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Plott C, Harb T, Arvanitis M, Gerstenblith G, Blumenthal R, Leucker T. Neurocardiac Axis Physiology and Clinical Applications. IJC HEART & VASCULATURE 2024; 54:101488. [PMID: 39224460 PMCID: PMC11367645 DOI: 10.1016/j.ijcha.2024.101488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Revised: 08/05/2024] [Accepted: 08/08/2024] [Indexed: 09/04/2024]
Abstract
The neurocardiac axis constitutes the neuronal circuits between the arteries, heart, brain, and immune organs (including thymus, spleen, lymph nodes, and mucosal associated lymphoid tissue) that together form the cardiovascular brain circuit. This network allows the individual to maintain homeostasis in a variety of environmental situations. However, in dysfunctional states, such as exposure to environments with chronic stressors and sympathetic activation, this axis can also contribute to the development of atherosclerotic vascular disease as well as other cardiovascular pathologies and it is increasingly being recognized as an integral part of the pathogenesis of cardiovascular disease. This review article focuses on 1) the normal functioning of the neurocardiac axis; 2) pathophysiology of the neurocardiac axis; 3) clinical implications of this axis in hypertension, atherosclerotic disease, and heart failure with an update on treatments under investigation; and 4) quantification methods in research and clinical practice to measure components of the axis and future research areas.
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Affiliation(s)
- Caroline Plott
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Tarek Harb
- Ciccarone Center for the Prevention of Cardiovascular Disease, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Marios Arvanitis
- Ciccarone Center for the Prevention of Cardiovascular Disease, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Gary Gerstenblith
- Ciccarone Center for the Prevention of Cardiovascular Disease, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Roger Blumenthal
- Ciccarone Center for the Prevention of Cardiovascular Disease, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Thorsten Leucker
- Ciccarone Center for the Prevention of Cardiovascular Disease, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
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2
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Sprick JD, Jeong J, Sabino-Carvalho JL, Li S, Park J. Neurocirculatory regulation and adaptations to exercise in chronic kidney disease. Am J Physiol Heart Circ Physiol 2023; 324:H843-H855. [PMID: 37000610 PMCID: PMC10191135 DOI: 10.1152/ajpheart.00115.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 04/01/2023]
Abstract
Chronic kidney disease (CKD) is characterized by pronounced exercise intolerance and exaggerated blood pressure reactivity during exercise. Classic mechanisms of exercise intolerance in CKD have been extensively described previously and include uremic myopathy, chronic inflammation, malnutrition, and anemia. We contend that these classic mechanisms only partially explain the exercise intolerance experienced in CKD and that alterations in cardiovascular and autonomic regulation also play a key contributing role. The purpose of this review is to examine the physiological factors that contribute to neurocirculatory dysregulation during exercise and discuss the adaptations that result from regular exercise training in CKD. Key neurocirculatory mechanisms contributing to exercise intolerance in CKD include augmentation of the exercise pressor reflex, aberrations in neurocirculatory control, and increased neurovascular transduction. In addition, we highlight how some contributing factors may be improved through exercise training, with a specific focus on the sympathetic nervous system. Important areas for future work include understanding how the exercise prescription may best be optimized in CKD and how the beneficial effects of exercise training may extend to the brain.
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Affiliation(s)
- Justin D Sprick
- Department of Kinesiology, Health Promotion and Recreation, University of North Texas, Denton, Texas, United States
| | - Jinhee Jeong
- Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Department of Veterans Affairs Health Care System, Research Service Line, Decatur, Georgia, United States
| | - Jeann L Sabino-Carvalho
- Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Department of Veterans Affairs Health Care System, Research Service Line, Decatur, Georgia, United States
| | - Sabrina Li
- Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Department of Veterans Affairs Health Care System, Research Service Line, Decatur, Georgia, United States
| | - Jeanie Park
- Division of Renal Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Department of Veterans Affairs Health Care System, Research Service Line, Decatur, Georgia, United States
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Lezama-Martinez D, Elena Hernandez-Campos M, Flores-Monroy J, Valencia-Hernandez I, Martinez-Aguilar L. Time-Dependent Effects of Individual and Combined Treatments With Nebivolol, Lisinopril, and Valsartan on Blood Pressure and Vascular Reactivity to Angiotensin II and Norepinephrine. J Cardiovasc Pharmacol Ther 2021; 26:490-499. [PMID: 33779339 DOI: 10.1177/10742484211001861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Clinical guidelines suggest the combination of 2 drugs as a strategy to treat hypertension. However, some antihypertensive combinations have been shown to be ineffective. Therefore, it is necessary to determine whether differences exist between the results of monotherapy and combination therapy by temporal monitoring of the responses to angiotensin II and norepinephrine, which are vasoconstrictors involved in the development of hypertension. Thus, the purpose of this work was to determine the vascular reactivity to angiotensin II and norepinephrine in spontaneously hypertensive rat (SHR) aortic rings after treatment with valsartan, lisinopril, nebivolol, nebivolol-lisinopril, and nebivolol-valsartan for different periods of time. In this study, male SHR and Wistar Kyoto normotensive (WKY) rats were divided into 7 groups treated for 1, 2, and 4 weeks: (1) WKY + vehicle, (2) SHR + vehicle; (3) SHR + nebivolol; (4) SHR + lisinopril; (5) SHR + valsartan; (6) SHR + nebivolol-lisinopril; and (7) SHR + nebivolol-valsartan. Blood pressure was measured by the tail-cuff method, and vascular reactivity was determined from the concentration-response curve to angiotensin II and norepinephrine in aortic rings. The results showed that the combined and individual treatments reduced mean blood pressure at all times evaluated. All treatments decreased vascular reactivity to angiotensin II; however, in the case of lisinopril and nebivolol-lisinopril, the effect observed was significant up to 2 weeks. All treatments decreased the reactivity to norepinephrine up to week 4. These results show a time-dependent difference in vascular reactivity between the pharmacological treatments, with nebivolol-valsartan and nebivolol-lisinopril being both effective combinations. Additionally, the results suggest crosstalk between the renin-angiotensin and sympathetic nervous systems to reduce blood pressure and to improve treatment efficacy.
