1
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Zhou W, Lee A, Zhou A, Lombardo D. Integrative care: acupuncture based neuromodulation therapy for diabetes and heart failure. Front Neurosci 2024; 18:1332957. [PMID: 38298910 PMCID: PMC10827876 DOI: 10.3389/fnins.2024.1332957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/05/2024] [Indexed: 02/02/2024] Open
Abstract
The relationship between heart failure and diabetes is intricate and bidirectional. Individuals with diabetes face an elevated risk of developing heart failure due to factors like insulin resistance, chronic inflammation, and metabolic irregularities. Elevated blood sugar levels can harm blood vessels and nerves, culminating in the buildup of fatty deposits in arteries, atherosclerosis, and hypertension, which significantly contribute to heart failure. Furthermore, diabetes can adversely impact the structure and function of the heart muscle, impairing its pumping capacity. Conversely, heart failure can also contribute to the onset of diabetes by disrupting the body's metabolic processes and amplifying insulin resistance. The complex interaction between these conditions mandates a comprehensive approach to managing individuals with both diabetes and heart failure, underscoring the importance of addressing both aspects for enhanced patient outcomes. Although existing pharmacological treatments are limited and frequently associated with undesirable side effects, acupuncture has established itself as a traditional practice with a legacy. It remains a supplementary option for treating cardiovascular diseases. Heart failure and diabetes are both heavily associated with chronic upregulation of the sympathetic nervous system, which has been identified as a pivotal factor in the progression of disease. Mechanistic interplays such as the attenuation of central nitric oxide signaling may interfere with the production or availability of nitric oxide in key areas of the central nervous system, including the brainstem and hypothalamus. This review will delve into the current understanding of acupuncture on the autonomic nervous system and offer insights into its potential role in the future treatment landscape for diabetes and heart failure.
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Affiliation(s)
- Wei Zhou
- Division of Cardiology, University of California, Irvine, Orange, CA, United States
| | - Andy Lee
- Division of Cardiology, University of California, Irvine, Orange, CA, United States
| | - Aren Zhou
- Irvine Valley College, Irvine, CA, United States
| | - Dawn Lombardo
- Division of Cardiology, University of California, Irvine, Orange, CA, United States
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2
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Wafi AM. Nrf2 and autonomic dysregulation in chronic heart failure and hypertension. Front Physiol 2023; 14:1206527. [PMID: 37719456 PMCID: PMC10500196 DOI: 10.3389/fphys.2023.1206527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 08/14/2023] [Indexed: 09/19/2023] Open
Abstract
Redox imbalance plays essential role in the pathogenesis of cardiovascular diseases. Chronic heart failure (CHF) and hypertension are associated with central oxidative stress, which is partly mediated by the downregulation of antioxidant enzymes in the central autonomic neurons that regulate sympathetic outflow, resulting in sympathoexcitation. Antioxidant proteins are partially regulated by the transcriptional factor nuclear factor erythroid 2-related factor 2 (Nrf2). Downregulation of Nrf2 is key to disrupting central redox homeostasis and mediating sympathetic nerve activity in the setting of Chronic heart failure and hypertension. Nrf2, in turn, is regulated by various mechanisms, such as extracellular vesicle-enriched microRNAs derived from several cell types, including heart and skeletal muscle. In this review, we discuss the role of Nrf2 in regulating oxidative stress in the brain and its impact on sympathoexcitation in Chronic heart failure and hypertension. Importantly, we also discuss interorgan communication via extracellular vesicle pathways that mediate central redox imbalance through Nrf2 signaling.
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Affiliation(s)
- Ahmed M. Wafi
- Physiology Department, Faculty of Medicine, Jazan University, Jizan, Saudi Arabia
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3
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Alieva AM, Teplova NV, Reznik EV, Ettinger OA, Faradzhov RA, Khachirova EA, Kovtiukh IV, Kotikova IA, Sysoeva DA, Bigushev IR, Nikitin IG. Catestanin – a promising biological marker for heart failure: A review. CONSILIUM MEDICUM 2022. [DOI: 10.26442/20751753.2022.10.201873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The epidemic of heart failure (HF) is one of the problems that the global health system has been facing for decades. HF is a multicomponent clinical syndrome caused by dysfunction of the heart and its pathological remodeling. In addition to the well-known natriuretic peptides, a number of cardiovascular biological markers have now been identified that provide clinicians with additional opportunities in diagnosing, classifying, predicting, and monitoring the effectiveness of treating patients with HF. From the position of establishing the sympathetic load in patients with HF, it seems very promising to assess the concentrations of catestatin. The presented data of our literature review suggest that catestatin is probably a reliable biological marker of the activity of the sympathetic division of the autonomic nervous system, and its elevated concentrations in patients with HF reflect the severity of the pathological process. However, despite the reliable results of studies, the clinical significance of assessing the values of this marker both separately and in the framework of a multimarker model requires further study in larger prospective clinical studies.
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4
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Li YL. Stellate Ganglia and Cardiac Sympathetic Overactivation in Heart Failure. Int J Mol Sci 2022; 23:ijms232113311. [PMID: 36362099 PMCID: PMC9653702 DOI: 10.3390/ijms232113311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 10/28/2022] [Accepted: 10/29/2022] [Indexed: 11/06/2022] Open
Abstract
Heart failure (HF) is a major public health problem worldwide, especially coronary heart disease (myocardial infarction)-induced HF with reduced ejection fraction (HFrEF), which accounts for over 50% of all HF cases. An estimated 6 million American adults have HF. As a major feature of HF, cardiac sympathetic overactivation triggers arrhythmias and sudden cardiac death, which accounts for nearly 50–60% of mortality in HF patients. Regulation of cardiac sympathetic activation is highly integrated by the regulatory circuitry at multiple levels, including afferent, central, and efferent components of the sympathetic nervous system. Much evidence, from other investigators and us, has confirmed the afferent and central neural mechanisms causing sympathoexcitation in HF. The stellate ganglion is a peripheral sympathetic ganglion formed by the fusion of the 7th cervical and 1st thoracic sympathetic ganglion. As the efferent component of the sympathetic nervous system, cardiac postganglionic sympathetic neurons located in stellate ganglia provide local neural coordination independent of higher brain centers. Structural and functional impairments of cardiac postganglionic sympathetic neurons can be involved in cardiac sympathetic overactivation in HF because normally, many effects of the cardiac sympathetic nervous system on cardiac function are mediated via neurotransmitters (e.g., norepinephrine) released from cardiac postganglionic sympathetic neurons innervating the heart. This review provides an overview of cardiac sympathetic remodeling in stellate ganglia and potential mechanisms and the role of cardiac sympathetic remodeling in cardiac sympathetic overactivation and arrhythmias in HF. Targeting cardiac sympathetic remodeling in stellate ganglia could be a therapeutic strategy against malignant cardiac arrhythmias in HF.
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Affiliation(s)
- Yu-Long Li
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; ; Tel.: +1-402-559-3016; Fax: +1-402-559-9659
- Department of Cellular & Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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5
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Multiple Aspects of Inappropriate Action of Renin-Angiotensin, Vasopressin, and Oxytocin Systems in Neuropsychiatric and Neurodegenerative Diseases. J Clin Med 2022; 11:jcm11040908. [PMID: 35207180 PMCID: PMC8877782 DOI: 10.3390/jcm11040908] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/04/2022] [Accepted: 02/05/2022] [Indexed: 02/04/2023] Open
Abstract
The cardiovascular system and the central nervous system (CNS) closely cooperate in the regulation of primary vital functions. The autonomic nervous system and several compounds known as cardiovascular factors, especially those targeting the renin–angiotensin system (RAS), the vasopressin system (VPS), and the oxytocin system (OTS), are also efficient modulators of several other processes in the CNS. The components of the RAS, VPS, and OTS, regulating pain, emotions, learning, memory, and other cognitive processes, are present in the neurons, glial cells, and blood vessels of the CNS. Increasing evidence shows that the combined function of the RAS, VPS, and OTS is altered in neuropsychiatric/neurodegenerative diseases, and in particular in patients with depression, Alzheimer’s disease, Parkinson’s disease, autism, and schizophrenia. The altered function of the RAS may also contribute to CNS disorders in COVID-19. In this review, we present evidence that there are multiple causes for altered combined function of the RAS, VPS, and OTS in psychiatric and neurodegenerative disorders, such as genetic predispositions and the engagement of the RAS, VAS, and OTS in the processes underlying emotions, memory, and cognition. The neuroactive pharmaceuticals interfering with the synthesis or the action of angiotensins, vasopressin, and oxytocin can improve or worsen the effectiveness of treatment for neuropsychiatric/neurodegenerative diseases. Better knowledge of the multiple actions of the RAS, VPS, and OTS may facilitate programming the most efficient treatment for patients suffering from the comorbidity of neuropsychiatric/neurodegenerative and cardiovascular diseases.
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6
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Tedeschi A, Agostoni P, Pezzuto B, Corra’ U, Scrutinio D, La Gioia R, Raimondo R, Passantino A, Piepoli MF. Role of comorbidities in heart failure prognosis Part 2: Chronic kidney disease, elevated serum uric acid. Eur J Prev Cardiol 2020; 27:35-45. [PMID: 33238740 PMCID: PMC7691631 DOI: 10.1177/2047487320957793] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/18/2020] [Indexed: 12/18/2022]
Abstract
Despite improvements in pharmacotherapy, morbidity and mortality rates in community-based populations with chronic heart failure still remain high. The increase in medical complexity among patients with heart failure may be reflected by an increase in concomitant non-cardiovascular comorbidities, which are recognized as independent prognostic factors in this population. Heart failure and chronic kidney disease share many risk factors, and often coexist. The presence of kidney failure is associated with incremented risk of cardiovascular and non-cardiovascular mortality in heart failure patients. Chronic kidney disease is also linked with underutilization of evidence-based heart failure therapy that may reduce morbidity and mortality. More targeted therapies would be important to improve the prognosis of patients with these diseases. In recent years, serum uric acid as a determinant of cardiovascular risk has gained interest. Epidemiological, experimental and clinical data show that patients with hyperuricaemia are at increased risk of cardiac, renal and vascular damage and cardiovascular events. Moreover, elevated serum uric acid predicts worse outcome in both acute and chronic heart failure. While studies have raised the possibility of preventing heart failure through the use of uric acid lowering agents, the literature is still inconclusive on whether the reduction in uric acid will result in a measurable clinical benefit. Available evidences suggest that chronic kidney disease and elevated uric acid could worsen heart failure patients' prognosis. The aim of this review is to analyse a possible utilization of these comorbidities in risk stratification and as a therapeutic target to get a prognostic improvement in heart failure patients.
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Affiliation(s)
- Andrea Tedeschi
- Cardiology Dept, Guglielmo da Saliceto Hospital, AUSL Piacenza
and University of Parma, Italy
| | - Piergiuseppe Agostoni
- Clinical Cardiology and Rehabilitation Unit, Università degli
Studi di Milano, Centro Cardiologico Monzino IRCCS, Italy
| | - Beatrice Pezzuto
- Clinical Cardiology and Rehabilitation Unit, Università degli
Studi di Milano, Centro Cardiologico Monzino IRCCS, Italy
| | - Ugo Corra’
- Centro Cardiologico di Veruno, Istituti Clinici Maugeri,
Italy
| | - Domenico Scrutinio
- Istituti Clinici Scientifici Maugeri-SPA SB. I.R.C.C.S.
Institute of Bari, Italy
| | - Rocco La Gioia
- Istituti Clinici Scientifici Maugeri-SPA SB. I.R.C.C.S.
Institute of Bari, Italy
| | - Rosa Raimondo
- Istituti Clinici Scientifici Maugeri-SPA SB. I.R.C.C.S.
Institute of Bari, Italy
| | - Andrea Passantino
- Istituti Clinici Scientifici Maugeri-SPA SB. I.R.C.C.S.
Institute of Bari, Italy
| | - Massimo F Piepoli
- Cardiology Dept, Guglielmo da Saliceto Hospital, AUSL Piacenza
and University of Parma, Italy
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7
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Borovac JA, D'Amario D, Bozic J, Glavas D. Sympathetic nervous system activation and heart failure: Current state of evidence and the pathophysiology in the light of novel biomarkers. World J Cardiol 2020; 12:373-408. [PMID: 32879702 PMCID: PMC7439452 DOI: 10.4330/wjc.v12.i8.373] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 05/19/2020] [Accepted: 07/19/2020] [Indexed: 02/06/2023] Open
Abstract
Heart failure (HF) is a complex clinical syndrome characterized by the activation of at least several neurohumoral pathways that have a common role in maintaining cardiac output and adequate perfusion pressure of target organs and tissues. The sympathetic nervous system (SNS) is upregulated in HF as evident in dysfunctional baroreceptor and chemoreceptor reflexes, circulating and neuronal catecholamine spillover, attenuated parasympathetic response, and augmented sympathetic outflow to the heart, kidneys and skeletal muscles. When these sympathoexcitatory effects on the cardiovascular system are sustained chronically they initiate the vicious circle of HF progression and become associated with cardiomyocyte apoptosis, maladaptive ventricular and vascular remodeling, arrhythmogenesis, and poor prognosis in patients with HF. These detrimental effects of SNS activity on outcomes in HF warrant adequate diagnostic and treatment modalities. Therefore, this review summarizes basic physiological concepts about the interaction of SNS with the cardiovascular system and highlights key pathophysiological mechanisms of SNS derangement in HF. Finally, special emphasis in this review is placed on the integrative and up-to-date overview of diagnostic modalities such as SNS imaging methods and novel laboratory biomarkers that could aid in the assessment of the degree of SNS activation and provide reliable prognostic information among patients with HF.
