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Dobson GP, Morris JL, Letson HL. Adenosine, lidocaine and Mg 2+ update: teaching old drugs new tricks. Front Med (Lausanne) 2023; 10:1231759. [PMID: 37828944 PMCID: PMC10565858 DOI: 10.3389/fmed.2023.1231759] [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: 05/31/2023] [Accepted: 09/11/2023] [Indexed: 10/14/2023] Open
Abstract
If a trauma (or infection) exceeds the body's evolutionary design limits, a stress response is activated to quickly restore homeostasis. However, when the injury severity score is high, death is often imminent. The goal of this review is to provide an update on the effect of small-volume adenosine, lidocaine and Mg2+ (ALM) therapy on increasing survival and blunting secondary injury after non-compressible hemorrhagic shock and other trauma and infective/endotoxemic states. Two standout features of ALM therapy are: (1) resuscitation occurs at permissive hypotensive blood pressures (MAPs 50-60 mmHg), and (2) the drug confers neuroprotection at these low pressures. The therapy appears to reset the body's baroreflex to produce a high-flow, hypotensive, vasodilatory state with maintained tissue O2 delivery. Whole body ALM protection appears to be afforded by NO synthesis-dependent pathways and shifting central nervous system (CNS) control from sympathetic to parasympathetic dominance, resulting in improved cardiovascular function, reduced immune activation and inflammation, correction of coagulopathy, restoration of endothelial glycocalyx, and reduced energy demand and mitochondrial oxidative stress. Recently, independent studies have shown ALM may also be useful for stroke, muscle trauma, and as an adjunct to Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA). Ongoing studies have further shown ALM may have utility for burn polytrauma, damage control surgery and orthopedic surgery. Lastly, we discuss the clinical applications of ALM fluid therapy for prehospital and military far-forward use for non-compressible hemorrhage and traumatic brain injury (TBI).
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Affiliation(s)
- Geoffrey P. Dobson
- Heart and Trauma Research Laboratory, College of Medicine and Dentistry, James Cook University, Townsville, QLD, Australia
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Gurel NZ, Sudarshan KB, Hadaya J, Karavos A, Temma T, Hori Y, Armour JA, Kember G, Ajijola OA. Metrics of high cofluctuation and entropy to describe control of cardiac function in the stellate ganglion. eLife 2022; 11:e78520. [PMID: 36426848 PMCID: PMC9815826 DOI: 10.7554/elife.78520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 11/25/2022] [Indexed: 11/27/2022] Open
Abstract
Stellate ganglia within the intrathoracic cardiac control system receive and integrate central, peripheral, and cardiopulmonary information to produce postganglionic cardiac sympathetic inputs. Pathological anatomical and structural remodeling occurs within the neurons of the stellate ganglion (SG) in the setting of heart failure (HF). A large proportion of SG neurons function as interneurons whose networking capabilities are largely unknown. Current therapies are limited to targeting sympathetic activity at the cardiac level or surgical interventions such as stellectomy, to treat HF. Future therapies that target the SG will require understanding of their networking capabilities to modify any pathological remodeling. We observe SG networking by examining cofluctuation and specificity of SG networked activity to cardiac cycle phases. We investigate network processing of cardiopulmonary transduction by SG neuronal populations in porcine with chronic pacing-induced HF and control subjects during extended in-vivo extracellular microelectrode recordings. We find that information processing and cardiac control in chronic HF by the SG, relative to controls, exhibits: (i) more frequent, short-lived, high magnitude cofluctuations, (ii) greater variation in neural specificity to cardiac cycles, and (iii) neural network activity and cardiac control linkage that depends on disease state and cofluctuation magnitude.
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Affiliation(s)
- Nil Z Gurel
- UCLA Cardiac Arrhythmia Center and UCLA Neurocardiology Research Program of ExcellenceLos AngelesUnited States
| | - Koustubh B Sudarshan
- Department of Engineering Mathematics and Internetworking, Dalhousie UniversityNova ScotiaCanada
| | - Joseph Hadaya
- UCLA Cardiac Arrhythmia Center and UCLA Neurocardiology Research Program of ExcellenceLos AngelesUnited States
- UCLA Molecular, Cellular, and Integrative Physiology ProgramLos AngelesUnited States
| | - Alex Karavos
- Department of Engineering Mathematics and Internetworking, Dalhousie UniversityNova ScotiaCanada
| | - Taro Temma
- UCLA Cardiac Arrhythmia Center and UCLA Neurocardiology Research Program of ExcellenceLos AngelesUnited States
| | - Yuichi Hori
- UCLA Cardiac Arrhythmia Center and UCLA Neurocardiology Research Program of ExcellenceLos AngelesUnited States
| | - J Andrew Armour
- UCLA Cardiac Arrhythmia Center and UCLA Neurocardiology Research Program of ExcellenceLos AngelesUnited States
| | - Guy Kember
- Department of Engineering Mathematics and Internetworking, Dalhousie UniversityNova ScotiaCanada
| | - Olujimi A Ajijola
- UCLA Cardiac Arrhythmia Center and UCLA Neurocardiology Research Program of ExcellenceLos AngelesUnited States
- UCLA Molecular, Cellular, and Integrative Physiology ProgramLos AngelesUnited States
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Xia Z, Vellichirammal NN, Han L, Gao L, Boesen EI, Schiller AM, Pellegrino PR, Lisco SJ, Guda C, Zucker IH, Wang HJ. Cardiac Spinal Afferent Denervation Attenuates Renal Dysfunction in Rats With Cardiorenal Syndrome Type 2. JACC Basic Transl Sci 2022; 7:582-596. [PMID: 35818505 PMCID: PMC9270585 DOI: 10.1016/j.jacbts.2022.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 11/27/2022]
Abstract
Epicardial application of RTX at the time of MI largely prevented renal dysfunction, attenuated renal congestion, and partially restored renal blood flow in rats with CHF. RNA sequencing analysis showed that renal injury, inflammation, hypoxia, and apoptosis genes were significantly up-regulated in the renal tissue of CHF rats, which was largely prevented by epicardial RTX at the time of MI. Cardiac afferent ablation by intra–stellate ganglia injection of RTX or unilateral renal denervation 4 weeks after MI had similar renal protective effects on renal tubular damage in CHF rats. These data provide evidence for cardiac spinal afferent modulation of renal function and a potential targeted therapy.
Cardiorenal syndrome type 2 (CRS2) is defined as a chronic cardiovascular disease, usually chronic heart failure (CHF), resulting in chronic kidney disease. We hypothesized that the cardiac spinal afferent reflex (CSAR) plays a critical role in the development of CRS2. Our data suggest that cardiac afferent ablation by resiniferatoxin not only improves cardiac function but also benefits the kidneys and increases long-term survival in the myocardial infarction model of CHF. We also found that renal denervation has a similar reno-protective effect in CHF rats. We believe this novel work contributes to the development of a unique neuromodulation therapy to treat CHF patients.
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Affiliation(s)
- Zhiqiu Xia
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | | | - Li Han
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Lie Gao
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Erika I. Boesen
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Alicia M. Schiller
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Peter R. Pellegrino
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Steven J. Lisco
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Chittibabu Guda
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Bioinformatics and Systems Biology Core, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Irving H. Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Han-Jun Wang
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Address for correspondence: Dr Han-Jun Wang, Department of Anesthesiology, University of Nebraska Medical Center, 985850, 42nd and Emile Streets, Omaha, Nebraska 68198, USA.
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Patel KP, Katsurada K, Zheng H. Cardiorenal Syndrome: The Role of Neural Connections Between the Heart and the Kidneys. Circ Res 2022; 130:1601-1617. [PMID: 35549375 PMCID: PMC9179008 DOI: 10.1161/circresaha.122.319989] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The maintenance of cardiovascular homeostasis is highly dependent on tightly controlled interactions between the heart and the kidneys. Therefore, it is not surprising that a dysfunction in one organ affects the other. This interlinking relationship is aptly demonstrated in the cardiorenal syndrome. The characteristics of the cardiorenal syndrome state include alterations in neurohumoral drive, autonomic reflexes, and fluid balance. The evidence suggests that several factors contribute to these alterations. These may include peripheral and central nervous system abnormalities. However, accumulating evidence from animals with experimental models of congestive heart failure and renal dysfunction as well as humans with the cardiorenal syndrome suggests that alterations in neural pathways, from and to the kidneys and the heart, including the central nervous system are involved in regulating sympathetic outflow and may be critically important in the alterations in neurohumoral drive, autonomic reflexes, and fluid balance commonly observed in the cardiorenal syndrome. This review focuses on studies implicating neural pathways, particularly the afferent and efferent signals from the heart and the kidneys integrating at the level of the paraventricular nucleus in the hypothalamus to alter neurohumoral drive, autonomic pathways, and fluid balance. Further, it explores the potential mechanisms of action for the known beneficial use of various medications or potential novel therapeutic manipulations for the treatment of the cardiorenal syndrome. A comprehensive understanding of these mechanisms will enhance our ability to treat cardiorenal conditions and their cardiovascular complications more efficaciously and thoroughly.
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Affiliation(s)
- Kaushik P Patel
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha (K.P.P.)
| | - Kenichi Katsurada
- Division of Cardiovascular Medicine, Department of Internal Medicine (K.K.), Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan.,Division of Clinical Pharmacology, Department of Pharmacology (K.K.), Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Hong Zheng
- Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion (H.Z.)