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Affiliation(s)
- Diego Lezama-Martinez
- Laboratory of Pharmacology, F.E.S.-Cuautitlan, 7180Universidad Nacional Autonoma de Mexico, Cuautitlan Izcalli, Mexico, Mexico
- Laboratory of Pharmacodynamics, Escuela Superior de Medicina, 27740Instituto Politecnico Nacional, D.F., Mexico, Mexico
| | - Maria Elena Hernandez-Campos
- Laboratory of Pharmacodynamics, Escuela Superior de Medicina, 27740Instituto Politecnico Nacional, D.F., Mexico, Mexico
| | - Jazmin Flores-Monroy
- Laboratory of Pharmacology, F.E.S.-Cuautitlan, 7180Universidad Nacional Autonoma de Mexico, Cuautitlan Izcalli, Mexico, Mexico
| | - Ignacio Valencia-Hernandez
- Laboratory of Pharmacodynamics, Escuela Superior de Medicina, 27740Instituto Politecnico Nacional, D.F., Mexico, Mexico
| | - Luisa Martinez-Aguilar
- Laboratory of Pharmacology, F.E.S.-Cuautitlan, 7180Universidad Nacional Autonoma de Mexico, Cuautitlan Izcalli, Mexico, Mexico
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Sasaki K, Kumagai K, Maeda K, Akiyama M, Ito K, Matsuo S, Katahira S, Suzuki T, Suzuki Y, Kaiho Y, Sugawara Y, Tsuji I, Saiki Y. Preventive effect of low-dose landiolol on postoperative atrial fibrillation study (PELTA study). Gen Thorac Cardiovasc Surg 2020; 68:1240-1251. [PMID: 32372277 PMCID: PMC7581600 DOI: 10.1007/s11748-020-01364-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 03/26/2020] [Indexed: 11/25/2022]
Abstract
Objective To investigate the efficacy of prophylactic administration of low-dose landiolol on postoperative atrial fibrillation (POAF) in patients after cardiovascular surgery. Methods Consecutive 150 patients over 70 years of age who underwent cardiovascular surgery for valvular, ischemic heart, and aortic diseases were enrolled in this single-center prospective randomized control study from 2010 to 2014. They were assigned to three treatment groups: 1γ group (landiolol at 1 μg/kg/min), 2γ group (landiolol at 2 μg/kg/min), or control group (no landiolol). In the two landiolol groups, landiolol hydrochloride was intravenously administered for a period of 4 days postoperatively. Electrocardiography was continuously monitored during the study period, and cardiologists eventually assessed whether POAF occurred or not. Results POAF occurred in 24.4% of patients in the control group, 18.2% in 1γ group, and 11.1% in 2γ group (p = 0.256). Multivariate logistic regression analysis showed that the incidence of POAF tended to decrease depending on the dose of landiolol (trend-p = 0.120; 1γ group: OR = 0.786, 95% CI 0.257–2.404; 2γ group: OR = 0.379, 95% CI 0.112–1.287). Subgroup analysis showed a significant dose-dependent reduction in POAF among categories of female sex, non-use of angiotensin II receptor blockers (ARBs) before surgery, and valve surgery (each trend-p = 0.02, 0.03, and 0.004). Conclusions These findings indicate that prophylactic administration of low-dose landiolol may not be effective for preventing the occurrence of POAF in overall patients after cardiovascular surgery, but the administration could be beneficial to female patients, patients not using ARBs preoperatively, and those after valvular surgery.
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Affiliation(s)
- Konosuke Sasaki
- Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Kiichiro Kumagai
- Research Division of Sciences for Aortic Disease, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kay Maeda
- Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Masatoshi Akiyama
- Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Koki Ito
- Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Satoshi Matsuo
- Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Shintaro Katahira
- Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Tomoyuki Suzuki
- Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Yusuke Suzuki
- Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Yu Kaiho
- Division of Epidemiology, Department of Health Informatics and Public Health, Tohoku University School of Public Health, Graduate School of Medicine, Sendai, Japan
| | - Yumi Sugawara
- Division of Epidemiology, Department of Health Informatics and Public Health, Tohoku University School of Public Health, Graduate School of Medicine, Sendai, Japan
| | - Ichiro Tsuji
- Division of Epidemiology, Department of Health Informatics and Public Health, Tohoku University School of Public Health, Graduate School of Medicine, Sendai, Japan
| | - Yoshikatsu Saiki
- Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan. .,Research Division of Sciences for Aortic Disease, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Hajmohammadi M, Khaksari M, Soltani Z, Shahrokhi N, Najafipour H, Abbasi R. The Effect of Candesartan Alone and Its Combination With Estrogen on Post-traumatic Brain Injury Outcomes in Female Rats. Front Neurosci 2019; 13:1043. [PMID: 31849571 PMCID: PMC6901902 DOI: 10.3389/fnins.2019.01043] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 09/13/2019] [Indexed: 01/31/2023] Open
Abstract
Aim: The aim of this study was to evaluate the effect of candesartan (angiotensin II type I receptor blocker) alone and its combination with estrogen on the changes in brain edema, intracranial pressure (ICP), and cerebral perfusion pressure (CPP) following diffuse traumatic brain injury (TBI) in female rats. Methods: TBI was induced in ovariectomized female rats using Marmarou's method. The treatment groups received low-dose (LC) and high-dose (HC) candesartan, estrogen (E2), a combination of estrogen vehicle and candesartan vehicle (oil + vehicle), or a combination of estrogen with low-dose (E2 + LC), or with high-dose (E2 + HC) candesartan. ICP and CPP were measured before and several times after TBI, and the brain water content (brain edema) was measured 24 h after TBI. Results: After the TBI, brain edema and ICP in the estrogen group were lower than in the vehicle and TBI groups. Brain edema and ICP in the HC group were lower than in the vehicle group after TBI. Although there was no significant difference in brain edema and ICP between the LC and vehicle groups, significant differences in these variables were observed when the E2 + LC and E2 + HC groups were compared with the oil + vehicle group after TBI. A significant increase in CPP was observed in the estrogen group 4 and 24 h post-TBI, while this increase was found in the HC and E2 + LC groups 24 h post-TBI. Conclusions: A low dose of candesartan did not exert a protective effect on TBI outcomes, but such an effect did appear after combination with estrogen. This finding suggests that interaction between low-dose candesartan and estrogen improves TBI-induced consequences.