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Affiliation(s)
- Josip Anđelo Borovac
- Department of Pathophysiology, University of Split School of Medicine, Split 21000, Croatia
- Working Group on Heart Failure of Croatian Cardiac Society, Zagreb 10000, Croatia
| | - Domenico D'Amario
- Department of Cardiovascular and Thoracic Sciences, IRCCS Fondazione Policlinico A. Gemelli, Universita Cattolica Sacro Cuore, Rome 00168, Italy
| | - Josko Bozic
- Department of Pathophysiology, University of Split School of Medicine, Split 21000, Croatia
| | - Duska Glavas
- Working Group on Heart Failure of Croatian Cardiac Society, Zagreb 10000, Croatia
- Clinic for Cardiovascular Diseases, University Hospital of Split, Split 21000, Croatia
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8
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Xu J, Molinas AJR, Mukerjee S, Morgan DA, Rahmouni K, Zsombok A, Lazartigues E. Activation of ADAM17 (A Disintegrin and Metalloprotease 17) on Glutamatergic Neurons Selectively Promotes Sympathoexcitation. Hypertension 2019; 73:1266-1274. [PMID: 31006330 DOI: 10.1161/hypertensionaha.119.12832] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Chronic activation of the brain renin-angiotensin system contributes to the development of hypertension by altering autonomic balance. Beyond the essential role of Ang II (angiotensin II) type 1 receptors, ADAM17 (A disintegrin and metalloprotease 17) is also found to promote brain renin-angiotensin system overactivation. ADAM17 is robustly expressed in various cell types within the central nervous system. The aim of this study was to determine whether ADAM17 modulates presympathetic neuronal activity to promote autonomic dysregulation in salt-sensitive hypertension. To test our hypothesis, ADAM17 was selectively knocked down in glutamatergic neurons using Cre-loxP technology. In mice lacking ADAM17 in glutamatergic neurons, the blood pressure increase induced by deoxycorticosterone acetate-salt treatment was blunted. Deoxycorticosterone acetate-salt significantly elevated cardiac and vascular sympathetic drive in control mice, while such effects were reduced in mice with ADAM17 knockdown. This blunted sympathoexcitation was extended to the spleen, with a lesser activation of the peripheral immune system, translating into a sequestration of circulating T cells within this organ, compared with controls. Within the paraventricular nucleus, Ang II-induced activation of kidney-related presympathetic glutamatergic neurons was reduced in ADAM17 knockdown mice, with the majority of cells no longer responding to Ang II stimulation, confirming the supportive role of ADAM17 in increasing presympathetic neuronal activity. Overall, our data highlight the pivotal role of neuronal ADAM17 in regulating sympathetic activity and demonstrate that activation of ADAM17 in glutamatergic neurons leads to a selective increase of sympathetic output, but not vagal tone, to specific organs, ultimately contributing to dysautonomia and salt-sensitive hypertension.
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Affiliation(s)
- Jiaxi Xu
- From the Department of Pharmacology and Experimental Therapeutics (J.X., S.M., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Cardiovascular Center of Excellence (J.X., S.M., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Neuroscience Center of Excellence (J.X., S.M., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Research and Development, SouthEast Louisiana Veterans Health Care System, New Orleans (J.X., E.L.)
| | - Adrien J R Molinas
- Department of Physiology, Tulane University, New Orleans, LA (A.J.R.M., A.Z.)
| | - Snigdha Mukerjee
- From the Department of Pharmacology and Experimental Therapeutics (J.X., S.M., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Cardiovascular Center of Excellence (J.X., S.M., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Neuroscience Center of Excellence (J.X., S.M., E.L.), Louisiana State University Health Sciences Center, New Orleans
| | - Donald A Morgan
- Department of Pharmacology, University of Iowa, Iowa City, IA (D.A.M., K.R.)
| | - Kamal Rahmouni
- Department of Pharmacology, University of Iowa, Iowa City, IA (D.A.M., K.R.)
| | - Andrea Zsombok
- Department of Physiology, Tulane University, New Orleans, LA (A.J.R.M., A.Z.)
| | - Eric Lazartigues
- From the Department of Pharmacology and Experimental Therapeutics (J.X., S.M., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Cardiovascular Center of Excellence (J.X., S.M., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Neuroscience Center of Excellence (J.X., S.M., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Research and Development, SouthEast Louisiana Veterans Health Care System, New Orleans (J.X., E.L.)
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9
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Thorsdottir D, Cruickshank NC, Einwag Z, Hennig GW, Erdos B. BDNF downregulates β-adrenergic receptor-mediated hypotensive mechanisms in the paraventricular nucleus of the hypothalamus. Am J Physiol Heart Circ Physiol 2019; 317:H1258-H1271. [PMID: 31603352 DOI: 10.1152/ajpheart.00478.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) is upregulated in the paraventricular nucleus of the hypothalamus (PVN) in response to hypertensive stimuli such as stress and hyperosmolality, and BDNF acting in the PVN plays a key role in elevating sympathetic activity and blood pressure. However, downstream mechanisms mediating these effects remain unclear. We tested the hypothesis that BDNF increases blood pressure, in part by diminishing inhibitory hypotensive input from nucleus of the solitary tract (NTS) catecholaminergic neurons projecting to the PVN. Male Sprague-Dawley rats received bilateral PVN injections of viral vectors expressing either green fluorescent protein (GFP) or BDNF and bilateral NTS injections of vehicle or anti-dopamine-β-hydroxylase-conjugated saporin (DSAP), a neurotoxin that selectively lesions noradrenergic and adrenergic neurons. BDNF overexpression in the PVN without NTS lesioning significantly increased mean arterial pressure (MAP) in awake animals by 18.7 ± 1.8 mmHg. DSAP treatment also increased MAP in the GFP group, by 9.8 ± 3.2 mmHg, but failed to affect MAP in the BDNF group, indicating a BDNF-induced loss of NTS catecholaminergic hypotensive effects. In addition, in α-chloralose-urethane-anesthetized rats, hypotensive responses to PVN injections of the β-adrenergic agonist isoprenaline were significantly attenuated by BDNF overexpression, whereas PVN injections of phenylephrine had no effect on blood pressure. BDNF treatment was also found to significantly reduce β1-adrenergic receptor mRNA expression in the PVN, whereas expression of other adrenergic receptors was unaffected. In summary, increased BDNF expression in the PVN elevates blood pressure, in part by downregulating β-receptor signaling and diminishing hypotensive catecholaminergic input from the NTS to the PVN.NEW & NOTEWORTHY We have shown that BDNF, a key hypothalamic regulator of blood pressure, disrupts catecholaminergic signaling between the NTS and the PVN by reducing the responsiveness of PVN neurons to inhibitory hypotensive β-adrenergic input from the NTS. This may be occurring partly via BDNF-mediated downregulation of β1-adrenergic receptor expression in the PVN and results in an increase in blood pressure.
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Affiliation(s)
| | | | - Zachary Einwag
- Department of Pharmacology, University of Vermont, Burlington, Vermont
| | - Grant W Hennig
- Department of Pharmacology, University of Vermont, Burlington, Vermont
| | - Benedek Erdos
- Department of Pharmacology, University of Vermont, Burlington, Vermont
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10
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Chan JYH, Chan SHH. Differential impacts of brain stem oxidative stress and nitrosative stress on sympathetic vasomotor tone. Pharmacol Ther 2019; 201:120-136. [PMID: 31153955 DOI: 10.1016/j.pharmthera.2019.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 05/24/2019] [Indexed: 02/07/2023]
Abstract
Based on work-done in the rostral ventrolateral medulla (RVLM), this review presents four lessons learnt from studying the differential impacts of oxidative stress and nitrosative stress on sympathetic vasomotor tone and their clinical and therapeutic implications. The first lesson is that an increase in sympathetic vasomotor tone because of augmented oxidative stress in the RVLM is responsible for the generation of neurogenic hypertension. On the other hand, a shift from oxidative stress to nitrosative stress in the RVLM underpins the succession of increase to decrease in sympathetic vasomotor tone during the progression towards brain stem death. The second lesson is that, by having different cellular sources, regulatory mechanisms on synthesis and degradation, kinetics of chemical reactions, and downstream signaling pathways, reactive oxygen species and reactive nitrogen species should not be regarded as a singular moiety. The third lesson is that well-defined differential roles of oxidative stress and nitrosative stress with distinct regulatory mechanisms in the RVLM during neurogenic hypertension and brain stem death clearly denote that they are not interchangeable phenomena with unified cellular actions. Special attention must be paid to their beneficial or detrimental roles under a specific disease or a particular time-window of that disease. The fourth lesson is that, to be successful, future antioxidant therapies against neurogenic hypertension must take into consideration the much more complicated picture than that presented in this review on the generation, maintenance, regulation or modulation of the sympathetic vasomotor tone. The identification that the progression towards brain stem death entails a shift from oxidative stress to nitrosative stress in the RVLM may open a new vista for therapeutic intervention to slow down this transition.
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Affiliation(s)
- Julie Y H Chan
- Institute for Translational Research in Biomedicine, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Samuel H H Chan
- Institute for Translational Research in Biomedicine, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China.
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11
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Shell B, Farmer GE, Nedungadi TP, Wang LA, Marciante AB, Snyder B, Cunningham RL, Cunningham JT. Angiotensin type 1a receptors in the median preoptic nucleus support intermittent hypoxia-induced hypertension. Am J Physiol Regul Integr Comp Physiol 2019; 316:R651-R665. [PMID: 30892911 PMCID: PMC6589598 DOI: 10.1152/ajpregu.00393.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/25/2019] [Accepted: 03/13/2019] [Indexed: 01/19/2023]
Abstract
Chronic intermittent hypoxia (CIH) is a model of the hypoxemia from sleep apnea that causes a sustained increase in blood pressure. Inhibition of the central renin-angiotensin system or FosB in the median preoptic nucleus (MnPO) prevents the sustained hypertensive response to CIH. We tested the hypothesis that angiotensin type 1a (AT1a) receptors in the MnPO, which are upregulated by CIH, contribute to this hypertension. In preliminary experiments, retrograde tract tracing studies showed AT1a receptor expression in MnPO neurons projecting to the paraventricular nucleus. Adult male rats were exposed to 7 days of intermittent hypoxia (cycling between 21% and 10% O2 every 6 min, 8 h/day during light phase). Seven days of CIH was associated with a FosB-dependent increase in AT1a receptor mRNA without changes in the permeability of the blood-brain barrier in the MnPO. Separate groups of rats were injected in the MnPO with an adeno-associated virus containing short hairpin (sh)RNA against AT1a receptors to test their role in intermittent hypoxia hypertension. Injections of shRNA against AT1a in MnPO blocked the increase in mRNA associated with CIH, prevented the sustained component of the hypertension during normoxia, and reduced circulating advanced oxidation protein products, an indicator of oxidative stress. Rats injected with shRNA against AT1a and exposed to CIH had less FosB staining in MnPO and the rostral ventrolateral medulla after intermittent hypoxia than rats injected with the control vector that were exposed to CIH. Our results indicate AT1a receptors in the MnPO contribute to the sustained blood pressure increase to intermittent hypoxia.