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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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Letson HL, Dobson GP. The Role of Nitric Oxide in the Efficacy of Adenosine, Lidocaine, and Magnesium Treatment for Experimental Hemorrhagic Shock in Rats. Curr Ther Res Clin Exp 2021; 95:100655. [PMID: 34917219 PMCID: PMC8665347 DOI: 10.1016/j.curtheres.2021.100655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/12/2021] [Indexed: 11/25/2022] Open
Abstract
Background Nitric oxide (NO) plays multiple roles regulating the central nervous, cardiovascular, and immune systems. Objective Our aim was to investigate the role of NO in the efficacy of hypertonic saline (7.5% sodium chloride [NaCl]) adenosine, lidocaine, and magnesium (ALM) to improve mean arterial pressure (MAP) and heart rate following hemorrhagic shock. Methods One hundred one male Sprague-Dawley rats (mean [SD] weight = 425 [6] g) were randomly assigned to 20 groups (groups of 4–8 rats each). Hemorrhagic shock (MAP < 40 mm Hg) was induced by 20-minute pressure-controlled bleeding (∼40% blood volume), and the animal was left in shock (MAP = 35-40 mm Hg) for 60 minutes. The NO synthase (NOS) inhibitor L-NAME was administered with a 0.3-mL bolus of different combinations of 7.5% NaCl ALM active ingredients and hemodynamic parameters were monitored for 60 minutes. A number of specific NOS and NO inhibitors were tested. Results We found that 7.5% NaCl ALM corrected MAP after hemorrhagic shock. In contrast, the addition of L-NAME to 7.5% NaCl ALM led to a rapid fall in MAP, sustained ventricular arrhythmias, and 100% mortality. Saline controls receiving 7.5% NaCl with NG-nitro-l-arginine methyl ester (L-NAME) showed improved MAP with no deaths. None of the specific NOS and NO inhibitors mimicked L-NAME's effect on ALM. The addition of inducible NOS inhibitor 1400W to 7.5% NaCl ALM failed to resuscitate, whereas the NO scavenger PTIO and the PI3K inhibitor wortmannin reduced MAP recovery during 60-minute resuscitation. Conclusions The ability of 7.5% NaCl ALM to resuscitate appears to be linked to 1 or more NO-producing pathways. Nonspecific NOS inhibition with L-NAME blocked ALM resuscitation and led to cardiovascular collapse. More studies are required to examine NO site-specific contributions to ALM resuscitation. (Curr Ther Res Clin Exp. 2022; 82:XXX–XXX)
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Affiliation(s)
- Hayley L Letson
- Heart, Trauma, and Sepsis Research Laboratory, College of Medicine & Dentistry, James Cook University, Townsville, Queensland, Australia
| | - Geoffrey P Dobson
- Heart, Trauma, and Sepsis Research Laboratory, College of Medicine & Dentistry, James Cook University, Townsville, Queensland, Australia
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Iturriaga R, Alcayaga J, Chapleau MW, Somers VK. Carotid body chemoreceptors: physiology, pathology, and implications for health and disease. Physiol Rev 2021; 101:1177-1235. [PMID: 33570461 PMCID: PMC8526340 DOI: 10.1152/physrev.00039.2019] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The carotid body (CB) is the main peripheral chemoreceptor for arterial respiratory gases O2 and CO2 and pH, eliciting reflex ventilatory, cardiovascular, and humoral responses to maintain homeostasis. This review examines the fundamental biology underlying CB chemoreceptor function, its contribution to integrated physiological responses, and its role in maintaining health and potentiating disease. Emphasis is placed on 1) transduction mechanisms in chemoreceptor (type I) cells, highlighting the role played by the hypoxic inhibition of O2-dependent K+ channels and mitochondrial oxidative metabolism, and their modification by intracellular molecules and other ion channels; 2) synaptic mechanisms linking type I cells and petrosal nerve terminals, focusing on the role played by the main proposed transmitters and modulatory gases, and the participation of glial cells in regulation of the chemosensory process; 3) integrated reflex responses to CB activation, emphasizing that the responses differ dramatically depending on the nature of the physiological, pathological, or environmental challenges, and the interactions of the chemoreceptor reflex with other reflexes in optimizing oxygen delivery to the tissues; and 4) the contribution of enhanced CB chemosensory discharge to autonomic and cardiorespiratory pathophysiology in obstructive sleep apnea, congestive heart failure, resistant hypertension, and metabolic diseases and how modulation of enhanced CB reactivity in disease conditions may attenuate pathophysiology.
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Affiliation(s)
- Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile, and Centro de Excelencia en Biomedicina de Magallanes, Universidad de Magallanes, Punta Arenas, Chile
| | - Julio Alcayaga
- Laboratorio de Fisiología Celular, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Mark W Chapleau
- Department of Internal Medicine, University of Iowa and Department of Veterans Affairs Medical Center, Iowa City, Iowa
| | - Virend K Somers
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota
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Paraventricular Nucleus P2X7 Receptors Aggravate Acute Myocardial Infarction Injury via ROS-Induced Vasopressin-V1b Activation in Rats. Neurosci Bull 2021; 37:641-656. [PMID: 33620697 PMCID: PMC8099953 DOI: 10.1007/s12264-021-00641-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 09/16/2020] [Indexed: 12/27/2022] Open
Abstract
The present study was designed to investigate the mechanisms by which P2X7 receptors (P2X7Rs) mediate the activation of vasopressinergic neurons thereby increasing sympathetic hyperactivity in the paraventricular nucleus (PVN) of the hypothalamus of rats with acute myocardial ischemia (AMI). The left anterior descending branch of the coronary artery was ligated to induce AMI in rats. The rats were pretreated with BBG (brilliant blue G, a P2X7R antagonist), nelivaptan (a vasopressin V1b receptor antagonist), or diphenyleneiodonium (DPI) [an nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor]. Hemodynamic parameters of the heart were monitored. Myocardial injury and cardiomyocyte apoptosis were assessed. In the PVN of AMI rats, P2X7R mediated microglial activation, while reactive oxygen species (ROS) and NADPH oxidase 2 (NOX2) were higher than in the sham group. Intraperitoneal injection of BBG effectively reduced ROS production and vasopressin expression in the PVN of AMI rats. Moreover, both BBG and DPI pretreatment effectively reduced sympathetic hyperactivity and ameliorated AMI injury, as represented by reduced inflammation and apoptosis of cardiomyocytes. Furthermore, microinjection of nelivaptan into the PVN improved cardiac function and reduced the norepinephrine (AE) levels in AMI rats. Collectively, the results suggest that, within the PVN of AMI rats, P2X7R upregulation mediates microglial activation and the overproduction of ROS, which in turn activates vasopressinergic neuron-V1b receptors and sympathetic hyperactivity, hence aggravating myocardial injury in the AMI setting.
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Hong J, Lisco AM, Rudebush TL, Yu L, Gao L, Kitzerow O, Zucker IH, Wang HJ. Identification of Cardiac Expression Pattern of Transient Receptor Potential Vanilloid Type 1 (TRPV1) Receptor using a Transgenic Reporter Mouse Model. Neurosci Lett 2020; 737:135320. [PMID: 32841712 DOI: 10.1016/j.neulet.2020.135320] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 10/23/2022]
Abstract
Transient receptor potential vanilloid type 1 (TRPV1) channels are structurally related, non-selective cation channels that exhibit a high permeability to calcium. Sensory nerve endings expressing TRPV1 channels play a prominent role in regulating the cardiac sympathetic afferent reflex and contribute to cardiac remodeling and dysfunction in chronic heart failure. However, the precise expression of TRPV1 channels in cardiomyocytes vs. non-cardiomyocytes remains debated. Here we utilized a tdTomato-GFP reporter mouse crossed with a mouse line expressing Cre recombinase under the control of the TRPV1 promoter to map the TRPV1 expression pattern in heart. In this model, TRPV1-negative cells express tdTomato protein (red), whereas TRPV1-positive cells express GFP protein (green). As we expected, substantial GFP expression was found in many small and medium diameter dorsal root ganglia neurons in heterozygous TRPV1-Cre +/-, tdTomato flox/flox +/- male mice, suggesting that this heterozygous model is sufficient for labeling TRPV1-positive cells. Furthermore, these results showed that GFP green staining was not detectable in cardiomyocytes. Instead, we found strong GFP green staining in cardiac blood vessels-thought to be arterioles-in the heart. We also observed strong GFP signals on PGP9.5-positive cardiac nerve endings in the epicardium. In summary, this study does not support the concept that TRPV1 channels are strongly expressed in mouse cardiomyocytes. We conclude that TRPV1 channels in mouse heart are mostly expressed on non-cardiomyocyte cells including cardiac nerve endings and vessels. These data have important implications for the modulations of cardiogenic reflexes.
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Affiliation(s)
- Juan Hong
- Department of Anesthesiology, University of Nebraska Medical Center, NE, 68198, USA
| | - Amanda M Lisco
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, NE, 68198, USA
| | - Tara L Rudebush
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, NE, 68198, USA
| | - Li Yu
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, NE, 68198, USA
| | - Lie Gao
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, NE, 68198, USA
| | - Oliver Kitzerow
- Department of Anesthesiology, University of Nebraska Medical Center, NE, 68198, USA
| | - Irving H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, NE, 68198, USA
| | - Han-Jun Wang
- Department of Anesthesiology, University of Nebraska Medical Center, NE, 68198, USA; Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, NE, 68198, USA.