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Affiliation(s)
- Mojdeh Hajmohammadi
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Khaksari
- Endocrinology and Metabolism Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran
| | - Zahra Soltani
- Endocrinology and Metabolism Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran
| | - Nader Shahrokhi
- Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Hamid Najafipour
- Cardiovascular Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran
| | - Reza Abbasi
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
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Firoozmand LT, Sanches A, Damaceno-Rodrigues NR, Perez JD, Aragão DS, Rosa RM, Marcondes FK, Casarini DE, Caldini EG, Cunha TS. Blockade of AT1 type receptors for angiotensin II prevents cardiac microvascular fibrosis induced by chronic stress in Sprague-Dawley rats. Stress 2018; 21:484-493. [PMID: 29676198 DOI: 10.1080/10253890.2018.1462328] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
To test the effects of chronic-stress on the cardiovascular system, the model of chronic mild unpredictable stress (CMS) has been widely used. The CMS protocol consists of the random, intermittent, and unpredictable exposure of laboratory animals to a variety of stressors, during 3 consecutive weeks. In this study, we tested the hypothesis that exposure to the CMS protocol leads to left ventricle microcirculatory remodeling that can be attenuated by angiotensin II receptor blockade. Male Sprague-Dawley rats were randomly assigned into four groups: Control, Stress, Control + losartan, and Stress + losartan (N = 6, each group, losartan: 20 mg/kg/day). The rats were euthanized 15 days after CMS exposure, and blood samples and left ventricle were collected. Rats submitted to CMS presented increased glycemia, corticosterone, noradrenaline and adrenaline concentration, and losartan reduced the concentration of the circulating amines. Cardiac angiotensin II, measured by high-performance liquid chromatography (HPLC), was significantly increased in the CMS group, and losartan treatment reduced it, while angiotensin 1-7 was significantly higher in the CMS losartan-treated group as compared with CMS. Histological analysis, verified by transmission electron microscopy, showed that rats exposed to CMS presented increased perivascular collagen and losartan effectively prevented the development of this process. Hence, CMS induced a state of microvascular disease, with increased perivascular collagen deposition, that may be the trigger for further development of cardiovascular disease. In this case, CMS fibrosis is associated with increased production of catecholamines and with a disruption of renin-angiotensin system balance, which can be prevented by angiotensin II receptor blockade.
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Affiliation(s)
| | - Andrea Sanches
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas (FOP-UNICAMP), Piracicaba, Brazil
| | - Nilsa Regina Damaceno-Rodrigues
- Laboratory of Cell Biology (LIM59), Department of Pathology, School of Medicine, University of São Paulo (USP), São Paulo, Brazil
| | - Juliana Dinéia Perez
- Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | | | - Rodolfo Mattar Rosa
- Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Fernanda Klein Marcondes
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas (FOP-UNICAMP), Piracicaba, Brazil
| | - Dulce Elena Casarini
- Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Elia Garcia Caldini
- Laboratory of Cell Biology (LIM59), Department of Pathology, School of Medicine, University of São Paulo (USP), São Paulo, Brazil
| | - Tatiana Sousa Cunha
- Institute of Science and Technology, Department of Science and Technology, Federal University of São Paulo (UNIFESP), São José dos Campos, Brazil
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Georgiopoulos G, Katsi V, Oikonomou D, Vamvakou G, Koutli E, Laina A, Tsioufis C, Nihoyannopoulos P, Tousoulis D. Azilsartan as a Potent Antihypertensive Drug with Possible Pleiotropic Cardiometabolic Effects: A Review Study. Front Pharmacol 2016; 7:235. [PMID: 27536242 PMCID: PMC4971108 DOI: 10.3389/fphar.2016.00235] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 07/20/2016] [Indexed: 12/14/2022] Open
Abstract
Background: Hypertension related cardiovascular (CV) complications could be amplified by the presence of metabolic co-morbidities. Azilsartan medoxomil (AZL-M) is the eighth approved member of angiotensin II receptor blockers (ARBs), a drug class of high priority in the management of hypertensive subjects with diabetes mellitus type II (DMII). Methods: Under this prism, we performed a systematic review of the literature for all relevant articles in order to evaluate the efficacy, safety, and possible clinical role of AZL-M in hypertensive diabetic patients. Results: AZL-M was found to be more effective in terms of reducing indices of blood pressure over alternative ARBs or angiotensin-converting enzyme (ACE) inhibitors with minimal side effects. Preclinical studies have established pleiotropic effects for AZL-M beyond its primary antihypertensive role through differential gene expression, up-regulation of membrane receptors and favorable effect on selective intracellular biochemical and pro-atherosclerotic pathways. Conclusion: Indirect but accumulating evidence from recent literature supports the efficacy and safety of AZL-M among diabetic patients. However, no clinical data exist to date that evince a beneficial role of AZL-M in patients with metabolic disorders on top of its antihypertensive effect. Further clinical studies are warranted to assess the pleiotropic cardiometabolic benefits of AZL-M that are derived from preclinical research.