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MESH Headings
- Angiotensin II/administration & dosage
- Animals
- Blood Pressure/drug effects
- Disease Models, Animal
- Hypertension/etiology
- Hypertension/genetics
- Hypertension/metabolism
- Hypertension/physiopathology
- Hypoxia/complications
- Hypoxia/genetics
- Hypoxia/metabolism
- Hypoxia/physiopathology
- Injections, Intraventricular
- Male
- Oxidative Stress
- Preoptic Area/drug effects
- Preoptic Area/metabolism
- Preoptic Area/physiopathology
- Proto-Oncogene Proteins c-fos/genetics
- Proto-Oncogene Proteins c-fos/metabolism
- RNA Interference
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Rats, Sprague-Dawley
- Receptor, Angiotensin, Type 1/agonists
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Signal Transduction
- Up-Regulation
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Affiliation(s)
- Brent Shell
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - George E Farmer
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - T Prashant Nedungadi
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Lei A Wang
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Alexandria B Marciante
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Brina Snyder
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Rebecca L Cunningham
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - J Thomas Cunningham
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
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12
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Guyenet PG, Stornetta RL, Holloway BB, Souza GMPR, Abbott SBG. Rostral Ventrolateral Medulla and Hypertension. Hypertension 2019; 72:559-566. [PMID: 30354763 DOI: 10.1161/hypertensionaha.118.10921] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Patrice G Guyenet
- From the Department of Pharmacology, University of Virginia, Charlottesville
| | - Ruth L Stornetta
- From the Department of Pharmacology, University of Virginia, Charlottesville
| | - Benjamin B Holloway
- From the Department of Pharmacology, University of Virginia, Charlottesville
| | - George M P R Souza
- From the Department of Pharmacology, University of Virginia, Charlottesville
| | - Stephen B G Abbott
- From the Department of Pharmacology, University of Virginia, Charlottesville
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13
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Nakayama Y, Fujiu K. Maladaptive Alterations of Autonomic Nerve System in Cardiovascular Disorders. Int Heart J 2019; 60:4-6. [DOI: 10.1536/ihj.18-677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Yukiteru Nakayama
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
| | - Katsuhito Fujiu
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
- Department of Advanced Cardiology, The University of Tokyo
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Szczepanska-Sadowska E, Czarzasta K, Cudnoch-Jedrzejewska A. Dysregulation of the Renin-Angiotensin System and the Vasopressinergic System Interactions in Cardiovascular Disorders. Curr Hypertens Rep 2018; 20:19. [PMID: 29556787 PMCID: PMC5859051 DOI: 10.1007/s11906-018-0823-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Purpose of Review In many instances, the renin-angiotensin system (RAS) and the vasopressinergic system (VPS) are jointly activated by the same stimuli and engaged in the regulation of the same processes. Recent Findings Angiotensin II (Ang II) and arginine vasopressin (AVP), which are the main active compounds of the RAS and the VPS, interact at several levels. Firstly, Ang II, acting on AT1 receptors (AT1R), plays a significant role in the release of AVP from vasopressinergic neurons and AVP, stimulating V1a receptors (V1aR), regulates the release of renin in the kidney. Secondly, Ang II and AVP, acting on AT1R and V1aR, respectively, exert vasoconstriction, increase cardiac contractility, stimulate the sympathoadrenal system, and elevate blood pressure. At the same time, they act antagonistically in the regulation of blood pressure by baroreflex. Thirdly, the cooperative action of Ang II acting on AT1R and AVP stimulating both V1aR and V2 receptors in the kidney is necessary for the appropriate regulation of renal blood flow and the efficient resorption of sodium and water. Furthermore, both peptides enhance the release of aldosterone and potentiate its action in the renal tubules. Summary In this review, we (1) point attention to the role of the cooperative action of Ang II and AVP for the regulation of blood pressure and the water-electrolyte balance under physiological conditions, (2) present the subcellular mechanisms underlying interactions of these two peptides, and (3) provide evidence that dysregulation of the cooperative action of Ang II and AVP significantly contributes to the development of disturbances in the regulation of blood pressure and the water-electrolyte balance in cardiovascular diseases.
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Affiliation(s)
- Ewa Szczepanska-Sadowska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, 02-097, Warsaw, Poland.
| | - Katarzyna Czarzasta
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, 02-097, Warsaw, Poland
| | - Agnieszka Cudnoch-Jedrzejewska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, 02-097, Warsaw, Poland
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15
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Jain S, Puri N, Rana A, Sirianni N, Mopidevi B, Kumar A. Metabolic Syndrome Induces Over Expression of the Human AT1R: A Haplotype-Dependent Effect With Implications on Cardio-Renal Function. Am J Hypertens 2018; 31:495-503. [PMID: 29036458 DOI: 10.1093/ajh/hpx176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 09/27/2017] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The transcriptional regulation of the human angiotensin receptor subtype 1 (AT1R) gene in pathophysiologies, like the metabolic syndrome, is poorly understood. The human AT1R gene has polymorphisms in its promoter that can be arranged in 2 haplotypes. Variants -810T, -713T, -214A, and -153A always occur together (Hap-I) and variants -810A, -713G, -214C, and -153G form Hap-II. We have hypothesized that high fat diet will alter cellular transcriptional milieu and increase hAT1R gene expression in a haplotype-dependent manner. This will set up an AT1R-mediated feed-forward loop promoting inflammation, oxidative stress, and hypertension in Hap-I mice. METHOD Since Hap-I of the human AT1R gene is associated with hypertension in Caucasians, we generated transgenic (TG) mice with Hap-I and Hap-II and studied the physiological significance of high fat diet (HFD) on haplotype specific gene expression. Animals were fed with HFD for 20 weeks followed by blood pressure (BP) analysis and collection of their tissues for molecular and biochemical studies. RESULTS After HFD treatment, as compared to Hap-II, TG mice with Hap-I show increased expression of hAT1R gene and higher BP; suppression of antioxidant defenses (HO1, SOD1) and increased expression of IL-6, TNFα, IL-1β, NOX1. In vivo ChIP assay has shown that transcription factors CEBPβ, STAT3, and USF bind more strongly to the chromatin obtained from Hap-I TG mice. CONCLUSIONS Taken together, our results suggest, that after HFD treatment, as compared to Hap-II, the TG mice with Hap-I overexpress the AT1R gene due to the stronger transcriptional activity, thus resulting in an increase in their BP.
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Affiliation(s)
- Sudhir Jain
- Department of Pathology, Basic Science Building, New York Medical College, Valhalla, New York, USA
| | - Nitin Puri
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, Ohio, USA
| | - Anita Rana
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, Ohio, USA
| | - Natalie Sirianni
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, Ohio, USA
| | - Brahmaraju Mopidevi
- Department of Pathology, Basic Science Building, New York Medical College, Valhalla, New York, USA
| | - Ashok Kumar
- Department of Pathology, Basic Science Building, New York Medical College, Valhalla, New York, USA
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16
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Watso JC, Babcock MC, Migdal KU, Robinson AT. The baroreflex effectiveness index as an early marker of autonomic dysfunction in heart failure. J Physiol 2017; 595:5013-5014. [PMID: 28605038 DOI: 10.1113/jp274664] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Joseph C Watso
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Matthew C Babcock
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Kamila U Migdal
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Austin T Robinson
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
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17
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Becker BK, Wang H, Zucker IH. Central TrkB blockade attenuates ICV angiotensin II-hypertension and sympathetic nerve activity in male Sprague-Dawley rats. Auton Neurosci 2017; 205:77-86. [PMID: 28549782 DOI: 10.1016/j.autneu.2017.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 05/17/2017] [Accepted: 05/17/2017] [Indexed: 02/07/2023]
Abstract
Increased sympathetic nerve activity and the activation of the central renin-angiotensin system are commonly associated with cardiovascular disease states such as hypertension and heart failure, yet the precise mechanisms contributing to the long-term maintenance of this sympatho-excitation are incompletely understood. Due to the established physiological role of neurotrophins contributing toward neuroplasticity and neuronal excitability along with recent evidence linking the renin-angiotensin system and brain-derived neurotrophic factor (BDNF) along with its receptor (TrkB), it is likely the two systems interact to promote sympatho-excitation during cardiovascular disease. However, this interaction has not yet been fully demonstrated, in vivo. Thus, we hypothesized that central angiotensin II (Ang II) treatment will evoke a sympatho-excitatory state mediated through the actions of BDNF/TrkB. We infused Ang II (20ng/min) into the right lateral ventricle of male Sprague-Dawley rats for twelve days with or without the TrkB receptor antagonist, ANA-12 (50ng/h). We found that ICV infusion of Ang II increased mean arterial pressure (+40.4mmHg), increased renal sympathetic nerve activity (+19.4% max activity), and induced baroreflex dysfunction relative to vehicle. Co-infusion of ANA-12 attenuated the increase in blood pressure (-20.6mmHg) and prevented the increase in renal sympathetic nerve activity (-22.2% max) and baroreflex dysfunction relative to Ang II alone. Ang II increased thirst and decreased food consumption, and Ang II+ANA-12 augmented the thirst response while attenuating the decrease in food consumption. We conclude that TrkB signaling is a mediator of the long-term blood pressure and sympathetic nerve activity responses to central Ang II activity. These findings demonstrate the involvement of neurotrophins such as BDNF in promoting Ang II-induced autonomic dysfunction and further implicate TrkB signaling in modulating presympathetic autonomic neurons during cardiovascular disease.
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Affiliation(s)
- Bryan K Becker
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Hanjun Wang
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE, USA.; Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Irving H Zucker
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA..
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18
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Lataro RM, Silva LEV, Silva CAA, Salgado HC, Fazan R. Baroreflex control of renal sympathetic nerve activity in early heart failure assessed by the sequence method. J Physiol 2017; 595:3319-3330. [PMID: 28261799 DOI: 10.1113/jp274065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 03/02/2017] [Indexed: 02/01/2023] Open
Abstract
KEY POINTS The integrity of the baroreflex control of sympathetic activity in heart failure (HF) remains under debate. We proposed the use of the sequence method to assess the baroreflex control of renal sympathetic nerve activity (RSNA). The sequence method assesses the spontaneous arterial pressure (AP) fluctuations and their related changes in heart rate (or other efferent responses), providing the sensitivity and the effectiveness of the baroreflex. Effectiveness refers to the fraction of spontaneous AP changes that elicits baroreflex-mediated variations in the efferent response. Using three different approaches, we showed that the baroreflex sensitivity between AP and RSNA is not altered in early HF rats. However, the sequence method provided evidence that the effectiveness of baroreflex in changing RSNA in response to AP changes is markedly decreased in HF. The results help us better understand the baroreflex control of the sympathetic nerve activity. ABSTRACT In heart failure (HF), the reflex control of the heart rate is known to be markedly impaired; however, the baroreceptor control of the sympathetic drive remains under debate. Applying the sequence method to a series of arterial pressure (AP) and renal sympathetic nerve activity (RSNA), we demonstrated a clear dysfunction in the baroreflex control of sympathetic activity in rats with early HF. We analysed the baroreflex control of the sympathetic drive using three different approaches: AP vs. RSNA curve, cross-spectral analysis and sequence method between AP and RSNA. The sequence method also provides the baroreflex effectiveness index (BEI), which represents the percentage of AP ramps that actually produce a reflex response. The methods were applied to control rats and rats with HF induced by myocardial infarction. None of the methods employed to assess the sympathetic baroreflex gain were able to detect any differences between the control and the HF group. However, rats with HF exhibited a lower BEI compared to the controls. Moreover, an optimum delay of 1 beat was observed, i.e. 1 beat is required for the RSNA to respond after AP changing, which corroborates with the findings related to the timing between these two variables. For delay 1, the BEI of the controls was 0.45 ± 0.03, whereas the BEI of rats with HF was 0.29 ± 0.09 (P < 0.05). These data demonstrate that while the gain of the baroreflex is not affected in early HF, its effectiveness is markedly decreased. The analysis of the spontaneous changes in AP and RSNA using the sequence method provides novel insights into arterial baroreceptor reflex function.
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Affiliation(s)
- Renata Maria Lataro
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luiz Eduardo Virgilio Silva
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Carlos Alberto Aguiar Silva
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Helio Cesar Salgado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Rubens Fazan
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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Moura AG, Pires W, Leite LH, da Cunha DNQ, Peçanha T, de Lima JRP, Natali AJ, Prímola-Gomes TN. Power spectrum analysis of cardiovascular variability during passive heating in conscious rats. J Therm Biol 2016; 62:20-29. [DOI: 10.1016/j.jtherbio.2016.08.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 08/05/2016] [Accepted: 08/22/2016] [Indexed: 11/28/2022]
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20
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Ichige MHA, Santos CR, Jordão CP, Ceroni A, Negrão CE, Michelini LC. Exercise training preserves vagal preganglionic neurones and restores parasympathetic tonus in heart failure. J Physiol 2016; 594:6241-6254. [PMID: 27444212 PMCID: PMC5088253 DOI: 10.1113/jp272730] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 07/08/2016] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS Heart Failure (HF) is accompanied by reduced ventricular function, activation of compensatory neurohormonal mechanisms and marked autonomic dysfunction characterized by exaggerated sympathoexcitation and reduced parasympathetic activity. With 6 weeks of exercise training, HF-related loss of choline acetyltransferase (ChAT)-positive vagal preganglionic neurones is avoided, restoring the parasympathetic tonus to the heart, and the immunoreactivity of dopamine β-hydroxylase-positive premotor neurones that drive sympathetic outflow to the heart is reduced. Training-induced correction of autonomic dysfunction occurs even with the persistence of abnormal ventricular function. Strong positive correlation between improved parasympathetic tonus to the heart and increased ChAT immunoreactivity in vagal preganglionic neurones after training indicates this is a crucial mechanism to restore autonomic function in heart failure. ABSTRACT Exercise training is an efficient tool to attenuate sympathoexcitation, a hallmark of heart failure (HF). Although sympathetic modulation in HF is widely studied, information regarding parasympathetic control is lacking. We examined the combined effects of sympathetic and vagal tonus to the heart in sedentary (Sed) and exercise trained (ET) HF rats and the contribution of respective premotor and preganglionic neurones. Wistar rats submitted to coronary artery ligation or sham surgery were assigned to training or sedentary protocols for 6 weeks. After haemodynamic, autonomic tonus (atropine and atenolol i.v.) and ventricular function determinations, brains were collected for immunoreactivity assays (choline acetyltransferase, ChATir; dopamine β-hydroxylase, DBHir) and neuronal counting in the dorsal motor nucleus of vagus (DMV), nucleus ambiguus (NA) and rostroventrolateral medulla (RVLM). HF-Sed vs. SHAM-Sed exhibited decreased exercise capacity, reduced ejection fraction, increased left ventricle end diastolic pressure, smaller positive and negative dP/dt, decreased intrinsic heart rate (IHR), lower parasympathetic and higher sympathetic tonus, reduced preganglionic vagal neurones and ChATir in the DMV/NA, and increased RVLM DBHir. Training increased treadmill performance, normalized autonomic tonus and IHR, restored the number of DMV and NA neurones and corrected ChATir without affecting ventricular function. There were strong positive correlations between parasympathetic tonus and ChATir in NA and DMV. RVLM DBHir was also normalized by training, but there was no change in neurone number and no correlation with sympathetic tonus. Training-induced preservation of preganglionic vagal neurones is crucial to normalize parasympathetic activity and restore autonomic balance to the heart even in the persistence of cardiac dysfunction.
