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de Souza JA, Becker LK, Batista MAC, de Assis Braga DC, Gomes PM, Alzamora AC, Vieira MAR, de Lima WG, Andrade MGC, de Lima Sanches B, Totou NL, de Assis Dias Martins Júnior F, de Oliveira LB, Antunes VR, Cardoso LM. Swimming training improves cardiovascular autonomic dysfunctions and prevents renal damage in rats fed a high-sodium diet from weaning. Exp Physiol 2020; 106:412-426. [PMID: 33347659 DOI: 10.1113/ep088892] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 12/03/2020] [Indexed: 01/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? How does swimming exercise training impact hydro-electrolytic balance, renal function, sympathetic contribution to resting blood pressure and cerebrospinal fluid (CSF) [Na+ ] in rats fed a high-sodium diet from weaning? What is the main finding and its importance? An exercise-dependent reduction in blood pressure was associated with decreased CSF [Na+ ], sympathetically driven vasomotor tonus and renal fibrosis indicating that the anti-hypertensive effects of swimming training in rats fed a high-sodium diet might involve neurogenic mechanisms regulated by sodium levels in the CSF rather than changes in blood volume. ABSTRACT High sodium intake is an important factor associated with hypertension. High-sodium intake with exercise training can modify homeostatic hydro-electrolytic balance, but the effects of this association are mostly unknown. In this study, we sought to investigate the effects of swimming training (ST) on cerebrospinal fluid (CSF) Na+ concentration, sympathetic drive, blood pressure (BP) and renal function of rats fed a 0.9% Na+ (equivalent to 2% NaCl) diet with free access to water for 22 weeks after weaning. Male Wistar rats were assigned to two cohorts: (1) fed standard diet (SD) and (2) fed high-sodium (HS) diet. Each cohort was further divided into trained and sedentary groups. ST normalised BP levels of HS rats as well as the higher sympathetically related pressor activity assessed by pharmacological blockade of ganglionic transmission (hexamethonium). ST preserved the renal function and attenuated the glomerular shrinkage elicited by HS. No change in blood volume was found among the groups. CSF [Na+ ] levels were higher in sedentary HS rats but were reduced by ST. Our findings showed that ST effectively normalised BP of HS rats, independent of its effects on hydro-electrolytic balance, which might involve neurogenic mechanisms regulated by Na+ levels in the CSF as well as renal protection.
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Affiliation(s)
| | - Lenice Kappes Becker
- Physical Education School at the Federal University of Ouro Preto, Ouro Preto, MG, Brazil
| | | | | | - Paula Magalhães Gomes
- Deptartment of Physiology and Biophysics, ICB; University of São Paulo, São Paulo, SP, Brazil
| | - Andréia Carvalho Alzamora
- Department of Biological Sciences, ICEB at the Federal University of Ouro Preto, Ouro Preto, MG, Brazil
| | | | - Wanderson Geraldo de Lima
- Department of Biological Sciences, ICEB at the Federal University of Ouro Preto, Ouro Preto, MG, Brazil
| | | | - Bruno de Lima Sanches
- Department of Physiology and Biophysics, ICB; Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Nádia Lúcia Totou
- Department of Biological Sciences, ICEB at the Federal University of Ouro Preto, Ouro Preto, MG, Brazil
| | | | | | - Vagner Roberto Antunes
- Deptartment of Physiology and Biophysics, ICB; University of São Paulo, São Paulo, SP, Brazil
| | - Leonardo Máximo Cardoso
- Department of Biological Sciences, ICEB at the Federal University of Ouro Preto, Ouro Preto, MG, Brazil
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Combination of Exercise Training and SOD Mimetic Tempol Enhances Upregulation of Nitric Oxide Synthase in the Kidney of Spontaneously Hypertensive Rats. Int J Hypertens 2020; 2020:2142740. [PMID: 33145105 PMCID: PMC7596428 DOI: 10.1155/2020/2142740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 08/12/2020] [Accepted: 09/30/2020] [Indexed: 12/02/2022] Open
Abstract
Both exercise training (Ex) and superoxide dismutase (SOD) mimetic tempol have antihypertensive and renal protective effects in rodent models of several hypertensions. We recently reported that Ex increases nitric oxide (NO) production and the expression levels of endothelial and neuronal NO synthase (eNOS and nNOS) in the kidney and aorta of the spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto rats (WKY). We also found that endogenous hydrogen peroxide (H2O2) upregulates the expression levels of eNOS and nNOS in SHR. To elucidate the mechanism of the Ex-upregulated NO system in the kidney, we examined the additive effect of Ex and tempol on the renal NO system in SHR and WKY. Our data showed that, in SHR, both Ex and tempol increase the levels of H2O2 and nitrate/nitrite (NOx) in plasma and urine. We also observed an increased renal NOS activity and upregulated expression levels of eNOS and nNOS with decreased NADPH oxidase activity. The effects of the combination of Ex and tempol on these variables were cumulate in SHR. On the other hand, we found that Ex increases these variables with increased renal NADPH oxidase activity, but tempol did not change these variables or affect the Ex-induced upregulation in the activity and expression of NOS in WKY. The SOD activity in the kidney and aorta was activated by tempol only in SHR, but not in WKY; whereas Ex increased SOD activity only in the aorta in both SHR and WKY. These results indicate that Ex-induced endogenous H2O2 produced in the blood vessel and other organs outside of the kidney may be carried to the kidney by blood flow and stimulates the NO system in the kidney.
