID: 30061838 PMCID: PMC6055008 DOI: 10.3389/fphys.2018.00841] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 06/14/2018] [Indexed: 12/20/2022] Open
Abstract
Most exercise studies in mice have relied on forced training which can introduce psychological stress. Consequently, the utility of mouse models for understanding exercise-mediated effects in humans, particularly autonomic nervous system (ANS) remodeling, have been challenged. We compared the effects of voluntary free-wheel running vs. non-voluntary swimming on heart function in mice with a focus on the regulation of heart rate (HR) by the ANS. Under conditions where the total excess O2 consumption associated with exercise was comparable, the two exercise models led to similar improvements in ventricular function as well as comparable reductions in HR and its control by parasympathetic nervous activity (PNA) and sympathetic nervous activity (SNA), compared to sedentary mice. Both exercise models also increased HR variability (HRV) by similar amounts, independent of HR reductions. In all mice, HRV depended primarily on PNA, with SNA weakly affecting HRV at low frequencies. The differences in both HR and HRV between exercised vs. sedentary mice were eliminated by autonomic blockade, consistent with the similar intrinsic beating rates observed in atria isolated from exercised vs. sedentary mice. In conclusion, both forced and voluntary exercise induce comparable ventricular physiological remodeling as well as HR reductions and HR-independent enhancements of HRV which were both primarily dependent on increased PNA. New and noteworthy -No previous mouse studies have compared the effects of forced and voluntary exercise on the heart function and its modulation by the autonomic nervous system (ANS).-Both voluntary free-wheel running and forced swimming induced similar improvements in ventricular contractile function, reductions in heart rate (HR) and enhancements of HR variability (HRV).-HR regulation in exercised mice was linked to increased parasympathetic nerve activity and reduced sympathetic nerve activity.- HRV was independent of HR and depended primarily on PNA in both exercised and sedentary mice.- Complete cardiac autonomic blockade eliminated differences in both HR and HRV between exercised and sedentary mice.
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Affiliation(s)
- Robert Lakin
- Department of Exercise Sciences, University of Toronto, Toronto, ON, Canada.,Division of Cardiology, Mount Sinai Hospital, University Health Network, Toronto, ON, Canada
| | - Camilo Guzman
- Department of Biology, York University, Toronto, ON, Canada
| | - Farzad Izaddoustdar
- Division of Cardiology, Mount Sinai Hospital, University Health Network, Toronto, ON, Canada
| | - Nazari Polidovitch
- Division of Cardiology, Mount Sinai Hospital, University Health Network, Toronto, ON, Canada.,Department of Biology, York University, Toronto, ON, Canada
| | - Jack M Goodman
- Department of Exercise Sciences, University of Toronto, Toronto, ON, Canada.,Division of Cardiology, Mount Sinai Hospital, University Health Network, Toronto, ON, Canada
| | - Peter H Backx
- Division of Cardiology, Mount Sinai Hospital, University Health Network, Toronto, ON, Canada.,Department of Biology, York University, Toronto, ON, Canada
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Basalay MV, Davidson SM, Gourine AV, Yellon DM. Neural mechanisms in remote ischaemic conditioning in the heart and brain: mechanistic and translational aspects. Basic Res Cardiol 2018; 113:25. [PMID: 29858664 PMCID: PMC5984640 DOI: 10.1007/s00395-018-0684-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/02/2018] [Accepted: 05/23/2018] [Indexed: 12/13/2022]
Abstract
Remote ischaemic conditioning (RIC) is a promising method of cardioprotection, with numerous clinical studies having demonstrated its ability to reduce myocardial infarct size and improve prognosis. On the other hand, there are several clinical trials, in particular those conducted in the setting of elective cardiac surgery, that have failed to show any benefit of RIC. These contradictory data indicate that there is insufficient understanding of the mechanisms underlying RIC. RIC is now known to signal indiscriminately, protecting not only the heart, but also other organs. In particular, experimental studies have demonstrated that it is able to reduce infarct size in an acute ischaemic stroke model. However, the mechanisms underlying RIC-induced neuroprotection are even less well understood than for cardioprotection. The existence of bidirectional feedback interactions between the heart and the brain suggests that the mechanisms of RIC-induced neuroprotection and cardioprotection should be studied as a whole. This review, therefore, addresses the topic of the neural component of the RIC mechanism.