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Affiliation(s)
- Marcelo H A Ichige
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Carla R Santos
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Camila P Jordão
- Heart Institute, University of Sao Paulo, Medical School, Sao Paulo, SP, Brazil
| | - Alexandre Ceroni
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Carlos E Negrão
- Heart Institute, University of Sao Paulo, Medical School, Sao Paulo, SP, Brazil
- School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Lisete C Michelini
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of Sao Paulo, Sao Paulo, SP, Brazil.
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21
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Becker BK, Tian C, Zucker IH, Wang HJ. Influence of brain-derived neurotrophic factor-tyrosine receptor kinase B signalling in the nucleus tractus solitarius on baroreflex sensitivity in rats with chronic heart failure. J Physiol 2016; 594:5711-25. [PMID: 27151332 PMCID: PMC5043030 DOI: 10.1113/jp272318] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/28/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Impairment of baroreflex function is associated with the progression of chronic heart failure (CHF) and a poor prognosis. The baroreflex desensitization in CHF is at least partly the result of central neuronal network dysfunction. The dorsal medial nucleus tractus solitarius (dmNTS) has long been appreciated as a primary site of baroreceptor afferent termination in the central nervous system. However, the influence of neurotransmitters and neuromodulators in the dmNTS on baroreflex function both in normal and CHF states is not fully understood. The present study provides the first evidence showing a tonic sympatho-inhibitory role for brain-derived neurotrophic factor (BDNF) neurotransmission in the dmNTS. Most importantly, BDNF- tyrosine receptor kinase B (TrkB) signalling in the dmNTS is integral for normal baroreflex function as indicated by the blunting of baroreflex sensitivity (BRS) following the antagonization of TrkB, which inhibited baroreflex gain and range. Furthermore, we found that the tonic sympatho-inhibition of BDNF was withdrawn in the CHF state, thus contributing to the increased sympathetic tone associated with CHF. Consistent with this finding, BDNF/TrkB antagonism had little effect on reducing BRS in CHF animals, which is corroborated by the observation of decreased TrkB expression in the dmNTS during CHF. Taken together, these results implicate a reduction in BDNF-TrkB signalling in the dmNTS during CHF that contributes to sympatho-excitation and baroreflex desensitization. The observation that the BDNF/TrkB pathway is impaired in the dmNTS during CHF provides a novel mechanism for understanding the central alterations that contribute to baroreflex desensitization during CHF. ABSTRACT Chronic heart failure (CHF) results in blunting of arterial baroreflex sensitivity (BRS), which arises from alterations to both peripheral baroreceptors and central autonomic nuclei such as the nucleus tractus solitarius (NTS). Although glutamate is known to be an important neurotransmitter released from baroreceptor afferent synapses in the NTS, the influence of other neurotransmitters and neuromodulators remains unclear. Alterations to NTS signalling in CHF remain particularly undefined. The present study aimed to evaluate the role of brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB) receptor signalling in the NTS on baroreflex control both in healthy and CHF rats. To this end, we microinjected BDNF or the highly selective TrkB receptor antagonist [N2-2-2-oxoazepan-3-yl amino] carbonyl phenyl benzo (b)thiophene-2-carboxamide (ANA-12) into the dorsal medial NTS (dmNTS) of male Sprague-Dawley rats with coronary artery ligation-induced CHF and sham operated controls and recorded blood pressure and renal sympathetic nerve activity responses. We subsequently measured BRS before and after bilateral dmNTS microinjections of ANA-12. In sham rats, BDNF evoked a dose-dependent depressor and sympatho-inhibitory effect and ANA-12 produced the opposite response. Both of these responses were significantly blunted in CHF rats. Furthermore, bilateral microinjection of ANA-12 into the dmNTS greatly diminished baroreflex sensitivity in sham rats, whereas it had less of an effect in CHF rats. We observed decreased levels of TrkB protein and mRNA in the dmNTS of CHF rats. These data indicate that endogenous BDNF signalling in the NTS is integral for the maintenance of BRS and that BDNF/TrkB signalling is impaired in the NTS in the CHF state.
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Affiliation(s)
- Bryan K Becker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Nephrology/Cardio-Renal Physiology and Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Changhai Tian
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Irving H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Han-Jun Wang
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA.
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE, USA.
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Gowrisankar YV, Clark MA. Angiotensin II regulation of angiotensin-converting enzymes in spontaneously hypertensive rat primary astrocyte cultures. J Neurochem 2016; 138:74-85. [PMID: 27085714 DOI: 10.1111/jnc.13641] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 03/03/2016] [Accepted: 03/23/2016] [Indexed: 02/07/2023]
Abstract
Angiotensin (Ang) II plays a critical role in cardiovascular and blood pressure regulation. Ang II is produced by angiotensin-converting enzyme (ACE) and it interacts with the Ang AT1 receptor to cause much of its well-known cardiovascular effects. Ang-(1-7) is another active peptide produced by the rennin-angiotensin system. This peptide is produced from Ang I or Ang II by the catalytic activity of ACE2. Ang-(1-7) interacts with the Mas receptor to counteract many of the effects of Ang II. Thus, the ACE2/Ang-(1-7)/Mas axis acts opposite of the ACE/Ang II/AT1 axis. In this study we investigated how Ang II regulates the key enzymes of these axes, ACE and its homolog ACE2, and determined whether they are dysregulated in the hypertensive condition. Brainstem and cerebellum astrocytes isolated from the spontaneously hypertensive rat (SHR) were used in these studies. Ang II effect on the enzymes' mRNA and protein levels was measured using quantitative PCR and western blotting techniques, respectively. Results from this study showed that Ang II up-regulated ACE protein levels, but down-regulated ACE mRNA levels in brainstem and cerebellum astrocytes in both models. Ang II also reduced ACE2 mRNA expression in SHR and Wistar astrocytes isolated from both brain regions. Ang II effects on ACE2 protein were biphasic. In SHR astrocytes, Ang II-mediated ACE2 protein initially increased then decreased at later time points. In contrast, in Wistar astrocytes, Ang II initially decreased ACE2 protein expression, but up-regulated the protein at later time points. The findings of these studies suggest that Ang II has a differential effect on ACE and ACE2 expression. Furthermore, in the SHR model there may be alteration in the ACE/ACE2 balance in a manner that favors increased Ang II generation and decreased Ang-(1-7) production contributing to the hypertensive phenotype observed in this model. The levels of angiotensin (Ang) II depend on the actions of angiotensin-converting enzyme (ACE) and ACE2. We showed in astrocytes isolated from the SHRs that Ang II differentially affects ACE and ACE2 expression. There may be an alteration in the ACE/ACE2 balance favoring Ang II generation. This imbalance may contribute to the hypertensive phenotype observed in this SHR model.
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Affiliation(s)
- Yugandhar V Gowrisankar
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, Florida, USA
| | - Michelle A Clark
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, Florida, USA
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Abstract
Circulatory homeostasis is associated with interactions between multiple organs, and the disruption of dynamic circulatory homeostasis could be considered as heart failure. The brain is the central unit integrating neural and neurohormonal information from peripheral organs and controlling peripheral organs using the autonomic nervous system. Heart failure is worsened by abnormal sympathoexcitation associated with baroreflex failure and/or chemoreflex activation, and by vagal withdrawal, and autonomic modulation therapies have benefits for heart failure. Recently, we showed that baroreflex failure induces striking volume intolerance independent of left ventricular dysfunction. Many studies have indicated that an overactive renin-angiotensin system, excess oxidative stress and excess inflammation, and/or decreased nitric oxide in the brain cause sympathoexcitation in heart failure. We have demonstrated that angiotensin II type 1 receptor (AT1R)-induced oxidative stress in the rostral ventrolateral medulla (RVLM), which is known as a vasomotor center, causes prominent sympathoexcitation in heart failure model rats. Interestingly, systemic infusion of angiotensin II directly affects brain AT1R with sympathoexcitation and left ventricular diastolic dysfunction. Moreover, we have demonstrated that targeted deletion of AT1R in astrocytes strikingly improved survival with prevention of left ventricular remodeling and sympathoinhibition in myocardial infarction-induced heart failure. From these results, we believe it is possible that AT1R in astrocytes, not in neurons, have a key role in the pathophysiology of heart failure. We would like to propose a novel concept that the brain works as a central processing unit integrating neural and hormonal input, and that the disruption of dynamic circulatory homeostasis mediated by the brain causes heart failure.
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Affiliation(s)
- Takuya Kishi
- Collaborative Research Institute of Innovation for Cardiovascular Diseases, Kyushu University Center for Disruptive Cardiovascular Medicine
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24
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Effect of angiotensin II on voltage-gated sodium currents in aortic baroreceptor neurons and arterial baroreflex sensitivity in heart failure rats. J Hypertens 2016; 33:1401-10. [PMID: 25827427 DOI: 10.1097/hjh.0000000000000563] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Impairment of arterial baroreflex sensitivity is associated with mortality in patients with chronic heart failure (CHF). Elevation of plasma angiotension II (Ang II) contributes to arterial baroreflex dysfunction in CHF. A reduced number of voltage-gated sodium (Nav) channels in aortic baroreceptor neurons are involved in CHF-blunted arterial baroreflex. METHOD In this study, we investigated acute effect of Ang II on Nav currents in the aortic baroreceptor neuron and on arterial baroreflex in sham and coronary artery ligation-induced CHF rats. RESULTS Using Ang II I radioimmunoassay, real-time reverse transcription-PCR and western blot, we found that Ang II levels, and mRNA and protein expression of angiotension II type 1 receptor in nodose ganglia from CHF rats were higher than that from sham rats. Local microinjection of Ang II (0.2 nmol) into the nodose ganglia decreased the arterial baroreflex sensitivity in sham rats, whereas losartan (1 nmol, an angiotension II type 1 receptor antagonist) improved the arterial baroreflex sensitivity in CHF rats. Data from patch-clamp recording showed that Ang II (100 nmol/l) acutely inhibited Nav currents in the aortic baroreceptor neurons from sham and CHF rats. In particular, inhibitory effect of Ang II on Nav currents in the aortic baroreceptor neurons was larger in CHF rats than that in sham rats. Losartan (1 μmol/l) totally abolished the inhibitory effect of Ang II on Nav currents in sham and CHF aortic baroreceptor neurons. CONCLUSION These results suggest that elevation of endogenous Ang II in the nodose ganglia contributes to impairment of the arterial baroreflex function in CHF rats through inhibiting Nav channels.
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Becker BK, Wang HJ, Tian C, Zucker IH. BDNF contributes to angiotensin II-mediated reductions in peak voltage-gated K+ current in cultured CATH.a cells. Physiol Rep 2015; 3:3/11/e12598. [PMID: 26537343 PMCID: PMC4673628 DOI: 10.14814/phy2.12598] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Increased central angiotensin II (Ang II) levels contribute to sympathoexcitation in cardiovascular disease states such as chronic heart failure and hypertension. One mechanism by which Ang II increases neuronal excitability is through a decrease in voltage-gated, rapidly inactivating K+ current (IA); however, little is known about how Ang II signaling results in reduced IA. Brain-derived neurotrophic factor (BDNF) has also been demonstrated to decrease IA and has signaling components common to Ang II. Therefore, we hypothesized that Ang II-mediated suppression of voltage-gated K+ currents is due, in part, to BDNF signaling. Differentiated CATH.a, catecholaminergic cell line treated with BDNF for 2 h exhibited a reduced IA in a manner similar to that of Ang II treatment as demonstrated by whole-cell patch-clamp analysis. Inhibiting BDNF signaling by pretreating neurons with an antibody against BDNF significantly attenuated the Ang II-induced reduction of IA. Inhibition of a common component of both BDNF and Ang II signaling, p38 MAPK, with SB-203580 attenuated the BDNF-mediated reductions in IA. These results implicate the involvement of BDNF signaling in Ang II-induced reductions of IA, which may cause increases in neuronal sensitivity and excitability. We therefore propose that BDNF may be a necessary component of the mechanism by which Ang II reduces IA in CATH.a cells.
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Affiliation(s)
- Bryan K Becker
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Han-Jun Wang
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Changhai Tian
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Irving H Zucker
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
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Zhang D, Muelleman RL, Li YL. Angiotensin II-superoxide-NFκB signaling and aortic baroreceptor dysfunction in chronic heart failure. Front Neurosci 2015; 9:382. [PMID: 26528122 PMCID: PMC4607814 DOI: 10.3389/fnins.2015.00382] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/02/2015] [Indexed: 11/13/2022] Open
Abstract
Chronic heart failure (CHF) affects approximately 5.7 million people in the United States. Increasing evidence from both clinical and experimental studies indicates that the sensitivity of arterial baroreflex is blunted in the CHF state, which is a predictive risk factor for sudden cardiac death. Normally, the arterial baroreflex regulates blood pressure and heart rate through sensing mechanical alteration of arterial vascular walls by baroreceptor terminals in the aortic arch and carotid sinus. There are aortic baroreceptor neurons in the nodose ganglion (NG), which serve as the main afferent component of the arterial baroreflex. Functional changes of baroreceptor neurons are involved in the arterial baroreflex dysfunction in CHF. In the CHF state, circulating angiotensin II (Ang II) and local Ang II concentration in the NG are elevated, and AT1R mRNA and protein are overexpressed in the NG. Additionally, Ang II-superoxide-NFκB signaling pathway regulates the neuronal excitability of aortic baroreceptors through influencing the expression and activation of Nav channels in aortic baroreceptors, and subsequently causes the impairment of the arterial baroreflex in CHF. These new findings provide a basis for potential pharmacological interventions for the improvement of the arterial baroreflex sensitivity in the CHF state. This review summarizes the mechanisms responsible for the arterial baroreflex dysfunction in CHF.