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Jakovljevic B, Plecevic S, Petkovic A, Turnic TN, Milosavljevic I, Radoman K, Srejovic I. Is 3 Weeks of Exercise Enough to Change Blood Pressure and Cardiac Redox State in Hypertensive Rats? SERBIAN JOURNAL OF EXPERIMENTAL AND CLINICAL RESEARCH 2019. [DOI: 10.1515/sjecr-2017-0049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Abstract
The investigation was aimed to evaluate the effects of 3-weeks swimming exercise on blood pressure and redox status in high-salt-induced hypertensive rats. Male Wistar albino rats (n=40, 6 weeks old) were divided into 4 groups: 1. hypertensive rats that swam for 3 weeks; 2. sedentary hypertensive control rats; 3. normotensive rats that swam for 3 weeks; 4. sedentary normotensive control rats. Hypertensive animals were on high concentrated sodium (8% NaCl) solution for 4 weeks (period of induction of hypertension). After sacrificing, hearts were isolated and perfused according to Langendorff technique at gradually increased coronary per-fusion pressure from 40–120 cmH2O. The oxidative stress markers were determined in coronary venous effluent: the index of lipid peroxidation (measured as TBARS), nitrites (NO2
−), superoxide anion radical (O2
−) and hydrogen peroxide (H2O2). Swimming did not lead to significant changes in levels of TBARS, NO2
−, O2
− in any of compared groups while levels of H2O2 were significantly higher in swimming hyper-tensive group comparing to swimming normotensive group at coronary perfusion pressure of 80–120 cmH2O. Our results indicate that the short-term swimming start to reduce blood pressure. In addition it seems that this type of swimming duration does not promote cardiac oxidative stress damages.
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Affiliation(s)
| | - Sasa Plecevic
- Sports Medicine Association of Serbia , Belgrade , Serbia
| | - Anica Petkovic
- University of Kragujevac , Faculty of Medical Sciences, Department of Pharmacy , Kragujevac , Serbia
| | - Tamara Nikolic Turnic
- University of Kragujevac , Faculty of Medical Sciences, Department of Pharmacy , Kragujevac , Serbia
| | - Isidora Milosavljevic
- University of Kragujevac , Faculty of Medical Sciences, Department of Pharmacy , Kragujevac , Serbia
| | | | - Ivan Srejovic
- University of Kragujevac , Faculty of Medical Sciences, Department of Physiology , Kragujevac , Serbia
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4
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Guers JJ, Kasecky-Lardner L, Farquhar WB, Edwards DG, Lennon SL. Voluntary wheel running prevents salt-induced endothelial dysfunction: role of oxidative stress. J Appl Physiol (1985) 2018; 126:502-510. [PMID: 30571282 DOI: 10.1152/japplphysiol.00421.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Diets high in salt can lead to endothelial dysfunction, a nontraditional risk factor for cardiovascular disease (CVD). Exercise is known to reduce CVD risk; however, it remains unknown whether chronic physical activity can attenuate salt-induced endothelial dysfunction independent of blood pressure (BP) and whether these changes are due to an upregulation in endogenous antioxidants. Eight-week-old Sprague-Dawley rats were fed either a normal (NS; 0.49%)- or a high (HS; 4.0%)-salt diet and further divided into voluntary wheel running (NS-VWR, HS-VWR) and sedentary (NS, HS) groups for 6 wk. BP was measured weekly and remained unchanged within groups ( P = 0.373). Endothelium-dependent relaxation (EDR) was impaired in the femoral artery of HS compared with NS (38.6 ± 4.0% vs. 65.0 ± 3.6%; P = 0.013) animals, whereas it was not different between NS and HS-VWR (73.4 ± 6.4%; P = 0.273) animals. Incubation with the antioxidants TEMPOL ( P = 0.024) and apocynin ( P = 0.013) improved EDR in HS animals, indicating a role for reactive oxygen species (ROS). Wheel running upregulated the antioxidant superoxide dismutase-2 (SOD-2) ( P = 0.011) under HS conditions and lowered NOX4 and Gp91-phox, two subunits of NADPH oxidase. Wheel running elevated phosphorylated endothelial nitric oxide synthase (eNOS) ( P = 0.014) in HS-fed rats, demonstrating a role for physical activity and eNOS activity under HS conditions. Finally, there was a reduction in EDR ( P = 0.038) when femoral arteries from NS-VWR animals were incubated with TEMPOL or