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Shvachiy L, Amaro-Leal Â, Machado F, Rocha I, Outeiro TF, Geraldes V. Gender-Specific Effects on the Cardiorespiratory System and Neurotoxicity of Intermittent and Permanent Low-Level Lead Exposures. Biomedicines 2024; 12:711. [PMID: 38672068 PMCID: PMC11048361 DOI: 10.3390/biomedicines12040711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/12/2024] [Accepted: 03/19/2024] [Indexed: 04/28/2024] Open
Abstract
Lead exposure is a significant health concern, ranking among the top 10 most harmful substances for humans. There are no safe levels of lead exposure, and it affects multiple body systems, especially the cardiovascular and neurological systems, leading to problems such as hypertension, heart disease, cognitive deficits, and developmental delays, particularly in children. Gender differences are a crucial factor, with women's reproductive systems being especially vulnerable, resulting in fertility issues, pregnancy complications, miscarriages, and premature births. The globalization of lead exposure presents new challenges in managing this issue. Therefore, understanding the gender-specific implications is essential for developing effective treatments and public health strategies to mitigate the impact of lead-related health problems. This study examined the effects of intermittent and permanent lead exposure on both male and female animals, assessing behaviours like anxiety, locomotor activity, and long-term memory, as well as molecular changes related to astrogliosis. Additionally, physiological and autonomic evaluations were performed, focusing on baro- and chemoreceptor reflexes. The study's findings revealed that permanent lead exposure has more severe health consequences, including hypertension, anxiety, and reactive astrogliosis, affecting both genders. However, males exhibit greater cognitive, behavioural, and respiratory changes, while females are more susceptible to chemoreflex hypersensitivity. In contrast, intermittent lead exposure leads to hypertension and reactive astrogliosis in both genders. Still, females are more vulnerable to cognitive impairment, increased respiratory frequency, and chemoreflex hypersensitivity, while males show more reactive astrocytes in the hippocampus. Overall, this research emphasizes the importance of not only investigating different types of lead exposure but also considering gender differences in toxicity when addressing this public health concern.
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Affiliation(s)
- Liana Shvachiy
- Center for Biostructural Imaging of Neurodegeneration, Department of Experimental Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany; (L.S.); (T.F.O.)
- Cardiovascular Centre of the University of Lisbon, 1649-028 Lisbon, Portugal; (F.M.); (I.R.)
- Institute of Physiology, Faculty of Medicine, University of Lisbon, 1649-028 Lisbon, Portugal;
| | - Ângela Amaro-Leal
- Institute of Physiology, Faculty of Medicine, University of Lisbon, 1649-028 Lisbon, Portugal;
- Egas Moniz Center for Interdisciplinary Research (CiiEM), Egas Moniz School of Health & Science, 2829-511 Almada, Portugal
| | - Filipa Machado
- Cardiovascular Centre of the University of Lisbon, 1649-028 Lisbon, Portugal; (F.M.); (I.R.)
| | - Isabel Rocha
- Cardiovascular Centre of the University of Lisbon, 1649-028 Lisbon, Portugal; (F.M.); (I.R.)
- Institute of Physiology, Faculty of Medicine, University of Lisbon, 1649-028 Lisbon, Portugal;
| | - Tiago F. Outeiro
- Center for Biostructural Imaging of Neurodegeneration, Department of Experimental Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany; (L.S.); (T.F.O.)
- Max Planck Institute for Natural Science, 37075 Göttingen, Germany
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Scientific Employee with an Honorary Contract at Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 37073 Göttingen, Germany
| | - Vera Geraldes
- Cardiovascular Centre of the University of Lisbon, 1649-028 Lisbon, Portugal; (F.M.); (I.R.)
- Institute of Physiology, Faculty of Medicine, University of Lisbon, 1649-028 Lisbon, Portugal;
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Carnevale D. Role of Inflammatory Processes in the Brain-Body Relationship Underlying Hypertension. Curr Hypertens Rep 2023; 25:455-461. [PMID: 37787865 PMCID: PMC10698121 DOI: 10.1007/s11906-023-01268-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2023] [Indexed: 10/04/2023]
Abstract
PURPOSE OF REVIEW Essential hypertension is a huge health problem that significantly impacts worldwide population in terms of morbidity and mortality. Idiopathic in its nature, elevated blood pressure results from a complex interaction between polygenic components and environmental and lifestyle factors. The constant growth in the burden of hypertension is at odds with expectations, considering the availability of therapeutic strategies. Hence, there is an endless need to further investigate the complexity of factors contributing to blood pressure elevation. RECENT FINDINGS Recent data indicate that bidirectional interactions between the nervous system and the immune system alter inflammation in the brain and periphery, contributing to chronic hypertension. These findings indicate that the nervous system is both a direct driver of hypertension and also a target of feedback that often elevates blood pressure further. Similarly, the immune system is both target and driver of the blood pressure increases. The contributions of the feedback loops among these systems appear to play an important role in hypertension. Together, recent mechanistic studies strongly suggest that the interactions among the brain, immune system, and inflammation affect the participation of each system in the pathogenesis of hypertension, and thus, all of these systems must be considered in concert to gain a full appreciation of the development and potential treatments of hypertension.
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Affiliation(s)
- Daniela Carnevale
- Department of Angiocardioneurology and Translational Medicine, IRCCS Neuromed, 86077, Pozzilli, IS, Italy.
- Department of Molecular Medicine, Sapienza University of Rome, 00161, Rome, Italy.
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Hu JR, Abdullah A, Nanna MG, Soufer R. The Brain-Heart Axis: Neuroinflammatory Interactions in Cardiovascular Disease. Curr Cardiol Rep 2023; 25:1745-1758. [PMID: 37994952 PMCID: PMC10908342 DOI: 10.1007/s11886-023-01990-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/30/2023] [Indexed: 11/24/2023]
Abstract
PURPOSE OF REVIEW The role of neuroimmune modulation and inflammation in cardiovascular disease has been historically underappreciated. Physiological connections between the heart and brain, termed the heart-brain axis (HBA), are bidirectional, occur through a complex network of autonomic nerves/hormones and cytokines, and play important roles in common disorders. RECENT FINDINGS At the molecular level, advances in the past two decades reveal complex crosstalk mediated by the sympathetic and parasympathetic nervous systems, the renin-angiotensin aldosterone and hypothalamus-pituitary axes, microRNA, and cytokines. Afferent pathways amplify proinflammatory signals via the hypothalamus and brainstem to the periphery, promoting neurogenic inflammation. At the organ level, while stress-mediated cardiomyopathy is the prototypical disorder of the HBA, cardiac dysfunction can result from a myriad of neurologic insults including stroke and spinal injury. Atrial fibrillation is not necessarily a causative factor for cardioembolic stroke, but a manifestation of an abnormal atrial substrate, which can lead to the development of stroke independent of AF. Central and peripheral neurogenic proinflammatory factors have major roles in the HBA, manifesting as complex bi-directional relationships in common conditions such as stroke, arrhythmia, and cardiomyopathy.
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Affiliation(s)
- Jiun-Ruey Hu
- Section of Cardiovascular Medicine, Yale School of Medicine, 789 Howard Ave, New Haven, CT, 06519, USA
| | - Ahmed Abdullah
- Section of Cardiovascular Medicine, Yale School of Medicine, 789 Howard Ave, New Haven, CT, 06519, USA
| | - Michael G Nanna
- Section of Cardiovascular Medicine, Yale School of Medicine, 789 Howard Ave, New Haven, CT, 06519, USA
| | - Robert Soufer
- Section of Cardiovascular Medicine, Yale School of Medicine, 789 Howard Ave, New Haven, CT, 06519, USA.
- VA Connecticut Healthcare System, 950 Campbell Ave, -111B, West Haven, CT, 06516, USA.
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Lamptey RNL, Sun C, Layek B, Singh J. Neurogenic Hypertension, the Blood-Brain Barrier, and the Potential Role of Targeted Nanotherapeutics. Int J Mol Sci 2023; 24:ijms24032213. [PMID: 36768536 PMCID: PMC9916775 DOI: 10.3390/ijms24032213] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/26/2023] Open
Abstract
Hypertension is a major health concern globally. Elevated blood pressure, initiated and maintained by the brain, is defined as neurogenic hypertension (NH), which accounts for nearly half of all hypertension cases. A significant increase in angiotensin II-mediated sympathetic nervous system activity within the brain is known to be the key driving force behind NH. Blood pressure control in NH has been demonstrated through intracerebrovascular injection of agents that reduce the sympathetic influence on cardiac functions. However, traditional antihypertensive agents lack effective brain permeation, making NH management extremely challenging. Therefore, developing strategies that allow brain-targeted delivery of antihypertensives at the therapeutic level is crucial. Targeting nanotherapeutics have become popular in delivering therapeutics to hard-to-reach regions of the body, including the brain. Despite the frequent use of nanotherapeutics in other pathological conditions such as cancer, their use in hypertension has received very little attention. This review discusses the underlying pathophysiology and current management strategies for NH, as well as the potential role of targeted therapeutics in improving current treatment strategies.
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Affiliation(s)
| | | | - Buddhadev Layek
- Correspondence: (B.L.); (J.S.); Tel.: +1-701-231-7906 (B.L.); +1-701-231-7943 (J.S.); Fax: +1-701-231-8333 (B.L. & J.S.)
| | - Jagdish Singh
- Correspondence: (B.L.); (J.S.); Tel.: +1-701-231-7906 (B.L.); +1-701-231-7943 (J.S.); Fax: +1-701-231-8333 (B.L. & J.S.)
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From Molecular to Functional Effects of Different Environmental Lead Exposure Paradigms. BIOLOGY 2022; 11:biology11081164. [PMID: 36009791 PMCID: PMC9405384 DOI: 10.3390/biology11081164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/22/2022] [Accepted: 07/30/2022] [Indexed: 12/05/2022]
Abstract
Simple Summary Our comparative study brings new insights regarding the effects of environmental lead exposure on the cardiorespiratory and nervous systems. We show how various kinds of exposure can lead to different toxicities, with various degrees of nefarious effects. The developmental period is of utmost importance to the toxicity of environmental lead; however, we found that the duration of exposure is the prime reason for stronger effects, even though the dual effect of intermittent exposure causes greater molecular neuronal alterations. Abstract Lead is a heavy metal whose widespread use has resulted in environmental contamination and significant health problems, particularly if the exposure occurs during developmental stages. It is a cumulative toxicant that affects multiple systems of the body, including the cardiovascular and nervous systems. Chronic lead exposure has been defined as a cause of behavioral changes, inflammation, hypertension, and autonomic dysfunction. However, different environmental lead exposure paradigms can occur, and the different effects of these have not been described in a broad comparative study. In the present study, rats of both sexes were exposed to water containing lead acetate (0.2% w/v), from the fetal period until adulthood. Developmental Pb-exposed (DevPb) pups were exposed to lead until 12 weeks of age (n = 13); intermittent Pb exposure (IntPb) pups drank leaded water until 12 weeks of age, tap water until 20 weeks, and leaded water for a second time from 20 to 28 weeks of age (n = 14); and the permanent (PerPb) exposure group were exposed to lead until 28 weeks of age (n = 14). A control group (without exposure, Ctrl), matched in age and sex was used. After exposure protocols, at 28 weeks of age, behavioral tests were performed for assessment of anxiety (elevated plus maze test), locomotor activity (open-field test), and memory (novel object recognition test). Metabolic parameters were evaluated for 24 h, and the acute experiment was carried out. Blood pressure (BP), electrocardiogram, and heart (HR) and respiratory (RF) rates were recorded. Baroreflex gain, chemoreflex sensitivity, and sympathovagal balance were calculated. Immunohistochemistry protocol for NeuN, Syn, Iba-1, and GFAP staining was performed. All Pb-exposed groups showed hypertension, concomitant with a decrease in baroreflex gain and chemoreceptor hypersensitivity, without significant changes in HR and RF. Long-term memory impairment associated with reactive astrogliosis and microgliosis in the dentate gyrus of the hippocampus, indicating the presence of neuroinflammation, was also observed. However, these alterations seemed to reverse after lead abstinence for a certain period (DevPb) and were enhanced when a second exposure occurred (IntPb), along with a synaptic loss. These results suggest that the duration of Pb exposure is more relevant than the timing of exposure, since the PerPb group presented more pronounced effects and a significant increase in the LF and HF bands and anxiety levels. In summary, this is the first study with the characterization and comparison of physiological, autonomic, behavioral, and molecular changes caused by different low-level environmental lead exposures, from the fetal period to adulthood, where the duration of exposure was the main factor for stronger adverse effects. These kinds of studies are of immense importance, showing the importance of the surrounding environment in health from childhood until adulthood, leading to the creation of new policies for toxicant usage control.
