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Tyagi SC, Pushpakumar S, Sen U, Akinterinwa OE, Zheng Y, Mokshagundam SPL, Kalra DK, Singh M. Role of circadian clock system in the mitochondrial trans-sulfuration pathway and tissue remodeling. Can J Physiol Pharmacol 2024; 102:105-115. [PMID: 37979203 DOI: 10.1139/cjpp-2023-0186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2023]
Abstract
Previous studies from our laboratory revealed that the gaseous molecule hydrogen sulfide (H2S), a metabolic product of epigenetics, involves trans-sulfuration pathway for ensuring metabolism and clearance of homocysteine (Hcy) from body, thereby mitigating the skeletal muscle's pathological remodeling. Although the master circadian clock regulator that is known as brain and muscle aryl hydrocarbon receptor nuclear translocator like protein 1 (i.e., BMAL 1) is associated with S-adenosylhomocysteine hydrolase (SAHH) and Hcy metabolism but how trans-sulfuration pathway is influenced by the circadian clock remains unexplored. We hypothesize that alterations in the functioning of circadian clock during sleep and wake cycle affect skeletal muscle's biology. To test this hypothesis, we measured serum matrix metalloproteinase (MMP) activities using gelatin gels for analyzing the MMP-2 and MMP-9. Further, employing casein gels, we also studied MMP-13 that is known to be influenced by the growth arrest and DNA damage-45 (GADD45) protein during sleep and wake cycle. The wild type and cystathionine β synthase-deficient (CBS-/+) mice strains were treated with H2S and subjected to measurement of trans-sulfuration factors from skeletal muscle tissues. The results suggested highly robust activation of MMPs in the wake mice versus sleep mice, which appears somewhat akin to the "1-carbon metabolic dysregulation", which takes place during remodeling of extracellular matrix during muscular dystrophy. Interestingly, the levels of trans-sulfuration factors such as CBS, cystathionine γ lyase (CSE), methyl tetrahydrofolate reductase (MTHFR), phosphatidylethanolamine N-methyltransferase (PEMT), and Hcy-protein bound paraoxonase 1 (PON1) were attenuated in CBS-/+ mice. However, treatment with H2S mitigated the attenuation of the trans-sulfuration pathway. In addition, levels of mitochondrial peroxisome proliferator-activated receptor-gamma coactivator 1-α (PGC 1-α) and mitofusin-2 (MFN-2) were significantly improved by H2S intervention. Our findings suggest participation of the circadian clock in trans-sulfuration pathway that affects skeletal muscle remodeling and mitochondrial regeneration.
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Affiliation(s)
- Suresh C Tyagi
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Sathnur Pushpakumar
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Utpal Sen
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Oluwaseun E Akinterinwa
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Yuting Zheng
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Sri Prakash L Mokshagundam
- Division of Endocrinology, Metabolism and Diabetes and Robley Rex VA Medical Center, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Dinesh K Kalra
- Division of Cardiovascular Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Mahavir Singh
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40202, USA
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Murase S, Sakitani N, Maekawa T, Yoshino D, Takano K, Konno A, Hirai H, Saito T, Tanaka S, Shinohara K, Kishi T, Yoshikawa Y, Sakai T, Ayaori M, Inanami H, Tomiyasu K, Takashima A, Ogata T, Tsuchimochi H, Sato S, Saito S, Yoshino K, Matsuura Y, Funamoto K, Ochi H, Shinohara M, Nagao M, Sawada Y. Interstitial-fluid shear stresses induced by vertically oscillating head motion lower blood pressure in hypertensive rats and humans. Nat Biomed Eng 2023; 7:1350-1373. [PMID: 37414976 PMCID: PMC10651490 DOI: 10.1038/s41551-023-01061-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 05/27/2023] [Indexed: 07/08/2023]
Abstract
The mechanisms by which physical exercise benefits brain functions are not fully understood. Here, we show that vertically oscillating head motions mimicking mechanical accelerations experienced during fast walking, light jogging or treadmill running at a moderate velocity reduce the blood pressure of rats and human adults with hypertension. In hypertensive rats, shear stresses of less than 1 Pa resulting from interstitial-fluid flow induced by such passive head motions reduced the expression of the angiotensin II type-1 receptor in astrocytes in the rostral ventrolateral medulla, and the resulting antihypertensive effects were abrogated by hydrogel introduction that inhibited interstitial-fluid movement in the medulla. Our findings suggest that oscillatory mechanical interventions could be used to elicit antihypertensive effects.
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Affiliation(s)
- Shuhei Murase
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
- Department of Orthopaedic Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Naoyoshi Sakitani
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
- Department of Cell Biology, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Takahiro Maekawa
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Daisuke Yoshino
- Division of Advanced Applied Physics, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Kouji Takano
- Department of Rehabilitation for Brain Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Ayumu Konno
- Department of Neurophysiology & Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Hirokazu Hirai
- Department of Neurophysiology & Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Taku Saito
- Department of Orthopaedic Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Sakae Tanaka
- Department of Orthopaedic Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Keisuke Shinohara
- Department of Cardiovascular Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takuya Kishi
- Department of Cardiology, Graduate School of Medicine, International University of Health and Welfare, Okawa, Japan
| | - Yuki Yoshikawa
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Takamasa Sakai
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | | | - Hirohiko Inanami
- Inanami Spine & Joint Hospital/Iwai Orthopaedic Medical Hospital, Iwai Medical Foundation, Tokyo, Japan
| | - Koji Tomiyasu
- Center of Sports Science and Health Promotion, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Atsushi Takashima
- Department of Assistive Technology, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Toru Ogata
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
- Department of Rehabilitation Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hirotsugu Tsuchimochi
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Shinya Sato
- Department of Advanced Medical Technologies, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Shigeyoshi Saito
- Department of Medical Physics and Engineering, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kohzoh Yoshino
- School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
| | - Yuiko Matsuura
- Department of Health and Sports, Niigata University of Health and Welfare, Niigata, Japan
| | | | - Hiroki Ochi
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Masahiro Shinohara
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Motoshi Nagao
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Yasuhiro Sawada
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan.
- Department of Orthopaedic Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
- Department of Cell Biology, National Cerebral and Cardiovascular Center, Suita, Japan.
- Division of Advanced Applied Physics, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Japan.
