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Prieto I, Segarra AB, Banegas I, Martínez-Cañamero M, Durán R, Vives F, Domínguez-Vías G, Ramírez-Sánchez M. Correlational Study of Aminopeptidase Activities between Left or Right Frontal Cortex versus the Hypothalamus, Pituitary, Adrenal Axis of Spontaneously Hypertensive Rats Treated with Hypotensive or Hypertensive Agents. Int J Mol Sci 2023; 24:16007. [PMID: 37958990 PMCID: PMC10647763 DOI: 10.3390/ijms242116007] [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: 09/07/2023] [Revised: 10/27/2023] [Accepted: 11/03/2023] [Indexed: 11/15/2023] Open
Abstract
It has been suggested that the neuro-visceral integration works asymmetrically and that this asymmetry is dynamic and modifiable by physio-pathological influences. Aminopeptidases of the renin-angiotensin system (angiotensinases) have been shown to be modifiable under such conditions. This article analyzes the interactions of these angiotensinases between the left or right frontal cortex (FC) and the same enzymes in the hypothalamus (HT), pituitary (PT), adrenal (AD) axis (HPA) in control spontaneously hypertensive rats (SHR), in SHR treated with a hypotensive agent in the form of captopril (an angiotensin-converting enzyme inhibitor), and in SHR treated with a hypertensive agent in the form of the L-Arginine hypertensive analogue L-NG-Nitroarginine Methyl Ester (L-NAME). In the control SHR, there were significant negative correlations between the right FC with HPA and positive correlations between the left FC and HPA. In the captopril group, the predominance of negative correlations between the right FC and HPA and positive correlations between the HPA and left FC was maintained. In the L-NAME group, a radical change in all types of interactions was observed; particularly, there was an inversion in the predominance of negative correlations between the HPA and left FC. These results indicated a better balance of neuro-visceral interactions after captopril treatment and an increase in these interactions in the hypertensive animals, especially in those treated with L-NAME.
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Affiliation(s)
- Isabel Prieto
- Department of Health Sciences, University of Jaén, 23071 Jaén, Spain; (I.P.); (A.B.S.); (I.B.); (M.M.-C.)
| | - Ana Belén Segarra
- Department of Health Sciences, University of Jaén, 23071 Jaén, Spain; (I.P.); (A.B.S.); (I.B.); (M.M.-C.)
| | - Inmaculada Banegas
- Department of Health Sciences, University of Jaén, 23071 Jaén, Spain; (I.P.); (A.B.S.); (I.B.); (M.M.-C.)
| | | | - Raquel Durán
- Department of Physiology, Faculty of Medicine, University of Granada, 18071 Granada, Spain; (R.D.); (F.V.)
| | - Francisco Vives
- Department of Physiology, Faculty of Medicine, University of Granada, 18071 Granada, Spain; (R.D.); (F.V.)
| | - Germán Domínguez-Vías
- Department of Physiology, Faculty of Health Sciences, Ceuta Campus, University of Granada, 18071 Granada, Spain;
| | - Manuel Ramírez-Sánchez
- Department of Health Sciences, University of Jaén, 23071 Jaén, Spain; (I.P.); (A.B.S.); (I.B.); (M.M.-C.)
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Iampanichakul M, Potue P, Rattanakanokchai S, Maneesai P, Khamseekaew J, Settheetham-Ishida W, Pakdeechote P. Limonin ameliorates cardiovascular dysfunction and remodeling in hypertensive rats. Life Sci 2023; 327:121834. [PMID: 37290669 DOI: 10.1016/j.lfs.2023.121834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 05/24/2023] [Accepted: 06/03/2023] [Indexed: 06/10/2023]
Abstract
AIMS Limonin is a tetracyclic triterpenoid isolated from citrus fruits. Here, the effects of limonin on cardiovascular abnormalities in nitric oxide-deficient rats induced by Nω-Nitrol-arginine methyl ester (L-NAME) were explored. MAIN METHODS Male Sprague Dawley rats were given L-NAME (40 mg/kg, drinking water) for 3 weeks and then treated daily with polyethylene glycol (vehicle), limonin (50 or 100 mg/kg) or telmisartan (10 mg/kg) for two weeks. KEY FINDINGS Limonin (100 mg/kg) markedly reduced L-NAME-induced hypertension, cardiovascular dysfunction and remodeling in rats (P < 0.05). Increases in systemic angiotensin-converting enzyme (ACE) activity and angiotensin II (Ang II) and a reduction in circulating ACE2 were restored in hypertensive rats treated with limonin (P < 0.05). Reductions in antioxidant enzymes and nitric oxide metabolites (NOx) and increases in oxidative stress components induced by L-NAME were relieved by limonin treatment (P < 0.05). Limonin suppressed the increased expression of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in cardiac tissue and circulating TNF-α in rats that received L-NAME (P < 0.05). Changes in Ang II receptor type I (AT1R), Mas receptor (MasR), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB) and NADPH oxidase subunit 2 (gp91phox) protein expression in cardiac and aortic tissue were normalized by limonin (P < 0.05). SIGNIFICANCE In conclusion, limonin ameliorated L-NAME-induced hypertension, cardiovascular dysfunction and remodeling in rats. These effects were relevant to restorations of the renin-angiotensin system, oxidative stress and inflammation in NO-deficient rats. The molecular mechanisms are associated with the modulation of AT1R, MasR, NF-ĸB and gp91phox protein expression in cardiac and aortic tissue.
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Affiliation(s)
- Metee Iampanichakul
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
| | - Prapassorn Potue
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
| | | | - Putcharawipa Maneesai
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
| | - Juthamas Khamseekaew
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
| | | | - Poungrat Pakdeechote
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
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Buzinari TC, de Moraes TF, Conceição-Filho JC, Cárnio EC, Almeida-Lopes L, Salgado HC, Rodrigues GJ. Nitric oxide storage levels modulate vasodilation and the hypotensive effect induced by photobiomodulation using an aluminum gallium arsenide (AlGaAs) diode laser (660 nm). Lasers Med Sci 2022; 37:2753-2762. [PMID: 35391589 DOI: 10.1007/s10103-022-03551-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/28/2022] [Indexed: 11/29/2022]
Abstract
The aim of this study was to evaluate the participation of nitric oxide (NO) in the hypotensive and vasorelaxation effect induced by PBM using an aluminum gallium arsenide (AlGaAs) diode laser (660 nm). Male Wistar rats were treated with the inhibitor of nitric oxide synthase (L-NAME). A red laser (660 nm; 63 J/cm2; 56 s/point) was applied to the abdominal region at six different points. Thoracic aorta was dissected for vascular reactivity study, and a laser (660 nm; 96 J/cm2; 56 s) was applied after incubation with the NO donor DETA-NO, PBS, or hydroxicobalamin. Endothelial cells (HUVEC) were treated with DETA-NO or CuSO4, and then, PBM (63 J/cm2) was applied, and the nitric oxide was detected. Hypertensive L-NAME rats did not exhibit a decrease in blood pressure after PBM. PBM promoted vasodilation in the aorta isolated from normotensive rats, and less effect in the aorta of L-NAME rats and the addition of the NO donor, DETA-NO, promoted greater vasodilation by PBM in the aorta of L-NAME rats. In endothelial cells, an increase in NO, after PBM, was detected; however, with the addition of CuSO4, which catalyzes the decomposition of NO storage, there was no detection of NO after PBM. The results of this study demonstrate that the hypotensive and vasodilatory effect of PBM with a red laser at 660 nm is modulated by the release of nitric oxide from the storage.
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Affiliation(s)
- Tereza Cristina Buzinari
- Department of Physiological Sciences, Federal University of São Carlos - UFSCar, Rod. Washington Luis, km 235, São Carlos, SP, 13565-905, Brazil.
| | - Thiago Francisco de Moraes
- Department of Physiological Sciences, Federal University of São Carlos - UFSCar, Rod. Washington Luis, km 235, São Carlos, SP, 13565-905, Brazil
| | - Julio Cesar Conceição-Filho
- Department of Physiological Sciences, Federal University of São Carlos - UFSCar, Rod. Washington Luis, km 235, São Carlos, SP, 13565-905, Brazil
| | - Evelin Capellari Cárnio
- Department of Nursing, General and Specialized, Nursing School of Ribeirão Preto, University of São Paulo - USP, Ribeirão Preto, SP, Brazil
| | - Luciana Almeida-Lopes
- Research and Education Center for Phototherapy in Health Sciences - NUPEN, São Carlos, SP, Brazil
| | - Helio Cesar Salgado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo - USP, Ribeirão Preto, SP, Brazil
| | - Gerson Jhonatan Rodrigues
- Department of Physiological Sciences, Federal University of São Carlos - UFSCar, Rod. Washington Luis, km 235, São Carlos, SP, 13565-905, Brazil
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Yu TY, Hong W, Jin S, Hur KY, Jee JH, Bae JC, Kim JH, Lee M. Delayed heart rate recovery after exercise predicts development of metabolic syndrome: A retrospective cohort study. J Diabetes Investig 2022; 13:167-176. [PMID: 34313016 PMCID: PMC8756310 DOI: 10.1111/jdi.13637] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 07/16/2021] [Accepted: 07/22/2021] [Indexed: 12/20/2022] Open
Abstract
AIMS/INTRODUCTION Several cross-sectional studies have shown that delayed heart rate recovery (HRR) after exercise is associated with the development of metabolic syndrome (MetS). However, there has been a lack of comprehensively designed longitudinal studies. Therefore, our aim was to evaluate the longitudinal association of delayed HRR following a graded exercise treadmill test (GTX) with incident MetS. MATERIALS AND METHODS This was a retrospective longitudinal cohort study of participants without MetS, diabetes, or cardiovascular diseases. The HRR was calculated as the peak heart rate minus the resting heart rate after a 1 min rest (HRR1), a 2 min rest (HRR2), and a 3 min rest (HRR3). Multivariate Cox proportional hazards analysis was performed to investigate the association between HRR and development of MetS. RESULTS There were 676 (31.2%) incident cases of MetS identified during the follow-up period (9,683 person-years). The only statistically significant relationship was between HRR3 and the development of MetS. The hazard ratios (HRs) (95% confidence interval [CI]) of incident MetS comparing the first and second tertiles to the third tertile of HRR3 were 1.492 (1.146-1.943) and 1.277 (1.004-1.624) with P = 0.003 after adjustment for multiple risk factors. As a continuous variable, the HR (95% CI) of incident MetS associated with each one-beat decrease in HRR3 was 1.015 (1.005-1.026) with P = 0.004 after full adjustments. An HRR3 value ≤45 beats per minute (bpm) was associated with a higher risk of incident MetS compared with values >45 bpm, with an HR (95% CI) of 1.304 (1.061-1.602) and P = 0.001. CONCLUSIONS The slow phase of HRR, particularly HRR3, might be more sensitive at predicting the risk of MetS.