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de Paula Facioli T, Vieira Philbois S, Augusto Aguilar B, Catarine Veiga A, Celso Dutra de Souza H. Combined effects of angiotensin receptor blocker use and physical training in hypertensive men. Clin Exp Hypertens 2022; 44:372-381. [PMID: 35343339 DOI: 10.1080/10641963.2022.2055763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE Pharmacological (angiotensin II receptor type 1 receptor blocker use) and non-pharmacological treatment (physical aerobic exercise) are important strategies to reduces blood pressure and control arterial hypertension; however, only few clinical studies have evaluated their combined effects on autonomic cardiovascular control. Therefore, we investigated the effect of a combination intervention that involved losartan administration and physical aerobic training on autonomic cardiovascular control. METHODS Thirty-two men (aged 40 to 60 years) were assigned into two groups: normotensive group, without any pharmacological treatment (NG, N = 16), or hypertensive group, with losartan administration (HG, N = 16). They underwent a physical aerobic training for 16 weeks, thrice a week. Hemodynamic parameters, heart rate variability (HRV), blood pressure variability, and spontaneous baroreflex sensitivity (BRS) were measured before and after training. RESULTS Before training, both the groups showed similar values of hemodynamic parameters. However, the HG showed decreased BRS and HRV, characterized by reduction in sympathetic (p = .02) and vagal (p < .001) modulation. After training, the NG exhibited decreased heart rate (HR) at rest (p < .001), whereas the HG showed decreased HR at rest (p < .001) and blood pressure (BP) (p = .001). The HG showed decreased sympathetic modulation (p = .02) and increased BRS (p < .001) and vagal modulation (p < .001), but HRV (p < .001) and BRS gain (p < .001) remained significantly lower when compared to the NG. CONCLUSIONS Physical aerobic training was essential to improve the BRS and HRV cardiac autonomic modulation in the HG. However, it was not sufficient to normalize the analyzed autonomic parameters.
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Affiliation(s)
- Tábata de Paula Facioli
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Stella Vieira Philbois
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Bruno Augusto Aguilar
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Ana Catarine Veiga
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Hugo Celso Dutra de Souza
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
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Řezáčová L, Vaněčková I, Hojná S, Vavřínová A, Valovič P, Rauchová H, Behuliak M, Zicha J. Both central sympathoexcitation and peripheral angiotensin II-dependent vasoconstriction contribute to hypertension development in immature heterozygous Ren-2 transgenic rats. Hypertens Res 2021; 45:414-423. [PMID: 34621032 DOI: 10.1038/s41440-021-00775-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/13/2021] [Accepted: 09/10/2021] [Indexed: 11/09/2022]
Abstract
Recently, we demonstrated that chronic blockade of the renin-angiotensin system (RAS) lowered the blood pressure (BP) of adult Ren-2 transgenic rats (TGR) mainly through the attenuation of central sympathoexcitation. However, the participation of central and peripheral mechanisms in the development of high BP in immature TGR remains unclear. In the present study, 6-week-old heterozygous TGR males were chronically treated with intracerebroventricular (ICV) or intraperitoneal (IP) infusions of the AT1 receptor inhibitor losartan (1 or 2 mg/kg/day) for 4 weeks. The influence of these treatments on sympathetic- and angiotensin II-dependent BP components (BP response to pentolinium or captopril, respectively) as well as on BP response to exogenous angiotensin II were determined to evaluate the participation of central and peripheral RAS in hypertension development. Chronic IP losartan administration (1 or 2 mg/kg/day) lowered the BP of immature TGR by reducing both sympathetic and angiotensin II-dependent BP components. The central action of IP-administered losartan was indicated by a reduced BP response to acute ICV angiotensin II injection. Chronic ICV administration of a lower losartan dose (1 mg/kg/day) reduced only the sympathetic BP component, whereas a higher ICV administered dose (2 mg/kg/day) was required to influence the angiotensin II-dependent BP component. Accordingly, chronic ICV losartan administration of 2 mg/kg/day (but not 1 mg/kg/day) attenuated the BP response to acute intravenous angiotensin II application. In conclusion, central sympathoexcitation seems to play an important role in hypertension development in immature TGR. Central sympathoexcitation is highly susceptible to inhibition by low doses of RAS-blocking agents, whereas higher doses also affect peripheral angiotensin II-dependent vasoconstriction.
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Affiliation(s)
- Lenka Řezáčová
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Ivana Vaněčková
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
| | - Silvie Hojná
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Anna Vavřínová
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Pavol Valovič
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Rauchová
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Michal Behuliak
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Josef Zicha
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
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Stoyell-Conti FF, Chabbra A, Puthentharayil J, Rigatto K, Speth RC. Chronic administration of pharmacological doses of angiotensin 1-7 and iodoangiotensin 1-7 has minimal effects on blood pressure, heart rate, and cognitive function of spontaneously hypertensive rats. Physiol Rep 2021; 9:e14812. [PMID: 33904655 PMCID: PMC8077095 DOI: 10.14814/phy2.14812] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/26/2022] Open
Abstract
Cardiovascular diseases are the principal cause of death worldwide, with hypertension being the most common cardiovascular disease risk factor. High blood pressure (BP) is also associated with an increased risk of poor cognitive performance and dementia including Alzheimer's disease. Angiotensin 1–7 (Ang 1‐7), a product of the renin‐angiotensin system (RAS), exhibits central and peripheral actions to reduce BP. Recent data from our lab reveals that the addition of a non‐radioactive iodine molecule to the tyrosine in position 4 of Ang 1‐7 (iodoAng 1‐7) makes it ~1000‐fold more potent than Ang 1‐7 in competing for the 125I‐Ang 1‐7 binding site (Stoyell‐Conti et al., 2020). Moreover, the addition of the non‐radioactive iodine molecule increases (~4‐fold) iodoAng 1‐7’s ability to bind to the AT1 receptor (AT1R), the primary receptor for Ang II. Preliminary data indicates that iodoAng 1‐7 can also compete for the 125I‐Ang IV binding site with a low micromolar IC50. Thus, our aims were to compare the effects of chronic treatment of the Spontaneously Hypertensive Rat (SHR) with iodoAng 1‐7 (non‐radioactive iodine isotope) and Ang 1‐7 on arterial pressure, heart rate, and cognitive function. For this study, male SHRs were divided into three groups and treated with Saline, Ang 1‐7, or iodoAng 1‐7 administrated subcutaneously using a 28‐day osmotic mini pump. Systolic BP was measured non‐invasively by the tail‐cuff technique. Cognitive function was assessed by Y‐Maze test and novel object recognition (NOR) test. We have demonstrated in SHRs that subcutaneous administration of high doses of iodoAng 1‐7 prevented the increase in heart rate with age, while Ang 1‐7 showed a trend toward preventing the increase in heart rate, possibly by improving baroreflex control of the heart. Conversely, neither Ang 1‐7 nor iodoAng 1‐7 administered subcutaneously affected BP nor cognitive function.
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Affiliation(s)
- Filipe F Stoyell-Conti
- College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL, USA.,Surgery Department, University of Miami, Miami, FL, USA
| | - Alesa Chabbra
- Halmos College of Natural Science & Oceanography, Nova Southeastern University, Fort Lauderdale, FL, USA
| | - Joseph Puthentharayil
- Halmos College of Natural Science & Oceanography, Nova Southeastern University, Fort Lauderdale, FL, USA
| | - Katya Rigatto
- Institute for Neuro-Immune Medicine, Nova Southeastern University, Fort Lauderdale, FL, USA.,Laboratório de Fisiologia Translacional, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil
| | - Robert C Speth
- College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL, USA.,Department of Pharmacology and Physiology, College of Medicine, Georgetown University, Washington, DC, USA
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Ally A, Powell I, Ally MM, Chaitoff K, Nauli SM. Role of neuronal nitric oxide synthase on cardiovascular functions in physiological and pathophysiological states. Nitric Oxide 2020; 102:52-73. [PMID: 32590118 DOI: 10.1016/j.niox.2020.06.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/15/2020] [Accepted: 06/15/2020] [Indexed: 12/16/2022]
Abstract
This review describes and summarizes the role of neuronal nitric oxide synthase (nNOS) on the central nervous system, particularly on brain regions such as the ventrolateral medulla (VLM) and the periaqueductal gray matter (PAG), and on blood vessels and the heart that are involved in the regulation and control of the cardiovascular system (CVS). Furthermore, we shall also review the functional aspects of nNOS during several physiological, pathophysiological, and clinical conditions such as exercise, pain, cerebral vascular accidents or stroke and hypertension. For example, during stroke, a cascade of molecular, neurochemical, and cellular changes occur that affect the nervous system as elicited by generation of free radicals and nitric oxide (NO) from vulnerable neurons, peroxide formation, superoxides, apoptosis, and the differential activation of three isoforms of nitric oxide synthases (NOSs), and can exert profound effects on the CVS. Neuronal NOS is one of the three isoforms of NOSs, the others being endothelial (eNOS) and inducible (iNOS) enzymes. Neuronal NOS is a critical homeostatic component of the CVS and plays an important role in regulation of different systems and disease process including nociception. The functional and physiological roles of NO and nNOS are described at the beginning of this review. We also elaborate the structure, gene, domain, and regulation of the nNOS protein. Both inhibitory and excitatory role of nNOS on the sympathetic autonomic nervous system (SANS) and parasympathetic autonomic nervous system (PANS) as mediated via different neurotransmitters/signal transduction processes will be explored, particularly its effects on the CVS. Because the VLM plays a crucial function in cardiovascular homeostatic mechanisms, the neuroanatomy and cardiovascular regulation of the VLM will be discussed in conjunction with the actions of nNOS. Thereafter, we shall discuss the up-to-date developments that are related to the interaction between nNOS and cardiovascular diseases such as hypertension and stroke. Finally, we shall focus on the role of nNOS, particularly within the PAG in cardiovascular regulation and neurotransmission during different types of pain stimulus. Overall, this review focuses on our current understanding of the nNOS protein, and provides further insights on how nNOS modulates, regulates, and controls cardiovascular function during both physiological activity such as exercise, and pathophysiological conditions such as stroke and hypertension.
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Affiliation(s)
- Ahmmed Ally
- Arkansas College of Osteopathic Medicine, Fort Smith, AR, USA.
| | - Isabella Powell
- All American Institute of Medical Sciences, Black River, Jamaica
| | | | - Kevin Chaitoff
- Interventional Rehabilitation of South Florida, West Palm Beach, FL, USA
| | - Surya M Nauli
- Chapman University and University of California, Irvine, CA, USA.
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Dupont AG, Légat L. GABA is a mediator of brain AT 1 and AT 2 receptor-mediated blood pressure responses. Hypertens Res 2020; 43:995-1005. [PMID: 32451494 DOI: 10.1038/s41440-020-0470-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/24/2020] [Accepted: 04/01/2020] [Indexed: 02/07/2023]
Abstract
The nucleus tractus solitarius (NTS), paraventricular nucleus (PVN), and rostral ventrolateral medulla (RVLM) are the most targeted regions of central blood pressure control studies. Glutamate and gamma-aminobutyric acid (GABA) interact within these brain regions to modulate blood pressure. The brain renin-angiotensin system also participates in central blood pressure control. Angiotensin II increases blood pressure through the stimulation of angiotensin II type 1 (AT1) receptors within the PVN and RVLM and attenuates baroreceptor sensitivity, resulting in elevated blood pressure within the NTS. Angiotensin II type 2 (AT2) receptors in cardiovascular control centers in the brain also appear to be involved in blood pressure control and counteract AT1 receptor-mediated effects. The current review is focused on the interaction of GABA with AT1 and AT2 receptors in the control of blood pressure within the RVLM, PVN and NTS. Within the NTS, GABA is released from local GABAergic interneurons that are stimulated by local AT1 receptors and mediates a hypertensive response. In contrast, the local increase in GABA levels observed after AT2 receptor stimulation within the RVLM, likely from GABAergic nerve endings originating in the caudal ventrolateral medulla, is important in the mediation of the hypotensive response. Preliminary results suggest that the hypertensive response to AT1 receptor stimulation within the RVLM is associated with a reduction in GABA release. The current experimental evidence therefore indicates that GABA is an important mediator of brainstem responses to AT1 and AT2 receptor stimulation and that increased GABA release may play a role in hypertensive and hypotensive responses, depending on the site of action.
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Affiliation(s)
- Alain G Dupont
- Department of Pharmacology, Research Group Experimental Pharmacology (EFAR), Center for Neurosciences, (C4N) Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, 1090, Belgium
| | - Laura Légat
- Department of Pharmacology, Research Group Experimental Pharmacology (EFAR), Center for Neurosciences, (C4N) Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, 1090, Belgium.