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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: 56] [Impact Index Per Article: 9.3] [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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Neuromodulation Therapies for Cardiac Disease. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00129-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Kolpakova J, Li L, Hatcher JT, Gu H, Zhang X, Chen J, Cheng ZJ. Responses of Nucleus Tractus Solitarius (NTS) early and late neurons to blood pressure changes in anesthetized F344 rats. PLoS One 2017; 12:e0169529. [PMID: 28384162 PMCID: PMC5383029 DOI: 10.1371/journal.pone.0169529] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 12/19/2016] [Indexed: 02/07/2023] Open
Abstract
Previously, many different types of NTS barosensitive neurons were identified. However, the time course of NTS barosensitive neuronal activity (NA) in response to arterial pressure (AP) changes, and the relationship of NA-AP changes, have not yet been fully quantified. In this study, we made extracellular recordings of single NTS neurons firing in response to AP elevation induced by occlusion of the descending aorta in anesthetized rats. Our findings were that: 1) Thirty-five neurons (from 46 neurons) increased firing, whereas others neurons either decreased firing upon AP elevation, or were biphasic: first decreased firing upon AP elevation and then increased firing during AP decrease. 2) Fourteen neurons with excitatory responses were activated and rapidly increased their firing during the early phase of AP increase (early neurons); whereas 21 neurons did not increase firing until the mean arterial pressure changes (ΔMAP) reached near/after the peak (late neurons). 3) The early neurons had a significantly higher firing rate than late neurons during AP elevation at a similar rate. 4) Early neuron NA-ΔMAP relationship could be well fitted and characterized by the sigmoid logistic function with the maximal gain of 29.3. 5) The increase of early NA correlated linearly with the initial heart rate (HR) reduction. 6) The late neurons did not contribute to the initial HR reduction. However, the late NA could be well correlated with HR reduction during the late phase. Altogether, our study demonstrated that the NTS excitatory neurons could be grouped into early and late neurons based on their firing patterns. The early neurons could be characterized by the sigmoid logistic function, and different neurons may differently contribute to HR regulation. Importantly, the grouping and quantitative methods used in this study may provide a useful tool for future assessment of functional changes of early and late neurons in disease models.
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Affiliation(s)
- Jenya Kolpakova
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando FL, United States of America
| | - Liang Li
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando FL, United States of America
| | - Jeffrey T. Hatcher
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando FL, United States of America
| | - He Gu
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando FL, United States of America
| | - Xueguo Zhang
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Jin Chen
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando FL, United States of America
| | - Zixi Jack Cheng
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando FL, United States of America
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Toschi-Dias E, Rondon MUPB, Cogliati C, Paolocci N, Tobaldini E, Montano N. Contribution of Autonomic Reflexes to the Hyperadrenergic State in Heart Failure. Front Neurosci 2017; 11:162. [PMID: 28424575 PMCID: PMC5372354 DOI: 10.3389/fnins.2017.00162] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 03/13/2017] [Indexed: 12/28/2022] Open
Abstract
Heart failure (HF) is a complex syndrome representing the clinical endpoint of many cardiovascular diseases of different etiology. Given its prevalence, incidence and social impact, a better understanding of HF pathophysiology is paramount to implement more effective anti-HF therapies. Based on left ventricle (LV) performance, HF is currently classified as follows: (1) with reduced ejection fraction (HFrEF); (2) with mid-range EF (HFmrEF); and (3) with preserved EF (HFpEF). A central tenet of HFrEF pathophysiology is adrenergic hyperactivity, featuring increased sympathetic nerve discharge and a progressive loss of rhythmical sympathetic oscillations. The role of reflex mechanisms in sustaining adrenergic abnormalities during HFrEF is increasingly well appreciated and delineated. However, the same cannot be said for patients affected by HFpEF or HFmrEF, whom also present with autonomic dysfunction. Neural mechanisms of cardiovascular regulation act as “controller units,” detecting and adjusting for changes in arterial blood pressure, blood volume, and arterial concentrations of oxygen, carbon dioxide and pH, as well as for humoral factors eventually released after myocardial (or other tissue) ischemia. They do so on a beat-to-beat basis. The central dynamic integration of all these afferent signals ensures homeostasis, at rest and during states of physiological or pathophysiological stress. Thus, the net result of information gathered by each controller unit is transmitted by the autonomic branch using two different codes: intensity and rhythm of sympathetic discharges. The main scope of the present article is to (i) review the key neural mechanisms involved in cardiovascular regulation; (ii) discuss how their dysfunction accounts for the hyperadrenergic state present in certain forms of HF; and (iii) summarize how sympathetic efferent traffic reveal central integration among autonomic mechanisms under physiological and pathological conditions, with a special emphasis on pathophysiological characteristics of HF.
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Affiliation(s)
- Edgar Toschi-Dias
- Heart Institute (InCor) do Hospital das Clínicas da Faculdade de Medicina da Universidade de São PauloSão Paulo, Brazil.,Department of Internal Medicine, Fondazione IRCCS Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy
| | | | - Chiara Cogliati
- Medicina ad Indirizzo Fisiopatologico, ASST Fatebenefratelli SaccoMilan, Italy
| | - Nazareno Paolocci
- Division of Cardiology, Department of Medicine, Johns Hopkins Medical InstitutionsBaltimore, MD, USA.,Dipartimento di Medicina Sperimentale, Universita' degli Studi di PerugiaPerugia, Italy
| | - Eleonora Tobaldini
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy.,Dipartimento di Dipartimento Scienze cliniche e di comunità, Università degli Studi di MilanoMilan, Italy
| | - Nicola Montano
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy.,Dipartimento di Dipartimento Scienze cliniche e di comunità, Università degli Studi di MilanoMilan, Italy
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14
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Wang HJ, Rozanski GJ, Zucker IH. Cardiac sympathetic afferent reflex control of cardiac function in normal and chronic heart failure states. J Physiol 2017; 595:2519-2534. [PMID: 28116751 DOI: 10.1113/jp273764] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 01/17/2017] [Indexed: 01/02/2023] Open
Abstract
KEY POINTS Cardiac sympathetic afferents are considered to be essential pathways for transmission of cardiac nociception to the central nervous system during myocardial ischaemia. However, a potential contribution of the CSAR control of cardiac dysfunction in both normal and chronic heart failure (CHF) states remains unknown. We found that activation of the CSAR evokes little increase in cardiac contractility with an exaggerated peripheral vasoconstriction in the CHF state. CSAR inhibition by epicardial lidocaine decreased cardiac contractility to a greater extent in CHF rats than sham rats. Furthermore, we also found that epicardial lidocaine paradoxically decreased left ventricular end-diastolic pressure (LVEDP) and left ventricular end-diastolic volume (preload) in CHF rats, which was not observed in sham rats. Chronic ablation of the CSAR by epicardial application of the afferent neurotoxin, RTX, selectively lowered diastolic blood pressure CHF rats. The observation suggests that CSAR has a differential effect on cardiac function in normal and CHF states. CSAR activation in normal state causes significant increase in cardiac contractility and cardiac output. ABSTRACT The enhanced 'cardiac sympathetic afferent reflex' (CSAR) critically contributes to the exaggerated global sympathetic tone in chronic heart failure (CHF). However, a potential contribution of the cardio-cardiac reflex control of cardiac function in both normal and CHF states remains unknown. In this study, we evaluated the effects of direct activation or inhibition of the CSAR on cardiac function by pressure-volume (P-V) loop analysis in ∼12-week sham-operated and myocardial infarcted (MI) rats. In sham rats, acute CSAR activation by epicardial application of bradykinin (BK) increased heart rate (HR), left ventricular systolic pressure (LVSP), the maximum first derivative of left ventricular pressure (dp/dtmax ), and the slope of the end-systolic P-V relationship (ESPVR), suggesting that acute CSAR activation in the normal state enhances myocardial contractility. CSAR activation also decreased left ventricular (LV) systolic and diastolic volumes with little effect on LV end-diastolic pressure (LVEDP) or the end-diastolic P-V relationship (EDPVR) in sham rats. Compared to sham, CHF rats exhibit a reduced increase in the slope of the ESPVR and dp/dtmax in response to BK, indicating a poor contractile response to CSAR activation. Interestingly, BK application in CHF rats increased cardiac systolic and diastolic volumes and further increased the elevated LVEDP, neither of which was seen in sham rats. Following CSAR inhibition by epicardial lidocaine, blood pressure, HR, LVSP, dp/dt, LVEDP and ESPVR decreased in CHF rats whereas lidocaine had little effect in sham rats, indicating that the CSAR is tonically active in CHF and contributes to cardiac dysfunction. Furthermore, we found that epicardial lidocaine paradoxically decreased LV end-diastolic volume (preload) in CHF rats, which was not observed in sham rats. The decreased preload by lidocaine in CHF rats may be due to a reduction in peripheral vascular resistance since epicardial lidocaine significantly lowered peripheral (renal) sympathetic nerve activity in CHF rats but not in sham rats. Furthermore, chronic ablation of CSAR by epicardial application of a selective afferent neurotoxin, resiniferatoxin, selectively lowered diastolic blood pressure both at daytime and night-time with less effect on systolic blood pressure in CHF rats. Our data suggest that there is an imbalance between cardiac and peripheral responses to CSAR in CHF animals compared to sham-operated controls.
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Affiliation(s)
- Han-Jun Wang
- Department of Anesthesiology, University of Nebraska Medical Center, 984455 Nebraska Medical Center, Omaha, NE, 68198-4455, USA.,Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, 985850 Nebraska Medical Center, Omaha, NE, 68198-5850, USA
| | - George J Rozanski
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, 985850 Nebraska Medical Center, Omaha, NE, 68198-5850, USA
| | - Irving H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, 985850 Nebraska Medical Center, Omaha, NE, 68198-5850, USA
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15
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Ichige MHA, Pereira MG, Brum PC, Michelini LC. Experimental Evidences Supporting the Benefits of Exercise Training in Heart Failure. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 999:181-206. [PMID: 29022264 DOI: 10.1007/978-981-10-4307-9_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Heart Failure (HF), a common end point for many cardiovascular diseases, is a syndrome with a very poor prognosis. Although clinical trials in HF have achieved important outcomes in reducing mortality, little is known about functional mechanisms conditioning health improvement in HF patients. In parallel with clinical studies, basic science has been providing important discoveries to understand the mechanisms underlying the pathophysiology of HF, as well as to identify potential targets for the treatment of this syndrome. In spite of being the end-point of cardiovascular derangements caused by different etiologies, autonomic dysfunction, sympathetic hyperactivity, oxidative stress, inflammation and hormonal activation are common factors involved in the progression of this syndrome. Together these causal factors create a closed link between three important organs: brain, heart and the skeletal muscle. In the past few years, we and other groups have studied the beneficial effects of aerobic exercise training as a safe therapy to avoid the progression of HF. As summarized in this chapter, exercise training, a non-pharmacological tool without side effects, corrects most of the HF-induced neurohormonal and local dysfunctions within the brain, heart and skeletal muscles. These adaptive responses reverse oxidative stress, reduce inflammation, ameliorate neurohormonal control and improve both cardiovascular and skeletal muscle function, thus increasing the quality of life and reducing patients' morbimortality.