apocynin, suggesting there may be a critical level of ROS needed to maintain endothelial function. In summary, physical activity protected HS-fed rats from reductions in endothelial function, likely through increased SOD-2 levels and reduced oxidative stress. NEW & NOTEWORTHY Our data suggest that voluntary wheel running can prevent impairments in endothelium-dependent relaxation in the femoral artery of rats fed a high-salt diet. This appears to be independent of blood pressure and mediated through a decrease in expression of NADPH oxidases as a result of physical activity. These data suggest that increased chronic physical activity can protect the vasculature from a diet high in salt, likely through a reduction in oxidative stress.
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Affiliation(s)
- John J Guers
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | | | - William B Farquhar
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware.,Department of Biological Sciences, University of Delaware , Newark, Delaware
| | - David G Edwards
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware.,Department of Biological Sciences, University of Delaware , Newark, Delaware
| | - Shannon L Lennon
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
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5
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Ito D, Ito O, Cao P, Mori N, Suda C, Muroya Y, Takashima K, Ito S, Kohzuki M. Effects of exercise training on nitric oxide synthase in the kidney of spontaneously hypertensive rats. Clin Exp Pharmacol Physiol 2013; 40:74-82. [DOI: 10.1111/1440-1681.12040] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 11/30/2013] [Accepted: 12/03/2012] [Indexed: 02/06/2023]
Affiliation(s)
- Daisuke Ito
- Department of Internal Medicine and Rehabilitation Science; Tohoku University Graduate School of Medicine; Sendai; Japan
| | | | - Pengyu Cao
- Department of Internal Medicine and Rehabilitation Science; Tohoku University Graduate School of Medicine; Sendai; Japan
| | | | - Chihiro Suda
- Department of Internal Medicine and Rehabilitation Science; Tohoku University Graduate School of Medicine; Sendai; Japan
| | - Yoshikazu Muroya
- Department of Internal Medicine and Rehabilitation Science; Tohoku University Graduate School of Medicine; Sendai; Japan
| | - Kenta Takashima
- Department of Internal Medicine and Rehabilitation Science; Tohoku University Graduate School of Medicine; Sendai; Japan
| | - Sadayoshi Ito
- Center for Advanced Integrated Renal Science; Tohoku University Graduate School of Medicine; Sendai; Japan
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Morris RT, Fine DM, Lees SJ, Booth FW, Link CD, Ferrario CM, Stump CS, Sowers JR. Exercise training prevents development of cardiac contractile dysfunction in hypertensive TG (mREN-2)27 rats. ACTA ACUST UNITED AC 2012; 1:393-9. [PMID: 19050745 DOI: 10.1016/j.jash.2007.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Angiotensin-II (Ang-II) contributes to cardiac remodeling and left ventricular dysfunction. In contrast, exercise may have beneficial effects on left ventricular structure and function. METHODS AND RESULTS We investigated the effects of low-intensity exercise training (ET) on in vivo cardiac function in hypertensive TG (mREN-2)27 rats (Ren-2) which develop left ventricular hypertrophy and dysfunction. Ren-2 rats and Sprague Dawley (SD) controls (4-5 weeks) began treadmill exercise every day for 5-6 weeks. Cardiac function was evaluated by echocardiography. Cardiac output and stroke volume were increased by ET in both 8-wk-old SD and Ren-2. Slope of mitral deceleration time, a non-invasive measure of diastolic function, was lower in the Ren-2 rats, but not changed by ET. LV collagen deposition, as assessed by hydroxyproline assay, was not affected by rat strain or ET at 10-11 weeks of age. Left ventricular B-type natriuretic peptide mRNA levels were higher in the Ren-2 rats (100%), but not affected by ET. Both alpha (~14.5 fold) and beta (~2.5 fold) myosin heavy chain mRNA were higher in the LV of Ren-2 rats (p < 0.05), but were not changed by ET. CONCLUSION Low-intensity exercise training in Ren-2 rats, a model of Ang-II-mediated hypertension, maintains cardiac index and stroke volume in the presence of impaired diastolic function at 8 wks of age.