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11
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Sayk F, Twesten C, Adametz I, Franzen K, Vonthein R, Dodt C, Meusel M. Angiotensin II-mediated nondipping during sleep in healthy humans: effects on baroreflex function at subsequent daytime. Am J Physiol Regul Integr Comp Physiol 2020; 318:R813-R821. [DOI: 10.1152/ajpregu.00355.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Blood pressure dipping at night is mediated by sleep-inherent, active downregulation of sympathetic vascular tone. Concomitantly, activity of the renin-angiotensin system is reduced, which might contribute to the beneficial effect of baroreflex downward resetting on daytime blood pressure homeostasis. To evaluate whether experimental nondipping mediated by angiotensin II during sleep would alter blood pressure and baroreflex function the next day in healthy humans, angiotensin-II or placebo (saline) was infused for a 7-h period at night, preventing blood pressure dipping in 11 sleeping normotensive individuals (5 males, balanced, crossover design). Baroreflex function was assessed about 1 h upon awakening and stop of infusion via microneurographic recordings of muscle sympathetic nerve activity (MSNA), showing that resting MSNA was significantly increased following angiotensin II nondipping compared with placebo ( P = 0.029), whereas blood pressure and heart rate remained unchanged. Baroreflex sensitivity in response to vasoactive drug challenge was preserved, and neuroendocrine markers of fluid balance and electrolytes did not differ between conditions. Ambulatory blood pressure during subsequent daytime was not altered. Data were compared with analog experiments previously performed within the same subjects during awake daytime (ANCOVA). We conclude that angiotensin-II mediated nocturnal nondipping did not induce blood pressure elevation at subsequent daytime in healthy humans but was linked to increased vasoconstrictive sympathetic activity. This is in contrast to a prolonged increase in blood pressure in corresponding daytime experiments of the same individuals. Evidently, sleep strongly preserves normotensive blood pressure homeostasis in healthy humans.
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Affiliation(s)
- Friedhelm Sayk
- Department of Internal Medicine, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Christoph Twesten
- Department of Internal Medicine, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Isabel Adametz
- Institute of Radiology, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Klaas Franzen
- Department of Internal Medicine, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Reinhard Vonthein
- Institute of Medical Biometry and Statistics, University of Lübeck, Lübeck, Germany
| | - Christoph Dodt
- Department of Emergency Medicine, München-Bogenhausen Hospital, München, Germany
| | - Moritz Meusel
- Department of Cardiology and Angiology, University Heart Center Lübeck, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
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Shvachiy L, Geraldes V, Amaro-Leal Â, Rocha I. Persistent Effects on Cardiorespiratory and Nervous Systems Induced by Long-Term Lead Exposure: Results from a Longitudinal Study. Neurotox Res 2020; 37:857-870. [PMID: 31997153 DOI: 10.1007/s12640-020-00162-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 02/06/2023]
Abstract
Long-term lead (Pb) exposure alters the normal development of the nervous system and physiology. It affects multiple organ systems, causing hypertension, cardiorespiratory dysfunction, being a well-known neurotoxin, inducing changes in neurogenesis, neurodegeneration, and glial cells. However, studies of the developmental effects of lead and its outcomes throughout life are lacking. Determine morphofunctional, behavioral, and cognitive developmental effects of long-term lead exposure at three different ages. Wistar rats were exposed to a Pb-acetate solution from fetal period until adulthood and compared to a non-exposed control group. General behavior and cognitive skills were evaluated by behavioral tests and physiological data and cardiorespiratory reflexes measured. Neurodegeneration, neuroinflammation, and synaptic activity were assessed by immunohistochemistry. Lead exposure caused long-lasting anxiety-like behavior and strong long-term memory impairment without changes in locomotor and exploratory activity. Hypertension was observed at all time points, concomitant with baroreflex impairment and increased chemoreflex sensitivity. Persistent neuroinflammation, transient synaptic overexcitation without neurodegeneration was observed. Long-term Pb exposure, since fetal period, causes long-lasting anxiety-like behavior, concomitant with hypertension, without general motor skills impairment. Synaptic overexcitation, reactive astrogliosis, and microgliosis could underlie behavioral and long-term memory changes, which might have been caused during developmental phases and consolidated during adulthood. Also, alterations observed in the cardiorespiratory reflexes can explain persistent hypertension. This longitudinal study identifies and characterizes lead toxicity nature and magnitude, important to devise and test potential interventions to attenuate the long-term harmful effects of lead on the nervous and cardiovascular systems.
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Affiliation(s)
- Liana Shvachiy
- Centro Cardiovascular da Universidade de Lisboa, Faculdade de Medicina, Universidade de Lisboa, Av Prof Egas Moniz, 1649-028, Lisbon, Portugal
| | - Vera Geraldes
- Centro Cardiovascular da Universidade de Lisboa, Faculdade de Medicina, Universidade de Lisboa, Av Prof Egas Moniz, 1649-028, Lisbon, Portugal.
| | - Ângela Amaro-Leal
- Centro Cardiovascular da Universidade de Lisboa, Faculdade de Medicina, Universidade de Lisboa, Av Prof Egas Moniz, 1649-028, Lisbon, Portugal
| | - Isabel Rocha
- Centro Cardiovascular da Universidade de Lisboa, Faculdade de Medicina, Universidade de Lisboa, Av Prof Egas Moniz, 1649-028, Lisbon, Portugal
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Asirvatham-Jeyaraj N, Jones AD, Burnett R, Fink GD. Brain Prostaglandin D2 Increases Neurogenic Pressor Activity and Mean Arterial Pressure in Angiotensin II-Salt Hypertensive Rats. Hypertension 2019; 74:1499-1506. [PMID: 31587572 DOI: 10.1161/hypertensionaha.119.13175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study tested whether brain L-PGDS (lipocalin-type prostaglandin [PG] D synthase), through prostanoid signaling, might increase neurogenic pressor activity and thereby cause hypertension. Sprague Dawley rats on high-salt diet received either vehicle or Ang II (angiotensin II) infusion. On day 4, the developmental stage of hypertension, brains from different sets of control and Ang II-treated rats were collected for measuring L-PGDS expression, PGD2 levels, and DP1R (type 1 PGD2 receptor) expression. In a different set of 14-day Ang II-salt-treated rats, mini-osmotic pumps were used to infuse either a nonselective COX (cyclooxygenase) inhibitor ketorolac, L-PGDS inhibitor AT56, or DP1R inhibitor BWA868C to test the role of brain COX-PGD2-DP1R signaling in Ang II-salt hypertension. The acute depressor response to ganglion blockade with hexamethonium was used to quantify neurogenic pressor activity. During the developmental stage of Ang II-salt hypertension, L-PGDS expression was higher in cerebrospinal fluid, and PGD2 levels were increased in the choroid plexus, cerebrospinal fluid, and the cardioregulatory brain region rostral ventrolateral medulla. DP1R expression was decreased in rostral ventrolateral medulla. Both brain COX inhibition with ketorolac and L-PGDS inhibition with AT56 lowered mean arterial pressure by altering neurogenic pressor activity compared with vehicle controls. Blockade of DP1R with BWA868C, however, increased the magnitude of Ang II-salt hypertension and significantly increased neurogenic pressor activity. In summary, we establish that the development of Ang II-salt hypertension requires increased COX- and L-PGDS-derived PGD2 production in the brain, making L-PGDS a possible target for treating neurogenic hypertension.
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Affiliation(s)
- Ninitha Asirvatham-Jeyaraj
- From the Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru (N.A.-J.).,Department of Pharmacology and Toxicology (N.A.-J., R.B., G.D.F.), Michigan State University, East Lansing
| | - A Daniel Jones
- Department of Biochemistry and Molecular Biology (A.D.J.), Michigan State University, East Lansing.,Department of Chemistry (A.D.J.), Michigan State University, East Lansing
| | - Robert Burnett
- Department of Pharmacology and Toxicology (N.A.-J., R.B., G.D.F.), Michigan State University, East Lansing
| | - Gregory D Fink
- Department of Pharmacology and Toxicology (N.A.-J., R.B., G.D.F.), Michigan State University, East Lansing
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14
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Abstract
Under conditions leading to aging and metabolic syndrome, the hypothalamus atypically undergoes proinflammatory signaling activation leading to a chronic and stable background inflammation, referred to as "hypothalamic microinflammation." Through the past decade of research, progress has been made to causally link this hypothalamic inflammation to the mechanism of aging as well as metabolic syndrome, promoting the "hypothalamic microinflammation" theory, which helps characterize the consensus of these epidemic health problems. In general, it is consistently appreciated that hypothalamic microinflammation emerges during the early stages of aging and metabolic syndrome and evolves to be multifaceted and advanced alongside disease progression, while inhibition of key inflammatory components in the hypothalamus has a broad range of effects in counteracting these disorders. Herein, focusing on aging and metabolic syndrome, this writing aims to provide an overview of and insights into the mediators, signaling components, cellular impacts, and physiological significance of this hypothalamic microinflammation.
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15
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Légat L, Smolders I, Dupont AG. AT1 Receptor Mediated Hypertensive Response to Ang II in the Nucleus Tractus Solitarii of Normotensive Rats Involves NO Dependent Local GABA Release. Front Pharmacol 2019; 10:460. [PMID: 31130861 PMCID: PMC6509664 DOI: 10.3389/fphar.2019.00460] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 04/11/2019] [Indexed: 11/30/2022] Open
Abstract
Aim It is well-established that angiotensin II exerts a dampening effect on the baroreflex within the nucleus tractus solitarii (NTS), the principal brainstem site for termination of baroreceptor afferents and which is densely populated with gamma-aminobutyric acid (GABA)ergic neurons and nerve terminals. The present study was designed to investigate whether local release of GABA is involved in the effects mediated by local angiotensin II within the NTS. Methods In vivo microdialysis was used for measurement of extracellular glutamate and GABA levels and for infusion of angiotensin II within the NTS of conscious normotensive Wistar rats. The mean arterial pressure (MAP) and heart rate response to local infusion of angiotensin II were subsequently monitored with a pressure transducer under anesthesia. The angiotensin II type 1 receptor (AT1R) antagonist, candesartan, was used to assess whether responses were AT1R dependent and the nitric oxide (NO) synthase inhibitor, N(ω)-nitro-L-arginine methyl ester (L-NAME), was used to assess the involvement of NO in the evoked responses by infusion of angiotensin II. The MAP and heart rate responses were monitored with a pressure transducer. Results Local infusion into the NTS of angiotensin II induced a significant to ninefold significantly increase in extracellular GABA levels; as well as MAP was increased by 15 mmHg. These responses were both abolished by co-infusion of either, the angiotensin II type 1 receptor antagonist, candesartan, or the NO synthase inhibitor, L-NAME, demonstrating that the effect is not only AT1R dependent but also NO dependent. The pressor response to angiotensin II was reversed by co-infusion with the GABAA receptor antagonist, bicuculline. Local blockade of NO synthase decreased both, GABA and glutamate concentrations. Conclusion Our results suggest that the AT1R mediated hypertensive response to angiotensin II within the NTS in normotensive rats is GABA and NO dependent. Nitric oxide produced within the NTS tonically potentiates local GABA and glutamate release.
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Affiliation(s)
- Laura Légat
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium.,Cardiovascular Center, Universitair Ziekenhuis Brussel, Brussels, Belgium.,Department of Clinical Pharmacology and Clinical Pharmacy, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Alain G Dupont
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium.,Cardiovascular Center, Universitair Ziekenhuis Brussel, Brussels, Belgium.,Department of Clinical Pharmacology and Clinical Pharmacy, Universitair Ziekenhuis Brussel, Brussels, Belgium
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Zubcevic J, Watkins J, Perez PD, Colon-Perez LM, Long MT, Febo M, Hayward L. MEMRI reveals altered activity in brain regions associated with anxiety, locomotion, and cardiovascular reactivity on the elevated plus maze in the WKY vs SHR rats. Brain Imaging Behav 2019; 12:1318-1331. [PMID: 29181695 DOI: 10.1007/s11682-017-9798-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Individuals with anxiety/depression often have exaggerated cardiovascular responses to stressful stimuli and a comorbidity with hypertension. Alternatively, individuals with hypertension can be more anxious. In the present study cardiovascular changes were evaluated during behavioral testing of anxious behavior on the elevated plus maze (EPM) in the spontaneously hypertensive rat (SHR), a rodent model of neurogenic hypertension, and compared to the response of the more anxious, but normotensive, Wistar-Kyoto rat (WKY). Manganese-enhanced magnetic resonance imaging (MEMRI) was used to identify regional differences in baseline brain activity. Parallel to indicators of elevated behavioral anxiety on the EPM, WKYs had a greater increase in blood pressure but not heart rate when compared to the SHR while on the EPM. Associated with differences in anxiety-related behavior and autonomic responses, we observed increased baseline activity in the amygdala, central gray, habenula and interpeduncular nucleus with MEMRI of the WKY compared to the SHR. Conversely, elevated baseline brain activity was found in regions associated with blood pressure control and system arousal, including the hypothalamus, locus coeruleus and pedunculopontine tegmental nucleus, in the SHR vs WKY, in-line with increased resting blood pressure and increased mobility in this strain. Lastly, reduced activity in hippocampal regions was identified in the SHR compared to the WKY and may be associated with cognitive impairment previously reported in the SHR. Thus, autonomic reactivity may be a true measure of stress in rodent models of anxiety and MEMRI presents a powerful technique to uncover novel brain mechanisms of blood pressure control.