- Department of Clinical Research, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan.
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Kishi T. Clarification of hypertension mechanisms provided by the research of central circulatory regulation. Hypertens Res 2023; 46:1908-1916. [PMID: 37277436 DOI: 10.1038/s41440-023-01335-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 06/07/2023]
Abstract
Sympathoexcitation, under the regulatory control of the brain, plays a pivotal role in the etiology of hypertension. Within the brainstem, significant structures involved in the modulation of sympathetic nerve activity include the rostral ventrolateral medulla (RVLM), caudal ventrolateral medulla (CVLM), nucleus tractus solitarius (NTS), and paraventricular nucleus (paraventricular). The RVLM, in particular, is recognized as the vasomotor center. Over the past five decades, fundamental investigations on central circulatory regulation have underscored the involvement of nitric oxide (NO), oxidative stress, the renin-angiotensin system, and brain inflammation in regulating the sympathetic nervous system. Notably, numerous significant findings have come to light through chronic experiments conducted in conscious subjects employing radio-telemetry systems, gene transfer techniques, and knockout methodologies. Our research has centered on elucidating the role of NO and angiotensin II type 1 (AT1) receptor-induced oxidative stress within the RVLM and NTS in regulating the sympathetic nervous system. Additionally, we have observed that various orally administered AT1 receptor blockers effectively induce sympathoinhibition by reducing oxidative stress via blockade of the AT1 receptor in the RVLM of hypertensive rats. Recent advances have witnessed the development of several clinical interventions targeting brain mechanisms. Nonetheless, Future and further basic and clinical research are needed.
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Affiliation(s)
- Takuya Kishi
- Department of Graduate School of Medicine (Cardiology), International University of Health and Welfare, Okawa, Japan.
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Chao YM, Rauchová H, Chan JYH. Disparate Roles of Oxidative Stress in Rostral Ventrolateral Medulla in Age-Dependent Susceptibility to Hypertension Induced by Systemic l-NAME Treatment in Rats. Biomedicines 2022; 10:biomedicines10092232. [PMID: 36140333 PMCID: PMC9496567 DOI: 10.3390/biomedicines10092232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/03/2022] [Accepted: 09/06/2022] [Indexed: 12/12/2022] Open
Abstract
This study aims to investigate whether tissue oxidative stress in the rostral ventrolateral medulla (RVLM), where sympathetic premotor neurons reside, plays an active role in age-dependent susceptibility to hypertension in response to nitric oxide (NO) deficiency induced by systemic l-NAME treatment, and to decipher the underlying molecular mechanisms. Systolic blood pressure (SBP) and heart rate (HR) in conscious rats were recorded, along with measurements of plasma and RVLM level of NO and reactive oxygen species (ROS), and expression of mRNA and protein involved in ROS production and clearance, in both young and adult rats subjected to intraperitoneal (i.p.) infusion of l-NAME. Pharmacological treatments were administered by oral gavage or intracisternal infusion. Gene silencing of target mRNA was made by bilateral microinjection into RVLM of lentivirus that encodes a short hairpin RNA (shRNA) to knock down gene expression of NADPH oxidase activator 1 (Noxa1). We found that i.p. infusion of l-NAME resulted in increases in SBP, sympathetic neurogenic vasomotor activity, and plasma norepinephrine levels in an age-dependent manner. Systemic l-NAME also evoked oxidative stress in RVLM of adult, but not young rats, accompanied by augmented enzyme activity of NADPH oxidase and reduced mitochondrial electron transport enzyme activities. Treatment with L-arginine via oral gavage or infusion into the cistern magna (i.c.), but not i.c. tempol or mitoQ10, significantly offset the l-NAME-induced hypertension in young rats. On the other hand, all treatments appreciably reduced l-NAME-induced hypertension in adult rats. The mRNA microarray analysis revealed that four genes involved in ROS production and clearance were differentially expressed in RVLM in an age-related manner. Of them, Noxa1, and GPx2 were upregulated and Duox2 and Ucp3 were downregulated. Systemic l-NAME treatment caused greater upregulation of Noxa1, but not Ucp3, mRNA expression in RVLM of adult rats. Gene silencing of Noxa1 in RVLM effectively alleviated oxidative stress and protected adult rats against l-NAME-induced hypertension. These data together suggest that hypertension induced by systemic l-NAME treatment in young rats is mediated primarily by NO deficiency that occurs both in vascular smooth muscle cells and RVLM. On the other hand, enhanced augmentation of oxidative stress in RVLM may contribute to the heightened susceptibility of adult rats to hypertension induced by systemic l-NAME treatment.
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Affiliation(s)
- Yung-Mei Chao
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan
| | - Hana Rauchová
- Institute of Physiology, Czech Academy of Sciences, 14200 Prague, Czech Republic
| | - Julie Y. H. Chan
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan
- Correspondence: ; Tel.: +886-77338415
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Renal denervation based on experimental rationale. Hypertens Res 2021; 44:1385-1394. [PMID: 34518650 PMCID: PMC9577563 DOI: 10.1038/s41440-021-00746-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/03/2021] [Accepted: 08/16/2021] [Indexed: 02/07/2023]
Abstract
Excessive activation of the sympathetic nervous system is one of the pathophysiological hallmarks of hypertension and heart failure. Within the central nervous system, the paraventricular nucleus (PVN) of the hypothalamus and the rostral ventrolateral medulla in the brain stem play critical roles in the regulation of sympathetic outflow to peripheral organs. Information from the peripheral circulation, including serum concentrations of sodium and angiotensin II, is conveyed to the PVN via adjacent structures with a weak blood-brain barrier. In addition, signals from baroreceptors, chemoreceptors and cardiopulmonary receptors as well as afferent input via the renal nerves are all integrated at the level of the PVN. The brain renin-angiotensin system and the balance between nitric oxide and reactive oxygen species in these brain areas also determine the final sympathetic outflow. Additionally, brain inflammatory responses have been shown to modulate these processes. Renal denervation interrupts both the afferent inputs from the kidney to the PVN and the efferent outputs from the PVN to the kidney, resulting in the suppression of sympathetic outflow and eliciting beneficial effects on both hypertension and heart failure.