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Affiliation(s)
- Marina V Basalay
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK
| | - Sean M Davidson
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK
| | - Andrey V Gourine
- Department of Cardiology, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Derek M Yellon
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK.
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Neto OB, de Sordi CC, da Mota GR, Marocolo M, Chriguer RS, da Silva VJD. Exercise training improves hypertension-induced autonomic dysfunction without influencing properties of peripheral cardiac vagus nerve. Auton Neurosci 2017; 208:66-72. [PMID: 28964689 DOI: 10.1016/j.autneu.2017.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 09/13/2017] [Accepted: 09/13/2017] [Indexed: 01/10/2023]
Abstract
We examined the vagal transfer function of autonomic heart rate (HR) control in anesthetized sedentary and exercise-trained Spontaneously Hypertensive Rats (SHR). To this end, male SHR and Wystar-Kyoto (WKY) rats with 48-50weeks of age-old were divided into 4 groups: sedentary (SHRS, n=12) and trained (SHRT, n=14) hypertensive rats, sedentary (WKYS, n=13) and trained (WKYT, n=13) normotensive rats. The trained groups were submitted to swimming protocol for 9weeks. Blood pressure (BP), HR, HR variability (HRV), BP variability (BPV), baroreflex sensitivity and cardiac tonus were recorded in baseline conditions. Following, electric stimulation of peripheral vagus nerve was performed in anesthetized conditions. Resting bradycardia was observed in SHRT and WKYT when compared to their respective sedentary groups (p<0.001). The BP was lower in SHRT than in SHRS (p<0.001). The SHRT and WKYT rats showed higher baroreflex-mediated tachycardia values when compared to their respective sedentary counterparts (p<0.001). Baroreflex bradycardic response in SHRT was higher than in SHRS (p<0.005). The SHRT and WKYT rats showed a decreased sympathetic activity in comparison to their respective sedentary groups (p<0.05). The cardiac vagal tonus was higher in SHRT than in SHRS (p<0.05). Regarding the dynamic transducer properties of peripheral vagus nerve to the heart no difference was observed among the groups. In conclusion, our results demonstrate that exercise training decreased BP in SHR and improved cardiovascular autonomic balance to the heart without changes in transduction properties of peripheral cardiac vagus nerve.
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Affiliation(s)
- Octávio Barbosa Neto
- Human Performance and Sport Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro, Uberaba, Brazil; Department of Physiology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Brazil.