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Affiliation(s)
- Jasenka Zubcevic
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, 1333 Center Dr., BSB 3-32, Gainesville, FL, 32610-0144, USA
| | - Jacqueline Watkins
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, 1333 Center Dr., BSB 3-32, Gainesville, FL, 32610-0144, USA
| | - Pablo D Perez
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, 32610-0256, USA
| | - Luis M Colon-Perez
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, 32610-0256, USA
| | - Maureen T Long
- Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32610-0123, USA
| | - Marcelo Febo
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, 32610-0256, USA
| | - Linda Hayward
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, 1333 Center Dr., BSB 3-32, Gainesville, FL, 32610-0144, USA.
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Powers SK, Morton AB, Hyatt H, Hinkley MJ. The Renin-Angiotensin System and Skeletal Muscle. Exerc Sport Sci Rev 2018; 46:205-214. [PMID: 30001274 DOI: 10.1249/jes.0000000000000158] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The renin-angiotensin system (RAS) plays a key role in the control of blood pressure and fluid homeostasis. Emerging evidence also reveals that hyperactivity of the RAS contributes to skeletal muscle wasting. This review discusses the key role that the RAS plays in skeletal muscle wasting due to congestive heart failure, chronic kidney disease, and ventilator-induced diaphragmatic wasting.
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Affiliation(s)
- Scott K Powers
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL
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18
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Intermittent low-level lead exposure provokes anxiety, hypertension, autonomic dysfunction and neuroinflammation. Neurotoxicology 2018; 69:307-319. [PMID: 30098355 DOI: 10.1016/j.neuro.2018.08.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/31/2018] [Accepted: 08/04/2018] [Indexed: 01/14/2023]
Abstract
BACKGROUND Exposures to lead (Pb) during developmental phases can alter the normal course of development, with lifelong health consequences. Permanent Pb exposure leads to behavioral changes, cognitive impairment, sympathoexcitation, tachycardia, hypertension and autonomic dysfunction. However, the effects of an intermittent lead exposure are not yet studied. This pattern of exposure has been recently increasing due to migrations, implementation of school exchange programs and/or residential changes. OBJECTIVE To determine and compare lead effects on mammal's behavior and physiology, using a rat model of intermittent and permanent Pb exposures. METHODS Fetuses were intermittently (PbI) or permanently (PbP) exposed to water containing lead acetate (0.2% w/v) throughout life until adulthood (28 weeks of age). A control group (CTL) without any exposure to lead was also used. Anxiety was assessed by elevated plus maze (EPM) and locomotor activity and exploration by open field test (OFT). Blood pressure (BP), electrocardiogram (ECG), heart rate (HR), respiratory frequency (RF), sympathetic and parasympathetic activity and baro- and chemoreceptor reflex profiles were evaluated. Immunohistochemistry protocol for the assessment of neuroinflammation, neuronal loss (NeuN), gliosis and synaptic alterations (Iba-1, GFAP, Syn), were performed at the hippocampus. One-way ANOVA with Tukey's multiple comparison between means were used (significance p < 0.05) for statistical analysis. RESULTS The intermittent lead exposure produced a significant increase in diastolic and mean BP values, concomitant with a tendency to sympathetic overactivity (estimated by increased low-frequency power) and without significant changes in systolic BP, HR and RF. A chemoreceptor hypersensitivity and a baroreflex impairment were also observed, however, less pronounced when compared to the permanent exposure. Regarding behavioral changes, both lead exposure profiles showed an anxiety-like behavior without changes in locomotor and exploratory activity. Increase in GFAP and Iba-1 positive cells, without changes in NeuN positive cells were found in both exposed groups. Syn staining suffered a significant decrease in PbI group and a significant increase in PbP group. CONCLUSION This study is the first to show that developmental Pb exposure since fetal period can cause lasting impairments in physiological parameters. The intermittent lead exposure causes adverse health effects, i.e, hypertension, increased respiratory frequency and chemoreflex sensitivity, baroreflex impairment, anxiety, decreased synaptic activity, neuroinflammation and reactive gliosis, in some ways similar to a permanent exposure, however some are lower-grade, due to the shorter duration of exposure. This study brings new insights on the environmental factors that influence autonomic and cardiovascular systems during development, which can help in creating public policy strategies to prevent and control the adverse effects of Pb toxicity.
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Oyarce MP, Iturriaga R. Contribution of Oxidative Stress and Inflammation to the Neurogenic Hypertension Induced by Intermittent Hypoxia. Front Physiol 2018; 9:893. [PMID: 30050461 PMCID: PMC6050421 DOI: 10.3389/fphys.2018.00893] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 06/21/2018] [Indexed: 12/11/2022] Open
Abstract
Chronic intermittent hypoxia (CIH), the hallmark of obstructive sleep apnea, is the main risk factor to develop systemic hypertension. Oxidative stress, inflammation, and sympathetic overflow have been proposed as possible mechanisms underlying the CIH-induced hypertension. CIH potentiates the carotid body (CB) chemosensory discharge leading to sympathetic overflow, autonomic dysfunction, and hypertension. Oxidative stress and pro-inflammatory molecules are involved in neurogenic models of hypertension, acting on brainstem and hypothalamic nuclei related to the cardiorespiratory control, such as the nucleus of the solitary tract, which is the primary site for the afferent inputs from the CB. Oxidative stress and pro-inflammatory molecules contribute to the activation of the CB chemoreflex pathway in CIH-induced hypertension. In this brief review, we will discuss new evidence for a critical role of oxidative stress and neuro-inflammation in development of the CIH-induced hypertension through activation of the CB chemoreflex pathway.
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Affiliation(s)
| | - Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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Wszedybyl-Winklewska M, Wolf J, Szarmach A, Winklewski PJ, Szurowska E, Narkiewicz K. Central sympathetic nervous system reinforcement in obstructive sleep apnoea. Sleep Med Rev 2018; 39:143-154. [DOI: 10.1016/j.smrv.2017.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 08/29/2017] [Accepted: 08/31/2017] [Indexed: 01/30/2023]
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Moralez G, Jouett NP, Tian J, Zimmerman MC, Bhella P, Raven PB. Effect of centrally acting angiotensin converting enzyme inhibitor on the exercise-induced increases in muscle sympathetic nerve activity. J Physiol 2018; 596:2315-2332. [PMID: 29635787 PMCID: PMC6002210 DOI: 10.1113/jp274697] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 03/21/2018] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS The arterial baroreflex's operating point pressure is reset upwards and rightwards from rest in direct relation to the increases in dynamic exercise intensity. The intraneural pathways and signalling mechanisms that lead to upwards and rightwards resetting of the operating point pressure, and hence the increases in central sympathetic outflow during exercise, remain to be identified. We tested the hypothesis that the central production of angiotensin II during dynamic exercise mediates the increases in sympathetic outflow and, therefore, the arterial baroreflex operating point pressure resetting during acute and prolonged dynamic exercise. The results identify that perindopril, a centrally acting angiotensin converting enzyme inhibitor, markedly attenuates the central sympathetic outflow during acute and prolonged dynamic exercise. ABSTRACT We tested the hypothesis that the signalling mechanisms associated with the dynamic exercise intensity related increases in muscle sympathetic nerve activity (MSNA) and arterial baroreflex resetting during exercise are located within the central nervous system. Participants performed three randomly ordered trials of 70° upright back-supported dynamic leg cycling after ingestion of placebo and two different lipid soluble angiotensin converting enzyme inhibitors (ACEi): perindopril (high lipid solubility), captopril (low lipid solubility). Repeated measurements of whole venous blood (n = 8), MSNA (n = 7) and arterial blood pressures (n = 14) were obtained at rest and during an acute (SS1) and prolonged (SS2) bout of steady state dynamic exercise. Arterial baroreflex function curves were modelled at rest and during exercise. Peripheral venous superoxide concentrations measured by electron spin resonance spectroscopy were elevated during exercise and were not altered by ACEi at rest (P ≥ 0.4) or during exercise (P ≥ 0.3). Baseline MSNA and mean arterial pressure were unchanged at rest (P ≥ 0.1; P ≥ 0.8, respectively). However, during both SS1 and SS2, the centrally acting ACEi perindopril attenuated MSNA compared to captopril and the placebo (P < 0.05). Arterial pressures at the operating point and threshold pressures were decreased with perindopril from baseline to SS1 with no further changes in the operating point pressure during SS2 under all three conditions. These data suggest that centrally acting ACEi is significantly more effective at attenuating the increase in the acute and prolonged exercise-induced increases in MSNA.
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Affiliation(s)
- Gilbert Moralez
- Institute for Cardiovascular and Metabolic DiseaseUniversity of North Texas Health Science CenterFort WorthTXUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical CenterDallasTXUSA
| | - Noah P. Jouett
- Institute for Cardiovascular and Metabolic DiseaseUniversity of North Texas Health Science CenterFort WorthTXUSA
| | - Jun Tian
- Department of Cellular and Integrative PhysiologyUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Matthew C. Zimmerman
- Department of Cellular and Integrative PhysiologyUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Paul Bhella
- Department of Cardiac Imaging at the John Peter Smith Health NetworkFort WorthTXUSA
- Department of Internal MedicineTCU and UNTHSC School of MedicineFort WorthTXUSA
| | - Peter B. Raven
- Institute for Cardiovascular and Metabolic DiseaseUniversity of North Texas Health Science CenterFort WorthTXUSA
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22
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Wang K, Duan S, Wen X, Wang W, Fang S, Qi D, Huan X, Wang L, He Z. Angiotensin II system in the nucleus tractus solitarii contributes to autonomic dysreflexia in rats with spinal cord injury. PLoS One 2017; 12:e0181495. [PMID: 28742157 PMCID: PMC5524360 DOI: 10.1371/journal.pone.0181495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 07/03/2017] [Indexed: 11/25/2022] Open
Abstract
Background Autonomic dysreflexia (AD) is a potentially life-threating complication after spinal cord injury (SCI), characterized by episodic hypertension induced by colon or bladder distension. The objective of this study was to determine the role of impaired baroreflex regulation by the nucleus tractus solitarii(NTS) in the occurrence of AD in a rat model. Methods T4 spinal cord transection animal model was used in this study, which included 40 Male rats Colorectal distension (CD) was performed to assess AD and compare the changes of BP, HR, and BRS, six weeks after operation. After that, SCI rats with successfully induced AD were selected. Losartan was microinjected into NTS in SCI rats, then 10, 30, 60 minutes later, CD was performed to calculate the changes of BP, HR, and BRS in order to explicit whether Ang II system was involved in the AD occurrence. Ang II was then Intra-cerebroventricular infused in sham operation rats with CD to mimic the activation of Ang II system in AD. Finally, the level of Ang II in NTS and colocalization of AT1R and NMDA receptor within the NTS neurons were also detected in SCI rats. Results Compared with sham operation, SCI significantly aggravated the elevation of blood pressure (BP) and impaired baroreflex sensitivity (BRS) induced by colorectal distension; both of which were significantly improved by microinjection of the angiotensin receptor type I (AT1R) antagonist losartan into the NTS. Level of angiotensin II (Ang II) in the NTS was significantly increased in the SCI rats than sham. Intracerebroventricular infusion of Ang II also mimicked changes in BP and BRS induced by colorectal distension. Blockade of baroreflex by sinoaortic denervation prevented beneficial effect of losartan on AD. Conclusion We concluded that the activation of Ang II system in NTS may impair blood pressure baroreflex, and contribute to AD after SCI.