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da Silva GM, da Silva MC, Nascimento DVG, Lima Silva EM, Gouvêa FFF, de França Lopes LG, Araújo AV, Ferraz Pereira KN, de Queiroz TM. Nitric Oxide as a Central Molecule in Hypertension: Focus on the Vasorelaxant Activity of New Nitric Oxide Donors. BIOLOGY 2021; 10:biology10101041. [PMID: 34681140 PMCID: PMC8533285 DOI: 10.3390/biology10101041] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/08/2021] [Accepted: 10/09/2021] [Indexed: 12/15/2022]
Abstract
Cardiovascular diseases include all types of disorders related to the heart or blood vessels. High blood pressure is an important risk factor for cardiac complications and pathological disorders. An increase in circulating angiotensin-II is a potent stimulus for the expression of reactive oxygen species and pro-inflammatory cytokines that activate oxidative stress, perpetuating a deleterious effect in hypertension. Studies demonstrate the capacity of NO to prevent platelet or leukocyte activation and adhesion and inhibition of proliferation, as well as to modulate inflammatory or anti-inflammatory reactions and migration of vascular smooth muscle cells. However, in conditions of low availability of NO, such as during hypertension, these processes are impaired. Currently, there is great interest in the development of compounds capable of releasing NO in a modulated and stable way. Accordingly, compounds containing metal ions coupled to NO are being investigated and are widely recognized as having great relevance in the treatment of different diseases. Therefore, the exogenous administration of NO is an attractive and pharmacological alternative in the study and treatment of hypertension. The present review summarizes the role of nitric oxide in hypertension, focusing on the role of new NO donors, particularly the metal-based drugs and their protagonist activity in vascular function.
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Affiliation(s)
- Gabriela Maria da Silva
- Laboratory of Nutrition, Physical Activity and Phenotypic Plasticity, Federal University of Pernambuco, Vitória de Santo Antão 55.608-680, PE, Brazil; (G.M.d.S.); (M.C.d.S.); (D.V.G.N.); (E.M.L.S.); (A.V.A.); (K.N.F.P.)
| | - Mirelly Cunha da Silva
- Laboratory of Nutrition, Physical Activity and Phenotypic Plasticity, Federal University of Pernambuco, Vitória de Santo Antão 55.608-680, PE, Brazil; (G.M.d.S.); (M.C.d.S.); (D.V.G.N.); (E.M.L.S.); (A.V.A.); (K.N.F.P.)
| | - Déborah Victória Gomes Nascimento
- Laboratory of Nutrition, Physical Activity and Phenotypic Plasticity, Federal University of Pernambuco, Vitória de Santo Antão 55.608-680, PE, Brazil; (G.M.d.S.); (M.C.d.S.); (D.V.G.N.); (E.M.L.S.); (A.V.A.); (K.N.F.P.)
| | - Ellen Mayara Lima Silva
- Laboratory of Nutrition, Physical Activity and Phenotypic Plasticity, Federal University of Pernambuco, Vitória de Santo Antão 55.608-680, PE, Brazil; (G.M.d.S.); (M.C.d.S.); (D.V.G.N.); (E.M.L.S.); (A.V.A.); (K.N.F.P.)
| | - Fabíola Furtado Fialho Gouvêa
- School of Technical Health, Health Sciences Center, Federal University of Paraíba, João Pessoa 58.051-900, PB, Brazil;
| | - Luiz Gonzaga de França Lopes
- Laboratory of Bioinorganic Chemistry, Department of Organic and Inorganic Chemistry, Federal University of Ceará, Fortaleza 60.020-181, CE, Brazil;
| | - Alice Valença Araújo
- Laboratory of Nutrition, Physical Activity and Phenotypic Plasticity, Federal University of Pernambuco, Vitória de Santo Antão 55.608-680, PE, Brazil; (G.M.d.S.); (M.C.d.S.); (D.V.G.N.); (E.M.L.S.); (A.V.A.); (K.N.F.P.)
| | - Kelli Nogueira Ferraz Pereira
- Laboratory of Nutrition, Physical Activity and Phenotypic Plasticity, Federal University of Pernambuco, Vitória de Santo Antão 55.608-680, PE, Brazil; (G.M.d.S.); (M.C.d.S.); (D.V.G.N.); (E.M.L.S.); (A.V.A.); (K.N.F.P.)
| | - Thyago Moreira de Queiroz
- Laboratory of Nutrition, Physical Activity and Phenotypic Plasticity, Federal University of Pernambuco, Vitória de Santo Antão 55.608-680, PE, Brazil; (G.M.d.S.); (M.C.d.S.); (D.V.G.N.); (E.M.L.S.); (A.V.A.); (K.N.F.P.)
- Correspondence:
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7
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Hirooka Y. Sympathetic Activation in Hypertension: Importance of the Central Nervous System. Am J Hypertens 2020; 33:914-926. [PMID: 32374869 DOI: 10.1093/ajh/hpaa074] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 04/18/2020] [Accepted: 05/01/2020] [Indexed: 12/20/2022] Open
Abstract
The sympathetic nervous system plays a critical role in the pathogenesis of hypertension. The central nervous system (CNS) organizes the sympathetic outflow and various inputs from the periphery. The brain renin-angiotensin system has been studied in various regions involved in controlling sympathetic outflow. Recent progress in cardiovascular research, particularly in vascular biology and neuroscience, as well as in traditional physiological approaches, has advanced the field of the neural control of hypertension in which the CNS plays a vital role. Cardiovascular research relating to hypertension has focused on the roles of nitric oxide, oxidative stress, inflammation, and immunity, and the network among various organs, including the heart, kidney, spleen, gut, and vasculature. The CNS mechanisms are similarly networked with these factors and are widely studied in neuroscience. In this review, I describe the development of the conceptual flow of this network in the field of hypertension on the basis of several important original research articles and discuss potential future breakthroughs leading to clinical precision medicine.