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Affiliation(s)
- Tae Yang Yu
- Division of Endocrinology and MetabolismDepartment of MedicineWonkwang Medical CenterWonkwang University School of MedicineIksanKorea
- Department of MedicineSungkyunkwan University Graduate School of MedicineSeoulKorea
| | - Won‐Jung Hong
- Division of Endocrinology and MetabolismDepartment of MedicineSamsung Medical CenterSungkyunkwan University School of MedicineSeoulKorea
| | - Sang‐Man Jin
- Division of Endocrinology and MetabolismDepartment of MedicineSamsung Medical CenterSungkyunkwan University School of MedicineSeoulKorea
| | - Kyu Yeon Hur
- Division of Endocrinology and MetabolismDepartment of MedicineSamsung Medical CenterSungkyunkwan University School of MedicineSeoulKorea
| | - Jae Hwan Jee
- Department of Health Promotion CenterSamsung Medical CenterSungkyunkwan University School of MedicineSeoulKorea
| | - Ji Cheol Bae
- Division of Endocrinology and MetabolismDepartment of MedicineSamsung Changwon HospitalSungkyunkwan University School of MedicineChangwonKorea
| | - Jae Hyeon Kim
- Division of Endocrinology and MetabolismDepartment of MedicineSamsung Medical CenterSungkyunkwan University School of MedicineSeoulKorea
| | - Moon‐Kyu Lee
- Division of Endocrinology and MetabolismDepartment of Internal MedicineUijeongbu Eulji Medical CenterEulji University School of MedicineUijeongbuKorea
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Yu TY, Lee MK. Autonomic dysfunction, diabetes and metabolic syndrome. J Diabetes Investig 2021; 12:2108-2111. [PMID: 34622579 PMCID: PMC8668070 DOI: 10.1111/jdi.13691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/14/2021] [Accepted: 09/16/2021] [Indexed: 11/29/2022] Open
Affiliation(s)
- Tae Yang Yu
- Division of Endocrinology and Metabolism, Department of Medicine, Wonkwang Medical Center, Wonkwang University School of Medicine, Iksan, Korea
| | - Moon-Kyu Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Uijeongbu Eulji Medical Center, Eulji University School of Medicine, Uijeongbu, Korea
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High-sodium diet does not worsen endothelial function in female patients with postural tachycardia syndrome. Clin Auton Res 2021; 31:563-571. [PMID: 33689063 DOI: 10.1007/s10286-021-00772-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/13/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE Postural tachycardia syndrome (POTS), a syndrome characterized by orthostatic symptoms and a heart rate increase of at least 30 beats per minute in the absence of hypotension upon standing, is often accompanied by increased sympathetic activity and low blood volume. A common non-pharmacologic recommendation for patients with POTS is a high-sodium (HS) diet with the goal of bolstering circulating blood volume. The objective of this study is to assess the effects of 6 days of a HS diet on endothelial function in POTS. METHODS A total of 14 patients with POTS and 13 age-matched healthy controls, all females, were studied following 6 days on a low-sodium (LS) diet (10 mEq/day) and 6 days on a HS diet (300 mEq/day) in a crossover design. We measured endothelial function following reactive hyperemia in the brachial artery using flow-mediated dilation (FMD), leg blood flow (LBF) using strain gauge plethysmography in the calf, and reactive hyperemic index (RHI) in the microcirculation of the hand using pulsatile arterial tonometry. RESULTS On the LS diet, FMD% did not differ between patients with POTS and the healthy controls although peak brachial artery diameter was lower for the patient group. RHI was higher for the patient group than for the controls, but there were no differences in post-ischemic LBF increase. On the HS diet, there were no between-group differences in FMD%, LBF increase, or RHI. CONCLUSION In summary, a HS diet for 6 days did not induce endothelial dysfunction. This non-pharmacologic treatment used for patients with POTS does not negatively affect endothelial function when used for a sub-acute duration. TRIAL REGISTRATION ClinicalTrials.gov NCT01550315; March 9, 2012.
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Kruse NT. Nutraceuticals as a potential adjunct therapy toward improving vascular health in CKD. Am J Physiol Regul Integr Comp Physiol 2019; 317:R719-R732. [PMID: 31577157 DOI: 10.1152/ajpregu.00152.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chronic kidney disease (CKD) is a major public health epidemic and increases risk for developing cardiovascular disease (CVD). Vascular dysfunction is a major independent risk factor toward increased risk for CVD in CKD. Several mechanisms have been postulated to result in vascular dysfunction in CKD, including oxidative stress-mediated inflammation by redox imbalance and reduced nitric oxide (NO) bioavailability and synthesis. Therefore, strategies that decrease oxidative stress and/or increase NO bioactivity may have major clinical implications toward improving vascular health and reducing the burden of CVD in CKD. Nutraceutical therapy in the form of polyphenols, dietary nitrates, or selective mitochondria-targeting therapies has recently been shown to improve vascular function by reducing oxidative stress and/or increasing NO bioavailability and synthesis. This review, therefore, highlights these three emerging nutraceuticals recently implicated in pathophysiological improvement of vascular function in CKD. This review also describes those pathophysiological mechanisms thought to be responsible for the beneficial effects on the vasculature and possible experimental considerations that may exist within human CKD populations. It is clear throughout this review that human-based mechanistic preclinical and health-related clinical studies are lacking regarding whether nutraceuticals do indeed improve vascular function in patients with CKD. As such, a comprehensive, detailed, and fully integrated understanding of nutraceuticals and vasculature function is necessary in patients with CKD. Many opportunities exist for original mechanistic and therapeutic discoveries and investigations on select nutraceuticals and their impact on vascular outcomes in patients with CKD, and these will remain exciting avenues of research in the future.
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Affiliation(s)
- Nicholas T Kruse
- Department of Internal Medicine, Division of Nephrology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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Sedaghat Z, Kadkhodaee M, Seifi B, Salehi E. Inducible and endothelial nitric oxide synthase distribution and expression with hind limb per-conditioning of the rat kidney. Arch Med Sci 2019; 15:1081-1091. [PMID: 31360203 PMCID: PMC6657261 DOI: 10.5114/aoms.2019.85651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 03/05/2017] [Indexed: 02/07/2023] Open
Abstract
INTRODUCTION We recently reported that a series of brief hind limb ischemia and reperfusion (IR) at the beginning of renal ischemia (remote per-conditioning - RPEC) significantly attenuated the ischemia/reperfusion-induced acute kidney injury. In the present study, we investigated whether the nitric oxide synthase (NOS) pathway is involved in the RPEC protection of the rat ischemic kidneys. MATERIAL AND METHODS Male rats were subjected to right nephrectomy and randomized as: (1) sham, no additional intervention; (2) IR, 45 min of renal ischemia followed by 24 h reperfusion; (3) RPEC, four 5 min cycles of lower limb IR administered at the beginning of renal ischemia; (4) RPEC+L-NAME (a non-specific NOS inhibitor, 10 mg/kg, i.p.) (5) RPEC + 1400W (a specific iNOS inhibitor, 1 mg/kg, i.p.). After 24 h, blood, urine and tissue samples were collected. RESULTS The protective effect of RPEC on renal function, oxidative stress indices, pro-inflammatory marker expression and histopathological changes of kidneys subjected to 45 min ischemia were completely inhibited by pretreatment with L-NAME or 1400W. It was accompanied by increased iNOS and eNOS expression in the RPEC group compared with the IR group. CONCLUSIONS These findings suggest that the protective effects of RPEC on renal IR injury are closely dependent on the nitric oxide production after the reperfusion and both eNOS and iNOS are involved in this protection.
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Affiliation(s)
- Zahra Sedaghat
- Department of Physiology, School of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehri Kadkhodaee
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Behjat Seifi
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Eisa Salehi
- Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Menegatti R, Carvalho FS, Lião LM, Villavicencio B, Verli H, Mourão AA, Xavier CH, Castro CH, Pedrino GR, Franco OL, Oliveira-Silva I, Ashpole NM, Silva ON, Costa EA, Fajemiroye JO. Novel choline analog 2-(4-((1-phenyl-1H-pyrazol-4-yl)methyl)piperazin-1-yl)ethan-1-ol produces sympathoinhibition, hypotension, and antihypertensive effects. Naunyn Schmiedebergs Arch Pharmacol 2019; 392:1071-1083. [DOI: 10.1007/s00210-019-01649-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/29/2019] [Indexed: 12/14/2022]
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Özakca I, Özçelikay AT. Chronic inhibition of nitric oxide synthase modulates calcium handling in rat heart 1. Can J Physiol Pharmacol 2018; 97:313-319. [PMID: 30388373 DOI: 10.1139/cjpp-2018-0388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Systemic infusion of nitric oxide synthase (NOS) inhibitors increases peripheral vascular resistance due to inhibition of endothelial NOS leading to the activation of the arterial baroreceptor mechanisms and inhibition of central sympathetic outflow. In the current study, we explored that systemic NOS blockage activates protein kinase A (PKA)-mediated signaling pathway through maintained cGMP-dependent protein kinase (PKG) activation. Rats were treated with 3 different concentrations of N(ω)-nitro-l-arginine methyl ester (L-NAME) for 14 days. Systemic L-NAME treatment induced a dose-dependent increase in blood pressure and increased mRNA levels of atrial natriuretic peptide (ANP) and phosphorylation levels of p44/42 MAPK without any change in cardiac mass. The cardiac cGMP levels and PKG-mediated phosphorylation of vasodilator-stimulated phosphoprotein (VASP) (Ser239) did not alter in any group. At the highest dose of treatment (100 mg/kg per day), PKA-mediated phosphorylations of VASP (Ser157) and troponin I (TnI) (Ser23/24) were enhanced significantly indicating the increase in PKA activation in response to chronic NOS blockage. Alterations in both phosphorylated phospholamban (Ser16/Thr17) and sarcoplasmic/endoplasmic Ca2+-ATPase (SERCA2) levels can increase cytosolic Ca2+ load and impair Ca2+ handling. Our data suggest that the increased PKA activation in response to chronic NOS blockage appears to be responsible for cardiac abnormalities that occur due to prolonged L-NAME treatment.