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Affiliation(s)
- Kai Wang
- Department of Anesthesiology, Central Hospital of Xuzhou, Jiangsu, China
| | - Shaoxia Duan
- Department of Anesthesiology and ICU, South Campus, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xueping Wen
- Department of Orthopedics, Ningxiang People’s Hospital of Hunan Province, Ningxiang, Hunan, China
| | - Weizhong Wang
- Department of Physiology, Second Military Medical University, Shanghai, China
| | - Shangping Fang
- Department of Anesthesiology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Dunyi Qi
- Department of Anesthesiology, Affiliated Hospital of Xuzhou Medical University, Jiangsu, China
| | - Xiang Huan
- Department of Anesthesiology, Central Hospital of Xuzhou, Jiangsu, China
| | - Liwei Wang
- Department of Anesthesiology, Central Hospital of Xuzhou, Jiangsu, China
- * E-mail: (ZH); (LW)
| | - Zhenzhou He
- Department of Anesthesiology and ICU, South Campus, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (ZH); (LW)
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23
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Hypothalamic and inflammatory basis of hypertension. Clin Sci (Lond) 2017; 131:211-223. [PMID: 28057892 DOI: 10.1042/cs20160001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 11/07/2016] [Accepted: 11/21/2016] [Indexed: 02/07/2023]
Abstract
Hypertension is a major health problem with great consequences for public health. Despite its role as the primary cause of significant morbidity and mortality associated with cardiovascular disease, the pathogenesis of essential hypertension remains largely unknown. The central nervous system (CNS) in general, and the hypothalamus in particular, are intricately involved in the development and maintenance of hypertension. Over the last several decades, the understanding of the brain's role in the development of hypertension has dramatically increased. This brief review is to summarize the neural mechanisms of hypertension with a focus on neuroendocrine and neurotransmitter involvement, highlighting recent findings that suggest that hypothalamic inflammation disrupts key signalling pathways to affect the central control of blood pressure, and therefore suggesting future development of interventional strategies that exploit recent findings pertaining to the hypothalamic control of blood pressure as well as the inflammatory-sympathetic mechanisms involved in hypertension.
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Huber G, Schuster F, Raasch W. Brain renin-angiotensin system in the pathophysiology of cardiovascular diseases. Pharmacol Res 2017; 125:72-90. [PMID: 28687340 DOI: 10.1016/j.phrs.2017.06.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/28/2017] [Accepted: 06/28/2017] [Indexed: 02/07/2023]
Abstract
Cardiovascular diseases (CVD) are among the main causes of death globally and in this context hypertension represents one of the key risk factors for developing a CVD. It is well established that the peripheral renin-angiotensin system (RAS) plays an important role in regulating blood pressure (BP). All components of the classic RAS can also be found in the brain but, in contrast to the peripheral RAS, how the endogenous RAS is involved in modulating cardiovascular effects in the brain is not fully understood yet. It is a complex system that may work differently in diverse areas of the brain and is linked to the peripheral system by the circumventricular organs (CVO), which do not have a blood brain barrier (BBB). In this review, we focus on the brain angiotensin peptides, their interactions with each other, and the consequences in the central nervous system (CNS) concerning cardiovascular control. Additionally, we present potential drug targets in the brain RAS for the treatment of hypertension.
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Affiliation(s)
- Gianna Huber
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Germany; CBBM (Center of Brain, Behavior and Metabolism), Lübeck, Germany
| | - Franziska Schuster
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Germany; CBBM (Center of Brain, Behavior and Metabolism), Lübeck, Germany
| | - Walter Raasch
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Germany; CBBM (Center of Brain, Behavior and Metabolism), Lübeck, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany.
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25
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Physical training associated with Enalapril but not to Losartan, results in better cardiovascular autonomic effects. Auton Neurosci 2017; 203:33-40. [DOI: 10.1016/j.autneu.2016.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 12/04/2016] [Accepted: 12/06/2016] [Indexed: 01/13/2023]
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De Mello WC, Gerena Y, Ayala-Peña S. Angiotensins and Huntington's Disease: A Study on Immortalized Progenitor Striatal Cell Lines. Front Endocrinol (Lausanne) 2017; 8:108. [PMID: 28596754 PMCID: PMC5442183 DOI: 10.3389/fendo.2017.00108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 05/03/2017] [Indexed: 12/21/2022] Open
Abstract
Neurons from mouse models of Huntington's disease (HD) exhibit altered electrophysiological properties, potentially contributing to neuronal dysfunction and neurodegeneration. The renin-angiotensin system (RAS) is a potential contributor to the pathophysiology of neurodegenerative diseases. However, the role of angiotensin II (Ang II) and angiotensin (1-7) has not been characterized in HD. We investigated the influence of Ang II and angiotensin (1-7) on total potassium current using immortalized progenitor mutant huntingtin-expressing (Q111) and wild-type (Q7) cell lines. Measurements of potassium current were performed using the whole cell configuration of pCLAMP. The results showed that (1) the effect of Ang II administered to the bath caused a negligible effect on potassium current in mutant Q111 cells compared with wild-type Q7 cells and that intracellular administration of Ang II reduced the potassium current in wild type but not in mutant cells; (2) the small effect of Ang II was abolished by losartan; (3) intracellular administration of Ang II performed in mutant huntingtin-expressing Q111 cells revealed a negligible effect of the peptide on potassium current; (4) flow cytometer analysis indicated a low expression of Ang II AT1 receptors in mutant Q111 cells; (5) mutant huntingtin-expressing striatal cells are highly sensitive to Ang (1-7) and that the effect of Ang (1-7) is related to the activation of Mas receptors. In conclusion, mutant huntingtin-expressing cells showed a negligible effect of Ang II on potassium current, a result probably due to the reduced expression of AT1 receptors at the surface cell membrane. In contrast, administration of Ang (1-7) to the bath showed a significant decline of the potassium current in mutant cells, an effect dependent on the activation of Mas receptors. Ang II had an intracrine effect in wild-type cells and Ang (1-7) exerted a significant effect in mutant huntingtin-expressing striatal cells.
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Affiliation(s)
- Walmor C. De Mello
- Department of Pharmacology and Toxicology, School of Medicine, Medical Sciences Campus, University of Puerto Rico, San Juan, PR, USA
| | - Yamil Gerena
- Department of Pharmacology and Toxicology, School of Medicine, Medical Sciences Campus, University of Puerto Rico, San Juan, PR, USA
| | - Sylvette Ayala-Peña
- Department of Pharmacology and Toxicology, School of Medicine, Medical Sciences Campus, University of Puerto Rico, San Juan, PR, USA
- *Correspondence: Sylvette Ayala-Peña,
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27
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Han C, Rice MW, Cai D. Neuroinflammatory and autonomic mechanisms in diabetes and hypertension. Am J Physiol Endocrinol Metab 2016; 311:E32-41. [PMID: 27166279 PMCID: PMC4967151 DOI: 10.1152/ajpendo.00012.2016] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/03/2016] [Indexed: 02/07/2023]
Abstract
Interdisciplinary studies in the research fields of endocrinology and immunology show that obesity-associated overnutrition leads to neuroinflammatory molecular changes, in particular in the hypothalamus, chronically causing various disorders known as elements of metabolic syndrome. In this process, neural or hypothalamic inflammation impairs the neuroendocrine and autonomic regulation of the brain over blood pressure and glucose homeostasis as well as insulin secretion, and elevated sympathetic activation has been appreciated as a critical mediator. This review describes the involved physiology and mechanisms, with a focus on glucose and blood pressure balance, and suggests that neuroinflammation employs the autonomic nervous system to mediate the development of diabetes and hypertension.
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Affiliation(s)
- Cheng Han
- Department of Molecular Pharmacology, Diabetes Research Center, Institute of Aging, Albert Einstein College of Medicine, Bronx, New York
| | - Matthew W Rice
- Department of Molecular Pharmacology, Diabetes Research Center, Institute of Aging, Albert Einstein College of Medicine, Bronx, New York
| | - Dongsheng Cai
- Department of Molecular Pharmacology, Diabetes Research Center, Institute of Aging, Albert Einstein College of Medicine, Bronx, New York
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28
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Geraldes V, Carvalho M, Goncalves-Rosa N, Tavares C, Laranjo S, Rocha I. Lead toxicity promotes autonomic dysfunction with increased chemoreceptor sensitivity. Neurotoxicology 2016; 54:170-177. [PMID: 27133440 DOI: 10.1016/j.neuro.2016.04.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 04/11/2016] [Accepted: 04/26/2016] [Indexed: 02/07/2023]
Abstract
Mortality and morbidity by toxic metals is an important issue of occupational health. Lead is an ubiquitous heavy metal in our environment despite having no physiological role in biological systems. Being an homeostatic controller is expected that the autonomic nervous system would show a degree of impairment in lead toxicity. In fact, sympathoexcitation associated to high blood pressure and tachypnea has been described together with baroreflex dysfunction. However, the mechanisms underlying the autonomic dysfunction and the interplay between baro- and chemoreflex are not yet fully clarified. The angiotensinogenic PVN-NTS axis (paraventricular nucleus of the hypothalamus - nucleus tractus solitarius axis) is a particularly important neuronal pathway that could be responsible for the autonomic dysfunction and the cardiorespiratory impairment in lead toxicity. Within the current work, we addressed in vivo, baro- and chemoreceptor reflex behaviour, before and after central angiotensin inhibition, in order to better understand the cardiorespiratory autonomic mechanisms underlying the toxic effects of long-term lead exposure. For that, arterial pressure, heart rate, respiratory rate, sympathetic and parasympathetic activity and baro- and chemoreceptor reflex profiles of anaesthetized young adult rats exposed to lead, from foetal period to adulthood, were evaluated. Results showed increased chemosensitivity together with baroreceptor reflex impairment, sympathetic over-excitation, hypertension and tachypnea. Chemosensitivity and sympathetic overexcitation were reversed towards normality values by NTS treatment with A-779, an angiotensin (1-7) antagonist. No parasympathetic changes were observed before and after A-799 treatment. In conclusion, angiotensin (1-7) at NTS level is involved in the autonomic dysfunction observed in lead toxicity. The increased sensitivity of chemoreceptor reflex expresses the clear impairment of autonomic outflow to the cardiovascular and respiratory systems induced by putative persistent, long duration, alert reaction evoked by the long term exposure to lead toxic effects. The present study brings new insights on the central mechanisms implicated in the autonomic dysfunction induced by lead exposure which are relevant for the development of additional therapeutic options to tackle lead toxicity symptoms.
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Affiliation(s)
- Vera Geraldes
- Institute of Physiology, Faculty of Medicine of the University of Lisbon, Av. Prof Egas Moniz, 1649-028 Lisbon, Portugal; Cardiovascular Centre of the University of Lisbon, Av. Prof Egas Moniz, 1649-028 Lisbon, Portugal
| | - Mafalda Carvalho
- Cardiovascular Centre of the University of Lisbon, Av. Prof Egas Moniz, 1649-028 Lisbon, Portugal
| | - Nataniel Goncalves-Rosa
- Institute of Physiology, Faculty of Medicine of the University of Lisbon, Av. Prof Egas Moniz, 1649-028 Lisbon, Portugal; Cardiovascular Centre of the University of Lisbon, Av. Prof Egas Moniz, 1649-028 Lisbon, Portugal
| | - Cristiano Tavares
- Institute of Physiology, Faculty of Medicine of the University of Lisbon, Av. Prof Egas Moniz, 1649-028 Lisbon, Portugal; Cardiovascular Centre of the University of Lisbon, Av. Prof Egas Moniz, 1649-028 Lisbon, Portugal
| | - Sérgio Laranjo
- Cardiovascular Centre of the University of Lisbon, Av. Prof Egas Moniz, 1649-028 Lisbon, Portugal
| | - Isabel Rocha
- Institute of Physiology, Faculty of Medicine of the University of Lisbon, Av. Prof Egas Moniz, 1649-028 Lisbon, Portugal; Cardiovascular Centre of the University of Lisbon, Av. Prof Egas Moniz, 1649-028 Lisbon, Portugal.
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29
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Biancardi VC, Stern JE. Compromised blood-brain barrier permeability: novel mechanism by which circulating angiotensin II signals to sympathoexcitatory centres during hypertension. J Physiol 2016; 594:1591-600. [PMID: 26580484 PMCID: PMC4799983 DOI: 10.1113/jp271584] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 10/23/2015] [Indexed: 12/14/2022] Open
Abstract
Angiotensin II (AngII) is a pivotal peptide implicated in the regulation of blood pressure. In addition to its systemic vascular and renal effects, AngII acts centrally to modulate the activities of neuroendocrine and sympathetic neuronal networks, influencing in turn sympatho-humoral outflows to the circulation. Moreover, a large body of evidence supports AngII signalling dysregulation as a key mechanism contributing to exacerbated sympathoexcitation during hypertension. Due to its hydrophilic actions, circulating AngII does not cross the blood-brain barrier (BBB), signalling to the brain via the circumventricular organs which lack a tight BBB. In this review, we present and discuss recent studies from our laboratory showing that elevated circulating levels of AngII during hypertension result in disruption of the BBB integrity, allowing access of circulating AngII to critical sympathoexcitatory brain centres such as the paraventricular nucleus of the hypothalamus and the rostral ventrolateral medulla. We propose the novel hypothesis that AngII-driven BBB breakdown constitutes a complementary mechanism by which circulating AngII, working in tandem with the central renin-angiotensin system, further exacerbates sympatho-humoral activation during hypertension. These results are discussed within the context of a growing body of evidence in the literature supporting AngII as a pro-inflammatory signal, and brain microglia as key cell targets mediating central AngII actions during hypertension.