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Affiliation(s)
- Marcelo H A Ichige
- Department of Physiology & Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Marcelo G Pereira
- Department of Biodynamics of Human Body Movement, School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil
| | - Patrícia C Brum
- Department of Biodynamics of Human Body Movement, School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil. .,National Institute for Science & Technology - INCT (In)activity & Exercise, CNPq - Niterói (RJ), Rio de Janeiro, Brazil.
| | - Lisete C Michelini
- Department of Physiology & Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.,National Institute for Science & Technology - INCT (In)activity & Exercise, CNPq - Niterói (RJ), Rio de Janeiro, Brazil
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16
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Ardell JL, Andresen MC, Armour JA, Billman GE, Chen PS, Foreman RD, Herring N, O'Leary DS, Sabbah HN, Schultz HD, Sunagawa K, Zucker IH. Translational neurocardiology: preclinical models and cardioneural integrative aspects. J Physiol 2016; 594:3877-909. [PMID: 27098459 DOI: 10.1113/jp271869] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/14/2016] [Indexed: 12/15/2022] Open
Abstract
Neuronal elements distributed throughout the cardiac nervous system, from the level of the insular cortex to the intrinsic cardiac nervous system, are in constant communication with one another to ensure that cardiac output matches the dynamic process of regional blood flow demand. Neural elements in their various 'levels' become differentially recruited in the transduction of sensory inputs arising from the heart, major vessels, other visceral organs and somatic structures to optimize neuronal coordination of regional cardiac function. This White Paper will review the relevant aspects of the structural and functional organization for autonomic control of the heart in normal conditions, how these systems remodel/adapt during cardiac disease, and finally how such knowledge can be leveraged in the evolving realm of autonomic regulation therapy for cardiac therapeutics.
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Affiliation(s)
- J L Ardell
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
| | - M C Andresen
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA
| | - J A Armour
- University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, USA.,UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, CA, USA
| | - G E Billman
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - P-S Chen
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - R D Foreman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - N Herring
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - D S O'Leary
- Department of Physiology, Wayne State University, Detroit, MI, USA
| | - H N Sabbah
- Department of Medicine, Henry Ford Hospital, Detroit, MI, USA
| | - H D Schultz
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - K Sunagawa
- Department of Cardiovascular Medicine, Kyushu University, Fukuoka, Japan
| | - I H Zucker
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
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17
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Calegari L, Mozzaquattro BB, Rossato DD, Quagliotto E, Ferreira JB, Rasia-Filho A, Dal Lago P. Exercise training attenuates the pressor response evoked by peripheral chemoreflex in rats with heart failure. Can J Physiol Pharmacol 2016; 94:979-86. [PMID: 27295522 DOI: 10.1139/cjpp-2015-0518] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effects of exercise training (ExT) on the pressor response elicited by potassium cyanide (KCN) in the rat model of ischemia-induced heart failure (HF) are unknown. We evaluated the effects of ExT on chemoreflex sensitivity and its interaction with baroreflex in rats with HF. Wistar rats were divided into four groups: trained HF (Tr-HF), sedentary HF (Sed-HF), trained sham (Tr-Sham), and sedentary sham (Sed-Sham). Trained animals underwent to a treadmill running protocol for 8 weeks (60 m/day, 5 days/week, 16 m/min). After ExT, arterial pressure (AP), baroreflex sensitivity (BRS), peripheral chemoreflex (KCN: 100 μg/kg body mass), and cardiac function were evaluated. The results demonstrate that ExT induces an improvement in BRS and attenuates the pressor response to KCN relative to the Sed-HF group (P < 0.05). The improvement in BRS was associated with a reduction in the pressor response following ExT in HF rats (P < 0.05). Moreover, ExT induced a reduction in left ventricular end-diastolic pressure and pulmonary congestion compared with the Sed-HF group (P < 0.05). The pressor response to KCN in the hypotensive state is decreased in sedentary HF rats. These results suggest that ExT improves cardiac function and BRS and attenuates the pressor response evoked by KCN in HF rats.
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Affiliation(s)
- Leonardo Calegari
- a Laboratory of Physiology, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil.,b Faculty of Physical Education and Physical Therapy, University of Passo Fundo, Brazil
| | - Bruna B Mozzaquattro
- a Laboratory of Physiology, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | | | - Edson Quagliotto
- a Laboratory of Physiology, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | - Janaina B Ferreira
- d Hypertension Unit, Heart Institute (InCor), University of São Paulo, Brazil
| | - Alberto Rasia-Filho
- a Laboratory of Physiology, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | - Pedro Dal Lago
- a Laboratory of Physiology, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil.,e Department of Physical Therapy, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
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18
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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 DOI: 10.1113/jp272318] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [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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19
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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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Abstract
OBJECTIVE The purpose of the study was to determine whether exposure to chronic mild stress (CMS) affects expression of angiotensin II Type 1a receptor (AT1aR) messenger RNA (mRNA) in the brain and kidney. METHODS Male Sprague-Dawley rats were divided into an unchallenged control group, which remained at rest, and an experimental group, exposed to CMS produced by a series of unexpected, disturbing stimuli applied at random over a period of 4 weeks. After sacrificing the animals, samples of the septal/accumbal and hypothalamic/thalamic diencephalon, brain medulla, cerebellum, and the renal medulla were harvested for determination of AT1aR mRNA. RESULTS Expression of AT1a receptor mRNA was significantly greater in the rats in the CMS condition than in the controls (septal/accumbal diencephalon: 1.689 [0.205] versus 0.027 [0.004], hypothalamic/thalamic diencephalon: 1.239 [0.101] versus 0.003 [0.001], brain medulla: 2.694 [0.295] versus 0.028 [0.003], cerebellum: 0.013 [0.002] versus 0.005 [0.001; p < .001 for all comparisons], and renal medulla: 409.92 [46.92] versus 208.06 [30.56; p < .01]). There was a significant positive correlation between AT1a mRNA expression in the septal/accumbal diencephalon and brain medulla (p < .025). CONCLUSIONS The results provide evidence that CMS significantly enhances expression of the AT1aR gene in the brain and kidney and indicate that changes in expression of AT1aR mRNA in different brain regions during CMS may be causally related. It is suggested that the up-regulation of AT1a receptors by chronic stress may potentiate negative effects of angiotensin II in pathologies associated with activation of the renin-angiotensin system.
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21
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The PI3K signaling-mediated nitric oxide contributes to cardiovascular effects of angiotensin-(1-7) in the nucleus tractus solitarii of rats. Nitric Oxide 2016; 52:56-65. [DOI: 10.1016/j.niox.2015.12.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/11/2015] [Accepted: 12/03/2015] [Indexed: 01/19/2023]
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22
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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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23
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Xu B, Li H. Brain mechanisms of sympathetic activation in heart failure: Roles of the renin‑angiotensin system, nitric oxide and pro‑inflammatory cytokines (Review). Mol Med Rep 2015; 12:7823-9. [PMID: 26499491 PMCID: PMC4758277 DOI: 10.3892/mmr.2015.4434] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 09/10/2015] [Indexed: 12/14/2022] Open
Abstract
Patients with chronic heart failure (CHF) have an insufficient perfusion to the peripheral tissues due to decreased cardiac output. The compensatory mechanisms are triggered even prior to the occurrence of clinical symptoms, which include activation of the sympathetic nervous system (SNS) and other neurohumoral factors. However, the long‑term activation of the SNS contributes to progressive cardiac dysfunction and has toxic effects on the cardiomyocytes. The mechanisms leading to the activation of SNS include changes in peripheral baroreceptor and chemoreceptor reflexes and the abnormal regulation of sympathetic nerve activity (SNA) in the central nervous system (CNS). Recent studies have focused on the role of brain mechanisms in the regulation of SNA and the progression of CHF. The renin‑angiotensin system, nitric oxide and pro‑inflammatory cytokines were shown to be involved in the abnormal regulation of SNA in the CNS. The alteration of these neurohumoral factors during CHF influences the activity of neurons in the autonomic regions and finally increase the sympathetic outflow. The present review summarizes the brain mechanisms contributing to sympathoexcitation in CHF.
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Affiliation(s)
- Bin Xu
- Department of Cardiology, Shanghai First People's Hospital, College of Medicine, Shanghai Jiaotong University, Shanghai 200080, P.R. China
| | - Hongli Li
- Department of Cardiology, Shanghai First People's Hospital, College of Medicine, Shanghai Jiaotong University, Shanghai 200080, P.R. China
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24
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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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25
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Central nervous system circuits modified in heart failure: pathophysiology and therapeutic implications. Heart Fail Rev 2015; 19:759-79. [PMID: 24573960 DOI: 10.1007/s10741-014-9427-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The pathophysiology of heart failure (HF) is characterized by an abnormal activation of neurohumoral systems, including the sympathetic nervous and the renin-angiotensin-aldosterone systems, which have long-term deleterious effects on the disease progression. Perpetuation of this neurohumoral activation is partially dependent of central nervous system (CNS) pathways, mainly involving the paraventricular nucleus of the hypothalamus and some regions of the brainstem. Modifications in these integrative CNS circuits result in the attenuation of sympathoinhibitory and exacerbation of sympathoexcitatory pathways. In addition to the regulation of sympathetic outflow, these central pathways coordinate a complex network of agents with an established pathophysiological relevance in HF such as angiotensin, aldosterone, and proinflammatory cytokines. Central pathways could be potential targets in HF therapy since the current mainstay of HF pharmacotherapy aims primarily at antagonizing the peripheral mechanisms. Thus, in the present review, we describe the role of CNS pathways in HF pathophysiology and as potential novel therapeutic targets.