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Affiliation(s)
- Işıl Özakca
- Department of Pharmacology, Faculty of Pharmacy, Ankara University, Ankara, Turkey.,Department of Pharmacology, Faculty of Pharmacy, Ankara University, Ankara, Turkey
| | - A Tanju Özçelikay
- Department of Pharmacology, Faculty of Pharmacy, Ankara University, Ankara, Turkey.,Department of Pharmacology, Faculty of Pharmacy, Ankara University, Ankara, Turkey
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Rodriguez-Iturbe B, Pons H, Johnson RJ. Role of the Immune System in Hypertension. Physiol Rev 2017; 97:1127-1164. [PMID: 28566539 PMCID: PMC6151499 DOI: 10.1152/physrev.00031.2016] [Citation(s) in RCA: 247] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 02/07/2023] Open
Abstract
High blood pressure is present in more than one billion adults worldwide and is the most important modifiable risk factor of death resulting from cardiovascular disease. While many factors contribute to the pathogenesis of hypertension, a role of the immune system has been firmly established by a large number of investigations from many laboratories around the world. Immunosuppressive drugs and inhibition of individual cytokines prevent or ameliorate experimental hypertension, and studies in genetically-modified mouse strains have demonstrated that lymphocytes are necessary participants in the development of hypertension and in hypertensive organ injury. Furthermore, immune reactivity may be the driving force of hypertension in autoimmune diseases. Infiltration of immune cells, oxidative stress, and stimulation of the intrarenal angiotensin system are induced by activation of the innate and adaptive immunity. High blood pressure results from the combined effects of inflammation-induced impairment in the pressure natriuresis relationship, dysfunctional vascular relaxation, and overactivity of the sympathetic nervous system. Imbalances between proinflammatory effector responses and anti-inflammatory responses of regulatory T cells to a large extent determine the severity of inflammation. Experimental and human studies have uncovered autoantigens (isoketal-modified proteins and heat shock protein 70) of potential clinical relevance. Further investigations on the immune reactivity in hypertension may result in the identification of new strategies for the treatment of the disease.
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Affiliation(s)
- Bernardo Rodriguez-Iturbe
- Renal Service, Hospital Universitario, Universidad del Zulia, and Instituto Venezolano de Investigaciones Científicas (IVIC)-Zulia, Maracaibo, Venezuela; and Division of Renal Diseases and Hypertension, University of Colorado, Anschutz Campus, Aurora, Colorado
| | - Hector Pons
- Renal Service, Hospital Universitario, Universidad del Zulia, and Instituto Venezolano de Investigaciones Científicas (IVIC)-Zulia, Maracaibo, Venezuela; and Division of Renal Diseases and Hypertension, University of Colorado, Anschutz Campus, Aurora, Colorado
| | - Richard J Johnson
- Renal Service, Hospital Universitario, Universidad del Zulia, and Instituto Venezolano de Investigaciones Científicas (IVIC)-Zulia, Maracaibo, Venezuela; and Division of Renal Diseases and Hypertension, University of Colorado, Anschutz Campus, Aurora, Colorado
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Physiological approaches to assess diminished sympathetic activity in the conscious rat. J Pharmacol Toxicol Methods 2017; 88:64-71. [PMID: 28658603 DOI: 10.1016/j.vascn.2017.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 06/16/2017] [Accepted: 06/24/2017] [Indexed: 12/27/2022]
Abstract
The purpose of this study was to evaluate functional measures of diminished sympathetic activity after postganglionic neuronal loss in the conscious rat. To produce variable degrees of sympathetic postganglionic neuronal loss, adult rats were treated daily with toxic doses of guanethidine (100mg/kg) for either 5days or 11days, followed by a recovery period of at least 18days. Heart rate, blood pressure, cardiac baroreflex responsiveness, urinalysis (for catecholamine metabolite, 3-methoxy-4-hydroxyphenylethylenglycol; MHPG), and pupillometry were performed during the recovery period. At the end of the recovery period stereology of superior cervical ganglia (SCG) was performed to determine the degree of neuronal loss. Total number of SCG neurons was correlated to physiological outcomes using regression analysis. Whereas guanethidine treatment for 11days caused significant reduction in the number of neurons (15,646±1460 vs. 31,958±1588), guanethidine treatment for 5days caused variable levels of neuronal depletion (26,009±3518). Regression analysis showed that only changes in urinary MHPG levels and systolic blood pressure significantly correlated with reduction of SCG neurons (r2=0.45 and 0.19, both p<0.05). Although cardiac baroreflex-induced reflex tachycardia (345.7±19.6 vs. 449.7±20.3) and pupil/iris ratio (0.50±0.03% vs. 0.61±0.02%) were significantly attenuated in the 11-day guanethidine treated rats there was no significant relationship between these measurements and the number of remaining SCG neurons after treatment (p>0.05). These data suggest that basal systolic blood pressure and urinary MHPG levels predict drug-induced depletion of sympathetic activity in vivo.
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Puzserova A, Bernatova I. Blood pressure regulation in stress: focus on nitric oxide-dependent mechanisms. Physiol Res 2017; 65:S309-S342. [PMID: 27775419 DOI: 10.33549/physiolres.933442] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Stress is considered a risk factor associated with the development of various civilization diseases including cardiovascular diseases, malignant tumors and mental disorders. Research investigating mechanisms involved in stress-induced hypertension have attracted much attention of physicians and researchers, however, there are still ambiguous results concerning a causal relationship between stress and long-term elevation of blood pressure (BP). Several studies have observed that mechanisms involved in the development of stress-induced hypertension include increased activity of sympathetic nervous system (SNS), glucocorticoid (GC) overload and altered endothelial function including decreased nitric oxide (NO) bioavailability. Nitric oxide is well known neurotransmitter, neuromodulator and vasodilator involved in regulation of neuroendocrine mechanisms and cardiovascular responses to stressors. Thus NO plays a crucial role in the regulation of the stress systems and thereby in the BP regulation in stress. Elevated NO synthesis, especially in the initial phase of stress, may be considered a stress-limiting mechanism, facilitating the recovery from stress to the resting levels via attenuation of both GC release and SNS activity as well as by increased NO-dependent vasorelaxation. On the other hand, reduced levels of NO were observed in the later phases of stress and in subjects with genetic predisposition to hypertension, irrespectively, in which reduced NO bioavailability may account for disruption of NO-mediated BP regulatory mechanisms and accentuated SNS and GC effects. This review summarizes current knowledge on the role of stress in development of hypertension with a special focus on the interactions among NO and other biological systems affecting blood pressure and vascular function.
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Affiliation(s)
- A Puzserova
- Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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Brunová A, Bencze M, Behuliak M, Zicha J. Acute and chronic role of nitric oxide, renin-angiotensin system and sympathetic nervous system in the modulation of calcium sensitization in Wistar rats. Physiol Res 2016; 64:447-57. [PMID: 26291725 DOI: 10.33549/physiolres.933094] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Principal vasoactive systems - renin-angiotensin system (RAS), sympathetic nervous system (SNS), nitric oxide (NO) and prostanoids - exert their vascular effects through the changes in calcium levels and/or calcium sensitization. To estimate a possible modulation of calcium sensitization by the above vasoactive systems, we studied the influence of acute and chronic blockade of particular vasoactive systems on blood pressure (BP) changes elicited in conscious normotensive rats by acute dose-dependent administration of Rho-kinase inhibitor fasudil. Adult male chronically cannulated Wistar rats were used throughout this study. The acute inhibition of NO synthase (NOS) by L-NAME enhanced BP response to fasudil, the effect being considerably augmented in rats deprived of endogenous SNS. The acute inhibition of prostanoid synthesis by indomethacin modified BP response to fasudil less than the acute NOS inhibition. The chronic NOS inhibition caused moderate BP elevation and a more pronounced augmentation of fasudil-induced BP changes compared to the effect of acute NOS inhibition. This indicates both short-term and long-term NO-dependent attenuation of calcium sensitization. Long-term inhibition of RAS by captopril caused a significant attenuation of BP changes elicited by fasudil. In contrast, a long-term attenuation of SNS by chronic guanethidine treatment (in youth or adulthood) had no effect on BP response to fasudil, suggesting the absence of SNS does not affect calcium sensitization in vascular smooth muscle of normotensive rats. In conclusion, renin-angiotensin system contributes to the long-term increase of calcium sensitization and its effect is counterbalanced by nitric oxide which decreases calcium sensitization in Wistar rats.
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Affiliation(s)
- A Brunová
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
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Brown R, Celermajer D, Macefield V, Sander M. The Effect of Nitric Oxide Inhibition in Spinal Cord Injured Humans with and without Preserved Sympathetic Control of the Vasculature. Front Neurosci 2016; 10:95. [PMID: 27013957 PMCID: PMC4785190 DOI: 10.3389/fnins.2016.00095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 02/24/2016] [Indexed: 11/13/2022] Open
Abstract
Systemic pharmacological inhibition of nitric oxide (NO) causes a hypertensive response, which has been attributed both to inhibition of peripheral NO-mediated vasodilatation and to inhibition of central nervous NO-production leading to a later onset sympathetic vasoconstriction. In the present study we aimed to test the importance of these two mechanisms by comparing the time-courses of the hypertensive responses in spinal cord injured (SCI) subjects with varying degrees of loss of sympathetic vascular control depending on level of injury as well as able-bodied controls. We hypothesized that high level SCI with no sympathetic vasoconstrictor control would have an abbreviated time-course of the hypertensive response to the NO-inhibitor L-NAME, because they would lack the late onset sympathetic component to the hypertensive response. NO production was blocked in 12 subjects with SCI and 6 controls by intravenous infusion of L-NAME (1.55–2.7 mg/kg). We measured blood pressure, heart rate, and vascular conductance in the carotid, brachial, and femoral arteries before, during, and after 1 h of L-NAME in a 4-h protocol. Peak increases in mean arterial pressure were significantly larger in high level SCI vs. controls: 32 ± 6 vs. 12 ± 2 mmHg (both groups received 1.55 mg/kg). The decreases in vascular conductance in the brachial and femoral vascular beds were also larger in the high level SCI group, whereas decreases in heart rate and carotid conductance were not significantly different between the groups. There were no indications of any abbreviated responses in blood pressure or vascular conductance in the high level SCI compared to control. The mid level and low-level SCI subject had responses similar to controls. These data confirm previous reports that NO inhibition causes a larger increase in blood pressure in high level SCI, and extend these data by providing evidence for differences in vascular conductance in the limbs. The current data do not support an obligatory important role for sympathetic vasoconstriction in maintaining the hypertensive response to L-NAME in humans.