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Affiliation(s)
- Yoshitaka Hirooka
- Department of Medical Technology and Sciences, School of Health Sciences at Fukuoka, International University of Health and Welfare, Okawa City, Fukuoka, Japan
- Department of Cardiovascular Medicine, Hypertension and Heart Failure Center, Takagi Hospital, Okawa City, Fukuoka, Japan
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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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Impaired l-arginine-nitric oxide pathway contributes to the pathogenesis of resistant hypertension. Clin Sci (Lond) 2020; 133:2061-2067. [PMID: 31654065 DOI: 10.1042/cs20190851] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 08/22/2019] [Accepted: 09/16/2019] [Indexed: 01/13/2023]
Abstract
The precise mechanisms underlying resistant hypertension remain elusive. Reduced nitric oxide (NO) bioavailability is frequently documented in chronic kidney disease, obesity, diabetes and advanced age, all of which are risk factors for resistant hypertension. Sympathetic overactivity and chronic activation of the renin-angiotensin system are salient features of resistant hypertension. Interestingly, recent data indicate that renal sympathetic overactivity can reduce the expression of neuronal nitric oxide synthase in the paraventricular nucleus. Reduced NO levels in the paraventricular nucleus can increase sympathetic outflow and this can create a vicious cycle contributing to resistant hypertension. Angiotensin II can reduce l-arginine transport and hence NO production. Reduced NO levels may reduce the formation of angiotensin 1-7 dampening the cardio-protective effects of the renin-angiotensin system contributing to resistant hypertension. In addition, interleukin-6 (IL-6) is demonstrated to be independently associated with resistant hypertension, and IL-6 can reduce NO synthesis. Despite this, NO levels have not been quantified in resistant hypertension. Findings from a small proof of concept study indicate that NO donors can reduce blood pressure in patients with resistant hypertension but more studies are required to validate these preliminary findings. In the present paper, we put forward the hypothesis that reduced NO bioavailability contributes substantially to the development of resistant hypertension.
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Raven PB, Young BE, Fadel PJ. Arterial Baroreflex Resetting During Exercise in Humans: Underlying Signaling Mechanisms. Exerc Sport Sci Rev 2020; 47:129-141. [PMID: 30921029 DOI: 10.1249/jes.0000000000000190] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The arterial baroreflex (ABR) resets during exercise in an intensity-dependent manner to operate around a higher blood pressure with maintained sensitivity. This review provides a historical perspective of ABR resetting and the involvement of other neural reflexes in mediating exercise resetting. Furthermore, we discuss potential underlying signaling mechanisms that may contribute to exercise ABR resetting in physiological and pathophysiological conditions.
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Affiliation(s)
- Peter B Raven
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth
| | - Benjamin E Young
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX
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12
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Sodium Valproate Improves Skin Flap Survival via Gamma-Aminobutyric Acid and Histone Deacetylase Inhibitory System. J Surg Res 2020; 246:519-526. [DOI: 10.1016/j.jss.2019.09.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 07/23/2019] [Accepted: 09/18/2019] [Indexed: 11/15/2022]
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13
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Lee DE, Jung TH, Jo YN, Yun SS, Han KS. Enzymatic Hydrolysis of Egg White Protein Exerts a Hypotensive Effect in Spontaneously Hypertensive Rats. Food Sci Anim Resour 2019; 39:980-987. [PMID: 31950113 PMCID: PMC6949517 DOI: 10.5851/kosfa.2019.e91] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 12/12/2022] Open
Abstract
This study was conducted to investigate the hypotensive effect of egg white
protein (EWP) hydrolysate (EWH) in spontaneously hypertensive rats (SHRs). The
hydrolysis of EWP was effectively performed with a combination of 0.5% bromelain
and 1% papain at 50°C for 60 min. The resulting hydrolysate did not
elicit an allergic reaction as confirmed by human mast cell activation test. The
systolic and diastolic blood pressures of the SHRs fed the EWH diet were
observed to be significantly or numerically lower than those of the other groups
during the experimental period of 28 d. EWH treatment significantly
(p<0.05) upregulated the nitric oxide levels in hCMEC/D3 cells and the
plasma of the SHRs compared to those in the control. Moreover, EWH ingestion
significantly (p<0.01) reduced the plasma angiotensin II level of the
SHRs compared with that in the control. In conclusion, beyond its basic
nutritional value, EWH prevents and manages hypertension, and thus can be an
invaluable resource for functional food development.
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Affiliation(s)
- Da-Eon Lee
- Department of Food and Biotechnology, Sahmyook University, Seoul 01795, Korea
| | - Tae-Hwan Jung
- Convergence Research Center, Sahmyook University, Seoul 01795, Korea
| | - Yu-Na Jo
- Department of Food and Biotechnology, Sahmyook University, Seoul 01795, Korea
| | - Sung-Seob Yun
- R&D Department, Bioprofoods Co. Ltd., Seoul 01795, Korea
| | - Kyoung-Sik Han
- Department of Food and Biotechnology, Sahmyook University, Seoul 01795, Korea.,Convergence Research Center, Sahmyook University, Seoul 01795, Korea
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14
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Kobuch S, Macefield VG, Henderson LA. Resting regional brain activity and connectivity vary with resting blood pressure but not muscle sympathetic nerve activity in normotensive humans: An exploratory study. J Cereb Blood Flow Metab 2019; 39:2433-2444. [PMID: 30182800 PMCID: PMC6893974 DOI: 10.1177/0271678x18798442] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Blood pressure is tightly controlled by the central nervous system, particularly the brainstem. The aim of this study was to investigate the relationship between mean blood pressure (MBP), muscle sympathetic nerve activity (MSNA) and resting regional brain activity in healthy human subjects. Pseudocontinuous arterial spin labeling and functional magnetic resonance imaging of the brain were performed immediately following a laboratory microneurography recording of MSNA and BP measurement in 31 young, healthy normotensive subjects. Regional cerebral blood flow (CBF) correlated significantly with resting MBP levels in the region encompassing the rostroventrolateral medulla (RVLM), dorsolateral pons, and insular, prefrontal and cingulate cortices. Functional connectivity analysis revealed that the ventrolateral prefrontal cortex displayed greater resting connectivity strength within the RVLM in the lower compared with the higher MBP group. No significant differences in CBF were found when subjects were divided based on their MSNA levels. These results suggest that even subtle differences in resting MBP are associated with significant differences in resting activity in brain regions, which are well known to play a role in cardiovascular function. These data raise the question of the potential long-term consequences of differences in regional brain activity levels and their relationship with systemic blood pressure.