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Affiliation(s)
- V C Biancardi
- Department of Physiology, Georgia Regents University, Augusta, GA, USA
| | - J E Stern
- Department of Physiology, Georgia Regents University, Augusta, GA, USA
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30
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Tsai CT, Chang YM, Lin SL, Chen YS, Yeh YL, Padma VV, Tsai CC, Chen RJ, Ho TJ, Huang CY. Alpinate Oxyphyllae Fructus Inhibits IGFII-Related Signaling Pathway to Attenuate Ang II-Induced Pathological Hypertrophy in H9c2 Cardiomyoblasts. J Med Food 2016; 19:300-9. [DOI: 10.1089/jmf.2014.3340] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
| | - Yung-Ming Chang
- 1PT Biotechnology Co., Ltd., Taichung, Taiwan
- The School of Chinese Medicine for Post-Baccalaureate, I-Shou University, Kaohsiung, Taiwan
- Chinese Medicine Department, E-DA Hospital, Kaohsiung, Taiwan
| | - Shu-Luan Lin
- 1PT Lukang Chinese Medicine Clinics, Changhua, Taiwan
| | - Yueh-Sheng Chen
- School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Yu-Lan Yeh
- Department of pathology, Changhua Christian Hospital, Changhua, Taiwan
- Department of Medical Technology, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli, Taiwan
| | | | - Chin-Chuan Tsai
- The School of Chinese Medicine for Post-Baccalaureate, I-Shou University, Kaohsiung, Taiwan
- Chinese Medicine Department, E-DA Hospital, Kaohsiung, Taiwan
| | - Ray-Jade Chen
- Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tsung-Jung Ho
- School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Chih-Yang Huang
- School of Chinese Medicine, China Medical University, Taichung, Taiwan
- Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
- Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan
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31
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Anderson WD, Makadia HK, Vadigepalli R. Molecular variability elicits a tunable switch with discrete neuromodulatory response phenotypes. J Comput Neurosci 2016; 40:65-82. [PMID: 26621106 PMCID: PMC4867553 DOI: 10.1007/s10827-015-0584-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 10/28/2015] [Accepted: 11/02/2015] [Indexed: 01/08/2023]
Abstract
Recent single cell studies show extensive molecular variability underlying cellular responses. We evaluated the impact of molecular variability in the expression of cell signaling components and ion channels on electrophysiological excitability and neuromodulation. We employed a computational approach that integrated neuropeptide receptor-mediated signaling with electrophysiology. We simulated a population of neurons in which expression levels of a neuropeptide receptor and multiple ion channels were simultaneously varied within a physiological range. We analyzed the effects of variation on the electrophysiological response to a neuropeptide stimulus. Our results revealed distinct response patterns associated with low versus high receptor levels. Neurons with low receptor levels showed increased excitability and neurons with high receptor levels showed reduced excitability. These response patterns were separated by a narrow receptor level range forming a separatrix. The position of this separatrix was dependent on the expression levels of multiple ion channels. To assess the relative contributions of receptor and ion channel levels to the response profiles, we categorized the responses into six phenotypes based on response kinetics and magnitude. We applied several multivariate statistical approaches and found that receptor and channel expression levels influence the neuromodulation response phenotype through a complex though systematic mapping. Our analyses extended our understanding of how cellular responses to neuromodulation vary as a function of molecular expression. Our study showed that receptor expression and biophysical state interact with distinct relative contributions to neuronal excitability.
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Affiliation(s)
- Warren D Anderson
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
- Graduate program in Neuroscience, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
- Department of Pathology, Anatomy, and Cell Biology, Sidney Kimmel Medical College, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
| | - Hirenkumar K Makadia
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
- Department of Pathology, Anatomy, and Cell Biology, Sidney Kimmel Medical College, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
| | - Rajanikanth Vadigepalli
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA.
- Graduate program in Neuroscience, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA.
- Department of Pathology, Anatomy, and Cell Biology, Sidney Kimmel Medical College, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA.
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32
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Sayk F, Wobbe I, Twesten C, Meusel M, Wellhöner P, Derad I, Dodt C. Prolonged blood pressure elevation following continuous infusion of angiotensin II-a baroreflex study in healthy humans. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1406-14. [PMID: 26400183 DOI: 10.1152/ajpregu.00111.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 09/22/2015] [Indexed: 02/07/2023]
Abstract
ANG II interacts with the sympathetic nervous system at central nervous blood pressure-regulating structures, including the baroreflex. It is unknown whether prolonged BP elevation mediated by high ANG II plasma levels could induce a persistent shift of the central nervous baroreflex setpoint, lasting beyond the short ANG II plasmatic half time of a few seconds, thereby consolidating elevated BP and/or increased SNA in healthy humans. In a blinded crossover design, ANG II or placebo (saline) was infused for a 6-h period in 12 resting normotensive students (6 males, 6 females) raising BP to borderline hypertensive levels. Between 60 and 120 min after the infusion period, muscle sympathetic nerve activity (MSNA) was assessed microneurographically and correlated with oscillometric BP measurements and heart rate at supine rest (baseline) and during pharmacologic baroreceptor challenge. Infusion of ANG II increased BP to borderline-hypertensive levels, as intended, whereas heart rate remained unaltered. At baroreflex assessment (i.e., 60-120 min after end of infusion period), systolic BP was significantly higher compared with placebo (Δ8.4 ± 3.1 mmHg; P < 0.05), whereas diastolic values were nearly equal between conditions. Baseline MSNA was neither decreased nor increased, and baroreflex sensitivity to vasoactive drug challenge was not altered. Our results show that elevation of ANG II plasma levels over 6 h was able to increase systolic, but not diastolic, BP far beyond blood-mediated ANG II effects. MSNA or heart rate did not counter-regulate this BP elevation, indicating that ANG II had sustainably reset the central nervous BP threshold of sympathetic baroreflex function to accept elevated BP input signals without counter-regulatory response.
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Affiliation(s)
- Friedhelm Sayk
- Department of Internal Medicine I, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany; Department of Internal Medicine II, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany;
| | - Isabel Wobbe
- Institute of Radiology, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany; and
| | - Christoph Twesten
- Department of Internal Medicine I, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Moritz Meusel
- Department of Internal Medicine II, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Peter Wellhöner
- Department of Internal Medicine I, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Inge Derad
- Department of Internal Medicine I, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Christoph Dodt
- Department of Emergency Medicine, München-Bogenhausen Hospital, München, Germany
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33
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Multiscale model of dynamic neuromodulation integrating neuropeptide-induced signaling pathway activity with membrane electrophysiology. Biophys J 2015; 108:211-23. [PMID: 25564868 DOI: 10.1016/j.bpj.2014.11.1851] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 10/21/2014] [Accepted: 11/11/2014] [Indexed: 02/07/2023] Open
Abstract
We developed a multiscale model to bridge neuropeptide receptor-activated signaling pathway activity with membrane electrophysiology. Typically, the neuromodulation of biochemical signaling and biophysics have been investigated separately in modeling studies. We studied the effects of Angiotensin II (AngII) on neuronal excitability changes mediated by signaling dynamics and downstream phosphorylation of ion channels. Experiments have shown that AngII binding to the AngII receptor type-1 elicits baseline-dependent regulation of cytosolic Ca(2+) signaling. Our model simulations revealed a baseline Ca(2+)-dependent response to AngII receptor type-1 activation by AngII. Consistent with experimental observations, AngII evoked a rise in Ca(2+) when starting at a low baseline Ca(2+) level, and a decrease in Ca(2+) when starting at a higher baseline. Our analysis predicted that the kinetics of Ca(2+) transport into the endoplasmic reticulum play a critical role in shaping the Ca(2+) response. The Ca(2+) baseline also influenced the AngII-induced excitability changes such that lower Ca(2+) levels were associated with a larger firing rate increase. We examined the relative contributions of signaling kinases protein kinase C and Ca(2+)/Calmodulin-dependent protein kinase II to AngII-mediated excitability changes by simulating activity blockade individually and in combination. We found that protein kinase C selectively controlled firing rate adaptation whereas Ca(2+)/Calmodulin-dependent protein kinase II induced a delayed effect on the firing rate increase. We tested whether signaling kinetics were necessary for the dynamic effects of AngII on excitability by simulating three scenarios of AngII-mediated KDR channel phosphorylation: (1), an increased steady state; (2), a step-change increase; and (3), dynamic modulation. Our results revealed that the kinetics emerging from neuromodulatory activation of the signaling network were required to account for the dynamical changes in excitability. In summary, our integrated multiscale model provides, to our knowledge, a new approach for quantitative investigation of neuromodulatory effects on signaling and electrophysiology.
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de Kloet AD, Liu M, Rodríguez V, Krause EG, Sumners C. Role of neurons and glia in the CNS actions of the renin-angiotensin system in cardiovascular control. Am J Physiol Regul Integr Comp Physiol 2015; 309:R444-58. [PMID: 26084692 DOI: 10.1152/ajpregu.00078.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 06/15/2015] [Indexed: 02/07/2023]
Abstract
Despite tremendous research efforts, hypertension remains an epidemic health concern, leading often to the development of cardiovascular disease. It is well established that in many instances, the brain plays an important role in the onset and progression of hypertension via activation of the sympathetic nervous system. Further, the activity of the renin-angiotensin system (RAS) and of glial cell-mediated proinflammatory processes have independently been linked to this neural control and are, as a consequence, both attractive targets for the development of antihypertensive therapeutics. Although it is clear that the predominant effector peptide of the RAS, ANG II, activates its type-1 receptor on neurons to mediate some of its hypertensive actions, additional nuances of this brain RAS control of blood pressure are constantly being uncovered. One of these complexities is that the RAS is now thought to impact cardiovascular control, in part, via facilitating a glial cell-dependent proinflammatory milieu within cardiovascular control centers. Another complexity is that the newly characterized antihypertensive limbs of the RAS are now recognized to, in many cases, antagonize the prohypertensive ANG II type 1 receptor (AT1R)-mediated effects. That being said, the mechanism by which the RAS, glia, and neurons interact to regulate blood pressure is an active area of ongoing research. Here, we review the current understanding of these interactions and present a hypothetical model of how these exchanges may ultimately regulate cardiovascular function.
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Affiliation(s)
- Annette D de Kloet
- Department of Physiology and Functional Genomics, and McKnight Brain Institute, University of Florida College of Medicine, Gainesville, Florida; and
| | - Meng Liu
- Department of Physiology and Functional Genomics, and McKnight Brain Institute, University of Florida College of Medicine, Gainesville, Florida; and
| | - Vermalí Rodríguez
- Department of Physiology and Functional Genomics, and McKnight Brain Institute, University of Florida College of Medicine, Gainesville, Florida; and
| | - Eric G Krause
- Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, Florida
| | - Colin Sumners
- Department of Physiology and Functional Genomics, and McKnight Brain Institute, University of Florida College of Medicine, Gainesville, Florida; and
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Winklewski PJ, Radkowski M, Wszedybyl-Winklewska M, Demkow U. Brain inflammation and hypertension: the chicken or the egg? J Neuroinflammation 2015; 12:85. [PMID: 25935397 PMCID: PMC4432955 DOI: 10.1186/s12974-015-0306-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/23/2015] [Indexed: 12/24/2022] Open
Abstract
Inflammation of forebrain and hindbrain nuclei controlling the sympathetic nervous system (SNS) outflow from the brain to the periphery represents an emerging concept of the pathogenesis of neurogenic hypertension. Angiotensin II (Ang-II) and prorenin were shown to increase production of reactive oxygen species and pro-inflammatory cytokines (interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α)) while simultaneously decreasing production of interleukin-10 (IL-10) in the paraventricular nucleus of the hypothalamus and the rostral ventral lateral medulla. Peripheral chronic inflammation and Ang-II activity seem to share a common central mechanism contributing to an increase in sympathetic neurogenic vasomotor tone and entailing neurogenic hypertension. Both hypertension and obesity facilitate the penetration of peripheral immune cells in the brain parenchyma. We suggest that renin-angiotensin-driven hypertension encompasses feedback and feedforward mechanisms in the development of neurogenic hypertension while low-intensity, chronic peripheral inflammation of any origin may serve as a model of a feedforward mechanism in this condition.