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Affiliation(s)
- Rachael Brown
- School of Medicine, Western Sydney UniversitySydney, NSW, Australia; Neuroscience Research AustraliaSydney, NSW, Australia
| | - David Celermajer
- Department of Medicine, Sydney Medical School, University of Sydney Sydney, NSW, Australia
| | - Vaughan Macefield
- School of Medicine, Western Sydney UniversitySydney, NSW, Australia; Neuroscience Research AustraliaSydney, NSW, Australia
| | - Mikael Sander
- Neuroscience Research Australia Sydney, NSW, Australia
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Salman IM. Cardiovascular Autonomic Dysfunction in Chronic Kidney Disease: a Comprehensive Review. Curr Hypertens Rep 2016; 17:59. [PMID: 26071764 DOI: 10.1007/s11906-015-0571-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cardiovascular autonomic dysfunction is a major complication of chronic kidney disease (CKD), likely contributing to the high incidence of cardiovascular mortality in this patient population. In addition to adrenergic overdrive in affected individuals, clinical and experimental evidence now strongly indicates the presence of impaired reflex control of both sympathetic and parasympathetic outflow to the heart and vasculature. Although the principal underlying mechanisms are not completely understood, potential involvements of altered baroreceptor, cardiopulmonary, and chemoreceptor reflex function, along with factors including but not limited to increased renin-angiotensin-aldosterone system activity, activation of the renal afferents and cardiovascular structural remodeling have been suggested. This review therefore analyzes potential mechanisms underpinning autonomic imbalance in CKD, covers results accumulated thus far on cardiovascular autonomic function studies in clinical and experimental renal failure, discusses the role of current interventional and therapeutic strategies in ameliorating autonomic deficits associated with chronic renal dysfunction, and identifies gaps in our knowledge of neural mechanisms driving cardiovascular disease in CKD.
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Affiliation(s)
- Ibrahim M Salman
- The Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia,
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Bertera FM, Del Mauro JS, Lovera V, Chiappetta D, Polizio AH, Taira CA, Höcht C. Enantioselective pharmacokinetics and cardiovascular effects of nebivolol in L-NAME hypertensive rats. Hypertens Res 2013; 37:194-201. [DOI: 10.1038/hr.2013.140] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/16/2013] [Accepted: 07/22/2013] [Indexed: 12/22/2022]
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Blood pressure regulation VIII: resistance vessel tone and implications for a pro-atherogenic conduit artery endothelial cell phenotype. Eur J Appl Physiol 2013; 114:531-44. [PMID: 23860841 DOI: 10.1007/s00421-013-2684-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 06/15/2013] [Indexed: 10/26/2022]
Abstract
Dysfunction of the endothelium is proposed as the primary initiator of atherosclerotic peripheral artery disease, which occurs mainly in medium- to large-sized conduit arteries of the lower extremities (e.g., iliac, femoral, popliteal arteries). In this review article, we propose the novel concept that conduit artery endothelial cell phenotype is determined, in part, by microvascular tone in skeletal muscle resistance arteries through both changes in arterial blood pressure as well as upstream conduit artery shear stress patterns. First, we summarize the literature supporting the involvement of sympathetic nerve activity (SNA) and nitric oxide (NO) in the modulation of microvascular tone and arterial blood pressure. We then focus on the role of elevated blood pressure and shear stress profiles in modulating conduit artery endothelial cell phenotype. Last, we discuss findings from classic and emerging studies indicating that increased vascular resistance, as it occurs in the context of increased SNA and/or reduced NO bioavailability, is associated with greater oscillatory shear stress (e.g., increased retrograde shear) in upstream conduit arteries. The ideas put forth in this review set the stage for a new paradigm concerning the mechanistic link between increased microvascular tone and development of conduit artery endothelial dysfunction and thus increased risk for peripheral artery disease. Indeed, a vast amount of evidence supports the notion that excessive blood pressure and oscillatory shear stress are potent pro-atherogenic signals to the endothelium.
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L-NAME in the cardiovascular system - nitric oxide synthase activator? Pharmacol Rep 2013; 64:511-20. [PMID: 22814004 DOI: 10.1016/s1734-1140(12)70846-0] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 02/14/2012] [Indexed: 11/21/2022]
Abstract
L-arginine analogues are widely used inhibitors of nitric oxide synthase (NOS) activity both in vitro and in vivo, with N(ω)-nitro-L-arginine methyl ester (L-NAME) being at the head. On the one hand, acute and chronic L-NAME treatment leads to changes in blood pressure and vascular reactivity due to decreased nitric oxide (NO) bioavailability. However, lower doses of L-NAME may also activate NO production via feedback regulatory mechanisms if administered for longer time. Such L-NAME-induced activation has been observed in both NOS expression and activity and revealed considerable differences in regulatory mechanisms of NO production between particular tissues depending on the amount of L-NAME. Moreover, feedback activation of NO production by L-NAME seems to be regulated diversely under conditions of hypertension. This review summarizes the mechanisms of NOS regulation in order to better understand the apparent discrepancies found in the current literature.
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Gamboa A, Okamoto LE, Raj SR, Diedrich A, Shibao CA, Robertson D, Biaggioni I. Nitric oxide and regulation of heart rate in patients with postural tachycardia syndrome and healthy subjects. Hypertension 2013; 61:376-81. [PMID: 23283362 DOI: 10.1161/hypertensionaha.111.00203] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The objective is to study the role of nitric oxide (NO) on cardiovascular regulation in healthy subjects and postural tachycardia syndrome (POTS) patients. Reduced neuronal NO function, which could contribute to a hyperadrenergic state, and increased NO-induced vasodilation, which could contribute to orthostatic intolerance, have been reported in POTS. In protocol 1, 13 healthy volunteers (33 ± 3 years) underwent autonomic blockade with trimethaphan and were administered equipressor doses of Nω-monomethyl-L-arginine (L-NMMA, a NO synthase inhibitor) and phenylephrine to determine the direct chronotropic effects of NO (independent of baroreflex modulation). In protocol 2, we compared the effects of L-NMMA in 9 POTS patients (31 ± 3 years) and 14 healthy (32 ± 2 years) volunteers, during autonomic blockade. During autonomic blockade, L-NMMA and phenylephrine produced similar increases in systolic blood pressure (27 ± 2 versus 27 ± 3 mm Hg). Phenylephrine produced only minimal heart rate changes, whereas L-NMMA produced a modest, but significant, bradycardia (-0.8 ± 0.4 versus -4.8 ± 1.2 bpm; P=0.011). There were no differences between POTS and healthy volunteers in the systolic blood pressure increase (22 ± 2 and 28 ± 5 mm Hg) or heart rate decrease (-6 ± 2 and -4 ± 1 bpm for POTS and controls, respectively) produced by L-NMMA. In the absence of baroreflex buffering, inhibition of endogenous NO synthesis results in a significant bradycardia, reflecting direct tonic modulation of heart rate by NO in healthy individuals. We found no evidence of a primary alteration in NO function in POTS. If NO dysfunction plays a role in POTS, it is through its interaction with the autonomic nervous system.
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Affiliation(s)
- Alfredo Gamboa
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
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Bruno RM, Ghiadoni L, Seravalle G, Dell'oro R, Taddei S, Grassi G. Sympathetic regulation of vascular function in health and disease. Front Physiol 2012; 3:284. [PMID: 22934037 PMCID: PMC3429057 DOI: 10.3389/fphys.2012.00284] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 06/29/2012] [Indexed: 01/16/2023] Open
Abstract
The sympathetic nervous system (SNS) is known to play a pivotal role in short- and long-term regulation of different functions of the cardiovascular system. In the past decades increasing evidence demonstrated that sympathetic neural control is involved not only in the vasomotor control of small resistance arteries but also in modulation of large artery function. Sympathetic activity and vascular function, both of which are key factors in the development and prognosis of cardiovascular events and disease, are linked at several levels. Evidence from experimental studies indicates that the SNS is critically influenced, at the central and also at the peripheral level, by the most relevant factors regulating vascular function, such as nitric oxide (NO), reactive oxygen species (ROS), endothelin (ET), the renin-angiotensin system. Additionally, there is indirect evidence of a reciprocal relationship between endothelial function and activity of the SNS. A number of cardiovascular risk factors and diseases are characterized both by increased sympathetic outflow and decreased endothelial function. In healthy subjects, muscle sympathetic nerve activity (MSNA) appears to be related to surrogate markers of endothelial function, and an acute increase in sympathetic activity has been associated with a decrease in endothelial function in healthy subjects. However, direct evidence of a cause-effect relationship from human studies is scanty. In humans large artery stiffness has been associated with increased sympathetic discharge, both in healthy subjects and in renal transplant recipients. Peripheral sympathetic discharge is also able to modulate wave reflection. On the other hand, large artery stiffness can interfere with autonomic regulation by impairing carotid baroreflex sensitivity.
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Affiliation(s)
- Rosa M Bruno
- Department of Internal Medicine University of Pisa, Italy
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Gamboa A, Okamoto LE, Diedrich A, Choi L, Robertson D, Farley G, Paranjape S, Biaggioni I. Sympathetic activation and nitric oxide function in early hypertension. Am J Physiol Heart Circ Physiol 2012; 302:H1438-43. [PMID: 22287587 DOI: 10.1152/ajpheart.01020.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to determine if tonic restrain of blood pressure by nitric oxide (NO) is impaired early in the development of hypertension. Impaired NO function is thought to contribute to hypertension, but it is not clear if this is explained by direct effects of NO on vascular tone or indirect modulation of sympathetic activity. We determined the blood pressure effect of NO synthase inhibition with N(ω)-monomethyl-l-arginine (L-NMMA) during autonomic blockade with trimethaphan to eliminate baroreflex buffering and NO modulation of autonomic tone. In this setting, impaired NO modulation of vascular tone would be reflected as a blunted pressor response to L-NMMA. We enrolled a total of 66 subjects (39 ± 1.3 yr old, 30 females), 20 normotensives, 20 prehypertensives (blood pressure between 120/80 and 140/90 mmHg), 17 hypertensives, and 9 smokers (included as "positive" controls of impaired NO function). Trimethaphan normalized blood pressure in hypertensives, suggesting increased sympathetic tone contributing to hypertension. In contrast, L-NMMA produced similar increases in systolic blood pressure in normal, prehypertensive, and hypertensive subjects (31 ± 2, 32 ± 2, and 30 ± 3 mmHg, respectively), whereas the response of smokers was blunted (16 ± 5 mmHg, P = 0.012). Our results suggest that sympathetic activity plays a role in hypertension. NO tonically restrains blood pressure by ∼30 mmHg, but we found no evidence of impaired modulation by NO of vascular tone contributing to the early development of hypertension. If NO deficiency contributes to hypertension, it is likely to be through its modulation of the autonomic nervous system, which was excluded in this study.
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Affiliation(s)
- Alfredo Gamboa
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University, Nashville, Tennessee, USA.