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Affiliation(s)
- R Tyler Morris
- Department of Medical Pharmacology and Physiology, School of Medicine
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7
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Cardoso AM, Martins CC, Fiorin FDS, Schmatz R, Abdalla FH, Gutierres J, Zanini D, Fiorenza AM, Stefanello N, Serres JDDS, Carvalho F, Castro VP, Mazzanti CM, Royes LFF, Belló-Klein A, Goularte JF, Morsch VM, Bagatini MD, Schetinger MRC. Physical training prevents oxidative stress in L-NAME-induced hypertension rats. Cell Biochem Funct 2012; 31:136-51. [DOI: 10.1002/cbf.2868] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/26/2012] [Accepted: 07/30/2012] [Indexed: 01/01/2023]
Affiliation(s)
- Andréia Machado Cardoso
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Caroline Curry Martins
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Fernando da Silva Fiorin
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Roberta Schmatz
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Fátima Husein Abdalla
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Jessié Gutierres
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Daniela Zanini
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Amanda Maino Fiorenza
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Naiara Stefanello
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Jonas Daci da Silva Serres
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Fabiano Carvalho
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Verônica Paiva Castro
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Cinthia Melazzo Mazzanti
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Luiz Fernando Freire Royes
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | - Adriane Belló-Klein
- Health Basic Sciences Institut, Department of Physiology; Federal University of Rio Grande do Sul; Porto Alegre; RS; Brazil
| | - Jeferson Ferraz Goularte
- Health Basic Sciences Institut, Department of Physiology; Federal University of Rio Grande do Sul; Porto Alegre; RS; Brazil
| | - Vera Maria Morsch
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
| | | | - Maria Rosa Chitolina Schetinger
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry of the Center of Natural and Exact Sciences; Federal University of Santa Maria; Santa Maria; RS; Brazil
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8
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Cardoso AM, Bagatini MD, Martins CC, Abdalla FH, Zanini D, Schmatz R, Gutierres J, Pimentel VC, Thomé G, Leal CAM, Vieira JM, Stefanello N, da Silva Fiorin F, Baldissareli J, Royes LFF, Klein AB, Morsch VM, Schetinger MRC. Exercise training prevents ecto-nucleotidases alterations in platelets of hypertensive rats. Mol Cell Biochem 2012; 371:147-56. [PMID: 22915168 DOI: 10.1007/s11010-012-1431-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 08/03/2012] [Indexed: 11/30/2022]
Abstract
In this study, we investigated the effect of 6 weeks of swimming training on the ecto-nucleotidase activities and platelet aggregation from rats that developed hypertension in response to oral administration of L-NAME. The rats were divided into four groups: control (n = 10), exercise (n = 10), L-NAME (n = 10), and exercise L-NAME (n = 10). The animals were trained five times per week in an adapted swimming system for 60 min with a gradual increase of the workload up to 5 % of animal's body weight. The results showed an increase in ATP, ADP, AMP, and adenosine hydrolysis, indicating an augment in NTPDase (from 35.3 ± 8.1 to 53.0 ± 15.1 nmol Pi/min/mg protein for ATP; and from 21.7 ± 7.0 to 46.4 ± 15.6 nmol Pi/min/mg protein for ADP as substrate), ecto-5'-nucleotidase (from 8.0 ± 5.7 to 28.1 ± 6.9 nmol Pi/min/mg protein), and ADA (from 0.8 ± 0.5 to 3.9 ± 0.8 U/L) activities in platelets from L-NAME-treated rats when compared to other groups (p < 0.05). A significant augment on platelet aggregation in L-NAME group was also observed. Exercise training was efficient in preventing these alterations in the exercise L-NAME group, besides showing a significant hypotensive effect. In conclusion, our results clearly indicated a protector action of moderate intensity exercise on nucleotides and nucleoside hydrolysis and on platelet aggregation, which highlights the exercise training effect to avoid hypertension complications related to ecto-nucleotidase activities.