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Affiliation(s)
- Georgios Georgiopoulos
- 1st Department of Cardiology, 'Hippokration' Hospital, University of Athens Medical School Athens, Greece
| | - Vasiliki Katsi
- 1st Department of Cardiology, 'Hippokration' Hospital, University of Athens Medical School Athens, Greece
| | - Dimitrios Oikonomou
- 1st Department of Cardiology, 'Hippokration' Hospital, University of Athens Medical School Athens, Greece
| | - Georgia Vamvakou
- 1st Department of Cardiology, 'Hippokration' Hospital, University of Athens Medical School Athens, Greece
| | - Evangelia Koutli
- Department of Internal Medicine, 'Hippokration' Hospital, University of Athens Medical School Athens, Greece
| | - Aggeliki Laina
- 1st Department of Cardiology, 'Hippokration' Hospital, University of Athens Medical School Athens, Greece
| | - Constantinos Tsioufis
- 1st Department of Cardiology, 'Hippokration' Hospital, University of Athens Medical School Athens, Greece
| | - Petros Nihoyannopoulos
- 1st Department of Cardiology, 'Hippokration' Hospital, University of Athens Medical SchoolAthens, Greece; Department of Cardiology, Imperial College London, Hammersmith HospitalLondon, UK
| | - Dimitrios Tousoulis
- 1st Department of Cardiology, 'Hippokration' Hospital, University of Athens Medical School Athens, Greece
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Michel MC, Brunner HR, Foster C, Huo Y. Angiotensin II type 1 receptor antagonists in animal models of vascular, cardiac, metabolic and renal disease. Pharmacol Ther 2016; 164:1-81. [PMID: 27130806 DOI: 10.1016/j.pharmthera.2016.03.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 03/30/2016] [Indexed: 02/07/2023]
Abstract
We have reviewed the effects of angiotensin II type 1 receptor antagonists (ARBs) in various animal models of hypertension, atherosclerosis, cardiac function, hypertrophy and fibrosis, glucose and lipid metabolism, and renal function and morphology. Those of azilsartan and telmisartan have been included comprehensively whereas those of other ARBs have been included systematically but without intention of completeness. ARBs as a class lower blood pressure in established hypertension and prevent hypertension development in all applicable animal models except those with a markedly suppressed renin-angiotensin system; blood pressure lowering even persists for a considerable time after discontinuation of treatment. This translates into a reduced mortality, particularly in models exhibiting marked hypertension. The retrieved data on vascular, cardiac and renal function and morphology as well as on glucose and lipid metabolism are discussed to address three main questions: 1. Can ARB effects on blood vessels, heart, kidney and metabolic function be explained by blood pressure lowering alone or are they additionally directly related to blockade of the renin-angiotensin system? 2. Are they shared by other inhibitors of the renin-angiotensin system, e.g. angiotensin converting enzyme inhibitors? 3. Are some effects specific for one or more compounds within the ARB class? Taken together these data profile ARBs as a drug class with unique properties that have beneficial effects far beyond those on blood pressure reduction and, in some cases distinct from those of angiotensin converting enzyme inhibitors. The clinical relevance of angiotensin receptor-independent effects of some ARBs remains to be determined.
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Affiliation(s)
- Martin C Michel
- Dept. Pharmacology, Johannes Gutenberg University, Mainz, Germany; Dept. Translational Medicine & Clinical Pharmacology, Boehringer Ingelheim, Ingelheim, Germany.
| | | | - Carolyn Foster
- Retiree from Dept. of Research Networking, Boehringer Ingelheim Pharmaceuticals Inc., Ridgefield, CT, USA
| | - Yong Huo
- Dept. Cardiology & Heart Center, Peking University First Hospital, Beijing, PR China
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9
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Angiotensin II increases nerve-evoked contractions in mouse tail artery by a T-type Ca2+ channel-dependent mechanism. Eur J Pharmacol 2015; 761:11-8. [DOI: 10.1016/j.ejphar.2015.04.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 04/16/2015] [Accepted: 04/20/2015] [Indexed: 12/31/2022]
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10
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Bohlender J, Nussberger J, Tevaearai H, Imboden H. [Autonomic angiotensinergic fibres in the human heart with an efferent sympathetic cophenotype]. Ann Cardiol Angeiol (Paris) 2015; 64:175-9. [PMID: 26049899 DOI: 10.1016/j.ancard.2015.04.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 04/28/2015] [Indexed: 02/04/2023]
Abstract
AIM The autonomic innervation of the heart consists of sympathetic and parasympathetic nerve fibres, and fibres of the intrinsic ganglionated plexus with noradrenaline and acytylcholine as principal neurotransmitters. The fibres co-release neuropeptides to modulate intracardiac neurotransmission by specific presynaptic and postsynaptic receptors. The coexpression of angiotensin II in sympathetic fibres of the human heart and its role are not known so far. METHODS Autopsy specimens of human hearts were studied (n=3; ventricles). Using immunocytological methods, cryostat sections were stained by a murine monoclonal antibody (4B3) directed against angiotensin II and co-stained by polyclonal antibodies against tyrosine hydroxylase, a catecholaminergic marker. Visualisation of the antibodies was by confocal light microscopy or laser scanning microscopy. RESULTS Angiotensin II-positive autonomic fibres with and without a catecholaminergic cophenotype (hydroxylase-positive) were found in all parts of the human ventricles. In the epicardium, the fibres were grouped in larger bundles of up to 100 and more fibres. They followed the preformed anatomic septa and epicardial vessels towards the myocardium and endocardium where the bundles dissolved and the individual fibres spread between myocytes and within the endocardium. Generally, angiotensinergic fibres showed no synaptic enlargements or only a few if they were also catecholaminergic. The exclusively catechalominergic fibres were characterised by multiple beaded synapses. CONCLUSION The autonomic innervation of the human heart contains angiotensinergic fibres with a sympathetic efferent phenotype and exclusively angiotensinergic fibers representing probably afferents. Angiotensinergic neurotransmission may modulate intracardiac sympathetic and parasympathetic activity and thereby influence cardiac and circulatory function.