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23
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Toda N, Ayajiki K. Vascular actions of nitric oxide as affected by exposure to alcohol. Alcohol Alcohol 2010; 45:347-55. [PMID: 20522422 DOI: 10.1093/alcalc/agq028] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Vasodilator substances liberated from endothelial cells, mainly nitric oxide (NO), play important roles in physiologically regulating blood flow and blood pressure and preventing pathological vascular damage. Impairment of these actions promotes the genesis of cardiovascular diseases such as hypertension, cerebral and cardiac hypoperfusion, impaired vasodilatation and atherosclerosis. Low concentrations of alcohol induce increased release of NO from the endothelium due to activation and expression of NO synthase (NOS). In contrast, administration of high concentrations of alcohol or its chronic ingestion impairs endothelial functions in association with reduced NO bioavailability. The endogenous NOS inhibitor asymmetric dimethylarginine may participate in decreased synthesis of NO. Chronic alcohol intake also impairs penile erectile function possibly by interfering with endothelial, but not nitrergic nerve, function. This review article summarizes the vascular actions of NO derived from endothelial and neuronal NOS as affected by alcohol, other than wine, and acetaldehyde in healthy individuals, human materials and various experimental animals.
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Affiliation(s)
- Noboru Toda
- Toyama Institute for Cardiovascular Pharmacology Research, 7-13, 1-Chome, Azuchi-machi, Chuo-ku, Osaka 541-0052, Japan.
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Control of systemic and pulmonary blood pressure by nitric oxide formed through neuronal nitric oxide synthase. J Hypertens 2010; 27:1929-40. [PMID: 19587610 DOI: 10.1097/hjh.0b013e32832e8ddf] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Nitric oxide formed by neuronal nitric oxide synthase (nNOS) in the brain, autonomic inhibitory (nitrergic) nerves, and heart plays important roles in the control of blood pressure. Activation of nitrergic nerves innervating the systemic vasculature elicits vasodilatation, decreases peripheral resistance, and lowers blood pressure. Impairment of nitrergic nerve function, as well as endothelial dysfunction, results in systemic and pulmonary hypertension and decreased regional blood flow. Blockade of nNOS activity in the brain, particularly the medulla and hypothalamus, causes systemic hypertension. Under hypertensive states, such as those in spontaneously hypertensive and Dahl salt-sensitive rats, the expression of the nNOS gene in the brain is increased; this appears to counteract the activated sympathetic function in the vasomotor center. The present article summarizes information concerning the modulation of systemic and pulmonary hypertension through nNOS-derived nitric oxide produced in the brain and periphery.
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Young CN, Fisher JP, Gallagher KM, Whaley-Connell A, Chaudhary K, Victor RG, Thomas GD, Fadel PJ. Inhibition of nitric oxide synthase evokes central sympatho-excitation in healthy humans. J Physiol 2009; 587:4977-86. [PMID: 19723781 DOI: 10.1113/jphysiol.2009.177204] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Animal studies have indicated that nitric oxide is a key signalling molecule involved in the tonic restraint of central sympathetic outflow from the brainstem. Extension of these findings to humans has been difficult because systemic infusion of nitric oxide synthase (NOS) inhibitors increases blood pressure due to inhibition of endothelial NOS, resulting in activation of the arterial baroreflex and subsequent inhibition of central sympathetic outflow. To overcome this confounding inhibitory influence of the baroreflex, in the current study we directly measured skin sympathetic nerve activity (SNA), which is not under baroreceptor control. Healthy, normotensive humans were studied before, during a 60 min intravenous infusion of the NOS inhibitor N(G)-nitro-l-arginine methyl ester (l-NAME; 4 mg kg(1)), and for 120 min following the infusion (i.e. 180 min total). Skin SNA and arterial blood pressure (BP) were continuously measured. BP was increased from baseline at the end of the l-NAME infusion (14 +/- 2 mmHg; P < 0.05) and remained significantly elevated for the remainder of the experiment (18 +/- 3 mmHg; P < 0.05). Similarly, systemic NOS inhibition produced time-dependent increases in skin SNA, such that skin SNA was elevated at the end of the l-NAME infusion (total activity, 200 +/- 22% baseline; P = 0.08) and was further increased at the end of the study protocol (total activity, 350 +/- 41% baseline; P < 0.05). Importantly, skin SNA remained unchanged during time and hypertensive (phenylephrine) control experiments. These findings indicate that pharmacological inhibition of NOS causes sympathetic activation and support a role of nitric oxide in central sympathetic control in humans.
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Affiliation(s)
- Colin N Young
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
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Augustyniak RA, Picken MM, Leonard D, Zhou XJ, Zhang W, Victor RG. Sympathetic nerves and the progression of chronic kidney disease during 5/6 nephrectomy: studies in sympathectomized rats. Clin Exp Pharmacol Physiol 2009; 37:12-8. [PMID: 19566818 DOI: 10.1111/j.1440-1681.2009.05253.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Chronically increased sympathetic nerve activity is present during chronic kidney disease (CKD); however, its role in contributing to hypertension or the progression of CKD remains poorly understood. The aim of the present study was to determine whether neonatal sympathectomy attenuates hypertension in 5/6 nephrectomized rats and affects renal structure and function in a blood pressure-independent manner. 2. We performed 5/6 nephrectomy (referred to as CKD) in both sympathetically intact and sympathectomized (injected neonatally with guanethidine; referred to as CKD + Sympath) male Sprague-Dawley rats. Sham-operated sympathetically intact and sympathectomized rats (Sham and Sham + Sympath, respectively) were used as controls. Radiotelemetry was used to monitor blood pressure throughout the 6 week duration of the study, after which renal function and histology were assessed. 3. Overall average systolic arterial pressure and final urinary protein excretion were significantly lower in CKD + Sympath compared with CKD rats (168 +/- 7 mmHg and 33 +/- 5 mg/24 h vs. 184 +/- 6 mmHg and 66 +/- 7 mg/24 h, respectively). However, the level of proteinuria in the CKD + Sympath group was reduced to a greater extent than what would be expected solely on the basis of lower blood pressure. All other indices of renal function and histology were comparable between both CKD groups. All measurements were comparable between Sham and Sham + Sympath groups. 4. In conclusion, sympathectomy attenuated hypertension by approximately one-third in 5/6 nephrectomized rats. Furthermore, sympathetic nerves to the kidney during 5/6 nephrectomy may contribute to proteinuria in a blood pressure-independent manner.
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Affiliation(s)
- Robert A Augustyniak
- Department of Medicine and Physiology, Wayne State University, Detroit, Michigan 48201, USA.
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Central sympathetic overactivity: maladies and mechanisms. Auton Neurosci 2009; 148:5-15. [PMID: 19268634 DOI: 10.1016/j.autneu.2009.02.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 02/06/2009] [Accepted: 02/10/2009] [Indexed: 12/20/2022]
Abstract
There is growing evidence to suggest that many disease states are accompanied by chronic elevations in sympathetic nerve activity. The present review will specifically focus on central sympathetic overactivity and highlight three main areas of interest: 1) the pathological consequences of excessive sympathetic nerve activity; 2) the potential role of centrally derived nitric oxide in the genesis of neural dysregulation in disease; and 3) the promise of several novel therapeutic strategies targeting central sympathetic overactivity. The findings from both animal and human studies will be discussed and integrated in an attempt to provide a concise update on current work and ideas in these important areas.
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Abstract
Hypertension is a major risk factor for cardiovascular disease, and reduction of elevated blood pressure significantly reduces the risk of cardiovascular events. Endothelial dysfunction, which is characterized by impairment of nitric oxide (NO) bioavailability, is an important risk factor for both hypertension and cardiovascular disease and may represent a major link between the conditions. Evidence suggests that NO plays a major role in regulating blood pressure and that impaired NO bioactivity is an important component of hypertension. Mice with disruption of the gene for endothelial NO synthase have elevated blood pressure levels compared with control animals, suggesting a genetic component to the link between impaired NO bioactivity and hypertension. Clinical studies have shown that patients with hypertension have a blunted arterial vasodilatory response to infusion of endothelium-dependent vasodilators and that inhibition of NO raises blood pressure. Impaired NO bioactivity is also implicated in arterial stiffness, a major mechanism of systolic hypertension. Clarification of the mechanisms of impaired NO bioactivity in hypertension could have important implications for the treatment of hypertension.
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Affiliation(s)
- Matthias Hermann
- From the Department of Cardiology, the Cardiovascular Center, University Hospital Zurich, Switzerland
| | - Andreas Flammer
- From the Department of Cardiology, the Cardiovascular Center, University Hospital Zurich, Switzerland
| | - Thomas F. Lüscher
- From the Department of Cardiology, the Cardiovascular Center, University Hospital Zurich, Switzerland
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Ramchandra R, Barrett CJ, Guild SJ, McBryde F, Malpas SC. Role of renal sympathetic nerve activity in hypertension induced by chronic nitric oxide inhibition. Am J Physiol Regul Integr Comp Physiol 2007; 292:R1479-85. [PMID: 17218445 DOI: 10.1152/ajpregu.00435.2006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nitric oxide levels are diminished in hypertensive patients, suggesting nitric oxide might have an important role to play in the development of hypertension. Chronic blockade of nitric oxide leads to hypertension that is sustained throughout the period of the blockade in baroreceptor-intact animals. It has been suggested that the sympathetic nervous system is involved in the chronic increase in blood pressure; however, the evidence is inconclusive. We measured renal sympathetic nerve activity and blood pressure via telemetry in rabbits over 7 days of nitric oxide blockade. Nitric oxide blockade via Nω-nitro-l-arginine methyl ester (l-NAME) in the drinking water (50 mg·kg−1·day−1) for 7 days caused a significant increase in arterial pressure (7 ± 1 mmHg above control levels; P < 0.05). While the increase in blood pressure was associated with a decrease in heart rate (from 233 ± 6 beats/min before the l-NAME to 202 ± 6 beats/min on day 7), there was no change in renal sympathetic nerve activity (94 ± 4 %baseline levels on day 2 and 96 ± 5 %baseline levels on day 7 of l-NAME; baseline nerve activity levels were normalized to the maximum 2 s of nerve activity evoked by nasopharyngeal stimulation). The lack of change in renal sympathetic nerve activity during the l-NAME-induced hypertension indicates that the renal nerves do not mediate the increase in blood pressure in conscious rabbits.