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26
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Chen WW, Xiong XQ, Chen Q, Li YH, Kang YM, Zhu GQ. Cardiac sympathetic afferent reflex and its implications for sympathetic activation in chronic heart failure and hypertension. Acta Physiol (Oxf) 2015; 213:778-94. [PMID: 25598170 DOI: 10.1111/apha.12447] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 10/22/2014] [Accepted: 12/23/2014] [Indexed: 12/21/2022]
Abstract
Persistent excessive sympathetic activation greatly contributes to the pathogenesis of chronic heart failure (CHF) and hypertension. Cardiac sympathetic afferent reflex (CSAR) is a sympathoexcitatory reflex with positive feedback characteristics. Humoral factors such as bradykinin, adenosine and reactive oxygen species produced in myocardium due to myocardial ischaemia stimulate cardiac sympathetic afferents and thereby reflexly increase sympathetic activity and blood pressure. The CSAR is enhanced in myocardial ischaemia, CHF and hypertension. The enhanced CSAR at least partially contributes to the sympathetic activation and pathogenesis of these diseases. Nucleus of the solitary tract (NTS), hypothalamic paraventricular nucleus (PVN) and rostral ventrolateral medulla are the most important central sites involved in the modulation and integration of the CSAR. Angiotensin II, AT1 receptors and NAD(P)H oxidase-derived superoxide anions pathway in the PVN are mainly responsible for the enhanced CSAR in CHF and hypertension. Central angiotensin-(1-7), nitric oxide, endothelin, intermedin, hydrogen peroxide and several other signal molecules are involved in regulating CSAR. Blockade of the CSAR shows beneficial effects in CHF and hypertension. This review focuses on the anatomical and physiological basis of the CSAR, the interaction of CSAR with baroreflex and chemoreflex, and the role of enhanced CSAR in the pathogenesis of CHF and hypertension.
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Affiliation(s)
- W.-W. Chen
- Department of Physiology; Key Laboratory of Cardiovascular Disease and Molecular Intervention; Nanjing Medical University; Nanjing Jiangsu China
| | - X.-Q. Xiong
- Department of Physiology; Key Laboratory of Cardiovascular Disease and Molecular Intervention; Nanjing Medical University; Nanjing Jiangsu China
| | - Q. Chen
- Department of Pathophysiology; Nanjing Medical University; Nanjing Jiangsu China
| | - Y.-H. Li
- Department of Pathophysiology; Nanjing Medical University; Nanjing Jiangsu China
| | - Y.-M. Kang
- Department of Physiology and Pathophysiology; Cardiovascular Research Center; Xi'an Jiaotong University School of Medicine; Xi'an China
| | - G.-Q. Zhu
- Department of Physiology; Key Laboratory of Cardiovascular Disease and Molecular Intervention; Nanjing Medical University; Nanjing Jiangsu China
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27
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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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28
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Lu Y, Wu YS, Chen DS, Wang MM, Wang WZ, Yuan WJ. Microinjection of salusin-beta into the nucleus tractus solitarii inhibits cardiovascular function by suppressing presympathetic neurons in rostral ventrolateral medulla in rats. Physiol Res 2014; 64:161-71. [PMID: 25317687 DOI: 10.33549/physiolres.932616] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Salusin-beta is newly identified bioactive peptide of 20 amino acids, which is widely distributed in hematopoietic system, endocrine system, and the central nervous system (CNS). Although salusin-beta extensively expressed in the CNS, the central cardiovascular functions of salusin-beta are unclear. Our main objective was to determine the cardiovascular effect of microinjection of salusin-beta into the nucleus tractus solitarii (NTS) in anesthetized rats. Bilateral or unilateral microinjection of salusin-beta (0.94-94 microg/rat) into the NTS dose-dependently decreased blood pressure and heart rate. Bilateral NTS microinjection of salusin-beta (9.4 microg/rat) did not alter baroreflex sensitivity. Prior application of the glutamate receptor antagonist kynurenic acid (0.19 microg/rat, n=9) into the NTS did not alter the salusin-beta (9.4 microg/rat) induced hypotension and bradycardia. However, pretreatment with the GABA receptor agonist muscimol (0.5 ng/rat) within the rostral ventrolateral medulla (RVLM) completely abolished the hypotension (-14+/-5 vs. -3+/-5 mm Hg, P<0.05) and bradycardia (-22+/-6 vs. -6+/-5 bpm, P<0.05) evoked by intra-NTS salusin-beta (9.4 microg/rat). In addition, we found that vagotomy didn't influence the actions of salusin-beta (9.4 microg/rat) in the NTS. In conclusion, our present study shows that microinjection of salusin-beta into the NTS significantly produces hypotension and bradycardia, presumably by suppressing the activities of presympathetic neurons in the RVLM.
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Affiliation(s)
- Y Lu
- Department of Clinical Laboratory, San Ai Tang Hospital, Lanzhou, PR China. ; Department of Physiology and Key Lab of Ministry of Education in Fertility Preservation and Maintenance, Ningxia Medical University, Yinchuan, PR China.
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29
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Costa KM, Accorsi-Mendonça D, Moraes DJA, Machado BH. Evolution and physiology of neural oxygen sensing. Front Physiol 2014; 5:302. [PMID: 25161625 PMCID: PMC4129633 DOI: 10.3389/fphys.2014.00302] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 07/23/2014] [Indexed: 01/06/2023] Open
Abstract
Major evolutionary trends in animal physiology have been heavily influenced by atmospheric O2 levels. Amongst other important factors, the increase in atmospheric O2 which occurred in the Pre-Cambrian and the development of aerobic respiration beckoned the evolution of animal organ systems that were dedicated to the absorption and transportation of O2, e.g., the respiratory and cardiovascular systems of vertebrates. Global variations of O2 levels in post-Cambrian periods have also been correlated with evolutionary changes in animal physiology, especially cardiorespiratory function. Oxygen transportation systems are, in our view, ultimately controlled by the brain related mechanisms, which senses changes in O2 availability and regulates autonomic and respiratory responses that ensure the survival of the organism in the face of hypoxic challenges. In vertebrates, the major sensorial system for oxygen sensing and responding to hypoxia is the peripheral chemoreflex neuronal pathways, which includes the oxygen chemosensitive glomus cells and several brainstem regions involved in the autonomic regulation of the cardiovascular system and respiratory control. In this review we discuss the concept that regulating O2 homeostasis was one of the primordial roles of the nervous system. We also review the physiology of the peripheral chemoreflex, focusing on the integrative repercussions of chemoreflex activation and the evolutionary importance of this system, which is essential for the survival of complex organisms such as vertebrates. The contribution of hypoxia and peripheral chemoreflex for the development of diseases associated to the cardiovascular and respiratory systems is also discussed in an evolutionary context.
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Affiliation(s)
| | | | | | - Benedito H. Machado
- Laboratory of Autonomic and Respiratory Control, Department of Physiology, School of Medicine of Ribeirão Preto, University of São PauloRibeirão Preto, Brazil
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30
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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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31
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Transneuronal tracing of central autonomic regions involved in cardiac sympathetic afferent reflex in rats. J Neurol Sci 2014; 342:45-51. [DOI: 10.1016/j.jns.2014.04.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 03/25/2014] [Accepted: 04/21/2014] [Indexed: 01/08/2023]
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32
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Ostrowski TD, Hasser EM, Heesch CM, Kline DD. H₂O₂ induces delayed hyperexcitability in nucleus tractus solitarii neurons. Neuroscience 2014; 262:53-69. [PMID: 24397952 DOI: 10.1016/j.neuroscience.2013.12.055] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 12/23/2013] [Accepted: 12/24/2013] [Indexed: 12/19/2022]
Abstract
Hydrogen peroxide (H₂O₂) is a stable reactive oxygen species and potent neuromodulator of cellular and synaptic activity. Centrally, endogenous H₂O₂ is elevated during bouts of hypoxia-reoxygenation, a variety of disease states, and aging. The nucleus tractus solitarii (nTS) is the central termination site of visceral afferents for homeostatic reflexes and contributes to reflex alterations during these conditions. We determined the extent to which H₂O₂ modulates synaptic and membrane properties in nTS neurons in rat brainstem slices. Stimulation of the tractus solitarii (which contains the sensory afferent fibers) evoked synaptic currents that were not altered by 10-500 μM H₂O₂. However, 500 μM H₂O₂ modulated several intrinsic membrane properties of nTS neurons, including a decrease in input resistance (R(i)), hyperpolarization of resting membrane potential (RMP) and action potential (AP) threshold (THR), and an initial reduction in AP discharge to depolarizing current. H₂O₂ increased conductance of barium-sensitive potassium currents, and block of these currents ablated H₂O₂-induced changes in RMP, Ri and AP discharge. Following washout of H₂O₂ AP discharge was enhanced due to depolarization of RMP and a partially maintained hyperpolarization of THR. Hyperexcitability persisted with repeated H₂O₂ exposure. H₂O₂ effects on RMP and THR were ablated by intracellular administration of the antioxidant catalase, which was immunohistochemically identified in neurons throughout the nTS. Thus, H₂O₂ initially reduces excitability of nTS neurons that is followed by sustained hyperexcitability, which may play a profound role in cardiorespiratory reflexes.
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Affiliation(s)
- T D Ostrowski
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - E M Hasser
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - C M Heesch
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - D D Kline
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA.