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Affiliation(s)
- Pawel J Winklewski
- Institute of Human Physiology, Medical University of Gdansk, Tuwima Str. 15, 80-210, Gdansk, Poland.
| | - Marek Radkowski
- Department of Immunopathology of Infectious and Parasitic Diseases, Medical University of Warsaw, Pawinskiego Str. 3c, 02-106, Warsaw, Poland.
| | | | - Urszula Demkow
- Department of Laboratory Diagnostics and Clinical Immunology of Developmental Age, Medical University of Warsaw, Marszalkowska Str. 24, 00-576, Warsaw, Poland.
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36
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Marques-Lopes J, Lynch MK, Van Kempen TA, Waters EM, Wang G, Iadecola C, Pickel VM, Milner TA. Female protection from slow-pressor effects of angiotensin II involves prevention of ROS production independent of NMDA receptor trafficking in hypothalamic neurons expressing angiotensin 1A receptors. Synapse 2015; 69:148-65. [PMID: 25559190 PMCID: PMC4355104 DOI: 10.1002/syn.21800] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 12/23/2014] [Indexed: 12/21/2022]
Abstract
Renin–angiotensin system overactivity, upregulation of postsynaptic NMDA receptor function, and increased reactive oxygen species (ROS) production in the hypothalamic paraventricular nucleus (PVN) are hallmarks of angiotensin II (AngII)-induced hypertension, which is far more common in young males than in young females. We hypothesize that the sex differences in hypertension are related to differential AngII-induced changes in postsynaptic trafficking of the essential NMDA receptor GluN1 subunit and ROS production in PVN cells expressing angiotensin Type 1a receptor (AT1aR). We tested this hypothesis using slow-pressor (14-day) infusion of AngII (600 ng/kg/min) in mice, which elicits hypertension in males but not in young females. Two-month-old male and female transgenic mice expressing enhanced green fluorescent protein (EGFP) in AT1aR-containing cells were used. In males, but not in females, AngII increased blood pressure and ROS production in AT1aR–EGFP PVN cells at baseline and following NMDA treatment. Electron microscopy showed that AngII increased cytoplasmic and total GluN1–silver-intensified immunogold (SIG) densities and induced a trend toward an increase in near plasmalemmal GluN1–SIG density in AT1aR–EGFP dendrites of males and females. Moreover, AngII decreased dendritic area and diameter in males, but increased dendritic area of small (<1 µm) dendrites and decreased diameter of large (>1 µm) dendrites in females. Fluorescence microscopy revealed that AT1aR and estrogen receptor β do not colocalize, suggesting that if estrogen is involved, its effect is indirect. These data suggest that the sexual dimorphism in AngII-induced hypertension is associated with sex differences in ROS production in AT1aR-containing PVN cells but not with postsynaptic NMDA receptor trafficking.
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Affiliation(s)
- Jose Marques-Lopes
- Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY 10065
| | - Mary-Katherine Lynch
- Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY 10065
| | - Tracey A. Van Kempen
- Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY 10065
| | - Elizabeth M. Waters
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, New York, NY 10065
| | - Gang Wang
- Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY 10065
| | - Costantino Iadecola
- Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY 10065
| | - Virginia M. Pickel
- Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY 10065
| | - Teresa A. Milner
- Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY 10065
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, New York, NY 10065
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37
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Biancardi VC, Son SJ, Ahmadi S, Filosa JA, Stern JE. Circulating angiotensin II gains access to the hypothalamus and brain stem during hypertension via breakdown of the blood-brain barrier. Hypertension 2013; 63:572-9. [PMID: 24343120 DOI: 10.1161/hypertensionaha.113.01743] [Citation(s) in RCA: 182] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Angiotensin II-mediated vascular brain inflammation emerged as a novel pathophysiological mechanism in neurogenic hypertension. However, the precise underlying mechanisms and functional consequences in relation to blood-brain barrier (BBB) integrity and central angiotensin II actions mediating neurohumoral activation in hypertension are poorly understood. Here, we aimed to determine whether BBB permeability within critical hypothalamic and brain stem regions involved in neurohumoral regulation was altered during hypertension. Using digital imaging quantification after intravascularly injected fluorescent dyes and immunohistochemistry, we found increased BBB permeability, along with altered key BBB protein constituents, in spontaneously hypertensive rats within the hypothalamic paraventricular nucleus, the nucleus of the solitary tract, and the rostral ventrolateral medulla, all critical brain regions known to contribute to neurohumoral activation during hypertension. BBB disruption, including increased permeability and downregulation of constituent proteins, was prevented in spontaneously hypertensive rats treated with the AT1 receptor antagonist losartan, but not with hydralazine, a direct vasodilator. Importantly, we found circulating angiotensin II to extravasate into these brain regions, colocalizing with neurons and microglial cells. Taken together, our studies reveal a novel angiotensin II-mediated feed-forward mechanism during hypertension, by which circulating angiotensin II evokes increased BBB permeability, facilitating in turn its access to critical brain regions known to participate in blood pressure regulation.
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Inhibitory effect of alpinate Oxyphyllae fructus extracts on Ang II-induced cardiac pathological remodeling-related pathways in H9c2 cardiomyoblast cells. Biomedicine (Taipei) 2013. [DOI: 10.1016/j.biomed.2013.05.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Knight WD, Saxena A, Shell B, Nedungadi TP, Mifflin SW, Cunningham JT. Central losartan attenuates increases in arterial pressure and expression of FosB/ΔFosB along the autonomic axis associated with chronic intermittent hypoxia. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1051-8. [PMID: 24026072 PMCID: PMC3840317 DOI: 10.1152/ajpregu.00541.2012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 09/04/2013] [Indexed: 02/02/2023]
Abstract
Chronic intermittent hypoxia (CIH) increases mean arterial pressure (MAP) and FosB/ΔFosB staining in central autonomic nuclei. To test the role of the brain renin-angiotensin system (RAS) in CIH hypertension, rats were implanted with intracerebroventricular (icv) cannulae delivering losartan (1 μg/h) or vehicle (VEH) via miniosmotic pumps and telemetry devices for arterial pressure recording. A third group was given the same dose of losartan subcutaneously (sc). Two groups of losartan-treated rats served as normoxic controls. Rats were exposed to CIH or normoxia for 7 days and then euthanized for immunohistochemistry. Intracerebroventricular losartan attenuated CIH-induced increases in arterial pressure during CIH exposure (0800-1600 during the light phase) on days 1, 6, and 7 and each day during the normoxic dark phase. FosB/ΔFosB staining in the organum vasculosum of the lamina terminalis (OVLT), median preoptic nucleus (MnPO), paraventricular nucleus of the hypothalamus (PVN), the rostral ventrolateral medulla (RVLM), and the nucleus of the solitary tract (NTS) was decreased in icv losartan-treated rats. Subcutaneous losartan also reduced CIH hypertension during the last 2 days of CIH and produced bradycardia prior to the effect on blood pressure. Following sc losartan, FosB/ΔFosB staining was reduced only in the OVLT, MnPO, PVN, and NTS. These data indicate that the central and peripheral RAS contribute to CIH-induced hypertension and transcriptional activation of autonomic nuclei and that the contribution of the central RAS is greater during the normoxic dark phase of CIH hypertension.
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Affiliation(s)
- W David Knight
- Department of Molecular Biology and Chemistry, Christopher Newport University, Newport News, Virginia; and
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O'Callaghan EL, Choong YT, Jancovski N, Allen AM. Central angiotensinergic mechanisms associated with hypertension. Auton Neurosci 2013; 175:85-92. [PMID: 23466041 DOI: 10.1016/j.autneu.2013.01.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 01/23/2013] [Accepted: 01/23/2013] [Indexed: 12/20/2022]
Abstract
Following its generation by both systemic and tissue-based renin-angiotensin systems, angiotensin II interacts with specific, G-protein coupled receptors to modulate multiple physiological systems, including the cardiovascular system. Genetic models in which the different components of the renin-angiotensin system have been deleted show large changes in resting blood pressure. Interruption of the generation of angiotensin II, or its interaction with these receptors, decreases blood pressure in hypertensive humans and experimental animal models of hypertension. Whilst the interaction of angiotensin II with the kidney is pivotal in this modulation of blood pressure, an involvement of the system in other tissues is important. Both systemic angiotensins, acting via the blood-brain barrier deficient circumventricular organs, and centrally-generated angiotensin modulate cardiovascular control by regulating fluid and electrolyte ingestion, autonomic activity and neuroendocrine function. This review discusses the pathways in the brain that are involved in this regulation of blood pressure as well as examining the sites in which altered angiotensin function might contribute to the development and maintenance of high blood pressure.
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Affiliation(s)
- Erin L O'Callaghan
- Department of Physiology, University of Melbourne, Vic., 3010, Australia
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Alpinate oxyphyllae fructus (Alpinia Oxyphylla Miq) extracts inhibit angiotensin-II induced cardiac apoptosis in H9c2 cardiomyoblast cells. Biosci Biotechnol Biochem 2013; 77:229-34. [PMID: 23391902 DOI: 10.1271/bbb.120541] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Angiotensin II (Ang II) is a risk factor for cardiovascular disease. We used a traditional Chinese medicine, alpinate oxyphyllae fructus (AOF), to evaluate its effect on Ang II-induced cardiac apoptosis and mitochondrial dysfunction. Ang II-treated H9c2 cells were administered AOF of 20-100 µg/mL concentrations. Ang II significantly increased TUNEL-positive nuclei in the H9c2 cells, effect was inhibited by AOF administration in both pre-treated and post-treated H9c2 cells. Caspases 9 and 3 activities were increased by Ang II and downregulated by AOF administration, especially in pre-treatment. AOF treatment reversed Ang II-induced mitochondria membrane potential instability in H9c2 cells as observed by JC-1 stain assay. Furthermore, pro-apoptotic proteins Bad and cytochrome c increased and decreased respectively under AOF administration. The levels of p-Bad anti-apoptotic protein were significantly increased after AOF treatment. This study indicates that mitochondrial dependent apoptosis induced by Ang II.
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Zhao D, McCully BH, Brooks VL. Rosiglitazone improves insulin sensitivity and baroreflex gain in rats with diet-induced obesity. J Pharmacol Exp Ther 2012; 343:206-13. [PMID: 22815534 PMCID: PMC3464031 DOI: 10.1124/jpet.112.194738] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 07/17/2012] [Indexed: 12/24/2022] Open
Abstract
Obesity decreases baroreflex gain (BRG); however, the mechanisms are unknown. We tested the hypothesis that impaired BRG is related to the concurrent insulin resistance, and, therefore, BRG would be improved after treatment with the insulin-sensitizing drug rosiglitazone. Male rats fed a high-fat diet diverged into obesity-prone (OP) and obesity-resistant (OR) groups after 2 weeks. Then, OP and OR rats, as well as control (CON) rats fed a standard diet, were treated daily for 2 to 3 weeks with rosiglitazone (3 or 6 mg/kg) or its vehicle by gavage. Compared with OR and CON rats, conscious OP rats exhibited reductions in BRG (OP, 2.9 ± 0.1 bpm/mm Hg; OR, 4.0 ± 0.2 bpm/mm Hg; CON, 3.9 ± 0.2 bpm/mm Hg; P < 0.05) and insulin sensitivity (hyperinsulinemic euglycemic clamp; OP, 6.8 ± 0.9 mg/kg · min; OR, 22.2 ± 1.2 mg/kg · min; CON, 17.7 ± 0.8 mg/kg · min; P < 0.05), which were well correlated (r(2) = 0.49; P < 0.01). In OP rats, rosiglitazone dose-dependently improved (P < 0.05) insulin sensitivity (12.8 ± 0.6 mg/kg · min at 3 mg/kg; 16.0 ± 1.5 mg/kg · min at 6 mg/kg) and BRG (3.8 ± 0.4 bpm/mm Hg at 3 mg/kg; 5.3 ± 0.7 bpm/mm Hg at 6 mg/kg). However, 6 mg/kg rosiglitazone also increased BRG in OR rats without increasing insulin sensitivity, disrupted the correlation between BRG and insulin sensitivity (r(2) = 0.08), and, in OP and OR rats, elevated BRG relative to insulin sensitivity (analysis of covariance; P < 0.05). Moreover, in OP rats, stimulation of the aortic depressor nerve, to activate central baroreflex pathways, elicited markedly reduced decreases in heart rate and arterial pressure, but these responses were not improved by rosiglitazone. In conclusion, diet-induced obesity impairs BRG via a central mechanism that is related to the concurrent insulin resistance. Rosiglitazone normalizes BRG, but not by improving brain baroreflex processing or insulin sensitivity.