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Affiliation(s)
- Rohit Ramchandra
- Circulatory Control Laboratory, Department of Physiology, University of Auckland, Private Bag 92019, Auckland, New Zealand
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Biancardi V, Bergamaschi C, Lopes O, Campos R. Sympathetic activation in rats with L-NAME-induced hypertension. Braz J Med Biol Res 2007. [DOI: 10.1590/s0100-879x2006005000077] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
| | | | - O.U. Lopes
- Universidade Federal de São Paulo, Brasil
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Moreira TS, Takakura ACT, Sato MA, Menani JV, Colombari E. Antihypertensive responses elicited by central moxonidine in rats: possible role of nitric oxide. J Cardiovasc Pharmacol 2006; 47:780-7. [PMID: 16810079 DOI: 10.1097/01.fjc.0000211794.68152.04] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In the present study, we investigated the effects of pretreatment with NG-nitro-L-arginine methyl ester (L-NAME) (nitric oxide synthase inhibitor) injected intravenously (IV) on the hypotension, bradycardia, and vasodilation produced by moxonidine (alpha2-adrenergic/imidazoline receptor agonist) injected into the fourth brain ventricle (4th V) in rats submitted to acute hypertension that results from baroreflex blockade by bilateral injections of kynurenic acid (kyn, glutamatergic receptor antagonist) into the nucleus of the solitary tract (NTS) or in normotensive rats. Male Wistar rats (n=5 to 7/group) anesthetized with IV urethane (1.0 g kg(-1) of body weight) and alpha-chloralose (60 mg kg(-1) of body weight) were used. Bilateral injections of kyn (2.7 nmol 100 nL(-1)) into the NTS increased baseline mean arterial pressure (148 +/- 11 mm Hg, vs. control: 102 +/- 4 mm Hg) and baseline heart rate (417 +/- 11 bpm, vs. control: 379 +/- 6 bpm). Moxonidine (20 nmol microL(-1)) into the 4th V reduced mean arterial pressure and heart rate to similar levels in rats treated with kyn into the NTS (68 +/- 9 mm Hg and 359 +/- 7 bpm) or in control normotensive rats (66 +/- 7 mm Hg and 362 +/- 8 bpm, respectively). The pretreatment with L-NAME (25 micromol kg, IV) attenuated the hypotension produced by moxonidine into the 4th V in rats treated with kyn (104 +/- 6 mm Hg) or in normotensive rats (95 +/- 8 mm Hg), without changing bradycardia. Moxonidine into the 4th V also reduced renal, mesenteric, and hindquarter vascular resistances in rats treated or not with kyn into the NTS and the pretreatment with L-NAME IV reduced these effects of moxonidine. Therefore, these data indicate that nitric oxide mechanisms are involved in hypotension and mesenteric, renal, and hindquarter vasodilation induced by central moxonidine in normotensive and in acute hypertensive rats.
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Affiliation(s)
- Thiago Santos Moreira
- Department of Physiology, Universidade Federal de São Paulo-Escola Paulista de Medicina, 04023-060, São Paulo, Brazil
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Eldesoky ES. Effect of acute inhibition of nitric oxide synthesis by l-NAME on cardiovascular responses following peripheral autonomic blockade in rabbits. Fundam Clin Pharmacol 2006; 20:239-45. [PMID: 16671958 DOI: 10.1111/j.1472-8206.2006.00405.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The pressor and chronotropic responses to acute inhibition of nitric oxide synthase enzyme by N(G)-nitro-L-arginine methyl ester (L-NAME) were studied in anaesthetized rabbits with intact autonomic nervous system (ANS) activity. Also, they were investigated when administration of L-NAME was preceded by peripheral autonomic blockade. Autonomic blockade had different forms: ganglionic (hexamethonium-induced), post-ganglionic beta-adrenergic blockade (propranolol induced), parasympathetic blockade (atropine induced), and complete autonomic blockade by coadministration of hexamethonium and atropine simultaneously. L-NAME injected intravenously (10 mg/kg) in animals with intact and blocked autonomic activity induced a pressor response. This pressor response was accompanied by bradycardia in rabbits with either intact autonomic activity or hexamethonium-induced ganglionic blockade. L-NAME exerted no effect on heart rate in animals with beta-adrenergic blockade or parasympathetic blockade. In rabbits with complete autonomic blockade, L-NAME evoked tachycardia. These experiments indicate that L-NAME-induced hypertension is not relying only on ANS. Also, L-NAME-induced tachycardia in rabbits treated with atropine plus hexamethonium suggests other humoral mechanisms that may be involved in the L-NAME induced chronotropic response.
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Affiliation(s)
- Ehab S Eldesoky
- Pharmacology Department, Faculty of Medicine, Assiut University, Assiut 71515, Egypt.
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ZUCKER IRVINGH, WANG WEI, PLIQUETT RAINERU, LIU JUNLI, PATEL KAUSHIKP. The Regulation of Sympathetic Outflow in Heart Failure. Ann N Y Acad Sci 2006. [DOI: 10.1111/j.1749-6632.2001.tb03696.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Zucker IH, Liu JL. Angiotensin II--nitric oxide interactions in the control of sympathetic outflow in heart failure. Heart Fail Rev 2005; 5:27-43. [PMID: 16228914 DOI: 10.1023/a:1009894007055] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Activation of the sympathetic nervous system is a compensatory mechanism which initially provides support for the circulation in the face of a falling cardiac output. It has been recognized for some time that chronic elevation of sympathetic outflow with the consequent increase in plasma norepinephrine, is counterproductive to improving cardiac function. Indeed, therapeutic targeting to block excessive sympathetic activation in heart failure is becoming a more accepted modality. The mechanism(s) by which sympathetic excitation occurs in the heart failure state are not completely understood. Components of abnormal cardiovascular reflex regulation most likely contribute to this sympatho-excitation. However, central mechanisms which relate to the elaboration of angiotensin II (Ang II) and nitric oxide (NO) may also play an important role. Ang II has been shown to be a sympatho-excitatory peptide in the central nervous system while NO is sympatho-inhibitory. Recent studies have demonstrated that blockade of Ang II receptors of the AT(1) subtype augments arterial baroreflex control of sympathetic nerve activity in the heart failure state, thereby predisposing to a reduction in sympathetic tone. Ang II and NO interact to regulate sympathetic outflow. Blockade of NO production in normal conscious rabbits was only capable of increasing sympathetic outflow when accompanied by a background infusion of Ang II. Conversely, providing a source of NO to rabbits with heart failure reduced sympathetic nerve activity when accompanied by blockade of AT(1) receptors. Chronic heart failure is also associated with a decrease in NO synthesis in the brain as indicated by a reduction in the mRNA for the neuronal isoform (nNOS). Chronic blockade of Ang II receptors can up regulate nNOS expression. In addition, exercise training of rabbits with developing heart failure has been shown to reduce sympathetic tone, decrease plasma Ang II, improve arterial baroreflex function and increase nNOS expression in the central nervous system. This review summarizes a large number of studies which have concentrated on the mechanisms of sympatho-excitation in heart failure. It now seems clear that one mechanism which is important in regulating sympathetic outflow in this disease state depends upon a central interaction between Ang II and NO at the cellular and nuclear levels.
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Affiliation(s)
- I H Zucker
- Department of Physiology and Biophysics, University of Nebraska College of Medicine, 984575 Nebraska Medical Center, Omaha 68198-4575, USA.
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Abstract
A number of neurohumoral processes are activated in heart failure, including an increase in the plasma concentration of norepinephrine. Few studies have been performed to examine the role of the central nervous system in the activation of sympathetic outflow during heart failure (HF). In this paper I review these limited studies, with particular emphasis on examining the role of the paraventricular nucleus (PVN) in the exaggerated sympathetic outflow commonly observed in heart failure. The conclusion is that heart failure is associated with changes in specific areas in the brain and that alterations in the activation of neurons in the PVN are likely related to abnormalities in vasopressin production, blood volume regulation, and sympathoexcitation observed in the heart failure state. Furthermore, neuronal nitric oxide within the PVN that is involved in mediating sympathetic outflow via a GABA mechanism from the PVN may be deficient in inhibiting overall sympathetic outflow leading to the exaggerated sympathetic outflow commonly observed in heart failure.
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Affiliation(s)
- K P Patel
- Department of Physiology and Biophysics, University of Nebraska Medical Center, Omaha, Nebraska, 68198-4575, USA
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Augustyniak RA, Victor RG, Morgan DA, Zhang W. L-NAME- and ADMA-induced sympathetic neural activation in conscious rats. Am J Physiol Regul Integr Comp Physiol 2005; 290:R726-32. [PMID: 16239367 DOI: 10.1152/ajpregu.00768.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although studies in anesthetized, sino-aortic denervated animals indicate that inhibition of central nitric oxide (NO) causes an excitatory influence on efferent sympathetic nerve activity (SNA) that is normally offset by baroreflex activation, studies in conscious animals have not provided clear-cut evidence for a sympathoexcitatory effect of N(omega)-nitro-l-arginine methyl ester (L-NAME) or the endogenous circulating NO synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA). Thus our goals were to 1) use surgical sino-aortic denervation to test for a sympathoexcititatory effect of intravenous l-NAME in conscious rats, and 2) to determine whether SNA responses to intravenous L-NAME can be extrapolated directly to intravenous ADMA. We recorded mean arterial blood pressure and renal SNA in both intact and sino-aortic-denervated conscious rats during 3 h of continuous intravenous infusion with either L-NAME or ADMA. When we eliminated the confounding influence of the sino-aortic baroreceptors, L-NAME produced a progressive increase in SNA with the peak response exceeding the baseline level of nerve firing by 150%. The same type of frank sympathetic activation was observed with intravenous ADMA. Taken together, these data offer straightforward evidence for l-NAME, as well as ADMA-induced sympathetic activation with direct recordings of SNA in conscious animals. These data confirm and extend the concept that circulating endogenous NOS inhibitors can constitute an excitatory signal to SNA.
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Affiliation(s)
- Robert A Augustyniak
- Department of Internal Medicine, Division of Hypertension, The University of Texas Southwestern Medical Center at Dallas, USA
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Ramchandra R, Barrett CJ, Malpas SC. NITRIC OXIDE and SYMPATHETIC NERVE ACTIVITY IN THE CONTROL OF BLOOD PRESSURE. Clin Exp Pharmacol Physiol 2005; 32:440-6. [PMID: 15854155 DOI: 10.1111/j.1440-1681.2005.04208.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. Endothelial dysfunction marked by impairment in the release of nitric oxide (NO) is seen very early in the development of hypertension and is considered important in mediating the impaired vascular tone evident in essential hypertensive patients. 2. Recently, a hypothesis has emerged that NO acting as a neurotransmitter in the brain can modulate levels of sympathetic nerve activity and thereby blood pressure. The NO inhibition model of hypertension has been used to explore the possibility that a decrease in levels of NO can cause an increase in levels of sympathetic nerve activity that can mediate the hypertension. 3. In the present review, we examine the literature regarding the role of NO in setting the mean level of sympathetic nerve activity and blood pressure. Although the acute effects of NO inhibition are well understood, the chronic interaction between the sympathetic nervous system and NO has only been investigated using indirect measures of sympathetic nerve activity, such as ganglionic blockade. This has led to inconsistent results regarding the role of NO in modulating sympathetic nerve activity chronically. 4. Some of the conflicting results may be explained by differences in the 'background' levels of angiotensin (Ang) II. Evidence suggests that NO may interact with AngII and baroreceptor afferent inputs in the central nervous system to set the mean level of sympathetic nerve activity. 5. We suggest chronic NO inhibition can increase sympathetic nerve activity if baroreceptor input is intact and AngII levels are elevated. Although studies exploring the actions of NO or AngII in isolation are useful for gathering initial information, future studies should focus on their interactions and their role in setting the long-term levels of sympathetic activity and blood pressure.