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Affiliation(s)
- Dongze Zhang
- Department of Emergency Medicine, University of Nebraska Medical Center Omaha, NE, USA
| | - Robert L Muelleman
- Department of Emergency Medicine, University of Nebraska Medical Center Omaha, NE, USA
| | - Yu-Long Li
- Department of Emergency Medicine, University of Nebraska Medical Center Omaha, NE, USA
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27
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Hardwick JC, Ryan SE, Powers EN, Southerland EM, Ardell JL. Angiotensin receptors alter myocardial infarction-induced remodeling of the guinea pig cardiac plexus. Am J Physiol Regul Integr Comp Physiol 2015; 309:R179-88. [PMID: 25947168 PMCID: PMC4504959 DOI: 10.1152/ajpregu.00004.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 04/29/2015] [Indexed: 01/08/2023]
Abstract
Neurohumoral remodeling is fundamental to the evolution of heart disease. This study examined the effects of chronic treatment with an ACE inhibitor (captopril, 3 mg·kg(-1)·day(-1)), AT1 receptor antagonist (losartan, 3 mg·kg(-1)·day(-1)), or AT2 receptor agonist (CGP42112A, 0.14 mg·kg(-1)·day(-1)) on remodeling of the guinea pig intrinsic cardiac plexus following chronic myocardial infarction (MI). MI was surgically induced and animals recovered for 6 or 7 wk, with or without drug treatment. Intracellular voltage recordings from whole mounts of the cardiac plexus were used to monitor changes in neuronal responses to norepinephrine (NE), muscarinic agonists (bethanechol), or ANG II. MI produced an increase in neuronal excitability with NE and a loss of sensitivity to ANG II. MI animals treated with captopril exhibited increased neuronal excitability with NE application, while MI animals treated with CGP42112A did not. Losartan treatment of MI animals did not alter excitability with NE compared with untreated MIs, but these animals did show an enhanced synaptic efficacy. This effect on synaptic function was likely due to presynaptic AT1 receptors, since ANG II was able to reduce output to nerve fiber stimulation in control animals, and this effect was prevented by inclusion of losartan in the bath solution. Analysis of AT receptor expression by Western blot showed a decrease in both AT1 and AT2 receptors with MI that was reversed by all three drug treatments. These data indicate that neuronal remodeling of the guinea pig cardiac plexus following MI is mediated, in part, by activation of both AT1 and AT2 receptors.
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MESH Headings
- Action Potentials
- Angiotensin II/pharmacology
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Angiotensin II Type 2 Receptor Blockers/pharmacology
- Animals
- Disease Models, Animal
- Electric Stimulation
- Evoked Potentials
- Guinea Pigs
- Heart/innervation
- Male
- Myocardial Infarction/metabolism
- Myocardial Infarction/pathology
- Myocardial Infarction/physiopathology
- Norepinephrine/pharmacology
- Presynaptic Terminals/drug effects
- Presynaptic Terminals/metabolism
- Receptor, Angiotensin, Type 1/drug effects
- Receptor, Angiotensin, Type 1/metabolism
- Receptor, Angiotensin, Type 2/drug effects
- Receptor, Angiotensin, Type 2/metabolism
- Receptors, Presynaptic/antagonists & inhibitors
- Receptors, Presynaptic/metabolism
- Signal Transduction
- Time Factors
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Affiliation(s)
| | | | | | - E Marie Southerland
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Jeffrey L Ardell
- University of California at Los Angeles (UCLA) Neurocardiology Research Center of Excellence, Los Angeles, California; and UCLA Cardiac Arrhythmia Center, Los Angeles, California
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28
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Yu Y, Xue BJ, Wei SG, Zhang ZH, Beltz TG, Guo F, Johnson AK, Felder RB. Activation of central PPAR-γ attenuates angiotensin II-induced hypertension. Hypertension 2015; 66:403-11. [PMID: 26101342 DOI: 10.1161/hypertensionaha.115.05726] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 05/20/2015] [Indexed: 01/17/2023]
Abstract
Inflammation and renin-angiotensin system activity in the brain contribute to hypertension through effects on fluid intake, vasopressin release, and sympathetic nerve activity. We recently reported that activation of brain peroxisome proliferator-activated receptor (PPAR)-γ in heart failure rats reduced inflammation and renin-angiotensin system activity in the hypothalamic paraventricular nucleus and ameliorated the peripheral manifestations of heart failure. We hypothesized that the activation of brain PPAR-γ might have beneficial effects in angiotensin II-induced hypertension. Sprague-Dawley rats received a 2-week subcutaneous infusion of angiotensin II (120 ng/kg per minute) combined with a continuous intracerebroventricular infusion of vehicle, the PPAR-γ agonist pioglitazone (3 nmol/h) or the PPAR-γ antagonist GW9662 (7 nmol/h). Angiotensin II+vehicle rats had increased mean blood pressure, increased sympathetic drive as indicated by the mean blood pressure response to ganglionic blockade, and increased water consumption. PPAR-γ mRNA in subfornical organ and hypothalamic paraventricular nucleus was unchanged, but PPAR-γ DNA-binding activity was reduced. mRNA for interleukin-1β, tumor necrosis factor-α, cyclooxygenase-2, and angiotensin II type 1 receptor was augmented in both nuclei, and hypothalamic paraventricular nucleus neuronal activity was increased. The plasma vasopressin response to a 6-hour water restriction also increased. These responses to angiotensin II were exacerbated by GW9662 and ameliorated by pioglitazone, which increased PPAR-γ mRNA and PPAR-γ DNA-binding activity in subfornical organ and hypothalamic paraventricular nucleus. Pioglitazone and GW9662 had no effects on control rats. The results suggest that activating brain PPAR-γ to reduce central inflammation and brain renin-angiotensin system activity may be a useful adjunct in the treatment of angiotensin II-dependent hypertension.
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Affiliation(s)
- Yang Yu
- From the Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine (Y.Y., S.-G.W., Z.-H.Z., R.B.F.) and Department of Psychological and Brain Sciences (B.-.J.X., T.G.B., F.G., A.K.J.), University of Iowa, Iowa City; and Research Service, Veterans Affairs Medical Center, Iowa City, IA (R.B.F.)
| | - Bao-Jian Xue
- From the Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine (Y.Y., S.-G.W., Z.-H.Z., R.B.F.) and Department of Psychological and Brain Sciences (B.-.J.X., T.G.B., F.G., A.K.J.), University of Iowa, Iowa City; and Research Service, Veterans Affairs Medical Center, Iowa City, IA (R.B.F.)
| | - Shun-Guang Wei
- From the Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine (Y.Y., S.-G.W., Z.-H.Z., R.B.F.) and Department of Psychological and Brain Sciences (B.-.J.X., T.G.B., F.G., A.K.J.), University of Iowa, Iowa City; and Research Service, Veterans Affairs Medical Center, Iowa City, IA (R.B.F.)
| | - Zhi-Hua Zhang
- From the Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine (Y.Y., S.-G.W., Z.-H.Z., R.B.F.) and Department of Psychological and Brain Sciences (B.-.J.X., T.G.B., F.G., A.K.J.), University of Iowa, Iowa City; and Research Service, Veterans Affairs Medical Center, Iowa City, IA (R.B.F.)
| | - Terry G Beltz
- From the Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine (Y.Y., S.-G.W., Z.-H.Z., R.B.F.) and Department of Psychological and Brain Sciences (B.-.J.X., T.G.B., F.G., A.K.J.), University of Iowa, Iowa City; and Research Service, Veterans Affairs Medical Center, Iowa City, IA (R.B.F.)
| | - Fang Guo
- From the Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine (Y.Y., S.-G.W., Z.-H.Z., R.B.F.) and Department of Psychological and Brain Sciences (B.-.J.X., T.G.B., F.G., A.K.J.), University of Iowa, Iowa City; and Research Service, Veterans Affairs Medical Center, Iowa City, IA (R.B.F.)
| | - Alan Kim Johnson
- From the Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine (Y.Y., S.-G.W., Z.-H.Z., R.B.F.) and Department of Psychological and Brain Sciences (B.-.J.X., T.G.B., F.G., A.K.J.), University of Iowa, Iowa City; and Research Service, Veterans Affairs Medical Center, Iowa City, IA (R.B.F.)
| | - Robert B Felder
- From the Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine (Y.Y., S.-G.W., Z.-H.Z., R.B.F.) and Department of Psychological and Brain Sciences (B.-.J.X., T.G.B., F.G., A.K.J.), University of Iowa, Iowa City; and Research Service, Veterans Affairs Medical Center, Iowa City, IA (R.B.F.).
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29
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Mischel NA, Subramanian M, Dombrowski MD, Llewellyn-Smith IJ, Mueller PJ. (In)activity-related neuroplasticity in brainstem control of sympathetic outflow: unraveling underlying molecular, cellular, and anatomical mechanisms. Am J Physiol Heart Circ Physiol 2015; 309:H235-43. [PMID: 25957223 DOI: 10.1152/ajpheart.00929.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 05/08/2015] [Indexed: 02/07/2023]
Abstract
More people die as a result of physical inactivity than any other preventable risk factor including smoking, high cholesterol, and obesity. Cardiovascular disease, the number one cause of death in the United States, tops the list of inactivity-related diseases. Nevertheless, the vast majority of Americans continue to make lifestyle choices that are creating a rapidly growing burden of epidemic size and impact on the United States healthcare system. It is imperative that we improve our understanding of the mechanisms by which physical inactivity increases the incidence of cardiovascular disease and how exercise can prevent or rescue the inactivity phenotype. The current review summarizes research on changes in the brain that contribute to inactivity-related cardiovascular disease. Specifically, we focus on changes in the rostral ventrolateral medulla (RVLM), a critical brain region for basal and reflex control of sympathetic activity. The RVLM is implicated in elevated sympathetic outflow associated with several cardiovascular diseases including hypertension and heart failure. We hypothesize that changes in the RVLM contribute to chronic cardiovascular disease related to physical inactivity. Data obtained from our translational rodent models of chronic, voluntary exercise and inactivity suggest that functional, anatomical, and molecular neuroplasticity enhances glutamatergic neurotransmission in the RVLM of sedentary animals. Collectively, the evidence presented here suggests that changes in the RVLM resulting from sedentary conditions are deleterious and contribute to cardiovascular diseases that have an increased prevalence in sedentary individuals. The mechanisms by which these changes occur over time and their impact are important areas for future study.
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Affiliation(s)
- Nicholas A Mischel
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Madhan Subramanian
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Maryetta D Dombrowski
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Ida J Llewellyn-Smith
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and Cardiovascular Medicine, Physiology and Centre for Neuroscience, School of Medicine, Flinders University, Bedford Park, South Australia, Australia
| | - Patrick J Mueller
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
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30
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Zucker IH, Schultz HD, Patel KP, Wang H. Modulation of angiotensin II signaling following exercise training in heart failure. Am J Physiol Heart Circ Physiol 2015; 308:H781-91. [PMID: 25681422 PMCID: PMC4398865 DOI: 10.1152/ajpheart.00026.2015] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 02/04/2015] [Indexed: 02/07/2023]
Abstract
Sympathetic activation is a consistent finding in the chronic heart failure (CHF) state. Current therapy for CHF targets the renin-angiotensin II (ANG II) and adrenergic systems. Angiotensin converting enzyme (ACE) inhibitors and ANG II receptor blockers are standard treatments along with β-adrenergic blockade. However, the mortality and morbidity of this disease is still extremely high, even with good medical management. Exercise training (ExT) is currently being used in many centers as an adjunctive therapy for CHF. Clinical studies have shown that ExT is a safe, effective, and inexpensive way to improve quality of life, work capacity, and longevity in patients with CHF. This review discusses the potential neural interactions between ANG II and sympatho-excitation in CHF and the modulation of this interaction by ExT. We briefly review the current understanding of the modulation of the angiotensin type 1 receptor in sympatho-excitatory areas of the brain and in the periphery (i.e., in the carotid body and skeletal muscle). We discuss possible cellular mechanisms by which ExT may impact the sympatho-excitatory process by reducing oxidative stress, increasing nitric oxide. and reducing ANG II. We also discuss the potential role of ACE2 and Ang 1-7 in the sympathetic response to ExT. Fruitful areas of further investigation are the role and mechanisms by which pre-sympathetic neuronal metabolic activity in response to individual bouts of exercise regulate redox mechanisms and discharge at rest in CHF and other sympatho-excitatory states.
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Affiliation(s)
- Irving H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Harold D Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Kaushik P Patel
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Hanjun Wang
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
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31
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Abstract
The role of the brain in hypertension between the sexes is known to be important especially with regards to the effects of circulating sex hormones. A number of different brain regions important for regulation of sympathetic outflow and blood pressure express estrogen receptors (ERα and ERβ). Estradiol, acting predominantly via the ERα, inhibits angiotensin II activation of the area postrema and subfornical organ neurons and inhibits reactive oxygen generation that is required for the development of Angiotensin II-induced neurogenic hypertension. Estradiol activation of ERβ within the paraventricular nucleus and the rostral ventral lateral medulla inhibits these neurons and inhibits angiotensin II, or aldosterone induced increases in sympathetic outflow and hypertension. Understanding the cellular and molecular mechanisms underlying ERα and ERβ actions within key brain regions regulating blood pressure will be essential for the development of "next generation" selective estrogen receptor modulators (SERMS) that can be used clinically for the treatment of neurogenic hypertension.