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Affiliation(s)
- Andréia Machado Cardoso
- Post-Graduation Program in Toxicological Biochemistry, Department of Chemistry, Center of Natural and Exact Sciences, Federal University of Santa Maria, Santa Maria, RS, Brazil
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9
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Kuru O, Şentürk ÜK, Gülkesen H, Demir N, Gündüz F. Physical Training Increases Renal Injury in Rats with Chronic NOS Inhibition. Ren Fail 2009. [DOI: 10.1081/jdi-65388] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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10
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Libonati JR, Gaughan JP. Low-Intensity Exercise Training Improves Survival in Dahl Salt Hypertension. Med Sci Sports Exerc 2006; 38:856-8. [PMID: 16672837 DOI: 10.1249/01.mss.0000218129.03008.ab] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The present study examined whether exercise training could increase survival in a rodent model of salt-sensitive hypertension. METHODS Male, inbred Dahl salt-sensitive rats arriving at 8 wk of age were randomly divided into a sedentary control group (N = 5) or an exercise-trained group (N = 8). Exercise training consisted of running 20 m.min(-1), 0% incline, 60 min.d(-1), 5 d.wk(-1) on a motorized driven treadmill. On arrival, animals were fed a low-salt diet (0.12% NaCl) during a 1-wk acclimatization period. At the end of this period, all rats were then fed a high-salt diet (7.8% NaCl) for the remainder of the study. Arterial systolic blood pressure (SBP) was measured via the tail-cuff method. RESULTS Systolic blood pressure (SBP) measured on the low salt diet was similar between groups. After 2 wk of a high-salt diet, SBP was similarly significantly elevated in both control and exercise groups relative to the low salt diet. Kaplan-Meier analysis showed that exercise training increased survival (P < 0.02) with an approximate 30% increase in the mean days survived with exercise training (P < 0.02). CONCLUSION These data suggest that exercise training is an important intervention for salt-sensitive hypertension and that the enhanced survival observed with exercise training appears to be independent of training-induced SBP lowering effects.
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Affiliation(s)
- Joseph R Libonati
- Department of Kinesiology, Temple University, Philadelphia, PA 19122, USA.
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11
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Akiyama K, Sutoo D. Rectifying effect of exercise on hypertension in spontaneously hypertensive rats via a calcium-dependent dopamine synthesizing system in the brain. Brain Res 1999; 823:154-60. [PMID: 10095021 DOI: 10.1016/s0006-8993(99)01171-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The effect of exercise on blood pressure in spontaneously hypertensive rats (SHR) was investigated assuming a mechanism involving calcium-dependent dopamine synthesis in the brain. Male SHR (13 weeks of age) were forced to run for 1 h at a speed of 10 m/min using a programmed motor-driven wheel cage. Systolic blood pressure was reduced after running, and this effect of exercise was decreased by prior intracerebroventricular administration of EDTA (1 nmol/rat), alpha-methyltyrosine (inhibitor of tyrosine hydroxylase, 1 mg/rat), sulpiride (D2 receptor antagonist, 50 microg/rat) or eticlopride (D2 receptor antagonist, 100 microg/rat), but was not changed by administration of SCH 23390 (D1 receptor antagonist, 30 microg/rat). Also, the calcium levels in the serum and brain were increased by exercise. Combining these results with our previous reports, it is suggested that exercise leads to an increase in the serum calcium level and subsequently an increase in the brain calcium level. This, in turn, leads to increased brain dopamine synthesis through a calmodulin-dependent system, with the increased dopamine levels inhibiting sympathetic nerve activity via the dopamine D2 receptor in the brain and causing a reduction in blood pressure.