| | - Carla Cristina de Sordi
- Department of Endocrinology and Metabolism, Postgraduate Course on Health Science, Federal University of Triângulo Mineiro, Uberaba, Brazil
| | - Gustavo Ribeiro da Mota
- Human Performance and Sport Research Group, Department of Sport Sciences, Federal University of Triângulo Mineiro, Uberaba, Brazil
| | - Moacir Marocolo
- Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | | | - Valdo José Dias da Silva
- Department of Physiology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Brazil
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Beneficial Effect of Moderate Exercise in Kidney of Rat after Chronic Consumption of Cola Drinks. PLoS One 2016; 11:e0152461. [PMID: 27031710 PMCID: PMC4816544 DOI: 10.1371/journal.pone.0152461] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 03/15/2016] [Indexed: 01/25/2023] Open
Abstract
Aim The purpose of this study was to investigate the effect of moderate intensity exercise on kidney in an animal model of high consumption of cola soft drinks. Methods Forty-eight Wistar Kyoto rats (age: 16 weeks; weight: 350–400 g) were assigned to the following groups: WR (water runners) drank water and submitted to aerobic exercise; CR (cola runners) drank cola and submitted to aerobic exercise; WS (water sedentary) and CS (cola sedentary), not exercised groups. The aerobic exercise was performed for 5 days per week throughout the study (24 weeks) and the exercise intensity was gradually increased during the first 8 weeks until it reached 20 meters / minute for 30 minutes. Body weight, lipid profile, glycemia, plasma creatinine levels, atherogenic index of plasma (AIP) and systolic blood pressure (SBP) were determined. After 6 months all rats were sacrificed. A kidney histopathological score was obtained using a semiquantitative scale. Glomerular size and glomerulosclerosis were estimated by point-counting. The oxidative stress and pro-inflammatory status were explored by immunohistochemistry. A one way analysis of variance (ANOVA) with Tukey-Kramer post-hoc test or the Kruskal-Wallis test with Dunn’s post-hoc test was used for statistics. A value of p < 0.05 was considered significant. Results At 6 months, an increased consumption of cola soft drink was shown in CS and CR compared with water consumers (p<0.0001). Chronic cola consumption was associated with increased plasma triglycerides, AIP, heart rate, histopathological score, glomerulosclerosis, oxidative stress and pro-inflammatory status. On the other hand, moderate exercise prevented these findings. No difference was observed in the body weight, SBP, glycemia, cholesterol and plasma creatinine levels across experimental groups. Conclusions This study warns about the consequences of chronic consumption of cola drinks on lipid metabolism, especially regarding renal health. Additionally, these findings emphasize the protective role of exercise training on renal damage.
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Assessing autonomic response to repeated bouts of exercise below and above respiratory threshold: insight from dynamic analysis of RR variability. Eur J Appl Physiol 2014; 114:1269-79. [PMID: 24615057 DOI: 10.1007/s00421-014-2858-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 02/15/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE The dynamics of vagal withdrawal and reactivation during pulses of exercise are described by indices computed from heart period (RR) variations, which may be sensitive to duration and load. We sought to assess the consistency over time of these indices, which is not well established. METHODS We recorded continuous electrocardiogram during series of five successive bouts (2 min) of submaximal exercise (at 40 and 70% of VO(2peak), different days). Autonomic responsiveness was inferred from quantification of onset and offset of RR dynamics of each individual bout. Consistency of results was assessed with intraclass correlation (ICC). RESULTS During exercise bouts, indices from tachycardic and bradycardic transients reach lower levels in response to higher exercise loads and progression of exercise. There is a significant effect of load and time (i.e., bout repetition) for all examined variables, with a clear interaction. However, no interaction is observed with the 60 s change in heart rate. ICC analysis demonstrates that various indices are characterized by large differences in stability, which is generally greater within the same day (e.g., tachyspeed ICC at 40% = 0.751, at 70% = 0.704, both days = 0.633; bradyspeed, respectively, = 0.545, 0.666, 0.516). CONCLUSIONS Intensity and duration of exercise modulate vagal withdrawal and reactivation. Analysis of RR variations, during successive brief exercise bouts at lower and higher intensity, ensures a consistency similar to that reported for autonomic cardiac regulation at rest and might guide the choice among multiple indices that are obtained from the tachogram.
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Kawada T, Li M, Shimizu S, Kamiya A, Uemura K, Turner MJ, Mizuno M, Sugimachi M. High-frequency dominant depression of peripheral vagal control of heart rate in rats with chronic heart failure. Acta Physiol (Oxf) 2013; 207:494-502. [PMID: 23279751 DOI: 10.1111/apha.12055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 12/02/2012] [Accepted: 12/15/2012] [Indexed: 12/13/2022]
Abstract
AIM To examine whether dynamic characteristics of the peripheral vagal control of heart rate (HR) are altered in chronic heart failure (CHF). METHODS The right vagal nerve was electrically stimulated according to a binary white noise signal, and the transfer function from vagal nerve stimulation (VNS) to HR was estimated in the frequency range from 0.01 to 1 Hz in five control rats and five CHF rats under anaesthetized conditions. The rate of VNS was changed among 10, 20 and 40 Hz. RESULTS A multiple linear regression analysis indicated that the increase in the VNS rate augmented the ratio of the high-frequency (HF) gain to the steady-state gain in the control group but not in the CHF group. As a result, the dynamic gain of the transfer function in the frequencies near 1 Hz decreased more in the CHF group than in the control group. CONCLUSION Changes in the dynamic characteristics of the peripheral vagal control of HR may contribute to the manifestation of decreased HF components of HR variability observed in CHF.