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Affiliation(s)
- Rohit Ramchandra
- Circulatory Control Laboratory, Department of Physiology, University of Auckland, New Zealand
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López RM, Ortíz CS, Ruíz A, Vélez JM, Castillo C, Castillo EF. Impairment of smooth muscle function of rat thoracic aorta in an endothelium-independent manner by long-term administration of N(G)-nitro-L-arginine methyl ester. Fundam Clin Pharmacol 2005; 18:669-77. [PMID: 15548238 DOI: 10.1111/j.1472-8206.2004.00294.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study, we aimed to elucidate whether the daily hypertensive dose of long-term N(G)-nitro-l-arginine methyl ester (l-NAME) treatment, could make a difference between endothelial and smooth muscle functions in rat thoracic aorta. We test the hypothesis that high-dose, long-term l-NAME treatment has a depressive effect on vascular smooth muscle contractile activity which is not related with nitric oxide (NO) synthesis inhibition. After 14 days of treatment, isometric tension and (45)Ca(2+) influx were measured in aortic tissues isolated from l-NAME(10) and l-NAME(100) hypertensive (10 and 100 mg/kg/day, systolic blood pressures 167 +/- 7 and 172 +/- 10 mmHg, respectively) and control normotensive rats (132 +/- 7 mmHg). In l-NAME(10)- and l-NAME(100)-treated rats, acetylcholine-induced relaxation in aortic rings was suppressed with no significant difference between the treatments. l-NAME(100) (but not l-NAME(10)) treatment, significantly inhibited contractile responses to phenylephrine, angiotensin II, and K(+) (80 mm) in endothelium-intact tissues. The effect of l-NAME(100) on phenylephrine-induced contractile responses was not observed after 3 days of treatment. In endothelium-denuded aortic tissues of l-NAME(100) (but not l-NAME(10))-treated rats, phenylephrine (1 x 10(-6) m)- and K(+) (80 mm)-induced contractions and (45)Ca(2+) influxes were significantly reduced. In Ca(2+)-free medium (0.1 mm EDTA), on the contrary, the transient contractions obtained by either phenylephrine (1 x 10(-6) m) or caffeine (1 x 10(-2) m), or the sustained contractions induced by 12-o-tetradecanoylphorbol-13-acetate (1 x 10(-6) m; a protein kinase C activator) in endothelium-denuded aortic rings, were not modified by both l-NAME treatments. These results indicate that in aortic rings from l-NAME hypertensive rats, low and high doses, long-term l-NAME administration may be associated with equivalent inhibition in NO-dependent vasodilator tone (corresponding to equivalent hypertension values); whereas only high-dose, long-term l-NAME administration produces an endothelium-independent decrease in vasocontrictor activity, at least partly explained by a reduction in extracellular Ca(2+) influx.
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Affiliation(s)
- Ruth M López
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Diaz Mirón, Col. Casco de Santo Tomás, CP 11340, México, D.F., México
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Neumann J, Ligtenberg G, Klein II, Koomans HA, Blankestijn PJ. Sympathetic hyperactivity in chronic kidney disease: pathogenesis, clinical relevance, and treatment. Kidney Int 2004; 65:1568-76. [PMID: 15086894 DOI: 10.1111/j.1523-1755.2004.00552.x] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cardiovascular morbidity and mortality importantly influence live expectancy of patients with chronic renal disease (CKD). Traditional risk factors are usually present, but several other factors have recently been identified. There is now evidence that CKD is often characterized by an activated sympathetic nervous system. This may contribute to the pathogenesis of renal hypertension, but it may also adversely affect prognosis independently of its effect on blood pressure. The purpose of this review is to summarize available knowledge on the role of the sympathetic nervous system in the pathogenesis of renal hypertension, its clinical relevance, and the consequences of this knowledge for the choice of treatment.
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Affiliation(s)
- Jutta Neumann
- Department of Nephrology, University Medical Center Utrecht, The Netherlands
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Pechánová O, Dobesová Z, Cejka J, Kunes J, Zicha J. Vasoactive systems in L-NAME hypertension: the role of inducible nitric oxide synthase. J Hypertens 2004; 22:167-73. [PMID: 15106808 DOI: 10.1097/00004872-200401000-00026] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The contribution of the renin-angiotensin system (RAS) and the sympathetic nervous system (SNS) to blood pressure (BP) maintenance was evaluated in rats with N(omega)-nitro-L-arginine methyl ester (L-NAME) hypertension. Furthermore, we studied the extent of nitric oxide (NO) synthesis inhibition and the participation of remaining NO in the counterbalance of pressor systems, with a special reference to inducible nitric oxide synthase (iNOS). METHODS Wistar rats subjected to chronic L-NAME treatment (40 mg/kg per day for 4 weeks) were used. A consecutive blockade of RAS (captopril) and SNS (pentolinium) was followed by acute L-NAME injection. Dimethylguanidine or aminoguanidine were used to affect NO synthesis by iNOS. RESULTS L-NAME hypertensive rats had borderline augmentation of depressor response to captopril injection, but their BP fall after pentolinium was considerably enhanced compared with controls. Residual BP (recorded after simultaneous blockade of the RAS and the SNS) was elevated by 20-40% in hypertensive rats. Pronounced inhibition of NO synthase activity (50% reduction in the aorta and myocardium) was detected in L-NAME hypertensive rats in which the BP rise elicited by acute L-NAME injection was considerably attenuated (by 60-80%). In contrast, acute administration of dimethylguanidine [mixed endothelial NO synthase (eNOS)/iNOS inhibitor] to hypertensive rats induced a major BP rise similar to that caused by L-NAME injection in controls. Aminoguanidine (a selective iNOS inhibitor) caused a substantial BP rise in L-NAME hypertensive rats only. CONCLUSION The contribution of SNS to BP maintenance in L-NAME hypertension is more important than that of RAS. In L-NAME hypertensive rats the iNOS becomes a major source of hemodynamically important NO production, which is still insufficient to compensate prevailing vasoconstriction.
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Affiliation(s)
- Olga Pechánová
- Center for Experimental Cardiovascular Research, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Jones AM, Wilkerson DP, Campbell IT. Nitric oxide synthase inhibition with L-NAME reduces maximal oxygen uptake but not gas exchange threshold during incremental cycle exercise in man. J Physiol 2004; 560:329-38. [PMID: 15284344 PMCID: PMC1665192 DOI: 10.1113/jphysiol.2004.065664] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 07/28/2004] [Indexed: 12/25/2022] Open
Abstract
We hypothesized that the effective inhibition of nitric oxide synthase (NOS), achieved via systemic infusion of N(G)-nitro-l-arginine methyl ester (l-NAME), would reduce the gas exchange threshold (GET) and the maximal oxygen uptake (V(.)(O(2)max)) during incremental cycle exercise in man if NO is important in the regulation of muscle vasodilatation. Seven healthy males, aged 18-34 years, volunteered to participate in this ethically approved study. On two occasions, the subjects completed an incremental exercise test to exhaustion on an electrically braked cycle ergometer following the infusion of either l-NAME (4 mg kg(-1) in 50 ml saline) or placebo (50 ml saline, CON). At rest, the infusion of l-NAME resulted in a significant increase in mean arterial pressure (MAP; CON vs. l-NAME, 89 +/- 8 vs. 103 +/- 11 mmHg (mean +/- s.d.; P < 0.05)) and a significant reduction in heart rate (HR; CON vs. l-NAME, 60 +/- 12 vs. 51 +/- 8 beats min(-1); P < 0.01). At submaximal work rates, there was no significant difference in V(.)(O(2)) between the conditions and no difference in the GET (CON vs. l-NAME, 1.94 +/- 0.47 vs. 2.01 +/- 0.41 l min(-1)). However, at higher work rates, differences in V(.)(O(2)) between the conditions became more pronounced such that V(.)(O(2)max) was significantly lower with l-NAME (CON vs. l-NAME, 4.02 +/- 0.41 vs. 3.80 +/- 0.34 l min(-1); P < 0.05). The reduction in V(.)(O(2)max) was associated with a reduction in HR(max) (CON vs. l-NAME, 186 +/- 10 vs. 178 +/- 7 beats min(-1); P < 0.01). These results demonstrate that NOS inhibition with l-NAME has no effect on GET but reduces V(.)(O(2)max) during large muscle group exercise in man, presumably by direct or indirect effects on cardiac output and muscle blood flow.
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Affiliation(s)
- Andrew M Jones
- Department of Exercise and Sport Science, Manchester Metropolitan University, Hassall Road, Alsager, ST7 2HL, UK.
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Wilkerson DP, Campbell IT, Jones AM. Influence of nitric oxide synthase inhibition on pulmonary O2 uptake kinetics during supra-maximal exercise in humans. J Physiol 2004; 561:623-35. [PMID: 15358808 PMCID: PMC1665351 DOI: 10.1113/jphysiol.2004.071894] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We have recently reported that inhibition of nitric oxide synthase (NOS) with N(G)-nitro-L-arginine methyl ester (L-NAME) accelerates the 'phase II' pulmonary O2 uptake (VO2) kinetics following the onset of moderate and heavy intensity submaximal exercise in humans. These data suggest that the influence of nitric oxide (NO) on mitochondrial function is an important factor in the inertia to aerobic respiration that is evident in the transition from a lower to a higher metabolic rate. The purpose of the present study was to investigate the influence of L-NAME on pulmonary VO2 kinetics following the onset of supra-maximal exercise, where it has been suggested that O2 availability represents an additional limitation to VO2 kinetics. Seven healthy young men volunteered to participate in this study. Following an incremental cycle ergometer test for the determination of VO2max, the subjects returned on two occasions to perform a 'step' exercise test from a baseline of unloaded cycling to a work rate calculated to require 105% VO2max, preceded either by systemic infusion of L-NAME (4 mg kg(-1) in 50 ml saline) or 50 ml saline as a control (Con). Pulmonary gas exchange was measured on a breath-by-breath basis throughout the exercise tests. The duration of 'phase I' was greater with L-NAME (Con: 14.0 +/- 2.1 versus L-NAME: 16.0 +/- 1.6 s; P = 0.03), suggestive of a slower cardiovascular adaptation following the onset of exercise. However, the phase II VO2 time constant was reduced by 44% with L-NAME (Con: 36.3 +/- 17.3 versus L-NAME: 20.4 +/- 8.3 s; P = 0.01). The accumulation of blood lactate during exercise was also reduced with L-NAME (Con: 4.0 +/- 1.1 versus L-NAME: 2.7 +/- 2.1 mM; P = 0.04). These data indicate that skeletal muscle NO production represents an important limitation to the acceleration of oxidative metabolism following the onset of supra-maximal exercise in humans.