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Affiliation(s)
- Sophie Kobuch
- School of Medicine, Western Sydney University, Sydney, Australia
| | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, Australia.,Neuroscience Research Australia, Sydney, Australia.,Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Luke A Henderson
- Department of Anatomy and Histology, University of Sydney, Sydney, Australia
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15
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Chan JYH, Chan SHH. Differential impacts of brain stem oxidative stress and nitrosative stress on sympathetic vasomotor tone. Pharmacol Ther 2019; 201:120-136. [PMID: 31153955 DOI: 10.1016/j.pharmthera.2019.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 05/24/2019] [Indexed: 02/07/2023]
Abstract
Based on work-done in the rostral ventrolateral medulla (RVLM), this review presents four lessons learnt from studying the differential impacts of oxidative stress and nitrosative stress on sympathetic vasomotor tone and their clinical and therapeutic implications. The first lesson is that an increase in sympathetic vasomotor tone because of augmented oxidative stress in the RVLM is responsible for the generation of neurogenic hypertension. On the other hand, a shift from oxidative stress to nitrosative stress in the RVLM underpins the succession of increase to decrease in sympathetic vasomotor tone during the progression towards brain stem death. The second lesson is that, by having different cellular sources, regulatory mechanisms on synthesis and degradation, kinetics of chemical reactions, and downstream signaling pathways, reactive oxygen species and reactive nitrogen species should not be regarded as a singular moiety. The third lesson is that well-defined differential roles of oxidative stress and nitrosative stress with distinct regulatory mechanisms in the RVLM during neurogenic hypertension and brain stem death clearly denote that they are not interchangeable phenomena with unified cellular actions. Special attention must be paid to their beneficial or detrimental roles under a specific disease or a particular time-window of that disease. The fourth lesson is that, to be successful, future antioxidant therapies against neurogenic hypertension must take into consideration the much more complicated picture than that presented in this review on the generation, maintenance, regulation or modulation of the sympathetic vasomotor tone. The identification that the progression towards brain stem death entails a shift from oxidative stress to nitrosative stress in the RVLM may open a new vista for therapeutic intervention to slow down this transition.
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Affiliation(s)
- Julie Y H Chan
- Institute for Translational Research in Biomedicine, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China
| | - Samuel H H Chan
- Institute for Translational Research in Biomedicine, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China.
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16
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Lin HH, Cheng TT, Lo H, Lin YC, Lai CC. Spontaneously hypertensive rats exhibit higher sensitivity to ethanol-induced hypotensive effects: Role of NMDA receptors and nitric oxide in rostral ventrolateral medulla. Alcohol 2018; 73:25-35. [PMID: 30248576 DOI: 10.1016/j.alcohol.2018.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 11/30/2022]
Abstract
Intake of ethanol (alcohol) affects cardiovascular function. Acute ethanol intake has been shown to lower blood pressure (BP) in hypertensive patients. The present study was undertaken to examine the effects and mechanisms of acute administration of ethanol on BP in hypertensive and normotensive rats. Ethanol was given by intraperitoneal (i.p.) injection in male spontaneously hypertensive rats (SHRs) and the normotensive Wistar-Kyoto rats (WKYs). BP responses were measured in free-moving conscious rats or in urethane-anesthetized rats. Inhibitors were applied by bilateral microinjection into the rostral ventrolateral medulla (RVLM). Nitric oxide (NO•) levels and glutamate levels were determined by nitrate and nitrite (NOx) analyzer and HPLC-ECD, respectively. Intraperitoneal (i.p.) injection of ethanol (1.6 g/kg) caused a significant decrease in BP in free-moving or in anesthetized SHRs but not in WKYs. A higher dose (3.2 g/kg) of ethanol decreased BP in both SHRs and WKYs, although the depressor responses in SHRs occurred significantly earlier than those in WKYs. The blood ethanol concentrations 60 min after injection were similar in SHRs and WKYs. Bilateral microinjection of nitric oxide synthase (NOS) inhibitors or glutamatergic NMDA receptor antagonists into the RVLM 5 min after administration of ethanol significantly inhibited the ethanol-induced depressor effects in SHRs. The levels of NOx and glutamate release in the RVLM following ethanol administration and the NOx content in the RVLM areas 30 min after administration were significantly increased in SHRs, but not in WKYs. Our results showed that SHRs were more sensitive to ethanol-induced hypotensive effects than WKYs because of augmentation of ethanol-induced expression of the glutamatergic NMDA receptor/NO• signal in the RVLM of SHRs.
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Affiliation(s)
- Hsun-Hsun Lin
- Department of Physiology, School of Medicine, Tzu Chi University, Hualien 970, Taiwan
| | - Tz-Ting Cheng
- Master and Ph.D. Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien 970, Taiwan
| | - Hsuan Lo
- Master and Ph.D. Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien 970, Taiwan
| | - Yen-Chang Lin
- Master and Ph.D. Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien 970, Taiwan
| | - Chih-Chia Lai
- Master and Ph.D. Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien 970, Taiwan; Department of Pharmacology, School of Medicine, Tzu Chi University, Hualien 970, Taiwan.
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17
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Lo H, Lin HH, Chen JK, Situmorang JH, Lai CC. Involvement of NMDA Receptors, Nitric Oxide, and GABA in Rostral Ventrolateral Medulla in Acute Ethanol-Induced Cardiovascular Responses in Rats. Alcohol Clin Exp Res 2018; 42:1418-1430. [PMID: 29846938 DOI: 10.1111/acer.13800] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 05/22/2018] [Indexed: 12/23/2022]
Abstract
BACKGROUND Consumption of ethanol (EtOH) (alcohol) has many effects on physiological functions, particularly those in the central nervous system (CNS) and cardiovascular system. Acute excessive intake of EtOH (alcohol intoxication) may cause hypotension and tachycardia. In this study, we examined the mechanistic involvement of glutamatergic N-methyl-d-aspartate (NMDA) receptors, nitric oxide (NO), and γ-aminobutyric acid (GABA) pathways in the CNS in acute EtOH-induced cardiovascular effects. METHODS EtOH was administered by intraperitoneal (IP) injection in Sprague-Dawley rats. The blood pressure (BP) and heart rate (HR) were measured in conscious and in urethane-anesthetized rats. Inhibitors were applied by intracerebroventricular (ICV) injection or by microinjection into rostral ventrolateral medulla (RVLM). Microdialysis was used to determine the level of glutamate, NO, and GABA in the RVLM. RESULTS IP injection of EtOH (3.2 g/kg) caused a significant decrease in BP in conscious and anesthetized rats and a late increase in HR in conscious rats. The cardiovascular effects of EtOH were significantly attenuated by ICV or by RVLM post treatment with ketamine (an NMDA receptor antagonist), N5-(nitroamidino)-L-2,5-diaminopentanoic acid (L-NNA; a NO synthase inhibitor), or bicuculline (a GABA receptor antagonist). EtOH caused an increase in the level of glutamate, NO, and GABA in the RVLM during the hypotensive responses. RVLM posttreatment with ketamine blocked the increase in NO and GABA levels; post treatment with L-NNA blocked the increase in GABA level. CONCLUSIONS Our results indicate that EtOH augmentation of glutamatergic NMDA receptors/NO/GABA pathways in the RVLM may participate in the hypotensive effects induced by acute administration of EtOH.