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Affiliation(s)
- J Bohlender
- Département de néphrologie, hypertension et pharmacologie clinique, Inselspital, hôpital universitaire, université de Berne, 10, Freiburgstrasse, 3010 Berne, Suisse; Institut de biologie cellulaire, université de Berne, 2, Baltzerstrasse, 3012 Berne, Suisse.
| | - J Nussberger
- Département de médecine, centre hospitalier universitaire vaudois (CHUV), 5, avenue Pierre-Decker, 1011 Lausanne, Suisse
| | - H Tevaearai
- Départment de chirurgie cardiovasculaire, Inselspital, hôpital universitaire, université de Berne, 10, Freiburgstrasse, 3010 Berne, Suisse
| | - H Imboden
- Institut de biologie cellulaire, université de Berne, 2, Baltzerstrasse, 3012 Berne, Suisse
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11
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Abstract
Angiotensin II receptor blockers (ARBs, collectively called sartans) are widely used compounds therapeutically effective in cardiovascular disorders, renal disease, the metabolic syndrome, and diabetes. It has been more recently recognized that ARBs are neuroprotective and have potential therapeutic use in many brain disorders. ARBs ameliorate inflammatory and apoptotic responses to glutamate, interleukin 1β and bacterial endotoxin in cultured neurons, astrocytes, microglial, and endothelial cerebrovascular cells. When administered systemically, ARBs enter the brain, protecting cerebral blood flow, maintaining blood brain barrier function and decreasing cerebral hemorrhage, excessive brain inflammation and neuronal injury in animal models of stroke, traumatic brain injury, Alzheimer's and Parkinson's disease and other brain conditions. Epidemiological analyses reported that ARBs reduced the progression of Alzheimer's disease, and clinical studies suggested amelioration of cognitive loss following stroke and aging. ARBs are pharmacologically heterogeneous; their effects are not only the result of Ang II type 1(AT1) receptor blockade but also of additional mechanisms selective for only some compounds of the class. These include peroxisome proliferator-activated receptor gamma activation and other still poorly defined mechanisms. However, the complete pharmacological spectrum and therapeutic efficacy of individual ARBs have never been systematically compared, and the neuroprotective efficacy of these compounds has not been rigorously determined in controlled clinical studies. The accumulation of pre-clinical evidence should promote further epidemiological and controlled clinical studies. Repurposing ARBs for the treatment of brain disorders, currently without effective therapy, may be of immediate and major translational value.
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Affiliation(s)
- Sonia Villapol
- Department of Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Juan M Saavedra
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, District of Columbia, USA.
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Al Dera H, Brock JA. Spinal cord injury increases the reactivity of rat tail artery to angiotensin II. Front Neurosci 2015; 8:435. [PMID: 25610365 PMCID: PMC4285114 DOI: 10.3389/fnins.2014.00435] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 12/10/2014] [Indexed: 12/13/2022] Open
Abstract
Studies in individuals with spinal cord injury (SCI) suggest the vasculature is hyperreactive to angiotensin II (Ang II). In the present study, the effects of SCI on the reactivity of the rat tail and mesenteric arteries to Ang II have been investigated. In addition, the effects of SCI on the facilitatory action of Ang II on nerve-evoked contractions of these vessels were determined. Isometric contractions of artery segments from T11 (tail artery) or T4 (mesenteric arteries) spinal cord-transected rats and sham-operated rats were compared 6–7 weeks postoperatively. In both tail and mesenteric arteries, SCI increased nerve-evoked contractions. In tail arteries, SCI also greatly increased Ang II-evoked contractions and the facilitatory effect of Ang II on nerve-evoked contractions. By contrast, SCI did not detectably change the responses of mesenteric arteries to Ang II. These findings provide the first direct evidence that SCI increases the reactivity of arterial vessels to Ang II. In addition, in tail artery, the findings indicate that Ang II may contribute to modifying their responses following SCI.