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Affiliation(s)
- K Akiyama
- Institute of Medical Science, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
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12
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Sutoo D, Akiyama K. Regulation of blood pressure with calcium-dependent dopamine synthesizing system in the brain and its related phenomena. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1997; 25:1-26. [PMID: 9370048 DOI: 10.1016/s0165-0173(97)00018-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effects of calcium on blood pressure regulation remain controversial. Although the mechanism by which calcium increases blood pressure when it is given intravenously and acutely has been elucidated, that by which calcium reduces blood pressure when it is supplemented chronically and slightly through daily diet is unclear. From a number of animal experiments concerning the effects of calcium on blood pressure, we believe that calcium ions have two separate roles in the regulation of blood pressure through both central and peripheral systems: (1) calcium ions reduce blood pressure through a central, calcium/calmodulin-dependent dopamine-synthesizing system and (2) calcium ions increase blood pressure through an intracellular, calcium-dependent mechanism in the peripheral vasculature. These concepts were applied to elucidate the mechanisms underlying hypertension in spontaneously hypertensive rats (SHR) and changes in blood pressure in other experimental animals, and the following conclusions were reached. The decrease of the serum calcium level in spontaneously hypertensive rats (SHR) causes a decrease in calcium/calmodulin-dependent dopamine synthesis in the brain. The subsequent low level of brain dopamine induces hypertension. The increase in susceptibility to epileptic convulsions and the occurrence of hypertension in epileptic mice (El mice) may be linked through a lowering of calcium-dependent dopamine synthesis in the brain, and epilepsy and hypertension may be associated. Exercise leads to increases in calcium-dependent dopamine synthesis in the brain, and the increased dopamine levels induce physiological changes, including a decrease in blood pressure. Cadmium which is not distinguished from calcium by calmodulin, activates calmodulin-dependent functions in the brain, and increased dopamine levels may decrease blood pressure. In this report, our studies are considered in light of reports from many other laboratories.
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Affiliation(s)
- D Sutoo
- Institute of Medical Science, University of Tsukuba, Japan.
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Abstract
Exercise has multiple beneficial actions, both in normal subjects and in patients with coronary artery disease, which can be cardioprotective. Apart from reducing known risk factors and protecting against their deleterious effects, exercise also reduces the risk of coronary artery disease by increasing cardiovascular fitness. The exact contribution of each of these mechanisms in reducing coronary artery disease morbidity and mortality is unclear. Although fitness may be desirable, much of the cardioprotection can be achieved through increased leisure time and recreational physical activity. The risk-benefit ratio is very much in favor of moderate intensity exercise. Even in the absence of a controlled trial, the available evidence suggests that efforts to encourage physical activity are justified.
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Affiliation(s)
- Y Chandrashekhar
- Department of Cardiology, Postgraduate Institute of Medical Education & Research, Chandigarh, India
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14
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Melby CJ, Sanders BJ, Johnson AK. The effects of exercise training on salt-induced hypertension in the borderline hypertensive rat. CLINICAL AND EXPERIMENTAL HYPERTENSION. PART A, THEORY AND PRACTICE 1991; 13:865-72. [PMID: 1773519 DOI: 10.3109/10641969109042091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The borderline hypertensive rat (BHR) develops severe hypertension when chronically subjected to either a high salt diet or behavioral stress. Previous research has shown that daily exercise can attenuate the development of stress-induced hypertension in the BHR. The current study sought to determine whether exercise might also exert a similar protective effect on salt-induced hypertension. Two groups of BHR were placed on a high salt diet for 20 weeks; one of the groups also engaged in daily swim training for the entire 20 week period. A third group of BHR served as maturation controls. At the end of the experimental period, direct measurement of heart rate in conscious subjects revealed a significant resting bradycardia in the trained group on a high salt diet but no significant group differences with respect to blood pressure level. Cardiovascular responses to an episode of acute stress revealed that BHR are capable of elevating pressure in response to a novel stressor after swim training. These observations suggest that exercise may be an environmental intervention capable of increasing cardiovascular responses to acute stressors.
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Affiliation(s)
- C J Melby
- Department of Psychology, University of Iowa, Iowa City 52242
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Wei JY, Li Y, Lincoln T, Grossman W, Mendelowitz D. Chronic exercise training protects aged cardiac muscle against hypoxia. J Clin Invest 1989; 83:778-84. [PMID: 2921320 PMCID: PMC303747 DOI: 10.1172/jci113957] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
To test the hypothesis that chronic exercise may improve tolerance to hypoxia in aged hearts, we compared cardiac function of exercised rats to that of their age-matched, nonexercised controls. Right ventricular papillary muscles were removed from young adult (9 mo) and old (24-26 mo) male Fischer 344 rats that were chronically exercised on a rodent treadmill and from their age-matched, nonexercised controls. During isometric contraction, hypoxia depressed contraction and relaxation in all muscles, but to a lesser extent in the exercised groups. A significant exercise effect was observed in the following variables: the maximum developed tension, the maximum rate of tension development, the maximum rate of tension decline, and the time required for the hypoxia to reduce maximum tension by 20%. The maximum rate of tension decline was more sensitive to hypoxia than was the maximum rate of tension development in all groups. Exercise also had an effect on the temperature dependence of cardiac performance during hypoxia. Thus, chronic exercise results in the preservation of both contraction and relaxation during hypoxia for aged as well as young adult hearts.