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Affiliation(s)
- Hsuan Lo
- Master and Ph.D. Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Hsun-Hsun Lin
- Department of Physiology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Jun-Kai Chen
- Master and Ph.D. Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Jiro Hasegawa Situmorang
- Master and Ph.D. Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Chih-Chia Lai
- Master and Ph.D. Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien, Taiwan
- Department of Pharmacology, School of Medicine, Tzu Chi University, Hualien, Taiwan
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18
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Haspula D, Clark MA. Molecular Basis of the Brain Renin Angiotensin System in Cardiovascular and Neurologic Disorders: Uncovering a Key Role for the Astroglial Angiotensin Type 1 Receptor AT1R. J Pharmacol Exp Ther 2018; 366:251-264. [PMID: 29752427 DOI: 10.1124/jpet.118.248831] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
The central renin angiotensin system (RAS) is one of the most widely investigated cardiovascular systems in the brain. It is implicated in a myriad of cardiovascular diseases. However, studies from the last decade have identified its involvement in several neurologic abnormalities. Understanding the molecular functionality of the various RAS components can thus provide considerable insight into the phenotypic differences and mechanistic drivers of not just cardiovascular but also neurologic disorders. Since activation of one of its primary receptors, the angiotensin type 1 receptor (AT1R), results in an augmentation of oxidative stress and inflammatory cytokines, it becomes essential to investigate not just neuronal RAS but glial RAS as well. Glial cells are key homeostatic regulators in the brain and are critical players in the resolution of overt oxidative stress and neuroinflammation. Designing better and effective therapeutic strategies that target the brain RAS could well hinge on understanding the molecular basis of both neuronal and glial RAS. This review provides a comprehensive overview of the major studies that have investigated the mechanisms and regulation of the brain RAS, and it also provides insight into the potential role of glial AT1Rs in the pathophysiology of cardiovascular and neurologic disorders.
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Affiliation(s)
- Dhanush Haspula
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin (D.H.); and College of Pharmacy, Department of Pharmaceutical Sciences, Nova Southeastern University, Ft. Lauderdale, Florida (M.A.C.)
| | - Michelle A Clark
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin (D.H.); and College of Pharmacy, Department of Pharmaceutical Sciences, Nova Southeastern University, Ft. Lauderdale, Florida (M.A.C.)
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19
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Haspula D, Clark MA. Neuroinflammation and sympathetic overactivity: Mechanisms and implications in hypertension. Auton Neurosci 2018; 210:10-17. [DOI: 10.1016/j.autneu.2018.01.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 01/02/2018] [Accepted: 01/08/2018] [Indexed: 02/07/2023]
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20
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Kaur J, Young BE, Fadel PJ. Sympathetic Overactivity in Chronic Kidney Disease: Consequences and Mechanisms. Int J Mol Sci 2017; 18:ijms18081682. [PMID: 28767097 PMCID: PMC5578072 DOI: 10.3390/ijms18081682] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 07/20/2017] [Accepted: 07/28/2017] [Indexed: 12/19/2022] Open
Abstract
The incidence of chronic kidney disease (CKD) is increasing worldwide, with more than 26 million people suffering from CKD in the United States alone. More patients with CKD die of cardiovascular complications than progress to dialysis. Over 80% of CKD patients have hypertension, which is associated with increased risk of cardiovascular morbidity and mortality. Another common, perhaps underappreciated, feature of CKD is an overactive sympathetic nervous system. This elevation in sympathetic nerve activity (SNA) not only contributes to hypertension but also plays a detrimental role in the progression of CKD independent of any increase in blood pressure. Indeed, high SNA is associated with poor prognosis and increased cardiovascular morbidity and mortality independent of its effect on blood pressure. This brief review will discuss some of the consequences of sympathetic overactivity and highlight some of the potential pathways contributing to chronically elevated SNA in CKD. Mechanisms leading to chronic sympathoexcitation in CKD are complex, multifactorial and to date, not completely understood. Identification of the mechanisms and/or signals leading to sympathetic overactivity in CKD are crucial for development of effective therapeutic targets to reduce the increased cardiovascular risk in this patient group.
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Affiliation(s)
- Jasdeep Kaur
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX 76019, USA.
| | - Benjamin E Young
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX 76019, USA.
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX 76019, USA.