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Affiliation(s)
- Hussain Al Dera
- Department of Anatomy and Neuroscience, University of Melbourne Melbourne, VIC, Australia ; Basic Medical Sciences, College of Medicine, King Saud bin Abdulaziz University for Health Sciences Riyadh, Saudi Arabia
| | - James A Brock
- Department of Anatomy and Neuroscience, University of Melbourne Melbourne, VIC, Australia
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13
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Kusuyama T, Ogata H, Takeshita H, Kohno H, Shimodozono S, Iida H, Tsukazaki T. Effects of azilsartan compared to other angiotensin receptor blockers on left ventricular hypertrophy and the sympathetic nervous system in hemodialysis patients. Ther Apher Dial 2014; 18:398-403. [PMID: 24571483 DOI: 10.1111/1744-9987.12168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hypertension is a major risk factor for cardiovascular and cerebrovascular events, and most patients with hypertension are administered antihypertensive drugs. However, not all patients achieve normal blood pressure levels. The new angiotensin receptor blocker azilsartan (Takeda Pharmaceutical Company Limited, Osaka, Japan) has been reported to have a strong hypotensive effect. Our study investigated the efficacy of azilsartan compared with other angiotensin receptor blockers. This study included 17 hypertensive patients on HD, who had been administered angiotensin receptor blockers, except for azilsartan, for more than 6 months before enrolling, and after enrollment, they were switched to azilsartan. Blood tests, Holter electrocardiogram, ambulatory blood pressure monitoring, and echocardiography were performed at baseline and at the 6-month follow-up. The blood pressure from baseline to 6 months had significantly decreased (24-h systolic blood pressure from 150.9 ± 16.2 mm Hg to 131.3 ± 21.7 mm Hg, P = 0.008), awakening time systolic blood pressure from 152.1 ± 16.9 mm Hg to 131.7 ± 23.2 mm Hg, P = 0.01, sleep-time systolic blood pressure from 148.1 ± 19.7 mm Hg to 130.0 ± 20.1 mm Hg, P = 0.005). There was a significant reduction in serum noradrenaline levels as well as left ventricular mass index after switching to azilsartan (from 550.1 ± 282.9 pg/mL, to 351.7 ± 152.3 pg/mL, P = 0.002; from 117.0 ± 26.4 g/m(2) to 111.3 ± 23.9 g/m(2), P = 0.01, respectively). Azilsartan had a significantly stronger hypotensive effect than other angiotensin receptor blockers. Thus, the switch to azilsartan might improve prognosis of hemodialysis patients. We suggest that the strong anti-hypertensive effect of azilsartan originated from a combination of primary angiotensin receptor blocker class-effect and a stronger suppression of sympathetic nervous system.
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Lim HJ, Koh YY, Lim DY. Comparison of Inhibitory Effects between Enalapril and Losartan on Adrenal Catecholamine Secretion. ACTA ACUST UNITED AC 2014. [DOI: 10.5646/jksh.2014.20.2.51] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Hyo-Jeong Lim
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Veterans Health Service Medical Center, Seoul, Korea
| | - Young-Youp Koh
- Department of Internal Medicine, Chosun University School of Medicine, Gwangju, Korea
| | - Dong-Yoon Lim
- Department of Pharmacology, Chosun University School of Medicine, Gwangju, Korea
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15
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Michel MC, Foster C, Brunner HR, Liu L. A systematic comparison of the properties of clinically used angiotensin II type 1 receptor antagonists. Pharmacol Rev 2013; 65:809-48. [PMID: 23487168 DOI: 10.1124/pr.112.007278] [Citation(s) in RCA: 213] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Angiotensin II type 1 receptor antagonists (ARBs) have become an important drug class in the treatment of hypertension and heart failure and the protection from diabetic nephropathy. Eight ARBs are clinically available [azilsartan, candesartan, eprosartan, irbesartan, losartan, olmesartan, telmisartan, valsartan]. Azilsartan (in some countries), candesartan, and olmesartan are orally administered as prodrugs, whereas the blocking action of some is mediated through active metabolites. On the basis of their chemical structures, ARBs use different binding pockets in the receptor, which are associated with differences in dissociation times and, in most cases, apparently insurmountable antagonism. The physicochemical differences between ARBs also manifest in different tissue penetration, including passage through the blood-brain barrier. Differences in binding mode and tissue penetration are also associated with differences in pharmacokinetic profile, particularly duration of action. Although generally highly specific for angiotensin II type 1 receptors, some ARBs, particularly telmisartan, are partial agonists at peroxisome proliferator-activated receptor-γ. All of these properties are comprehensively reviewed in this article. Although there is general consensus that a continuous receptor blockade over a 24-hour period is desirable, the clinical relevance of other pharmacological differences between individual ARBs remains to be assessed.
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Affiliation(s)
- Martin C Michel
- Department of Clinical Development & Medical Affairs, Boehringer Ingelheim, 55216 Ingelheim, Germany.
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Macarthur H, Wilken GH, Westfall TC, Kolo LL. Neuronal and non-neuronal modulation of sympathetic neurovascular transmission. Acta Physiol (Oxf) 2011; 203:37-45. [PMID: 21362154 PMCID: PMC3139802 DOI: 10.1111/j.1748-1716.2010.02242.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Noradrenaline, neuropeptide Y and adenosine triphosphate are co-stored in, and co-released from, sympathetic nerves. Each transmitter modulates its own release as well as the release of one another; thus, anything affecting the release of one of these transmitters has consequences for all. Neurotransmission at the sympathetic neurovascular junction is also modulated by non-sympathetic mediators such as angiotensin II, serotonin, histamine, endothelin and prostaglandins through the activation of specific pre-junctional receptors. In addition, nitric oxide (NO) has been identified as a modulator of sympathetic neuronal activity, both as a physiological antagonist against the vasoconstrictor actions of the sympathetic neurotransmitters, and also by directly affecting transmitter release. Here, we review the modulation of sympathetic neurovascular transmission by neuronal and non-neuronal mediators with an emphasis on the actions of NO. The consequences for co-transmission are also discussed, particularly in light of hypertensive states where NO availability is diminished.