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33
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Sabharwal R, Chapleau MW. Autonomic, locomotor and cardiac abnormalities in a mouse model of muscular dystrophy: targeting the renin-angiotensin system. Exp Physiol 2013; 99:627-31. [PMID: 24334334 DOI: 10.1113/expphysiol.2013.074336] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
New Findings What is the topic of this review? This symposium report summarizes autonomic, cardiac and skeletal muscle abnormalities in sarcoglycan-δ-deficient mice (Sgcd-/-), a mouse model of limb girdle muscular dystrophy, with emphasis on the roles of autonomic dysregulation and activation of the renin-angiotensin system at a young age. What advances does it highlight? The contributions of the autonomic nervous system and the renin-angiotensin system to the pathogenesis of muscular dystrophy are highlighted. Results demonstrate that autonomic dysregulation precedes and predicts later development of cardiac dysfunction in Sgcd-/- mice and that treatment of young Sgcd-/- mice with the angiotensin type 1 receptor antagonist losartan or with angiotensin-(1-7) abrogates the autonomic dysregulation, attenuates skeletal muscle pathology and increases spontaneous locomotor activity. Muscular dystrophies are a heterogeneous group of genetic muscle diseases characterized by muscle weakness and atrophy. Mutations in sarcoglycans and other subunits of the dystrophin-glycoprotein complex cause muscular dystrophy and dilated cardiomyopathy in animals and humans. Aberrant autonomic signalling is recognized in a variety of neuromuscular disorders. We hypothesized that activation of the renin-angiotensin system contributes to skeletal muscle and autonomic dysfunction in mice deficient in the sarcoglycan-δ (Sgcd) gene at a young age and that this early autonomic dysfunction contributes to the later development of left ventricular (LV) dysfunction and increased mortality. We demonstrated that young Sgcd-/- mice exhibit histopathological features of skeletal muscle dystrophy, decreased locomotor activity and severe autonomic dysregulation, but normal LV function. Autonomic regulation continued to deteriorate in Sgcd-/- mice with age and was accompanied by LV dysfunction and dilated cardiomyopathy at older ages. Autonomic dysregulation at a young age predicted later development of LV dysfunction and higher mortality in Sgcd-/- mice. Treatment of Sgcd-/- mice with the angiotensin type 1 receptor blocker losartan for 8-9 weeks, beginning at 3 weeks of age, decreased fibrosis and oxidative stress in skeletal muscle, increased locomotor activity and prevented autonomic dysfunction. Chronic infusion of the counter-regulatory peptide angiotensin-(1-7) resulted in similar protection. We conclude that activation of the renin-angiotensin system, at a young age, contributes to skeletal muscle and autonomic dysfunction in muscular dystrophy. We speculate that the latter is mediated via abnormal sensory nerve and/or cytokine signalling from dystrophic skeletal muscle to the brain and contributes to age-related LV dysfunction, dilated cardiomyopathy, arrhythmias and premature death. Therefore, correcting the early autonomic dysregulation and renin-angiotensin system activation may provide a novel therapeutic approach in muscular dystrophy.
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Affiliation(s)
- Rasna Sabharwal
- * 607 MRC, Internal Medicine, University of Iowa Carver College of Medicine, 501 Newton Road, Iowa City, IA 52242, USA.
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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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35
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Hardwick JC, Ryan SE, Beaumont E, Ardell JL, Southerland EM. Dynamic remodeling of the guinea pig intrinsic cardiac plexus induced by chronic myocardial infarction. Auton Neurosci 2013; 181:4-12. [PMID: 24220238 DOI: 10.1016/j.autneu.2013.10.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 10/19/2013] [Accepted: 10/23/2013] [Indexed: 11/19/2022]
Abstract
Myocardial infarction (MI) is associated with remodeling of the heart and neurohumoral control systems. The objective of this study was to define time-dependent changes in intrinsic cardiac (IC) neuronal excitability, synaptic efficacy, and neurochemical modulation following MI. MI was produced in guinea pigs by ligation of the coronary artery and associated vein on the dorsal surface of the heart. Animals were recovered for 4, 7, 14, or 50 days. Intracellular voltage recordings were obtained in whole mounts of the cardiac neuronal plexus to determine passive and active neuronal properties of IC neurons. Immunohistochemical analysis demonstrated an immediate and persistent increase in the percentage of IC neurons immunoreactive for neuronal nitric oxide synthase. Examination of individual neuronal properties demonstrated that after hyperpolarizing potentials were significantly decreased in both amplitude and time course of recovery at 7 days post-MI. These parameters returned to control values by 50 days post-MI. Synaptic efficacy, as determined by the stimulation of axonal inputs, was enhanced at 7 days post-MI only. Neuronal excitability in absence of agonist challenge was unchanged following MI. Norepinephrine increased IC excitability to intracellular current injections, a response that was augmented post-MI. Angiotensin II potentiation of norepinephrine and bethanechol-induced excitability, evident in controls, was abolished post-MI. This study demonstrates that MI induces both persistent and transient changes in IC neuronal functions immediately following injury. Alterations in the IC neuronal network, which persist for weeks after the initial insult, may lead to alterations in autonomic signaling and cardiac control.
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Affiliation(s)
- Jean C Hardwick
- Department of Biology, Ithaca College, Ithaca, NY 14850, United States.
| | - Shannon E Ryan
- Department of Biology, Ithaca College, Ithaca, NY 14850, United States
| | - Eric Beaumont
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - Jeffrey L Ardell
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - E Marie Southerland
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
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Li P, Sun HJ, Han Y, Wang JJ, Zhang F, Tang CS, Zhou YB. Intermedin enhances sympathetic outflow via receptor-mediated cAMP/PKA signaling pathway in nucleus tractus solitarii of rats. Peptides 2013; 47:1-6. [PMID: 23816795 DOI: 10.1016/j.peptides.2013.05.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/07/2013] [Accepted: 05/07/2013] [Indexed: 10/26/2022]
Abstract
Direct administration of intermedin (IMD) into the brain elicits cardiovascular effects different from the systemic administration. Nucleus tractus solitarii (NTS) is an important region for the cardiovascular regulation. The present study was designed to determine the effect of IMD on modulating the sympathetic outflow and its related molecular mechanism in the NTS. Renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded in anesthetized rats. Site-specific microinjection of IMD (20pmol) bilaterally into the NTS significantly increased RSNA and MAP. IMD-evoked increases of RSNA and MAP were almost abolished by pretreatment with receptor antagonist ADM22-52, an adenylyl cyclase (AC) inhibitor SQ22536, or a protein kinase A (PKA) inhibitor Rp-cAMP. However, pretreatment with another receptor antagonist calcitonin gene-related peptide (CGRP)8-37 did not suppress the increases of RSNA and MAP induced by IMD. Furthermore, IMD increased the cyclic adenosine monophosphate (cAMP) level, which was inhibited by ADM22-52 pretreatment in the NTS. These results suggest that IMD participates in the sympathetic nerve activity and central regulation of the cardiovascular system and a receptor-mediated cAMP/PKA signaling pathway is involved in IMD-induced effects in the NTS.
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Affiliation(s)
- Peng Li
- Department of Physiology, Nanjing Medical University, Nanjing 210029, China
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Sabino JPJ, da Silva CAA, Giusti H, Glass ML, Salgado HC, Fazan R. Parasympathetic activation by pyridostigmine on chemoreflex sensitivity in heart-failure rats. Auton Neurosci 2013; 179:43-8. [PMID: 23911533 DOI: 10.1016/j.autneu.2013.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 07/02/2013] [Accepted: 07/03/2013] [Indexed: 10/26/2022]
Abstract
We evaluated the effects of parasympathetic activation by pyridostigmine (PYR) on chemoreflex sensitivity in a rat model of heart failure (HF rats). HF rats demonstrated higher pulmonary ventilation (PV), which was not affected by PYR. When HF and control rats treated or untreated with PYR were exposed to 15% O2, all groups exhibited prompt increases in respiratory frequency (RF), tidal volume (TV) and PV. When HF rats were exposed to 10% O2 they showed greater PV response which was prevented by PYR. The hypercapnia triggered by either 5% CO2 or 10% CO2 promoted greater RF and PV responses in HF rats. PYR blunted the RF response in HF rats but did not affect the PV response. In conclusion, PYR prevented increased peripheral chemoreflex sensitivity, partially blunted central chemoreflex sensitivity and did not affect basal PV in HF rats.
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Affiliation(s)
- João Paulo J Sabino
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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Xu B, Zheng H, Patel KP. Relative contributions of the thalamus and the paraventricular nucleus of the hypothalamus to the cardiac sympathetic afferent reflex. Am J Physiol Regul Integr Comp Physiol 2013; 305:R50-9. [PMID: 23616108 DOI: 10.1152/ajpregu.00004.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cardiac sympathetic afferent reflex (CSAR) is induced by stimulating the cardiac sympathetic afferents, which evokes increases in sympathetic outflow and arterial pressure. In the present study, we attempted to identify the contribution of thalamic and hypothalamic nuclei involved in the CSAR. First, we observed that there was an increase in the number of c-Fos-labeled cells in the paraventricular nucleus (PVN) (190 ± 18 vs. 101 ± 15; P < 0.05), the paraventricular nucleus of the thalamus (PVT) (239 ± 23 vs. 151 ± 15; P < 0.05), and the mediodorsal thalamic nucleus (MD) (92 ± 9 vs. 63 ± 6; P < 0.05) following epicardial application of bradykinin (BK) compared with the control group (P < 0.05). Second, using extracellular single-unit recording, we found 25% of spontaneously active neurons in the thalamus were stimulated by epicardial application of BK or capsaicin in intact rats. However, 24% of spontaneously active neurons in the thalamus were still stimulated by epicardial application of BK or capsaicin despite vagotomy and sinoaortic denervation. None of the neurons in the thalamus responded to baroreflex changes in arterial pressure, induced by intravenous injection of phenylephrine or sodium nitroprusside. The CSAR was inhibited by microinjection of muscimol or lidocaine into the PVN. However, it was not inhibited or blocked by microinjection of muscimol or lidocaine into the thalamus. Taken together, these data suggest that the thalamus, while activated, is not critical for autonomic adjustments in response to activation of the CSAR. On the other hand, the PVN is critically involved in the central pathway of the CSAR.