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Affiliation(s)
- Meredith Hay
- Department of Physiology, University of Arizona, 1501 N Campbell Rd Bldg 201, Rm 4103, Tucson, AZ, 85724, USA,
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32
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Zhang W, Chen L, Zhang L, Xiao M, Ding J, Goltzman D, Miao D. Administration of exogenous 1,25(OH)2D3 normalizes overactivation of the central renin-angiotensin system in 1α(OH)ase knockout mice. Neurosci Lett 2015; 588:184-9. [PMID: 25576706 DOI: 10.1016/j.neulet.2015.01.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/31/2014] [Accepted: 01/05/2015] [Indexed: 12/21/2022]
Abstract
Previously, we reported that active vitamin D deficiency in mice causes secondary hypertension and cardiac dysfunction, but the underlying mechanism remains largely unknown. To clarify whether exogenous active vitamin D rescues hypertension by normalizing the altered central renin-angiotensin system (RAS) via an antioxidative stress mechanism, 1-alpha-hydroxylase [1α(OH)ase] knockout mice [1α(OH)ase(-/-)] and their wild-type littermates were fed a normal diet alone or with 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], or a high-calcium, high-phosphorus "rescue" diet with or without antioxidant N-acetyl-l-cysteine (NAC) supplementation for 4 weeks. Compared with their wild-type littermates, 1α(OH)ase(-/-)mice had high mean arterial pressure, increased levels of renin, angiotensin II (Ang II), and Ang II type 1 receptor, and increased malondialdehyde levels, but decreased anti-peroxiredoxin I and IV proteins and the antioxidative genes glutathione reductase (Gsr) and glutathione peroxidase 4 (Gpx4) in the brain samples. Except Ang II type 1 receptor, these pathophysiological changes were rescued by exogenous 1,25(OH)2D3 or NAC plus rescue diet, but not by rescue diet alone. We conclude that 1,25(OH)2D3 normalizes the altered central RAS in 1α(OH)ase(-/-)mice, at least partially, through a central antioxidative mechanism.
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Affiliation(s)
- Wei Zhang
- Department of Human Anatomy, Nanjing Medical University, Nanjing, Jiangsu 210029, PR China; Department of Human Anatomy, Kangda College, Lianyungang, PR China
| | - Lulu Chen
- Department of Human Anatomy, Nanjing Medical University, Nanjing, Jiangsu 210029, PR China
| | - Luqing Zhang
- Department of Human Anatomy, Nanjing Medical University, Nanjing, Jiangsu 210029, PR China.
| | - Ming Xiao
- Department of Human Anatomy, Nanjing Medical University, Nanjing, Jiangsu 210029, PR China
| | - Jiong Ding
- Department of Human Anatomy, Nanjing Medical University, Nanjing, Jiangsu 210029, PR China
| | - David Goltzman
- Calcium Research Laboratory, McGill University Health Center and Department of Medicine, McGill University, Montréal, Québec, Canada
| | - Dengshun Miao
- Department of Human Anatomy, Nanjing Medical University, Nanjing, Jiangsu 210029, PR China
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Scrutinio D, Agostoni P, Gesualdo L, Corrà U, Mezzani A, Piepoli M, Di Lenarda A, Iorio A, Passino C, Magrì D, Masarone D, Battaia E, Girola D, Re F, Cattadori G, Parati G, Sinagra G, Villani GQ, Limongelli G, Pacileo G, Guazzi M, Metra M, Frigerio M, Cicoira M, Minà C, Malfatto G, Caravita S, Bussotti M, Salvioni E, Veglia F, Correale M, Scardovi AB, Emdin M, Giannuzzi P, Gargiulo P, Giovannardi M, Perrone-Filardi P, Raimondo R, Ricci R, Paolillo S, Farina S, Belardinelli R, Passantino A, La Gioia R. Renal Function and Peak Exercise Oxygen Consumption in Chronic Heart Failure With Reduced Left Ventricular Ejection Fraction. Circ J 2015; 79:583-91. [DOI: 10.1253/circj.cj-14-0806] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Domenico Scrutinio
- Division of Cardiology, “S. Maugeri” Foundation, IRCCS, Institute of Cassano Murge
| | - Piergiuseppe Agostoni
- Centro Cardiologico Monzino, IRCCS
- Department of Clinical Sciences and Community Health, Cardiovascular Section, University of Milano
| | - Loreto Gesualdo
- Renal, Dialysis and Transplant Unit, Department of Emergency and Organ Transplantation, University of Bari
| | - Ugo Corrà
- Division of Cardiology Rehabilitation, “S. Maugeri” Foundation, IRCCS, Scientific Institute of Veruno
| | - Alessandro Mezzani
- Division of Cardiology Rehabilitation, “S. Maugeri” Foundation, IRCCS, Scientific Institute of Veruno
| | | | - Andrea Di Lenarda
- Cardiovascular Center, Health Authority no.°1 and University of Trieste
| | - Annamaria Iorio
- Cardiovascular Department, Ospedali Riuniti and University of Trieste
| | - Claudio Passino
- Gabriele Monasterio Foundation, CNR-Regione Toscana
- Scuola Superiore S. Anna
| | - Damiano Magrì
- Department of Clinical and Molecular Medicine, Azienda Ospedaliera Sant’Andrea, “Sapienza” University of Roma
| | - Daniele Masarone
- Cardiology SUN, Monaldi Hospital (Azienda dei Colli), Second University of Napoli
| | - Elisa Battaia
- Section of Cardiology, Department of Medicine, University of Verona
| | - Davide Girola
- Cardiologic Department “A. De Gasperis”, Cà Granda-A.O. Hospital Niguarda
| | - Federica Re
- Cardiology Division, Cardiac Arrhythmia Center and Cardiomyopathies Unit, San Camillo-Forlanini Hospital
| | | | - Gianfranco Parati
- Department of Health Science, University of Milano Bicocca & Department of Cardiology, San Luca Hospital, Istituto Auxologico Italiano
| | | | | | - Giuseppe Limongelli
- Cardiology SUN, Monaldi Hospital (Azienda dei Colli), Second University of Napoli
| | - Giuseppe Pacileo
- Cardiology SUN, Monaldi Hospital (Azienda dei Colli), Second University of Napoli
| | - Marco Guazzi
- Heart Failure Unit, IRCCS Policlinico San Donato
| | - Marco Metra
- Cardiology, Department of Medical and Surgical Specialities, Radiological Sciences, and Public Health, University of Brescia
| | - Maria Frigerio
- Cardiologic Department “A. De Gasperis”, Cà Granda-A.O. Hospital Niguarda
| | | | - Chiara Minà
- ISMETT (Mediterranean Institute for Transplantation and Advanced Specialized Therapies)
| | - Gabriella Malfatto
- Department of Health Science, University of Milano Bicocca & Department of Cardiology, San Luca Hospital, Istituto Auxologico Italiano
| | - Sergio Caravita
- Department of Health Science, University of Milano Bicocca & Department of Cardiology, San Luca Hospital, Istituto Auxologico Italiano
| | - Maurizio Bussotti
- Division of Cardiology, Salvatore Maugeri Foundation, IRCCS, Institute of Milan
| | | | | | | | | | | | - Pantaleo Giannuzzi
- Division of Cardiology Rehabilitation, “S. Maugeri” Foundation, IRCCS, Scientific Institute of Veruno
| | - Paola Gargiulo
- SDN Foundation, Institute of Diagnostic and Nuclear Development
| | | | | | - Rosa Raimondo
- “S. Maugeri” Foundation, IRCCS, Institute of Tradate, Department of Medicine and Cardiorespiratory Rehabilitation, Unit of Cardiac Rehabilitation, Tradate
| | | | - Stefania Paolillo
- Department of Advanced Biomedical Sciences, “Federico II” University
| | | | | | - Andrea Passantino
- Division of Cardiology, “S. Maugeri” Foundation, IRCCS, Institute of Cassano Murge
| | - Rocco La Gioia
- Division of Cardiology, “S. Maugeri” Foundation, IRCCS, Institute of Cassano Murge
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Żera T, Ufnal M, Szczepańska-Sadowska E. TNF and angiotensin type 1 receptors interact in the brain control of blood pressure in heart failure. Cytokine 2014; 71:272-7. [PMID: 25481865 DOI: 10.1016/j.cyto.2014.10.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 07/31/2014] [Accepted: 10/28/2014] [Indexed: 02/04/2023]
Abstract
UNLABELLED Accumulating evidence suggests that the brain renin-angiotensin system and proinflammatory cytokines, such as TNF-α, play a key role in the neurohormonal activation in chronic heart failure (HF). In this study we tested the involvement of TNF-α and angiotensin type 1 receptors (AT1Rs) in the central control of the cardiovascular system in HF rats. METHODS we carried out the study on male Sprague-Dawley rats subjected to the left coronary artery ligation (HF rats) or to sham surgery (sham-operated rats). The rats were pretreated for four weeks with intracerebroventricular (ICV) infusion of either saline (0.25μl/h) or TNF-α inhibitor etanercept (0.25μg/0.25μl/h). At the end of the pretreatment period, we measured mean arterial blood pressure (MABP) and heart rate (HR) at baseline and during 60min of ICV administration of either saline (5μl/h) or AT1Rs antagonist losartan (10μg/5μl/h). After the experiments, we measured the left ventricle end-diastolic pressure (LVEDP) and the size of myocardial scar. RESULTS MABP and HR of sham-operated and HF rats were not affected by pretreatments with etanercept or saline alone. In sham-operated rats the ICV infusion of losartan did not affect MABP either in saline or in etanercept pretreated rats. In contrast, in HF rats the ICV infusion of losartan significantly decreased MABP in rats pretreated with saline, but not in those pretreated with etanercept. LVEDP was significantly elevated in HF rats but not in sham-operated ones. Surface of the infarct scar exceeded 30% of the left ventricle in HF groups, whereas sham-operated rats did not manifest evidence of cardiac scarring. CONCLUSIONS our study provides evidence that in rats with post-infarction heart failure the regulation of blood pressure by AT1Rs depends on centrally acting endogenous TNF-α.
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Affiliation(s)
- Tymoteusz Żera
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, The Medical University of Warsaw, Banacha 1B Str., 02-097 Warsaw, Poland.
| | - Marcin Ufnal
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, The Medical University of Warsaw, Banacha 1B Str., 02-097 Warsaw, Poland
| | - Ewa Szczepańska-Sadowska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, The Medical University of Warsaw, Banacha 1B Str., 02-097 Warsaw, Poland
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35
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Mousa TM, Schiller AM, Zucker IH. Disruption of cardiovascular circadian rhythms in mice post myocardial infarction: relationship with central angiotensin II receptor expression. Physiol Rep 2014; 2:2/11/e12210. [PMID: 25413327 PMCID: PMC4255816 DOI: 10.14814/phy2.12210] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Angiotensin II (Ang II) is well known to participate in the abnormal autonomic cardiovascular control that occurs during the development of chronic heart failure (CHF). Disrupted cardiovascular circadian rhythm in CHF is also well accepted; however, the mechanisms underlying and the role of central Ang II type 1 receptors (AT1R) and oxidative stress in mediating such changes are not clear. In a post myocardial infarction (MI) CHF mouse model we investigated the circadian rhythm for mean arterial pressure (MAP), heart rate (HR), and baroreflex sensitivity (BRS) following MI. The cardiovascular parameters represent the middle 6‐h averages during daytime (6:00–18:00) and nighttime (18:00–6:00). HR increased with the severity of CHF reaching its maximum by 12 weeks post‐MI; loss of circadian HR and BRS rhythms were observed as early as 4 weeks post‐MI in conjunction with a significant blunting of the BRS and an upregulation in the AT1R and gp91phox proteins in the brainstem. Loss of MAP circadian rhythm was observed 8 weeks post‐MI. Circadian AT1R expression was demonstrated in sham animals but was lost 8 weeks following MI. Losartan reduced AT1R expression in daytime (1.18 ± 0.1 vs. 0.85 ± 0.1; P < 0.05) with a trend toward a reduction in the AT1R mRNA expression in the nighttime (1.2 ± 0.1 vs. 1.0 ± 0.1; P > 0.05) but failed to restore circadian variability. The disruption of circadian rhythm for HR, MAP and BRS along with the upregulation of AT1 and gp91phox suggests a possible role for central oxidative stress as a mediator of circadian cardiovascular parameters in the post‐MI state. Increases in central angiotenisn II signaling provide a driving force for sympatho‐excitation in heart failure. In this study, we show a loss of circadian variability in angiotensin type 1 receptor expression in the brainstem of mice post myocardial infarction. These changes correlate with a loss of cardiovascular circadian variability. These data suggest that sympatho‐ excitation may be increased in the post‐MI state at times when sympathetic outflow is normally reduced.