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Affiliation(s)
- H Macarthur
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, MO 63104, USA.
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17
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Endothelium-derived vasoactive agents, AT1 receptors and inflammation. Pharmacol Ther 2011; 131:187-203. [DOI: 10.1016/j.pharmthera.2010.11.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 11/03/2010] [Indexed: 12/25/2022]
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18
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Byku M, Macarthur H, Westfall TC. Inhibitory effects of angiotensin-(1-7) on the nerve stimulation-induced release of norepinephrine and neuropeptide Y from the mesenteric arterial bed. Am J Physiol Heart Circ Physiol 2009; 298:H457-65. [PMID: 19933420 DOI: 10.1152/ajpheart.00400.2009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neuropeptide Y (NPY) is a cotransmitter with norepinephrine (NE) and ATP in sympathetic nerves. There is evidence for increased activity of the sympathetic nervous system and the renin-angiotensin system (RAS), as well as a role for NPY in the development of hypertension in experimental animal models and in humans. Angiotensin II (ANG II) is known to facilitate sympathetic neurotransmission, an effect greater in spontaneously hypertensive rats (SHR) than normotensive Wistar-Kyoto (WKY) rats. A newly discovered product of the RAS is angiotensin-(1-7) [ANG-(1-7)]. There is evidence suggesting that ANG-(1-7) opposes the actions of ANG II, resulting in hypotensive effects. The objective of this study was to investigate the role of ANG-(1-7) on the nerve-stimulated overflow of NE and NPY from the mesenteric arterial bed of SHR and the mechanisms involved in mediating any effects produced. ANG-(1-7) (0.001, 0.01, 0.1 microM) decreased nerve-stimulated NE and NPY overflow, as well as perfusion pressure in preparations obtained from SHR. This effect was greater in preparations of SHR than WKY controls. In addition, ANG-(1-7) decreased NE overflow to a greater extent than NPY overflow. Administration of the Mas receptor antagonist, D-Ala(7) ANG-(1-7), attenuated the decrease in both NE and NPY overflow due to ANG-(1-7) administration. However, the angiotensin type 2 receptor antagonist, PD-123391, attenuated the effect of ANG-(1-7) on NE overflow without affecting the decrease in NPY overflow. Moreover, in the presence of N(G)-nitro-L-arginine methyl ester, ANG-(1-7) decreased NPY overflow, but not NE overflow. ANG-(1-7) decreases the nerve-stimulated overflow of NE and NPY in preparations of SHR, whereas ANG II enhances it. Therefore, ANG-(1-7) may counteract the effects of ANG II by acting on ANG type 2 and Mas receptors.
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Affiliation(s)
- Mirnela Byku
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri, USA
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Lewandowski J, Abramczyk P, Dobosiewicz A, Bidiuk J, Sinski M, Gaciong Z. The Effect of Enalapril and Telmisartan on Clinical and Biochemical Indices of Sympathetic Activity in Hypertensive Patients. Clin Exp Hypertens 2009; 30:423-32. [DOI: 10.1080/10641960802279132] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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Chow L, Rezmann L, Catt KJ, Louis WJ, Frauman AG, Nahmias C, Louis SNS. Role of the renin-angiotensin system in prostate cancer. Mol Cell Endocrinol 2009; 302:219-29. [PMID: 18824067 DOI: 10.1016/j.mce.2008.08.032] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 08/29/2008] [Accepted: 08/29/2008] [Indexed: 11/19/2022]
Abstract
Prostate cancer is highly prevalent in Western society, and its early stages can be controlled by androgen ablation therapy. However, the cancer eventually regresses to an androgen-independent state for which there is no effective treatment. The renin-angiotensin system (RAS), in particular the octapeptide angiotensin II, is now recognised to have important effects on growth factor signalling and cell growth in addition to its well known actions on blood pressure, fluid homeostasis and electrolyte balance. All components of the RAS have been recently identified in the prostate, consistent with the expression of a local RAS system in this tissue. This review focuses on the role of the RAS in the prostate, and the possibility that this pathway may be a potential therapeutic target for the treatment of prostate cancer and other prostatic diseases.
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Affiliation(s)
- L Chow
- University of Melbourne, Department of Medicine, Austin Health, Heidelberg, Victoria, Australia
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21
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Affiliation(s)
- P A Van Zwieten
- Department of Pharmacotherapy, Academic Medical Centre, Amsterdam, The Netherlands
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22
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Huang BS, Ahmad M, Tan J, Leenen FHH. Sympathetic hyperactivity and cardiac dysfunction post-MI: Different impact of specific CNS versus general AT1 receptor blockade. J Mol Cell Cardiol 2007; 43:479-86. [PMID: 17714732 DOI: 10.1016/j.yjmcc.2007.07.047] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 06/19/2007] [Accepted: 07/10/2007] [Indexed: 01/29/2023]
Abstract
In rats, blockade of the brain renin-angiotensin-aldosterone system prevents sympathetic hyperactivity and markedly attenuates LV dysfunction post-MI. We evaluated whether peripheral administration of an AT(1) receptor blocker has similar effects. In the first experiment, Wistar rats were injected subcutaneously (sc) daily with losartan at a regular or high dose (15 or 100 mg/kg/day) starting 2 days post-MI. At 4 weeks, sympathetic reactivity to air stress was enhanced, baroreflex function was impaired and cardiac function clearly decreased. Increased AT(1) receptor binding densities post-MI were decreased by losartan towards (regular dose) or well below (high dose) levels of sham rats. Losartan at the high dose prevented sympathetic hyperactivity and baroreflex impairment, and lowered LVEDP but further decreased LVPSP and dP/dt(max). In the second experiment, as of 2 days post-MI, losartan (1 mg/kg/day), spironolactone (10 microg/kg/day) or vehicle was infused intracerebroventricularly (i.c.v), or losartan (100 mg/kg/day) was injected sc for 4 weeks. LV dysfunction and increased fibrosis and cardiomyocyte diameter were clearly present at 4 weeks. Icv losartan or spironolactone improved or normalized LV diastolic and systolic function, LV dimensions, fibrosis and myocyte diameter. In contrast, although sc losartan similarly improved fibrosis and LVEDP, again it did not improve LV systolic function. These data indicate that specific central and general AT(1) receptor blockade can similarly improve sympathetic hyperactivity, cardiac fibrosis and LVEDP, but only central blockade improves LV systolic function, possibly due to differences in the extent of blockade of AT(1) receptors in cardiac myocytes and/or peripheral sympathetic nerves.