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Affiliation(s)
- T. Kawada
- Department of Cardiovascular Dynamics; National Cerebral and Cardiovascular Center; Osaka; Japan
| | - M. Li
- Department of Cardiovascular Dynamics; National Cerebral and Cardiovascular Center; Osaka; Japan
| | - S. Shimizu
- Department of Cardiovascular Dynamics; National Cerebral and Cardiovascular Center; Osaka; Japan
| | - A. Kamiya
- Department of Cardiovascular Dynamics; National Cerebral and Cardiovascular Center; Osaka; Japan
| | - K. Uemura
- Department of Cardiovascular Dynamics; National Cerebral and Cardiovascular Center; Osaka; Japan
| | - M. J. Turner
- Department of Cardiovascular Dynamics; National Cerebral and Cardiovascular Center; Osaka; Japan
| | - M. Mizuno
- Department of Health Care Sciences; University of Texas Southwestern Medical Center; Dallas; TX; USA
| | - M. Sugimachi
- Department of Cardiovascular Dynamics; National Cerebral and Cardiovascular Center; Osaka; Japan
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Grant CC, Viljoen M, Janse van Rensburg DC, Wood PS. Heart rate variability assessment of the effect of physical training on autonomic cardiac control. Ann Noninvasive Electrocardiol 2012; 17:219-29. [PMID: 22816541 DOI: 10.1111/j.1542-474x.2012.00511.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The effect of exercise interventions on autonomic nervous system (ANS) control of the heart by heart rate variability (HRV) is often investigated in just one position. It was hypothesized that results of exercise-induced changes on ANS are dependent on body position and that it is possible to distinguish between exercise induced changes in vagal and sympathetic influence by taking measurements in different body positions. METHODS One hundred eighty-three (male = 100, female = 83) healthy volunteers, between 18 and 22 years, participated in a prospective twelve week medium to high intensity exercise intervention study with a self-control design. The influence of the exercise intervention was investigated on supine, rising, and standing as well as on the orthostatic response. Time domain, frequency domain and nonlinear (Poincaré) HRV analysis were performed. RESULTS The exercise intervention lead to a significant increase (P < 0.05) in vagal influence during supine, rising, and standing. Sympathetic control in the supine position was decreased and increased during rising and standing. In the initial orthostatic response to rising from the supine position, the exercise intervention lead to increased (P < 0.05) vagal withdrawal as well as increased sympathetic control. The orthostatic response measured as the difference between standing and supine indicated only an exercise induced increase in sympathetic control. CONCLUSIONS Exercise-induced changes in sympathetic and parasympathetic ANS control differ, depending on posture and period of measurement. Exercise induced changes in parasympathetic and sympathetic outflow, respectively, can be extracted from measurements from supine, through the orthostatic response, to standing, thereby detecting changes in ANS that are otherwise obscured.
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Affiliation(s)
- Catharina C Grant
- Section Sports Medicine, Faculty of Health Sciences, University of Pretoria, South Africa.
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Kawada T, Shimizu S, Li M, Kamiya A, Uemura K, Sata Y, Yamamoto H, Sugimachi M. Contrasting effects of moderate vagal stimulation on heart rate and carotid sinus baroreflex-mediated sympathetic arterial pressure regulation in rats. Life Sci 2011; 89:498-503. [DOI: 10.1016/j.lfs.2011.07.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 06/16/2011] [Accepted: 07/19/2011] [Indexed: 10/17/2022]
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