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Affiliation(s)
- J Y Wei
- Charles A Dana Research Institute, Beth Israel Hospital, Boston, MA 02215
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Jennings GL, Deakin G, Dewar E, Laufer E, Nelson L. Exercise, cardiovascular disease and blood pressure. CLINICAL AND EXPERIMENTAL HYPERTENSION. PART A, THEORY AND PRACTICE 1989; 11:1035-52. [PMID: 2529066 DOI: 10.3109/10641968909035390] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The "chronic" effect of exercise on blood pressure has been controversial and the debate has been confused by a large number of studies with inadequate methodology. Recent consistent findings in epidemiological, experimental and longitudinal intervention studies have suggested that a true antihypertensive effect which is independent of confounding effects of sodium intake, weight, etc. is more likely than not. Unlike some other measures of lowering blood pressure such as sodium restriction, alcohol moderation and some drugs, regular exercise is associated with beneficial effects on several risk factors and probably has an independent effect on cardiovascular mortality. The magnitude of the effect in previously sedentary subjects is greater than that of dietary measures which lower blood pressure except for weight reduction in the obese. Long-term effects on blood pressure are supported by evidence of a favourable influence on left ventricular hypertrophy. The mechanisms involved in the antihypertensive effect of exercise are unclear, but sympathetic withdrawal is one factor involved. Present evidence appears sufficient to include regular exercise amongst the useful therapies for hypertension.
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Affiliation(s)
- G L Jennings
- Clinical Research Unit, Alfred Hospital, Baker Medical Research Institute, Melbourne, Australia
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Hoffmann P, Friberg P, Ely D, Thorén P. Effect of spontaneous running on blood pressure, heart rate and cardiac dimensions in developing and established spontaneous hypertension in rats. ACTA PHYSIOLOGICA SCANDINAVICA 1987; 129:535-42. [PMID: 3591375 DOI: 10.1111/j.1748-1716.1987.tb08094.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The effect of chronic voluntary exercise on resting blood pressure and heart rate was measured in two different age groups of spontaneously hypertensive rats (SHR). In the younger group, left ventricular dimensions were also measured. The younger group was 9 weeks old at the start of the experiment and was in a period of rapid blood-pressure rise. The older group, 13 weeks old at the start of the experiment, already had established hypertension. During a period of 6 weeks, the animals ran spontaneously in wheels mounted in their cages and reached a maximum of 6-7 km per 24 h. Age-matched, sedentary SHR were used as controls. Both groups of runners showed a decrease in body weight in comparison to controls. The younger runners exhibited a delayed onset of hypertension. They also showed a significantly increased left ventricular (LV) end-diastolic volume for every measured end-diastolic pressure between 7.5 mmHg and 20 mmHg (P less than 0.05). This suggests the development of a structural growth-dependent increase of the internal LV radius while LV weight and wall-to-lumen ratio were largely unaltered in younger runners compared with controls. In SHR with established hypertension, physical training did not reduce arterial blood pressure but heart rate was significantly lower than in the controls. These results thus indicate that an early onset of physical exercise in SHR may delay the development of hypertension. In addition, a more favourable cardiac design could also be seen.