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Affiliation(s)
- Bo Xu
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA
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Role of hypothalamic angiotensin type 1 receptors in pressure overload-induced mineralocorticoid receptor activation and salt-induced sympathoexcitation. Hypertens Res 2013; 36:513-9. [DOI: 10.1038/hr.2012.221] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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40
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Wang Y, Seto SW, Golledge J. Angiotensin II, sympathetic nerve activity and chronic heart failure. Heart Fail Rev 2012; 19:187-98. [DOI: 10.1007/s10741-012-9368-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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41
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Haack KKV, Engler CW, Papoutsi E, Pipinos II, Patel KP, Zucker IH. Parallel changes in neuronal AT1R and GRK5 expression following exercise training in heart failure. Hypertension 2012; 60:354-61. [PMID: 22753221 DOI: 10.1161/hypertensionaha.112.195693] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although exercise training (ExT) is an important therapeutic strategy for improving quality of life in patients with chronic heart failure (CHF), the central mechanisms by which ExT is beneficial are not well understood. The angiotensin II type 1 receptor (AT1R) plays a pivotal role in the development of CHF and is upregulated in a number of tissues owing, in part, to transcription factor nuclear factor kappa B (NF-κB). In addition, AT1R is marked for internalization and recycling via G-protein-coupled receptor kinase (GRK) phosphorylation. Because previous studies have shown that the beneficial effects of ExT in CHF rely on a reduction in angiotensin II, we hypothesized ExT would decrease AT1R, GRK5, and NF-κB protein expression in the paraventricular nucleus and rostral ventrolateral medulla of CHF rats. Following infarction by coronary artery ligation, animals were exercised 4 weeks postsurgery on a treadmill at a final speed of 25 miles per minute for 60 minutes, 5 days per week for 6 weeks. Western blot analysis of paraventricular nucleus and rostral ventrolateral medulla micropunches revealed an upregulation of AT1R, GRK5, and NF-κB in the infarcted group that was reversed by ExT. Furthermore, the relative expression of phosphorylated AT1R and AT1R/GRK5 physical association was increased in the CHF sedentary group and reversed by ExT. Overexpression of GRK5 in cultured CATH.a neurons blunted angiotensin II-mediated upregulation of AT1R and NF-κB; conversely, silencing of GRK5 exacerbated angiotensin II-mediated AT1R and NF-κB upregulation. Taken together, increased GRK5 may regulate AT1R expression in CHF, and ExT mitigates AT1R and its pathway components.
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Affiliation(s)
- Karla K V Haack
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, USA
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Abstract
The temporal relationship between the development of heart failure and activation of the neurohumoral systems involved in chronic heart failure (CHF) has not been precisely defined. When a compensatory mechanism switches to a deleterious contributing factor in the progression of the disease is unclear. This article addresses these issues through evaluating the contribution of various cardiovascular reflexes and cellular mechanisms to the sympathoexcitation in CHF. It also sheds light on some of the important central mechanisms that contribute to the increase in sympathetic nerve activity in CHF.
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Affiliation(s)
- Irving H Zucker
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, USA.
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43
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Gan XB, Duan YC, Xiong XQ, Li P, Cui BP, Gao XY, Zhu GQ. Inhibition of cardiac sympathetic afferent reflex and sympathetic activity by baroreceptor and vagal afferent inputs in chronic heart failure. PLoS One 2011; 6:e25784. [PMID: 21991351 PMCID: PMC3185007 DOI: 10.1371/journal.pone.0025784] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 09/09/2011] [Indexed: 11/19/2022] Open
Abstract
Background Cardiac sympathetic afferent reflex (CSAR) contributes to sympathetic activation and angiotensin II (Ang II) in paraventricular nucleus (PVN) augments the CSAR in vagotomized (VT) and baroreceptor denervated (BD) rats with chronic heart failure (CHF). This study was designed to determine whether it is true in intact (INT) rats with CHF and to determine the effects of cardiac and baroreceptor afferents on the CSAR and sympathetic activity in CHF. Methodology/Principal Findings Sham-operated (Sham) or coronary ligation-induced CHF rats were respectively subjected to BD+VT, VT, cardiac sympathetic denervation (CSD) or INT. Under anesthesia, renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded, and the CSAR was evaluated by the RSNA and MAP responses to epicardial application of capsaicin. Either CSAR or the responses of RSNA, MAP and CSAR to Ang II in PVN were enhanced in CHF rats treated with BD+VT, VT or INT. Treatment with VT or BD+VT potentiated the CSAR and the CSAR responses to Ang II in both Sham and CHF rats. Treatment with CSD reversed the capsaicin-induced RSNA and MAP changes and the CSAR responses to Ang II in both Sham and CHF rats, and reduced the RSNA and MAP responses to Ang II only in CHF rats. Conclusions The CSAR and the CSAR responses to Ang II in PVN are enhanced in intact CHF rats. Baroreceptor and vagal afferent activities inhibit CSAR and the CSAR responses to Ang II in intact Sham and CHF rats.
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Affiliation(s)
- Xian-Bing Gan
- Department of Physiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, China
| | - Yang-Can Duan
- Department of Physiology, Nanjing Medical University, Nanjing, China
- Department of Medical Ultrasound, Affiliated Hospital of Jining Medical University, Jining, China
| | - Xiao-Qing Xiong
- Department of Physiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, China
| | - Peng Li
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Bai-Ping Cui
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Xing-Ya Gao
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Guo-Qing Zhu
- Department of Physiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, China
- * E-mail:
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Kar S, Gao L, Belatti DA, Curry PL, Zucker IH. Central angiotensin (1-7) enhances baroreflex gain in conscious rabbits with heart failure. Hypertension 2011; 58:627-34. [PMID: 21844487 DOI: 10.1161/hypertensionaha.111.177600] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In chronic heart failure (CHF), arterial baroreflex function is impaired, in part, by activation of the central renin-angiotensin system. A metabolite of angiotensin (Ang) II, Ang-(1-7), has been shown to exhibit cardiovascular effects that are in opposition to that of Ang II. However, the action of Ang-(1-7) on sympathetic outflow and baroreflex function is not well understood, especially in CHF. The aim of this study was to determine the effect of intracerebroventricular infusion of Ang-(1-7) on baroreflex control of heart rate and renal sympathetic nerve activity in conscious rabbits with CHF. We hypothesized that central Ang-(1-7) would improve baroreflex function in CHF. Ang-(1-7) (2 nmol/1 μL per hour) or artificial cerebrospinal fluid (1 μL per hour) was infused by an osmotic minipump for 4 days in sham and pacing-induced CHF rabbits (n=3 to 6 per group). Ang-(1-7) treatment had no effects in sham rabbits but reduced heart rate and increased baroreflex gain (7.4±1.5 versus 2.5±0.4 bpm/mm Hg; P<0.05) in CHF rabbits. The Ang-(1-7) antagonist A779 (8 nmol/1 μL per hour) blocked the improvement in baroreflex gain in CHF. Baroreflex gain increased in CHF+Ang-(1-7) animals when only the vagus was allowed to modulate baroreflex control by acute treatment with the β-1 antagonist metoprolol, indicating increased vagal tone. Baseline renal sympathetic nerve activity was significantly lower, and baroreflex control of renal sympathetic nerve activity was enhanced in CHF rabbits receiving Ang-(1-7). These data suggest that augmentation of central Ang-(1-7) inhibits sympathetic outflow and increases vagal outflow in CHF, thus contributing to enhanced baroreflex gain in this disease state.
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Affiliation(s)
- Sumit Kar
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA
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Diz DI, Arnold AC, Nautiyal M, Isa K, Shaltout HA, Tallant EA. Angiotensin peptides and central autonomic regulation. Curr Opin Pharmacol 2011; 11:131-7. [PMID: 21367658 DOI: 10.1016/j.coph.2011.02.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 02/08/2011] [Indexed: 10/18/2022]
Abstract
Aging, hypertension, and fetal-programmed cardiovascular disease are associated with a functional deficiency of angiotensin (Ang)-(1-7) in the brain dorsomedial medulla. The resulting unrestrained activity of Ang II in brainstem regions negatively impacts resting mean arterial pressure, sympathovagal balance, and baroreflex sensitivity for control of heart rate. The differential effects of Ang II and Ang-(1-7) may be related to the cellular sources of these peptides as well as different precursor pathways. Long-term alterations of the brain renin-angiotensin system may influence signaling pathways including phosphoinositol-3-kinase and mitogen-activated protein kinase and their downstream mediators, and as a consequence may influence metabolic function. Differential regulation of signaling pathways in aging and hypertension by Ang II versus Ang-(1-7) may contribute to the autonomic dysfunction accompanying these states.