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Affiliation(s)
- Tarek M Mousa
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Alicia M Schiller
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Irving H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
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Abstract
Heart failure (HF) is a syndrome characterized by upregulation of the sympathetic nervous system and abnormal responsiveness of the parasympathetic nervous system. Studies in the 1980s and 1990s demonstrated that inhibition of the renin-angiotensin-aldosterone system with angiotensin-converting enzyme inhibitors improved symptoms and mortality in HF resulting from systolic dysfunction, thus providing a framework to consider the use of β-blockers for HF therapy, contrary to the prevailing wisdom of the time. Against this backdrop, this article reviews the contemporary understanding of the sympathetic nervous system and the failing heart.
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Affiliation(s)
- David Y Zhang
- Section of Cardiology, Department of Medicine, University of Chicago, 5841 S. Maryland Ave, Chicago, IL 60637, USA
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Passamani LM, Abdala AP, Moraes DJDA, Sampaio KN, Mill JG, Paton JFR. Temporal profile and mechanisms of the prompt sympathoexcitation following coronary ligation in Wistar rats. PLoS One 2014; 9:e101886. [PMID: 25006809 PMCID: PMC4090177 DOI: 10.1371/journal.pone.0101886] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/12/2014] [Indexed: 11/18/2022] Open
Abstract
Our aim was to assess the timing and mechanisms of the sympathoexcitation that occurs immediately after coronary ligation. We recorded thoracic sympathetic (tSNA) and phrenic activities, heart rate (HR) and perfusion pressure in Wistar rats subjected to either ligation of the left anterior descending coronary artery (LAD) or Sham operated in the working heart-brainstem preparation. Thirty minutes after LAD ligation, tSNA had increased (basal: 2.5±0.2 µV, 30 min: 3.5±0.3 µV), being even higher at 60 min (5.2±0.5 µV, P<0.01); while no change was observed in Sham animals. HR increased significantly 45 min after LAD (P<0.01). Sixty minutes after LAD ligation, there was: (i) an augmented peripheral chemoreflex - greater sympathoexcitatory response (50, 45 and 27% of increase to 25, 50 and 75 µL injections of NaCN 0.03%, respectively, when compared to Sham, P<0.01); (ii) an elevated pressor response (32±1 versus 23±1 mmHg in Sham, P<0.01) and a reduced baroreflex sympathetic gain (1.3±0.1 versus Sham 2.0±0.1%.mmHg-1, P<0.01) to phenylephrine injection; (iii) an elevated cardiac sympathetic tone (ΔHR after atenolol: -108±8 versus -82±7 bpm in Sham, P<0.05). In contrast, no changes were observed in cardiac vagal tone and bradycardic response to both baroreflex and chemoreflex between LAD and Sham groups. The immediate sympathoexcitatory response in LAD rats was dependent on an excitatory spinal sympathetic cardiocardiac reflex, whereas at 3 h an angiotensin II type 1 receptor mechanism was essential since Losartan curbed the response by 34% relative to LAD rats administered saline (P<0.05). A spinal reflex appears key to the immediate sympathoexcitatory response after coronary ligation. Therefore, the sympathoexcitatory response seems to be maintained by an angiotensinergic mechanism and concomitant augmentation of sympathoexcitatory reflexes.
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Affiliation(s)
- Luciana Mesquita Passamani
- School of Physiology & Pharmacology, Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol, United Kingdom
- Department of Physiological Sciences, Health Sciences Center, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil
| | - Ana Paula Abdala
- School of Physiology & Pharmacology, Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - Davi José de Almeida Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Karla Nívea Sampaio
- Department of Pharmaceutical Sciences, Health Sciences Center, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil
| | - José Geraldo Mill
- Department of Physiological Sciences, Health Sciences Center, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil
| | - Julian Francis Richmond Paton
- School of Physiology & Pharmacology, Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol, United Kingdom
- * E-mail:
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Pliquett RU, Benkhoff S, Jung O, Brandes RP. Sympathoactivation and rho-kinase-dependent baroreflex function in experimental renovascular hypertension with reduced kidney mass. BMC PHYSIOLOGY 2014; 14:4. [PMID: 24946879 PMCID: PMC4074138 DOI: 10.1186/1472-6793-14-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 06/13/2014] [Indexed: 01/11/2023]
Abstract
BACKGROUND Dysregulation of the autonomic nervous system is frequent in subjects with cardiovascular disease. The contribution of different forms of renovascular hypertension and the mechanisms contributing to autonomic dysfunction in hypertension are incompletely understood. Here, murine models of renovascular hypertension with preserved (2-kidneys-1 clip, 2K1C) and reduced (1-kidney-1 clip, 1K1C) kidney mass were studied with regard to autonomic nervous system regulation (sympathetic tone: power-spectral analysis of systolic blood pressure; parasympathetic tone: power-spectral analysis of heart rate) and baroreflex sensitivity of heart rate by spontaneous, concomitant changes of systolic blood pressure and pulse interval. Involvement of the renin-angiotensin system and the rho-kinase pathway were determined by application of inhibitors. RESULTS C57BL6N mice (6 to 11) with reduced kidney mass (1K1C) or with preserved kidney mass (2K1C) developed a similar degree of hypertension. In comparison to control mice, both models presented with a significantly increased sympathetic tone and lower baroreflex sensitivity of heart rate. However, only 2K1C animals had a lower parasympathetic tone, whereas urinary norepinephrine excretion was reduced in the 1K1C model. Rho kinase inhibition given to a subset of 1K1C and 2K1C animals improved baroreflex sensitivity of heart rate selectively in the 1K1C model. Rho kinase inhibition had no additional effects on autonomic nervous system in either model of renovascular hypertension and did not change the blood pressure. Blockade of AT1 receptors (in 2K1C animals) normalized the sympathetic tone, decreased resting heart rate, improved baroreflex sensitivity of heart rate and parasympathetic tone. CONCLUSIONS Regardless of residual renal mass, blood pressure and sympathetic tone are increased, whereas baroreflex sensitivity is depressed in murine models of renovascular hypertension. Reduced norepinephrine excretion and/or degradation might contribute to sympathoactivation in renovascular hypertension with reduced renal mass (1K1C). Overall, the study helps to direct research to optimize medical therapy of hypertension.
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Affiliation(s)
- Rainer U Pliquett
- Institute for Cardiovascular Physiology, Vascular Research Centre, Fachbereich Medizin, Goethe University, Frankfurt (Main), Germany.
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Role of exercise training on autonomic changes and inflammatory profile induced by myocardial infarction. Mediators Inflamm 2014; 2014:702473. [PMID: 25045212 PMCID: PMC4090432 DOI: 10.1155/2014/702473] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/06/2014] [Accepted: 03/11/2014] [Indexed: 02/07/2023] Open
Abstract
The cardiovascular autonomic imbalance in patients after myocardial infarction (MI) provides a significant increase in mortality rate, and seems to precede metabolic, hormonal, and immunological changes. Moreover, the reduction in the parasympathetic function has been associated with inflammatory response in different pathological conditions. Over the years, most of the studies have indicated the exercise training (ET) as an important nonpharmacological tool in the management of autonomic dysfunction and reduction in inflammatory profile after a myocardial infarction. In this work, we reviewed the effects of ET on autonomic imbalance after MI, and its consequences, particularly, in the post-MI inflammatory profile. Clinical and experimental evidence regarding relationship between alterations in autonomic regulation and local or systemic inflammation response after MI were also discussed.
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Mori Y, Aritomi S, Niinuma K, Nakamura T, Matsuura K, Yokoyama J, Utsunomiya K. Additive effects of cilnidipine, an L-/N-type calcium channel blocker, and an angiotensin II receptor blocker on reducing cardiorenal damage in Otsuka Long-Evans Tokushima Fatty rats with type 2 diabetes mellitus. Drug Des Devel Ther 2014; 8:799-810. [PMID: 24970998 PMCID: PMC4069052 DOI: 10.2147/dddt.s47441] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Cilnidipine (Cil), which is an L-/N-type calcium channel blocker (CCB), has been known to provide renal protection by decreasing the activity of the sympathetic nervous system (SNS) and the renin–angiotensin system. In this study, we compared the effects of the combination of Cil and amlodipine (Aml), which is an L-type CCB, with an angiotensin (Ang) II receptor blocker on diabetic cardiorenal damage in spontaneously type 2 diabetic rats. Seventeen-week-old Otsuka Long-Evans Tokushima Fatty rats were randomly assigned to receive Cil, Aml, valsartan (Val), Cil + Val, Aml + Val, or a vehicle (eight rats per group) for 22 weeks. Antihypertensive potencies were nearly equal among the CCB monotherapy groups and the combination therapy groups. The lowering of blood pressure by either treatment did not significantly affect the glycemic variables. However, exacerbations of renal and heart failure were significantly suppressed in rats administered Cil or Val, and additional suppression was observed in those administered Cil + Val. Although Val increased the renin–Ang system, Aml + Val treatment resulted in additional increases in these parameters, while Cil + Val did not show such effects. Furthermore, Cil increased the ratio of Ang-(1–7) to Ang-I, despite the fact that Val and Aml + Val decreased the Ang-(1–7) levels. These actions of Cil + Val might be due to their synergistic inhibitory effect on the activity of the SNS, and on aldosterone secretion through N-type calcium channel antagonism and Ang II receptor type 1 antagonism. Thus, Cil may inhibit the progression of cardiorenal disease in type 2 diabetes patients by acting as an N-type CCB and inhibiting the aldosterone secretion and SNS activation when these drugs were administered in combination with an Ang II receptor blocker.
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Affiliation(s)
- Yutaka Mori
- Division of Diabetes and Endocrinology, Department of Internal Medicine, The Jikei University School of Medicine, Minato-ku, Japan ; Department of Clinical Research, National Hospital Organization, Utsunomiya National Hospital, Utsunomiya, Japan
| | - Shizuka Aritomi
- Research Center, Ajinomoto Pharmaceuticals Co, Ltd, Kanagawa, Japan
| | - Kazumi Niinuma
- Research Center, Ajinomoto Pharmaceuticals Co, Ltd, Kanagawa, Japan
| | - Tarou Nakamura
- Research Center, Ajinomoto Pharmaceuticals Co, Ltd, Kanagawa, Japan
| | - Kenichi Matsuura
- Division of Diabetes and Endocrinology, Department of Internal Medicine, The Jikei University School of Medicine, Minato-ku, Japan
| | - Junichi Yokoyama
- Division of Diabetes and Endocrinology, Department of Internal Medicine, The Jikei University School of Medicine, Minato-ku, Japan
| | - Kazunori Utsunomiya
- Division of Diabetes and Endocrinology, Department of Internal Medicine, The Jikei University School of Medicine, Minato-ku, Japan
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Narimatsu T, Ozawa Y, Miyake S, Nagai N, Tsubota K. Angiotensin II type 1 receptor blockade suppresses light-induced neural damage in the mouse retina. Free Radic Biol Med 2014; 71:176-185. [PMID: 24662196 DOI: 10.1016/j.freeradbiomed.2014.03.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 03/06/2014] [Accepted: 03/16/2014] [Indexed: 12/26/2022]
Abstract
Exposure to light contributes to the development and progression of retinal degenerative diseases. However, the mechanisms underlying light-induced tissue damage are not fully understood. Here, we examined the role of angiotensin II type 1 receptor (AT1R) signaling, which is part of the renin-angiotensin system, in light-induced retinal damage. Light-exposed Balb/c mice that were treated with the AT1R blockers (angiotensin II receptor blockers; ARBs) valsartan, losartan, and candesartan before and after the light exposure exhibited attenuated visual function impairment, compared to vehicle-treated mice. This effect was dose-dependent and observed across the ARB class of inhibitors. Further evaluation of valsartan showed that it suppressed a number of light-induced retinal effects, including thinning of the photoreceptor cell layer caused by apoptosis, shortening of the photoreceptor cell outer segment, and increased levels of reactive oxygen species (ROS). The role of ROS in retinal pathogenesis was investigated further using the antioxidant N-acetyl-l-cysteine (NAC). Treatment of light-exposed mice with NAC before the light exposure suppressed the visual function impairment and photoreceptor cell histological changes due to apoptosis. Moreover, treatment with valsartan or NAC suppressed the induction of c-fos (a component of the AP-1 transcription factor) and the upregulation of fasl (a proapoptotic molecule whose transcript is regulated downstream of AP-1). Our results suggest that AT1R signaling mediates light-induced apoptosis, by increasing the levels of ROS and proapoptotic molecules in the retina. Thus, AT1R blockade may represent a new therapeutic approach for preventing light-induced retinal neural tissue damage.
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Affiliation(s)
- Toshio Narimatsu
- Laboratory of Retinal Cell Biology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan; Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Yoko Ozawa
- Laboratory of Retinal Cell Biology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan; Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan.
| | - Seiji Miyake
- Laboratory of Retinal Cell Biology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Norihiro Nagai
- Laboratory of Retinal Cell Biology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan; Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
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Abstract
SIGNIFICANCE There is now compelling evidence to substantiate the notion that by depressing baroreflex regulation of blood pressure and augmenting central sympathetic outflow through their actions on the nucleus tractus solitarii (NTS) and rostral ventrolateral medulla (RVLM), brain stem nitric oxide synthase (NOS) and reactive oxygen species (ROS) are important contributing factors to neural mechanisms of hypertension. This review summarizes our contemporary views on the impact of NOS and ROS in the NTS and RVLM on neurogenic hypertension, and presents potential antihypertensive strategies that target brain stem NOS/ROS signaling. RECENT ADVANCES NO signaling in the brain stem may be pro- or antihypertensive depending on the NOS isoform that generates this gaseous moiety and the site of action. Elevation of the ROS level when its production overbalances its degradation in the NTS and RVLM underlies neurogenic hypertension. Interventional strategies with emphases on alleviating the adverse actions of these molecules on blood pressure regulation have been investigated. CRITICAL ISSUES The pathological roles of NOS in the RVLM and NTS in neural mechanisms of hypertension are highly complex. Likewise, multiple signaling pathways underlie the deleterious roles of brain-stem ROS in neurogenic hypertension. There are recent indications that interactions between brain stem ROS and NOS may play a contributory role. FUTURE DIRECTIONS Given the complicity of action mechanisms of brain-stem NOS and ROS in neural mechanisms of hypertension, additional studies are needed to identify the most crucial therapeutic target that is applicable not only in animal models but also in patients suffering from neurogenic hypertension.