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21
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Légat L, Brouwers S, Smolders IJ, Dupont AG. Hypotensive Response to Angiotensin II Type 2 Receptor Stimulation in the Rostral Ventrolateral Medulla Requires Functional GABA-A Receptors. Front Neurosci 2017; 11:346. [PMID: 28674483 PMCID: PMC5474467 DOI: 10.3389/fnins.2017.00346] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 06/02/2017] [Indexed: 11/16/2022] Open
Abstract
Objectives: Angiotensin II, glutamate and gamma-aminobutyric acid (GABA) interact within the rostral ventrolateral medulla (RVLM) and the paraventricular nucleus (PVN) modulating the central regulation of blood pressure and sympathetic tone. Our aim was to assess the effects of local angiotensin II type 2 receptor stimulation within the RVLM and the PVN on neurotransmitter concentrations and mean arterial pressure (MAP). Methods:In vivo microdialysis was used for measurement of extracellular glutamate and GABA levels and for local infusion of the angiotensin II type 2 receptor agonist Compound 21 in the RVLM and the PVN of conscious normotensive Wistar rats. The MAP response to local Compound 21 was monitored with a pressure transducer under anaesthesia. Angiotensin II type 2 receptor selectivity was assessed using the angiotensin II type 2 receptor antagonist PD123319; the GABA-A receptor antagonist bicuculline was used to assess the involvement of GABA-A receptors. Results: Infusion of Compound 21 (0.05 μg/μl/h) in the RVLM significantly increased GABA levels and lowered blood pressure. These effects were abolished by co-infusion with PD123319. No changes in neurotransmitter levels or effects on blood pressure were seen with PD123319 infusion alone. Co-infusion of bicuculline abolished the Compound 21 evoked decrease in MAP. Infusion of Compound 21 within the PVN did not change extracellular neurotransmitter levels nor MAP. Conclusion: Selective stimulation of angiotensin II type 2 receptor within the RVLM by local Compound 21 infusion reduces blood pressure and increases local GABA levels in normotensive rats. This hypotensive response requires functional GABA-A receptors, suggesting that GABAergic neurons are involved in the sympatho-inhibitory action underlying this hypotensive response.
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Affiliation(s)
- Laura Légat
- Laboratory of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit BrusselBrussels, Belgium.,Cardiovascular Center, Universitair Ziekenhuis BrusselBrussels, Belgium.,Department of Clinical Pharmacology and Clinical Pharmacy, Universitair Ziekenhuis BrusselBrussels, Belgium
| | - Sofie Brouwers
- Laboratory of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit BrusselBrussels, Belgium.,Cardiovascular Center, Universitair Ziekenhuis BrusselBrussels, Belgium.,Department of Clinical Pharmacology and Clinical Pharmacy, Universitair Ziekenhuis BrusselBrussels, Belgium
| | - Ilse J Smolders
- Laboratory of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit BrusselBrussels, Belgium
| | - Alain G Dupont
- Laboratory of Pharmaceutical Chemistry, Drug Analysis and Drug Information (FASC), Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit BrusselBrussels, Belgium.,Cardiovascular Center, Universitair Ziekenhuis BrusselBrussels, Belgium.,Department of Clinical Pharmacology and Clinical Pharmacy, Universitair Ziekenhuis BrusselBrussels, Belgium
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22
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Paolocci N, Cannavo A, Chelko SP, Montano N. Burning Redoxstats in the Brainstem: Lack of Nrf2 and the Rise of Hypertension. Hypertension 2017; 69:1019-1021. [PMID: 28461602 DOI: 10.1161/hypertensionaha.117.09238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Nazareno Paolocci
- From the Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD (N.P., S.P.C.); Department of Experimental Medicine, Universita' di Perugia, Italy (N.P.); Lewis Katz School of Medicine, Temple University, Philadelphia, PA (A.C.); and Fondazione IRCSS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Italy (N.M.).
| | - Alessandro Cannavo
- From the Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD (N.P., S.P.C.); Department of Experimental Medicine, Universita' di Perugia, Italy (N.P.); Lewis Katz School of Medicine, Temple University, Philadelphia, PA (A.C.); and Fondazione IRCSS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Italy (N.M.)
| | - Stephen P Chelko
- From the Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD (N.P., S.P.C.); Department of Experimental Medicine, Universita' di Perugia, Italy (N.P.); Lewis Katz School of Medicine, Temple University, Philadelphia, PA (A.C.); and Fondazione IRCSS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Italy (N.M.)
| | - Nicola Montano
- From the Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD (N.P., S.P.C.); Department of Experimental Medicine, Universita' di Perugia, Italy (N.P.); Lewis Katz School of Medicine, Temple University, Philadelphia, PA (A.C.); and Fondazione IRCSS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, University of Milan, Italy (N.M.)
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23
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Klimentova J, Cebova M, Barta A, Matuskova Z, Vrankova S, Rehakova R, Kovacsova M, Pechanova O. Effect of melatonin on blood pressure and nitric oxide generation in rats with metabolic syndrome. Physiol Res 2017; 65:S373-S380. [PMID: 27775422 DOI: 10.33549/physiolres.933436] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Melatonin, a multitasking indolamine, seems to be involved in a variety of physiological and metabolic processes via both receptor-mediated and receptor-independent mechanisms. The aim of our study was to find out whether melatonin can affect blood pressure (BP), nitric oxide synthase (NOS) activity, eNOS and nNOS protein expressions in rats with metabolic syndrome (SHR/cp). Rats were divided into four groups: 6-week-old male WKY andSHR/cp and age-matched WKY and SHR/cp treated with melatonin (10 mg/kg/day) for 3 weeks. BP was measured by tail-cuff plethysmography. NOS activity, eNOS and nNOS protein expressions were determined in the heart, aorta, brain cortex and cerebellum. MT(1) receptors were analyzed in the brain cortex and cerebellum. In SHR/cp rats, BP was decreased after melatonin treatment. In the same group, melatonin did not affect NOS activity and eNOS protein expression in the heart and aorta, while it increased both parameters in the brain cortex and cerebellum. Interestingly, melatonin elevated MT1 protein expression in the cerebellum. Neuronal NOS protein expression was not changed within the groups. In conclusion, increased NOS activity/eNOS upregulation in particular brain regions may contribute partially to BP decrease in SHR/cp rats after melatonin treatment. Participation of MT(1) receptors in this melatonin action may be supposed.
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Affiliation(s)
- J Klimentova
- Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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24
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Puzserova A, Bernatova I. Blood pressure regulation in stress: focus on nitric oxide-dependent mechanisms. Physiol Res 2017; 65:S309-S342. [PMID: 27775419 DOI: 10.33549/physiolres.933442] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Stress is considered a risk factor associated with the development of various civilization diseases including cardiovascular diseases, malignant tumors and mental disorders. Research investigating mechanisms involved in stress-induced hypertension have attracted much attention of physicians and researchers, however, there are still ambiguous results concerning a causal relationship between stress and long-term elevation of blood pressure (BP). Several studies have observed that mechanisms involved in the development of stress-induced hypertension include increased activity of sympathetic nervous system (SNS), glucocorticoid (GC) overload and altered endothelial function including decreased nitric oxide (NO) bioavailability. Nitric oxide is well known neurotransmitter, neuromodulator and vasodilator involved in regulation of neuroendocrine mechanisms and cardiovascular responses to stressors. Thus NO plays a crucial role in the regulation of the stress systems and thereby in the BP regulation in stress. Elevated NO synthesis, especially in the initial phase of stress, may be considered a stress-limiting mechanism, facilitating the recovery from stress to the resting levels via attenuation of both GC release and SNS activity as well as by increased NO-dependent vasorelaxation. On the other hand, reduced levels of NO were observed in the later phases of stress and in subjects with genetic predisposition to hypertension, irrespectively, in which reduced NO bioavailability may account for disruption of NO-mediated BP regulatory mechanisms and accentuated SNS and GC effects. This review summarizes current knowledge on the role of stress in development of hypertension with a special focus on the interactions among NO and other biological systems affecting blood pressure and vascular function.