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Lawler JE, Sanders BJ, Chen YF, Nagahama S, Oparil S. Hypertension produced by a high sodium diet in the borderline hypertensive rat (BHR). CLINICAL AND EXPERIMENTAL HYPERTENSION. PART A, THEORY AND PRACTICE 1987; 9:1713-31. [PMID: 3436073 DOI: 10.3109/10641968709158968] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The effect of high dietary sodium (8%) on blood pressure in spontaneously hypertensive (SHR), borderline hypertensive (BHR), and normotensive Wistar-Kyoto (WKY) rats was determined weekly by tail cuff plethysmography for one week of baseline and four weeks of diet. After 4 weeks, significant elevations in systolic blood pressure were found in SHR and BHR groups, but not in WKY. BHR studied an additional 4 weeks showed a further progression of hypertension, reaching levels nearly equal to control SHR. Direct measurement of arterial pressure in conscious animals in their home cage confirmed the elevation in pressure in both SHR and BHR groups. Metabolic studies revealed that the high sodium diet reduced body weight in SHR and BHR strains, but not in WKY. Although both urinary volumes and sodium excretion values were significantly lower in SHR and BHR compared with WKY, this effect disappeared when adjustments for body weight were made. Plasma norepinephrine determinations revealed a significant response to cold stress in all groups. Plasma epinephrine was elevated in all strains in response to cold stress; however, a consistent statistical elevation was seen only in WKY. The BHR is discussed as a model for determining the triggers responsible for environmentally-induced hypertension.
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Affiliation(s)
- J E Lawler
- Physiology Program, University of Tennessee, Knoxville 37996
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Shyu BC, Thorén P. Circulatory events following spontaneous muscle exercise in normotensive and hypertensive rats. ACTA PHYSIOLOGICA SCANDINAVICA 1986; 128:515-24. [PMID: 3028042 DOI: 10.1111/j.1748-1716.1986.tb08007.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In previous studies we have shown that spontaneously hypertensive rats (SHR) develop a running behaviour and, secondary to the running behaviour, develop an endorphin-mediated analgesic effect. In the present study the role of the central endorphin system in the cardiovascular responses to spontaneous exercise in normotensive Wistar Kyoto rats (WKY) and SHR was investigated. The experimental design allowed us to record mean arterial pressure (MAP) and heart rate (HR) continuously for more than 1 week without interfering with the daily activities of the animals. They were active in running wheels during the dark period (19.00-07.00 h) and the activity was accompanied by a marked rise in HR. In SHR, a clear depression of blood pressure lasting for about for about 50 min was noted following each running period. The MAP during the post-running depression was 131.4 +/- 1.6 mmHg which was significantly lower than the pre-running control value (145.2 +/- 2.3 mmHg, P less than 0.01). In contrast, MAP in the post-running period in WKY was not significantly different from the pre-running values. In addition, the depression period of SHR had a mean post-running length of 49.7 +/- 3.4 min, which is significantly longer than in the WKYs (37.8 +/- 3.5 min, P less than 0.05). In control rats, naloxone infusion had no effect on blood pressure but a marked bradycardia was observed. In nine running SHR receiving a naloxone infusion, their MAP during the depression period was not different from the control pressure. Our study indicates that endorphin systems are involved in the regulating of blood pressure and HR during muscle exercise in SHR. These systems trigger the transient depression of blood pressure observed immediately after a running period in the SHR.
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Cox RH, Hubbard JW, Lawler JE, Sanders BJ, Mitchell VP. Exercise training attenuates stress-induced hypertension in the rat. Hypertension 1985; 7:747-51. [PMID: 4030045 DOI: 10.1161/01.hyp.7.5.747] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The ability of exercise training to block the generation of hypertension produced by chronic stress in the borderline hypertensive rat was tested. Twenty-three male borderline hypertensive rats, F1 offspring of spontaneously hypertensive and Wistar-Kyoto rats, were divided into three groups. Two groups (8 rats per group) were subjected to 2 hours of daily, predictable, uncontrollable tail shock for 12 weeks. One of these groups was also given 2 hours of daily swim stress (exercise trained). A third group served as a maturation control and received neither intervention (n = 7). After 12 weeks of stress, direct recording of blood pressure verified the pattern observed with tail cuff: shock only group, 180/118 +/- 3/3 mm Hg; exercise-trained and shocked group, 166/108 +/- 4/2 mm Hg; and control group, 160/98 +/- 6/4 mm Hg (mean +/- SEM). Systolic and diastolic blood pressures in the shock only group were significantly higher than in both the other groups (p less than 0.05). The control group differed from the exercise-trained and shocked group only in diastolic BP (p less than 0.05). During a short-term stress session plasma norepinephrine levels in the exercise-trained and shocked group were significantly lower than those in the shock only group (555 +/- 56 vs 776 +/- 84 pg/ml; p less than 0.05). These results indicate that an alteration of autonomic function resulted from the exercise training, but its contribution to the resistance of the exercise-trained and shocked rats to stress-induced hypertension is unclear.
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