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Affiliation(s)
- Samuel H H Chan
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital , Kaohsiung, Taiwan, Republic of China
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Haack KKV, Mitra AK, Zucker IH. NF-κB and CREB are required for angiotensin II type 1 receptor upregulation in neurons. PLoS One 2013; 8:e78695. [PMID: 24244341 PMCID: PMC3823855 DOI: 10.1371/journal.pone.0078695] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 09/12/2013] [Indexed: 01/14/2023] Open
Abstract
Nuclear factor kappa B (NF-κB) and the Ets like gene-1 (Elk-1) are two transcription factors that have been previously established to contribute to the Angiotensin II mediated upregulation of Angiotensin II type 1 receptor (AT1R) in neurons. The cAMP response element binding protein (CREB) is another transcription factor that has also been implicated in AT1R gene transcription. The goal of the current study was to determine if NF-κB and CREB association was required for AT1R upregulation. We hypothesized that the transcription of the AT1R gene occurs via an orchestration of transcription factor interactions including NF-κB, CREB, and Elk-1. The synergistic role of CREB and NFκB in promoting AT1R gene expression was determined using siRNA-mediated silencing of CREB. Electrophorectic Mobility Shift Assay studies employing CREB and NF-κB demonstrated increased protein - DNA binding as a result of Ang II stimulation which was blunted by siRNA silencing of CREB. Upstream inhibition of p38 mitogen activated protein kinase (p38 MAPK) with SB203580 or inhibition of the calmodulin kinase (CAMK) pathway using KN-62 blunted changes in CREB and NF-κB expression. These findings suggest that Ang II may activate multiple signaling pathways involving p38 MAPK leading to the activation of NF-κB and CREB, which feed back to upregulate the AT1R gene. This study provides insight into the molecular mechanisms involving multiple transcription factor activation in a coordinated fashion which may be partially responsible for sympathoexcitation in clinical conditions associated with increased activation of the renin angiotensin system.
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Affiliation(s)
- Karla K. V. Haack
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Amit K. Mitra
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Irving H. Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
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Llewellyn TL, Sharma NM, Zheng H, Patel KP. Effects of exercise training on SFO-mediated sympathoexcitation during chronic heart failure. Am J Physiol Heart Circ Physiol 2013; 306:H121-31. [PMID: 24163080 DOI: 10.1152/ajpheart.00534.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Exercise training (ExT) has been shown to reduce sympathetic drive during heart failure (HF). The subfornical organ (SFO) is involved in the neural control of sympathetic drive. We hypothesized that an activated SFO contributes to enhanced sympathetic activity in HF. We also postulated that ExT would reduce the activation of the SFO and its contribution to the sympathetic drive during HF. Sprague-Dawley rats were subjected to coronary artery ligation to induce HF. Rats were assigned to ExT for 3-4 wk. Rats with HF had a 2.5-fold increase in FosB-positive cells in the SFO compared with sham-operated rats, and this was normalized by ExT. Microinjection of ANG II (100 pmol) into the SFO resulted in a greater increase in renal sympathetic nerve activity (RSNA), blood pressure, and heart rate in the HF group than in the sham-operated group. These responses were normalized after ExT (change in RSNA: 23 ± 3% vs. 8 ± 2%). ExT also abolished the decrease in RSNA in HF rats after the microinjection of losartan (200 pmol) into the SFO (-21 ± 4% vs. -2 ± 3%). Finally, there was elevated mRNA (5-fold) and protein expression (43%) of ANG II type 1 receptors in the SFO of rats with HF, which were reversed after ExT. These data suggest that the enhanced activity of the SFO by elevated tonic ANG II contributes to the enhanced sympathoexcitation exhibited in HF. The decrease in ANG II type 1 receptor expression in the SFO by ExT may be responsible for reversing the neuronal activation in the SFO and SFO-mediated sympathoexcitation in rats with HF.
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Affiliation(s)
- Tamra L Llewellyn
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
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45
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Chan SHH, Chan JYH. Angiotensin-generated reactive oxygen species in brain and pathogenesis of cardiovascular diseases. Antioxid Redox Signal 2013; 19:1074-84. [PMID: 22429119 DOI: 10.1089/ars.2012.4585] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
SIGNIFICANCE Overproduction of angiotensin II (Ang II) in brain contributes to the pathogenesis of cardiovascular diseases. One of the most promising theses that emerged during the last decade is that production of reactive oxygen species (ROS) and activation of redox-dependent signaling cascades underlie those Ang II actions. This review summarizes our status of understanding on the roles of ROS and redox-sensitive signaling in brain Ang II-dependent cardiovascular diseases, using hypertension and heart failure as illustrative examples. RECENT ADVANCES ROS generated by NADPH oxidase, mitochondrial electron transport chain, and proinflammatory cytokines activates mitogen-activated protein kinases and transcription factors, which in turn modulate ion channel functions and ultimately increase neuronal activity and sympathetic outflow in brain Ang II-dependent cardiovascular diseases. Antioxidants targeting ROS have been demonstrated to be beneficial to Ang II-induced hypertension and heart failure via protection from oxidative stress in brain regions that subserve cardiovascular regulation. CRITICAL ISSUES Intra-neuronal signaling and the downstream redox-sensitive proteins involved in controlling the neuronal discharge rate, the sympathetic outflow, and the pathogenesis of cardiovascular diseases need to be identified. The cross talk between Ang II-induced oxidative stress and neuroinflammation in neural mechanisms of cardiovascular diseases also warrants further elucidation. FUTURE DIRECTIONS Future studies are needed to identify new redox-based therapeutics that work not only in animal models, but also in patients suffering from the prevalent diseases. Upregulation of endogenous antioxidants in the regulation of ROS homeostasis is a potential therapeutic target, as are small molecule- or nanoformulated conjugate-based antioxidant therapy.
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Affiliation(s)
- Samuel H H Chan
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital , Kaohsiung, Taiwan, Republic of China
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Tu H, Liu J, Zhang D, Zheng H, Patel KP, Cornish KG, Wang WZ, Muelleman RL, Li YL. Heart failure-induced changes of voltage-gated Ca2+ channels and cell excitability in rat cardiac postganglionic neurons. Am J Physiol Cell Physiol 2013; 306:C132-42. [PMID: 24025863 DOI: 10.1152/ajpcell.00223.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chronic heart failure (CHF) is characterized by decreased cardiac parasympathetic and increased cardiac sympathetic nerve activity. This autonomic imbalance increases the risk of arrhythmias and sudden death in patients with CHF. We hypothesized that the molecular and cellular alterations of cardiac postganglionic parasympathetic (CPP) neurons located in the intracardiac ganglia and sympathetic (CPS) neurons located in the stellate ganglia (SG) possibly link to the cardiac autonomic imbalance in CHF. Rat CHF was induced by left coronary artery ligation. Single-cell real-time PCR and immunofluorescent data showed that L (Ca(v)1.2 and Ca(v)1.3), P/Q (Ca(v)2.1), N (Ca(v)2.2), and R (Ca(v)2.3) types of Ca2+ channels were expressed in CPP and CPS neurons, but CHF decreased the mRNA and protein expression of only the N-type Ca2+ channels in CPP neurons, and it did not affect mRNA and protein expression of all Ca2+ channel subtypes in the CPS neurons. Patch-clamp recording confirmed that CHF reduced N-type Ca2+ currents and cell excitability in the CPP neurons and enhanced N-type Ca2+ currents and cell excitability in the CPS neurons. N-type Ca2+ channel blocker (1 μM ω-conotoxin GVIA) lowered Ca2+ currents and cell excitability in the CPP and CPS neurons from sham-operated and CHF rats. These results suggest that CHF reduces the N-type Ca2+ channel currents and cell excitability in the CPP neurons and enhances the N-type Ca2+ currents and cell excitability in the CPS neurons, which may contribute to the cardiac autonomic imbalance in CHF.
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Affiliation(s)
- Huiyin Tu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, Nebraska
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Muller MD, Reed AB, Leuenberger UA, Sinoway LI. Physiology in medicine: peripheral arterial disease. J Appl Physiol (1985) 2013; 115:1219-26. [PMID: 23970534 DOI: 10.1152/japplphysiol.00885.2013] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Peripheral arterial disease (PAD) is an atherosclerotic condition that can provoke symptoms of leg pain ("intermittent claudication") during exercise. Because PAD is often observed with comorbid conditions such hypertension, dyslipidemia, diabetes, cigarette smoking, and/or physical inactivity, the pathophysiology of PAD is certainly complex and involves multiple organ systems. Patients with PAD are at high risk for myocardial infarction, stroke, and all-cause mortality. For this reason, a better physiological understanding of the pathogenesis and treatment options for PAD patients is necessary and forms the basis of this Physiology in Medicine review.
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Affiliation(s)
- Matthew D Muller
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
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Chao J, Gao J, Parbhu KJK, Gao L. Angiotensin type 2 receptors in the intermediolateral cell column of the spinal cord: negative regulation of sympathetic nerve activity and blood pressure. Int J Cardiol 2013; 168:4046-55. [PMID: 23871345 DOI: 10.1016/j.ijcard.2013.06.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 05/07/2013] [Accepted: 06/30/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Our previous study demonstrated that AT2R in brainstem nuclei participated in the regulation of sympathetic outflow and cardiovascular function. However, the functional significance of AT2R in the intermediolateral cell column (IML) of the thoracic spinal cord in normal rats remains elusive. We hypothesized that AT2R activation in the IML exerts a sympatho-inhibitory effect. METHODS AND RESULTS Using Western-blot analysis, immunohistochemical staining and quantitative real-time PCR, both AT1R and AT2R expressions were detected in the spinal cord. The highest AT2R protein expression was found in the IML, while AT1R expression didn't display regional differences within the gray matter. Microinjection of Ang II into the IML dose-dependently elevated mean blood pressure (MAP, employing a transducer-tipped catheter) and renal sympathetic nerve activity (RSNA, using a pair of platinum-iridium recording electrodes), which were completely abolished by Losartan, and attenuated by TEMPOL and apocynin. Activation of AT2R in the IML with CGP42112 evoked hypotension (ΔMAP: -21 ± 4 mmHg) and sympatho-inhibition (RSNA: 73 ± 3% of baseline), which were completely abolished by PD123319 and l-NAME. Blockade of AT2R in the IML with PD123319 significantly increased MAP (11 ± 1 mmHg) and sympathetic nerve activity (RSNA: 133 ± 13% of baseline). Moreover, PD123319 significantly enhanced the Ang II induced pressor response. Furthermore, in isolated IML neurons, CGP42112 treatment augmented potassium current and decreased resting membrane potential by employing whole-cell patch clamp. CONCLUSION In the normal condition, AT2R in the IML tonically inhibits sympathetic activity through an NO/NOS dependent pathway and subsequent potassium channel activation.
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Affiliation(s)
- Jie Chao
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, USA
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Ramchandra R, Yao ST, May CN. Organ Selective Regulation of Sympathetic Outflow by the Brain Angiotensin System. Curr Hypertens Rep 2013; 15:401-8. [DOI: 10.1007/s11906-013-0355-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Xiao L, Haack KKV, Zucker IH. Angiotensin II regulates ACE and ACE2 in neurons through p38 mitogen-activated protein kinase and extracellular signal-regulated kinase 1/2 signaling. Am J Physiol Cell Physiol 2013; 304:C1073-9. [PMID: 23535237 DOI: 10.1152/ajpcell.00364.2012] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Brain ANG II plays an important role in modulating sympathetic function and homeostasis. The generation and degradation of ANG II are carried out, to a large extent, through the angiotensin-converting enzyme (ACE) and ACE2, respectively. In disease states, such as hypertension and chronic heart failure, central expression of ACE is upregulated and ACE2 is decreased in central sympathoregulatory neurons. In this study, we determined the expression of ACE and ACE2 in response to ANG II in a neuronal cell culture and the subsequent signaling mechanism(s) involved. A mouse catecholaminergic neuronal cell line (CATH.a) was treated with ANG II (30, 100, and 300 nM) for 24 h, and protein expression was determined by Western blot analysis. ANG II induced a significant dose-dependent increase in ACE and decrease in ACE2 mRNA and protein expression in CATH.a neurons. This effect was abolished by pretreatment of the cells with the p38 MAPK inhibitor SB-203580 (10 μM) 30 min before administration of ANG II or the ERK1/2 inhibitor U-0126 (10 μM). These data suggest that ANG II increases ACE and attenuates ACE2 expression in neurons via the ANG II type 1 receptor, p38 MAPK, and ERK1/2 signaling pathways.
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Affiliation(s)
- Liang Xiao
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
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