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Affiliation(s)
- Ding Zhao
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97239, USA
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Arnold AC, Sakima A, Kasper SO, Vinsant S, Garcia-Espinosa MA, Diz DI. The brain renin-angiotensin system and cardiovascular responses to stress: insights from transgenic rats with low brain angiotensinogen. J Appl Physiol (1985) 2012; 113:1929-36. [PMID: 22984245 DOI: 10.1152/japplphysiol.00569.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The renin-angiotensin system (RAS) has been identified as an attractive target for the treatment of stress-induced cardiovascular disorders. The effects of angiotensin (ANG) peptides during stress responses likely result from an integration of actions by circulating peptides and brain peptides derived from neuronal and glial sources. The present review focuses on the contribution of endogenous brain ANG peptides to pathways involved in cardiovascular responses to stressors. During a variety of forms of stress, neuronal pathways in forebrain areas containing ANG II or ANG-(1-7) are activated to stimulate descending angiotensinergic pathways that increase sympathetic outflow to increase blood pressure. We provide evidence that glia-derived ANG peptides influence brain AT(1) receptors. This appears to result in modulation of the responsiveness of the neuronal pathways activated during stressors that elevate circulating ANG peptides to activate brain pathways involving descending hypothalamic projections. It is well established that increased cardiovascular reactivity to stress is a significant predictor of hypertension and other cardiovascular diseases. This review highlights the importance of understanding the impact of RAS components from the circulation, neurons, and glia on the integration of cardiovascular responses to stressors.
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Affiliation(s)
- Amy C Arnold
- The Hypertension & Vascular Research Center and the Departments of General Surgery and Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157-1032, USA
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Arakawa H, Kawabe K, Sapru HN. Angiotensin-(1-12) in the rostral ventrolateral medullary pressor area of the rat elicits sympathoexcitatory responses. Exp Physiol 2012; 98:94-108. [PMID: 22707504 DOI: 10.1113/expphysiol.2012.067116] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The rostral ventrolateral medullary pressor area (RVLM) is known to be critical in the regulation of cardiovascular function. In this study, it was hypothesized that the RVLM may be one of the sites of cardiovascular actions of a newly discovered angiotensin, angiotensin-(1-12) [Ang-(1-12)]. Experiments were carried out in urethane-anaesthetized, artificially ventilated, adult male Wistar rats. The RVLM was identified by microinjections of L-glutamate (5 mM). The volume of all microinjections into the RVLM was 100 nl. Microinjections of Ang-(1-12) (0.1-1.0 mM) into the RVLM elicited increases in mean arterial pressure and heart rate. Maximal cardiovascular responses were elicited by 0.5 mM Ang-(1-12); this concentration was used in the other experiments described. Microinjections of Ang-(1-12) increased greater splanchnic nerve activity. The tachycardic responses to Ang-(1-12) were not altered by bilateral vagotomy. The cardiovascular responses elicited by Ang-(1-12) were attenuated by microinjections of an angiotensin II type 1 receptor (AT(1)R) antagonist (losartan), but not an AT(2)R antagonist (PD123319), into the RVLM. Combined inhibition of angiotensin-converting enzyme and chymase in the RVLM abolished Ang-(1-12)-induced responses. Angiotensin-(1-12)-immunoreactive cells were present in the RVLM. Angiotensin II type 1 receptors and phenylethanolamine-N-methyl-transferase were present in the RVLM neurons retrogradely labelled by microinjections of Fluoro-Gold into the intermediolateral cell column of the thoracic spinal cord. Angiotensin-(1-12)-containing neurons in the hypothalamic paraventricular nucleus did not project to the RVLM. These results indicated that: (1) microinjections of Ang-(1-12) into the RVLM elicited increases in mean arterial pressure, heart rate and greater splanchnic nerve activity; (2) both angiotensin-converting enzyme and chymase were needed to convert Ang-(1-12) into angiotensin II; and (3) AT(1)Rs, but not AT(2)Rs, in the RVLM mediated the Ang-(1-12)-induced responses.
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Affiliation(s)
- Hideki Arakawa
- Department of Neurological Surgery, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
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Wang G, Coleman CG, Glass MJ, Zhou P, Yu Q, Park L, Anrather J, Pickel VM, Iadecola C. Angiotensin II type 2 receptor-coupled nitric oxide production modulates free radical availability and voltage-gated Ca2+ currents in NTS neurons. Am J Physiol Regul Integr Comp Physiol 2012; 302:R1076-83. [PMID: 22378773 PMCID: PMC3362142 DOI: 10.1152/ajpregu.00571.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 02/25/2012] [Indexed: 02/07/2023]
Abstract
The medial region of the nucleus tractus solitarius (mNTS) is a key brain stem site controlling cardiovascular function, wherein ANG II modulates neuronal L-type Ca(2+) currents via activation of ANG II type 1 receptors (AT(1)R) and production of reactive oxygen species (ROS). ANG II type 2 receptors (AT(2)R) induce production of nitric oxide (NO), which may interact with ROS and modulate AT(1)R signaling. We sought to determine whether AT(2)R-mediated NO production occurs in mNTS neurons and, if so, to elucidate the NO source and the functional interaction with AT(1)R-induced ROS or Ca(2+) influx. Electron microscopic (EM) immunolabeling showed that AT(2)R and neuronal NO synthase (nNOS) are coexpressed in neuronal somata and dendrites receiving synapses in the mNTS. In the presence of the AT(1)R antagonist losartan, ANG II increased NO production in isolated mNTS neurons, an effect blocked by the AT(2)R antagonist PD123319, but not the angiotensin (1-7) antagonist D-Ala. Studies in mNTS neurons of nNOS-null or endothelial NOS (eNOS)-null mice established nNOS as the source of NO. ANG II-induced ROS production was enhanced by PD123319, the NOS inhibitor N(G)-nitro-l-arginine (LNNA), or in nNOS-null mice. Moreover, in the presence of losartan, ANG II reduced voltage-gated L-type Ca(2+) current, an effect blocked by PD123319 or LNNA. We conclude that AT(2)R are closely associated and functionally coupled with nNOS in mNTS neurons. The resulting NO production antagonizes AT(1)R-mediated ROS and dampens L-type Ca(2+) currents. The ensuing signaling changes in the NTS may counteract the deleterious effects of AT(1)R on cardiovascular function.
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Affiliation(s)
- Gang Wang
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Cornell Medical College, New York 10065, USA.
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Hamada N, Nishi Y, Tajiri Y, Setoyama K, Kamimura R, Miyahara K, Nuruki N, Hosoda H, Kangawa K, Kojima M, Mifune H. Disrupted regulation of ghrelin production under antihypertensive treatment in spontaneously hypertensive rats. Circ J 2012; 76:1423-9. [PMID: 22447011 DOI: 10.1253/circj.cj-11-1345] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Ghrelin is an acylated peptide hormone mainly secreted from the stomach. When administrated externally it modulates vascular tone mainly through the regulation of autonomic nerve activity. However, the effects of blood pressure (BP) on the production and secretion of ghrelin remain to be clarified. METHODS AND RESULTS We examined the stomach and plasma levels of ghrelin in spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats after a 4-week-intervention with antihypertensive agents (candesartan-cilexetil [ARB], doxazosin [DZN], metoprolol [MP], reserpine [RES]) to clarify the influence of BP on the secretion of ghrelin. The effect of these agents on ghrelin production and secretion were examined by comparing vehicle-treated controls (WKY-Intact, SHR-Intact). Treatment with the 4 antihypertensive drugs all yielded a significant decline in systolic BP in both SHR and WKY. Under these conditions, significantly lower levels of stomach and plasma ghrelin were detected in WKY treated with ARB (P<0.05), DZN (P<0.05), MP (P<0.05) and RES (P<0.05) compared with WKY-Intact, whereas no significant change in the ghrelin levels in the stomach and plasma were detected in SHR under the same treatments. CONCLUSIONS The findings imply that the production and secretion of ghrelin are controlled by the ambient vascular tone and vice versa in normotensive WKY. This inter-relationship between ghrelin and BP seems to be disrupted in SHR.
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Affiliation(s)
- Naokazu Hamada
- Department of Digestive and Life-Style Related Disease, Health Research Course, Human and Environmental Sciences, Kagoshima University Graduate School of Medicine and Dental Sciences, Kagoshima, Japan
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Chitravanshi VC, Proddutur A, Sapru HN. Cardiovascular actions of angiotensin-(1-12) in the hypothalamic paraventricular nucleus of the rat are mediated via angiotensin II. Exp Physiol 2011; 97:1001-17. [PMID: 22125313 DOI: 10.1113/expphysiol.2011.062471] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The role of the hypothalamic paraventricular nucleus (PVN) in cardiovascular regulation is well established. In this study, it was hypothesized that the PVN may be one of the sites of cardiovascular actions of a newly discovered angiotensin, angiotensin-(1-12). Experiments were carried out in urethane-anaesthetized, artificially ventilated, adult male Wistar rats. The PVN was identified by microinjections of NMDA (10 mm). Microinjections (50 nl) of angiotensin-(1-12) (1 mm) into the PVN elicited increases in mean arterial pressure, heart rate and renal sympathetic nerve activity. The tachycardic responses to angiotensin-(1-12) were attenuated by bilateral vagotomy. The cardiovascular responses elicited by angiotensin-(1-12) were attenuated by microinjections of an angiotensin II type 1 receptor (AT(1)R) antagonist (losartan), but not an angiotensin II type 1 receptor (AT(2)R) antagonist (PD123319), into the PVN. Combined inhibition of angiotensin-converting enzyme and chymase in the PVN abolished angiotensin-(1-12)-induced responses. Angiotensin-(1-12)-immunoreactive cells and fibres were more numerous in the middle and caudal regions of the PVN. Angiotensin-(1-12) was present in many, but not all, vasopressinergic PVN cells. This peptide was also present in some non-vasopressinergic PVN cells, but not in oxytocin-containing PVN cells. These results can be summarized as follows: (1) microinjections of angiotensin-(1-12) into the PVN elicited increases in mean arterial pressure, heart rate and renal sympathetic nerve activity; (2) heart rate responses were mediated via both sympathetic and vagus nerves; (3) both angiotensin-converting enzyme and chymase were needed to convert angiotensin-(1-12) to angiotensin II in the PVN; and (4) AT(1)Rs, but not AT(2)Rs, in the PVN mediated angiotensin-(1-12)-induced responses. It was concluded that the cardiovascular actions of angiotensin-(1-12) in the PVN are mediated via its conversion to angiotensin II.
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Affiliation(s)
- Vineet C Chitravanshi
- Department of Neurological Surgery, MSB H-586, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
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Waki H, Gouraud SS, Maeda M, Raizada MK, Paton JFR. Contributions of vascular inflammation in the brainstem for neurogenic hypertension. Respir Physiol Neurobiol 2011; 178:422-8. [PMID: 21601658 DOI: 10.1016/j.resp.2011.05.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 05/06/2011] [Accepted: 05/06/2011] [Indexed: 02/07/2023]
Abstract
Essential hypertension is idiopathic although it is accepted as a complex polygenic trait with underlying genetic components, which remain unknown. Our supposition is that primary hypertension involves activation of the sympathetic nervous system. One pivotal region controlling arterial pressure set point is nucleus tractus solitarii (NTS). We recently identified that pro-inflammatory molecules, such as junctional adhesion molecule-1, were over expressed in endothelial cells of the microvasculature supplying the NTS in an animal model of human hypertension (the spontaneously hypertensive rat: SHR) compared to normotensive Wistar Kyoto (WKY) rats. We have also shown endogenous leukocyte accumulation inside capillaries within the NTS of SHR but not WKY rats. Despite the inflammatory state in the NTS of SHR, transcripts of some inflammatory molecules such as chemokine (C-C motif) ligand 5 (Ccl5), and its receptors, chemokine (C-C motif) receptor 1 and 3 were down-regulated in the NTS of SHR compared to WKY rats. This may be compensatory to avoid further strong inflammatory activity. More importantly, we found that down-regulation of Ccl5 in the NTS of SHR may be pro-hypertensive since microinjection of Ccl5 into the NTS of SHR decreased arterial pressure but was less effective in WKY rats. Leukocyte accumulation of the NTS microvasculature may also induce an increase in vascular resistance and hypoperfusion within the NTS; the latter may trigger release of pro-inflammatory molecules which via paracrine signaling may affect central neural cardiovascular activity conducive to neurogenic hypertension. All told, we suggest that vascular inflammation within the brainstem contributes to neurogenic hypertension by multiple pathways.
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Affiliation(s)
- Hidefumi Waki
- Department of Physiology, Wakayama Medical University School of Medicine, Wakayama 641-8509, Japan.
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Chen CC, Fan YP, Shin HS, Su CK. Basal sympathetic activity generated in neonatal mouse brainstem-spinal cord preparation requires T-type calcium channel subunit α1H. Exp Physiol 2011; 96:486-94. [DOI: 10.1113/expphysiol.2010.056085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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