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Affiliation(s)
- Bing S Huang
- Hypertension Unit, University of Ottawa Heart Institute, H360, 40 Ruskin Street, Ottawa, Ontario, Canada K1Y 4W7
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23
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Talaia C, Queiroz G, Pinheiro H, Moura D, Gonçalves J. Involvement of G-protein βγ subunits on the influence of inhibitory α2-autoreceptors on the angiotensin AT1-receptor modulation of noradrenaline release in the rat vas deferens. Neurochem Int 2006; 49:698-707. [PMID: 16962210 DOI: 10.1016/j.neuint.2006.07.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 06/12/2006] [Accepted: 07/07/2006] [Indexed: 02/05/2023]
Abstract
The influence of alpha2-autoreceptors on the facilitation of [3H]-noradrenaline release mediated by angiotensin II was studied in prostatic portions of rat vas deferens preincubated with [3H]-noradrenaline. Angiotensin II enhanced tritium overflow evoked by trains of 100 pulses at 8 Hz, an effect that was attenuated by the AT1-receptor antagonist losartan (0.3-1 microM), at concentrations suggesting the involvement of the AT1B subtype. The effect of angiotensin II was also attenuated by inhibition of phospholipase C (PLC) and protein kinase C (PKC) indicating that prejunctional AT1-receptors are coupled to the PLC-PKC pathway. Angiotensin II (0.3-100 nM) enhanced tritium overflow more markedly, up to 64%, under conditions that favor alpha2-autoinhibition, observed when stimulation consisted of 100 pulses at 8 Hz, than under poor alpha2-autoinhibition conditions, only up to 14%, observed when alpha2-adrenoceptors were blocked with yohimbine (1 microM) or when stimulation consisted of 20 pulses at 50 Hz. Activation of PKC with 12-myristate 13-acetate (PMA, 0.1-3 microM) also enhanced tritium overflow more markedly under strong alpha2-autoinhibition conditions. Inhibition of Gi/o-proteins with pertussis toxin (8 microg/ml) or blockade of Gbetagamma subunits with the anti-betagamma peptide MPS-Phos (30 microM) attenuated the effects of angiotensin II and PMA. The results indicate that activation of AT1-receptors coupled to the PLC-PKC pathway enhances noradrenaline release, an effect that is markedly favoured by an ongoing activation of alpha2-autoreceptors. Interaction between alpha2-adrenoceptors and AT1-receptors seems to involve the betagamma subunits released from the Gi/o-proteins coupled to alpha2-adrenoceptors and protein kinase C activated by AT1-receptors.
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MESH Headings
- Adrenergic alpha-Antagonists/pharmacology
- Angiotensin II/metabolism
- Angiotensin II/pharmacology
- Animals
- Autoreceptors/drug effects
- Autoreceptors/metabolism
- Electric Stimulation
- Enzyme Inhibitors/pharmacology
- GTP-Binding Protein beta Subunits/antagonists & inhibitors
- GTP-Binding Protein beta Subunits/metabolism
- GTP-Binding Protein gamma Subunits/antagonists & inhibitors
- GTP-Binding Protein gamma Subunits/metabolism
- Male
- Neural Inhibition/drug effects
- Neural Inhibition/physiology
- Norepinephrine/metabolism
- Pertussis Toxin/pharmacology
- Presynaptic Terminals/drug effects
- Presynaptic Terminals/metabolism
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/metabolism
- Rats
- Rats, Wistar
- Receptor Cross-Talk/drug effects
- Receptor Cross-Talk/physiology
- Receptor, Angiotensin, Type 1/drug effects
- Receptor, Angiotensin, Type 1/metabolism
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Adrenergic, alpha-2/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Sympathetic Fibers, Postganglionic/drug effects
- Sympathetic Fibers, Postganglionic/metabolism
- Synaptic Transmission/drug effects
- Synaptic Transmission/physiology
- Tritium
- Type C Phospholipases/antagonists & inhibitors
- Type C Phospholipases/metabolism
- Vas Deferens/drug effects
- Vas Deferens/innervation
- Vas Deferens/metabolism
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Affiliation(s)
- Carlos Talaia
- Laboratory of Pharmacology, CEQOFFUP, Faculty of Pharmacy, University of Porto, Rua Aníbal Cunha, 164, 4050-047 Porto, Portugal
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Saavedra JM, Pavel J. Angiotensin II AT1 receptor antagonists inhibit the angiotensin-CRF-AVP axis and are potentially useful for the treatment of stress-related and mood disorders. Drug Dev Res 2005. [DOI: 10.1002/ddr.20027] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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