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Affiliation(s)
- Daryl P Wilkerson
- Department of Exercise and Sport Science, Manchester Metropolitan University, Hassall Road, Alsager ST7 2HL, UK
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Campese VM, Ye S, Zhong H, Yanamadala V, Ye Z, Chiu J. Reactive oxygen species stimulate central and peripheral sympathetic nervous system activity. Am J Physiol Heart Circ Physiol 2004; 287:H695-703. [PMID: 15277201 DOI: 10.1152/ajpheart.00619.2003] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent studies have implicated reactive oxygen species (ROS) in the pathogenesis of hypertension and activation of the sympathetic nervous system (SNS). Because nitric oxide (NO) exerts a tonic inhibition of central SNS activity, increased production of ROS could enhance inactivation of NO and result in activation of the SNS. To test the hypothesis that ROS may modulate SNS activity, we infused Tempol (4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl), a superoxide dismutase mimetic, or vehicle either intravenously (250 microg x kg(-1) x min(-1)) or in the lateral ventricle (50 microg x kg body wt(-1) x min(-1)), and we determined the effects on blood pressure (BP), norepinephrine (NE) secretion from the posterior hypothalamus (PH) measured by the microdialysis technique, renal sympathetic nerve activity (RSNA) measured by direct microneurography, the abundance of neuronal NO synthase (nNOS)-mRNA in the PH, paraventricular nuclei (PVN), and locus coeruleus (LC) measured by RT-PCR, and the secretion of nitrate/nitrite (NO(x)) in the dialysate collected from the PH of Sprague-Dawley rats. Tempol reduced BP whether infused intravenously or intracerebroventricularly. Tempol reduced NE secretion from the PH and RSNA when infused intracerebroventricularly but raised NE secretion from the PH and RSNA when infused intravenously. The effects of intravenous Tempol on SNS activity were blunted or abolished by sinoaortic denervation. Tempol increased the abundance of nNOS in the PH, PVN, and LC when infused intracerebroventricularly, but it decreased the abundance of nNOS when infused intravenously. When given intracerebroventricularly, Tempol also reduced the concentration of NO(x) in the dialysate collected from the PH. Pretreatment with N(omega)-nitro-l-arginine methyl ester did not abolish the effects of intracerebral Tempol on BP, heart rate, NE secretion from the PH, and RSNA suggesting that the effects of Tempol on SNS activity may be in part dependent and in part independent of NO. In all, these studies support the notion that ROS may raise BP via activation of the SNS. This activation may be mediated in part by downregulation of nNOS and NO production, in part by mechanisms independent of NO. The discrepancy in results between intracerebroventricular and intravenous infusion of Tempol can be best explained by direct inhibitory actions on SNS activity when given intracerebral. By contrast, Tempol may exert direct vasodilation of the peripheral circulation and reflex activation of the SNS when given intravenously.
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Affiliation(s)
- Vito M Campese
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
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Zucker IH, Schultz HD, Li YF, Wang Y, Wang W, Patel KP. The origin of sympathetic outflow in heart failure: the roles of angiotensin II and nitric oxide. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2004; 84:217-32. [PMID: 14769437 DOI: 10.1016/j.pbiomolbio.2003.11.010] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The regulation of sympathetic nerve activity in chronic heart failure (CHF) has been an area of renewed investigation. Understanding the central mechanisms that are responsible for sympatho-excitation in this disease state may help in reducing the deleterious effects of chronic sympatho-excitation. This review will summarize our understanding of abnormal reflex control of the circulation in CHF. The roles of the arterial baroreflex, the chemoreflex, the cardiac sympathetic afferent reflex and the cardiopulmonary reflex are discussed. New experimental techniques that allow genetic manipulation of substances such as nitric oxide synthase in discrete areas of the brain aid in clarifying the role of NO in the modulation of sympathetic tone in the CHF state. Lastly, clinical implications of this work are discussed.
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Affiliation(s)
- Irving H Zucker
- Department of Physiology and Biophysics, University of Nebraska College of Medicine, Omaha, NE 68198-4575, USA.
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Head GA. The sympathetic nervous system in hypertension: assessment by blood pressure variability and ganglionic blockade. J Hypertens 2003; 21:1619-21. [PMID: 12923389 DOI: 10.1097/00004872-200309000-00006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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47
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Sunano S, Sekiguchi F. [Endothelium-derived factors in hypertensive blood vessels, especially nitric oxide and hypertension]. YAKUGAKU ZASSHI 2003; 123:495-515. [PMID: 12875234 DOI: 10.1248/yakushi.123.495] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endothelium-dependent relaxation (EDR) in the blood vessels of spontaneously hypertensive rats (SHR) and the role of nitric oxide (NO) in the initiation of hypertension are reviewed. EDR was impaired in blood vessels of SHR depending on age and degree of hypertension when compared with those of normotensive rats. The cause of the impairment varied among the type of blood vessels: a decrease in the production of NO and endothelium-derived relaxing factor (EDRF) and an increase in the production of endothelium-derived contracting factor (EDCF) are the main causes of the impairment in large arteries, while a decrease in endothelium-dependent hyperpolarization and increased release of EDCF are the main causes of the impairment in small arteries. Interactions among these endothelium-derived factors and changes in the interactions are also causes of impairment. Superoxide may be involved in the impairment of EDR by destroying NO. The endothelium depresses smooth muscle contraction, including spontaneous tone developed in vascular smooth muscle, and the depressing effect of the endothelium is impaired in the preparations from SHR. The endothelium of blood vessels of SHR are structurally injured as demonstrated by scanning electron microscopy. Antihypertensive treatment prevented these functional and structural changes. Chronic treatment with inhibitors of NO production in normotensive rats impaired EDR and elevated blood pressure. The impairment of EDR is a secondary change due to continued hypertension, and early initiation of antihypertensive therapy is recommended.
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Affiliation(s)
- Satoru Sunano
- School of Pharmaceutical Sciences and Pharmaceutical Research and Technology Institute, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan
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Lu N, Wang Y, Blecha F, Fels RJ, Hoch HP, Kenney MJ. Central interleukin-1beta antibody increases renal and splenic sympathetic nerve discharge. Am J Physiol Heart Circ Physiol 2003; 284:H1536-41. [PMID: 12531724 DOI: 10.1152/ajpheart.00891.2002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that intracerebroventricular (lateral ventricle) administration of interleukin-1beta (IL-1beta) antibody increases the level of sympathetic nerve discharge (SND) in alpha-chloralose-anesthetized rats. Mean arterial pressure (MAP), heart rate (HR), and SND (splenic and renal) were recorded before (Preinfusion), during (25 min), and for 45 min after infusion of IL-1beta antibody (15 microg, 50 microl icv) in baroreceptor-intact (intact) and sinoaortic-denervated (SAD) rats. The following observations were made. First, intracerebroventricular infusion of IL-1beta antibody (but not saline and IgG) significantly increased MAP and the pressor response was higher in SAD compared with intact rats. Second, renal and splenic SND were significantly increased during and after intracerebroventricular IL-1beta antibody infusion and sympathoexcitatory responses were higher in SAD compared with intact rats. Third, intracerebroventricular administration of a single dose of IL-1beta antibody (15 microg, 5 microl for 2 min) significantly increased splenic and renal SND in intact rats. These results suggest that under the conditions of the present experiments central neural IL-1beta plays a role in the tonic regulation of SND and arterial blood pressure.
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Affiliation(s)
- Ning Lu
- Department of Anatomy and Physiology, Kansas State University, 1600 Denison Avenue, Manhattan, KS 66506, USA
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Dobbins RL, Szczepaniak LS, Zhang W, McGarry JD. Chemical sympathectomy alters regulation of body weight during prolonged ICV leptin infusion. Am J Physiol Endocrinol Metab 2003; 284:E778-87. [PMID: 12626326 DOI: 10.1152/ajpendo.00128.2002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To assess the importance of the sympathetic nervous system in regulating body weight during prolonged leptin infusion, we evaluated food intake, body weight, and physical activity in conscious, unrestrained rats. Initial studies illustrated that prolonged intracerebroventricular (ICV) infusion of leptin enhanced substrate oxidation so that adipose tissue lipid stores were completely ablated, and muscle triglyceride and liver glycogen stores were depleted. After neonatal chemical sympathectomy, changes in weight and food intake were compared in groups of sympathectomized (SYM) and control (CON) adult animals during ICV infusion of leptin. CON animals lost 60 +/- 9 g over 10 days vs. 25 +/- 3 g in the SYM animals when food intake was matched between the two groups. Greater weight loss despite similar energy intake points to an important role of the sympathetic nervous system in stimulating energy expenditure during ICV leptin infusion by increasing the resting metabolic rate, since no differences in physical activity were observed between CON and SYM groups. In conclusion, activation of the SNS by leptin increases energy expenditure by augmenting the resting metabolic rate.
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Affiliation(s)
- Robert L Dobbins
- Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9135, USA.
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Abstract
The pressor effect of N -nitric-l-arginine methyl ester (l-NAME) in rats has been attributed to the inhibition of the endothelial nitric oxide synthase; however, recent findings suggest that the central and sympathetic nervous systems may be also involved. In the present work, the authors attempted to study the possible central and sympathetic mechanisms involved in the pressor effect of l-NAME. They compared mean arterial pressure response during 1 h of continuous infusion of normal saline or l-NAME (0.031 mg. kg. min ) in Wistar rats treated with reserpine, adrenal medullectomy, pithing, and pithing + medullectomy. After 15-20 min infusion, a significantly greater increase of mean arterial pressure was observed in anesthetized rats with l-NAME and l-NAME + medullectomy versus rats with l-NAME + reserpine and l-NAME + pithing, and the magnitude of the difference increased further during the continuous 1-h l-NAME infusion. Adrenal medullectomy totally abolished the pressor effect of l-NAME in pithed group. The present findings suggest that the central and sympathetic nervous systems play important roles in the maintenance of the pressor effect of l-NAME, while the adrenal medulla becomes important only when the sympathetic nervous system has been suppressed.
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Affiliation(s)
- Fengyang Huang
- Departamento de Farmacobiología, CINVESTAV-IPN, México, D.F., México
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