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Affiliation(s)
- Debra I Diz
- The Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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46
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Wang HJ, Li YL, Zhang LB, Zucker IH, Gao L, Zimmerman MC, Wang W. Endogenous reactive oxygen species modulates voltage-gated sodium channels in dorsal root ganglia of rats. J Appl Physiol (1985) 2011; 110:1439-47. [PMID: 21292836 DOI: 10.1152/japplphysiol.01409.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We recently reported that reactive oxygen species (ROS) plays an excitatory role in modulation of the exercise pressor reflex (EPR) in normal rats. In this study, we further tested two independent hypotheses: 1) ROS interacts with EPR-related ionotropic receptors such as the purinergic receptors (P(2)) and transient receptor potential vanilloid 1 receptors (TRPV1) to indirectly modulate the EPR function; 2) ROS directly affects excitability of muscle afferents by modulating the voltage-gated sodium (Na(v)) channels. To test the first hypothesis, we performed animal experiments to investigate the effect of the SOD mimetic 4-hydroxy-2,2,6,6-tetramethyl piperidine 1-oxyl (Tempol) on the pressor response to hindlimb intra-arterial (IA) injection of either α,β-methylene ATP (a P(2X) agonist) or capsaicin (a TRPV1 agonist) in decerebrate rats. To test the second hypothesis, we used the patch-clamp technique to determine the effect of ROS on Na(v) channels on the soma of muscle afferents. We also performed local microinjection of a sodium channel blocker, tetrodotoxin (TTX), into ipsilateral L4/L5 dorsal root ganglia (DRGs) to investigate whether the blockade of Na(v) channels by TTX affects the EPR function. We found that Tempol did not affect the pressor response to injection of either capsaicin or α,β-methylene ATP but significantly decreased the Na(v) current in small and medium-sized 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-labeled DRG neurons. A membrane-permeant superoxide dismutase, polyethylene glycol (PEG)-SOD, had an effect on the Na(v) current in these neurons similar to that of Tempol. Microinjection of TTX into L4/L5 DRGs dramatically attenuated the pressor response to static contraction induced by electrical stimulation of L4/L5 ventral roots. These data suggest that ROS modulates the EPR by affecting the activity of the Na(v) channels on muscle afferents.
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Affiliation(s)
- Han-Jun Wang
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA
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47
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Tang K, Li X, Zheng MQ, Rozanski GJ. Role of apoptosis signal-regulating kinase-1-c-Jun NH2-terminal kinase-p38 signaling in voltage-gated K+ channel remodeling of the failing heart: regulation by thioredoxin. Antioxid Redox Signal 2011; 14:25-35. [PMID: 20518594 PMCID: PMC3000643 DOI: 10.1089/ars.2010.3095] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
c-Jun NH(2)-terminal kinase (JNK) and p38 kinase are key regulators of cardiac hypertrophy and apoptosis during pathological stress, but their role in regulating ion channels in the diseased heart is unclear. Thus, we compared the kinase profile and electrophysiological phenotype of the rat ventricle 6-8 weeks after myocardial infarction (MI). Molecular analyses showed that JNK and p38 activities were markedly increased in post-MI hearts, while parallel voltage-clamp studies in ventricular myocytes revealed a characteristic downregulation of transient outward K(+) current (I(to)) density. When post-MI myocytes were treated with JNK or p38 inhibitors, I(to) density increased to control levels. Upregulation of I(to) was also elicited by insulin-like growth factor-1, which decreased JNK/p38 activity in post-MI hearts, and these changes were blocked by the thioredoxin (Trx) reductase inhibitor auranofin. Consistent with activation of JNK-p38 signaling, binding of apoptosis signal-regulating kinase-1 with Trx1 was also markedly decreased post-MI, and was reversed by insulin-like growth factor-1 in an auranofin-sensitive manner. We conclude that expression of ventricular K(+) channels is redox regulated and that chronic impairment of the Trx system in the post-MI heart contributes to I(to) remodeling through sustained activation of apoptosis signal-regulating kinase-1-JNK-p38 signaling. The cardiac Trx system may thus be a novel therapeutic target to reverse or prevent ventricular arrhythmias in the failing heart.
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Affiliation(s)
- Kang Tang
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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48
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Chitravanshi VC, Sapru HN. Cardiovascular responses elicited by a new endogenous angiotensin in the nucleus tractus solitarius of the rat. Am J Physiol Heart Circ Physiol 2010; 300:H230-40. [PMID: 21076017 DOI: 10.1152/ajpheart.00861.2010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cardiovascular effects of angiotensin-(1-12) [ANG-(1-12)] were studied in the medial nucleus of the tractus solitarius (mNTS) in anesthetized, artificially ventilated, adult male Wistar rats. Microinjections (100 nl) of ANG-(1-12) (0.06 mM) into the mNTS elicited maximum decreases in mean arterial pressure (MAP; 34 ± 5.8 mmHg) and heart rate (HR; 39 ± 3.7 beats/min). Bilateral vagotomy abolished ANG-(1-12)-induced bradycardia. Efferent greater splanchnic nerve activity was decreased by microinjections of ANG-(1-12) into the mNTS. Blockade of ANG type 1 receptors (AT(1)Rs; using ZD-7155 or L-158,809), but not ANG type 2 receptors (AT(2)Rs; using PD-123319), significantly attenuated ANG-(1-12)-induced cardiovascular responses. Simultaneous inhibition of both angiotensin-converting enzyme (ACE; using captopril) and chymase (using chymostatin) completely blocked the effects of ANG-(1-12). Microinjections of A-779 [ANG-(1-7) antagonist] did not attenuate ANG-(1-12)-induced responses. Pressure ejection of ANG-(1-12) (0.06 mM, 2 nl) caused excitation of barosensitive mNTS neurons, which was blocked by prior application of the AT(1)R antagonist. ANG-(1-12)-induced excitation of mNTS neurons was also blocked by prior sequential applications of captopril and chymostatin. These results indicate that 1) microinjections of ANG-(1-12) into the mNTS elicited depressor and bradycardic responses by exciting barosensitive mNTS neurons; 2) the decreases in MAP and HR were mediated via sympathetic and vagus nerves, respectively; 3) AT(1)Rs, but not AT(2)Rs, mediated these actions of ANG-(1-12); 4) the responses were mediated via the conversion of ANG-(1-12) to ANG II and both ACE and chymase were involved in this conversion; and 5) ANG-(1-7) was not one of the metabolites of ANG-(1-12) in the mNTS.
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Affiliation(s)
- Vineet C Chitravanshi
- Department of Neurological Surgery, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103, USA
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Wang HJ, Li YL, Gao L, Zucker IH, Wang W. Alteration in skeletal muscle afferents in rats with chronic heart failure. J Physiol 2010; 588:5033-47. [PMID: 21041525 DOI: 10.1113/jphysiol.2010.199562] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
An exaggerated exercise pressor reflex (EPR) contributes to exercise intolerance and excessive sympatho-excitation in the chronic heart failure (CHF) state. However, the components of this reflex that are responsible for the exaggerated EPR in CHF remain unknown. To determine whether muscle afferent function is altered in CHF, we recorded the discharge of group III and IV afferents in response to static contraction, passive stretch and hindlimb intra-arterial injection of capsaicin in sham and CHF rats. We also investigated the roles of purinergic 2X receptor (P2X) and the transient receptor potential vanilloid 1 (VR1) in mediating the altered sensitivity of muscle afferents. Compared with sham rats, CHF rats exhibited greater responses of group III afferents to contraction and stretch whereas the responses of group IV afferents to contraction and capsaicin were blunted. Hindlimb intra-arterial infusion of pyridoxal phosphate-6-azophenyl-2,4-disulfonic acid (PPADS), a P2X antagonist, attenuated the responses of group III afferents to contraction and stretch in CHF rats to a greater extent than in sham rats. Western blot data showed that P2X3 receptors were significantly upregulated in doral root ganglion (DRG) of CHF rats whereas VR1 receptors were significantly downregulated. Immunohistochemical evidence showed that immunostaining of the P2X3 receptors was more intense in both IB4-positive (C-fibre) and NF200-positive (A-fibre) neurons in DRG of CHF rats whereas the immunostaining of the VR1 receptors was decreased in IB4-positive neurons. These data suggest that group III afferents are sensitized whereas group IV afferents are desensitized in CHF, which is related to the dysfunction of P2X and VR1 receptors.
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Affiliation(s)
- Han-Jun Wang
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA
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50
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Margiocco ML, Borgarelli M, Musch TI, Hirai DM, Hageman KS, Fels RJ, Garcia AA, Kenney MJ. Effects of combined aging and heart failure on visceral sympathetic nerve and cardiovascular responses to progressive hyperthermia in F344 rats. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1555-63. [PMID: 20844265 DOI: 10.1152/ajpregu.00434.2010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Sympathetic nerve discharge (SND) responses to hyperthermia are attenuated in aged rats without heart failure (HF) and in young HF (Y(HF)) rats, demonstrating that individually aging and HF alter SND regulation. However, the combined effects of aging and HF on SND regulation to heat stress are unknown, despite the high prevalence of HF in aged individuals. We hypothesized that SND responses to heating would be additive when aging and HF are combined, demonstrated by marked reductions in SND and mean arterial pressure (MAP) responses to heating in aged HF (A(HF)) compared with aged sham HF (A(SHAM)) rats, and in A(HF) compared with Y(HF) rats. Renal and splenic SND responses to hyperthermia (colonic temperature increased to 41.5°C) were determined in anesthetized Y(HF), young sham (Y(SHAM)), A(HF), and A(SHAM) Fischer rats. HF was induced by myocardial infarction and documented using echocardiographic, invasive, and postmortem measures. The severity of HF was similar in Y(HF) and A(HF) rats. SND responses to heating were attenuated in Y(HF) compared with Y(SHAM) rats, demonstrating an effect of HF on SND regulation in young rats. In contrast, A(HF) and A(SHAM) rats demonstrated similar SND responses to heating, suggesting a prominent influence of age on SND regulation in A(HF) rats. Splenic SND and MAP responses to heating were similar in Y(HF), A(HF), and A(SHAM) rats, indicating that the imposition of HF in young rats changes the regulatory status of these variables to one consistent with aged rats. These data suggest that the effect of HF on SND regulation to hyperthermia is age dependent.
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Affiliation(s)
- M L Margiocco
- Dept. of Anatomy and Physiology, Kansas State Univ., Manhattan, KS 66506, USA
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