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Affiliation(s)
- A Puzserova
- Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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25
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Ogundele OM, Lee CC, Francis J. Age-dependent alterations to paraventricular nucleus insulin-like growth factor 1 receptor as a possible link between sympathoexcitation and inflammation. J Neurochem 2016; 139:706-721. [PMID: 27626839 DOI: 10.1111/jnc.13842] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 08/06/2016] [Accepted: 09/09/2016] [Indexed: 01/01/2023]
Abstract
Modifications to neural circuits of the paraventricular hypothalamic nucleus (PVN) have been implicated in sympathoexcitation and systemic cardiovascular dysfunction. However, to date, the role of insulin-like growth factor 1 receptor (IGF-1R) expression on PVN pathophysiology is unknown. Using confocal immunofluorescence quantification and electrophysiological recordings from acute PVN slices, we investigated the mechanism through which age-dependent IGF-1R depletion contributes to the progression of inflammation and sympathoexcitation in the PVN of spontaneously hypertensive rats (SHR). Four and twenty weeks old SHR and Wistar Kyoto (WKY) rats were used for this study. Our data showed that angiotensin I/II and pro-inflammatory high mobility box group protein 1 (HMGB1) exhibited increased expression in the PVN of SHR versus WKY at 4 weeks (p < 0.01), and were even more highly expressed with age in SHR (p < 0.001). This correlated with a significant decrease in IGF-1R expression, with age, in the PVN of SHR when compared with WKY (p < 0.001) and were accompanied by related changes in astrocytes and microglia. In subsequent analyses, we found an age-dependent change in the expression of proteins associated with IGF-1R signaling pathways involved in inflammatory responses and synaptic function in the PVN. MAPK/ErK was more highly expressed in the PVN of SHR by the fourth week (p < 0.001; vs. WKY), while expression of neuronal nitric oxide synthase (p < 0.001) and calcium-calmodulin-dependent kinase II alpha (CamKIIα; p < 0.001) were significantly decreased by the 4th and 20th week, respectively. Age-dependent changes in MAPK/ErK expression in the PVN correlated with an increase in the expression of vesicular glutamate transporter (p < 0.001 vs. WKY), while decreased levels of CamKIIα was associated with a decreased expression of tyrosine hydroxylase (p < 0.001) by the 20th week. In addition, reduced labeling for ϒ-aminobutyric acid in the PVN of SHR (p < 0.001) correlated with a decrease in neuronal nitric oxide synthase labeling (p < 0.001) when compared with the WKY by the 20th week. Electrophysiological recordings from neurons in acute slice preparations of the PVN of 4 weeks old SHR revealed spontaneous post-synaptic currents of higher frequency when compared with neurons from WKY PNV slices of the same age (p < 0.001; n = 14 cells). This also correlated with an increase in PSD-95 in the PVN of SHR when compared with the WKY (p < 0.001). Overall, we found an age-dependent reduction of IGF-1R, and related altered expression of associated downstream signaling molecules that may represent a link between the concurrent progression of synaptic dysfunction and inflammation in the PVN of SHR.
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Affiliation(s)
- Olalekan M Ogundele
- Department of Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana, USA
| | - Charles C Lee
- Department of Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana, USA
| | - Joseph Francis
- Department of Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana, USA
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Nishihara M, Takesue K, Hirooka Y. Renal denervation enhances GABA-ergic input into the PVN leading to blood pressure lowering in chronic kidney disease. Auton Neurosci 2016; 204:88-97. [PMID: 27729205 DOI: 10.1016/j.autneu.2016.09.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 08/30/2016] [Accepted: 09/30/2016] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Sympathoexcitation plays an important role in the pathogenesis of hypertension in patients with chronic kidney disease (CKD). The paraventricular nucleus of the hypothalamus (PVN) in the brain controls sympathetic outflow through γ-amino butyric acid (GABA)-ergic mechanisms. Renal denervation (RDN) exerts a long-term antihypertensive effect in hypertension with CKD; however, the effects of RDN on sympathetic nerve activity and GABA-ergic modulation in the PVN are not clear. We aimed to elucidate whether RDN modulates sympathetic outflow through GABA-ergic mechanisms in the PVN in hypertensive mice with CKD. METHODS AND RESULTS In 5/6-nephrectomized male Institute of Cancer Research mice (Nx) at 4 weeks after nephrectomy, systolic blood pressure (SBP) was significantly increased, accompanied by sympathoexcitation. The Nx-mice underwent RDN or sham operation, and the mice were divided into three groups (Control, Nx-Sham, and Nx-RDN). At 2 weeks after RDN, SBP was significantly decreased and urinary sodium excretion was increased in Nx-RDN compared with Nx-Sham. Urinary norepinephrine excretion (uNE) levels did not differ significantly between Nx-RDN and Nx-Sham. At 6 weeks after RDN, SBP continued to decrease and uNE levels also decreased in Nx-RDN compared with Nx-Sham. Bicuculline microinjection into the PVN increased mean arterial pressure and lumbar sympathetic nerve activity in all groups. The pressor responses and change in lumbar sympathetic nerve activity were significantly attenuated in Nx-Sham, but were enhanced in Nx-RDN at 6 weeks after RDN. CONCLUSIONS The findings from the present study indicate that RDN has a prolonged antihypertensive effect and, at least in the late phase, decreases sympathetic nerve activity in association with enhanced GABA-ergic input into the PVN in mice with CKD.
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Affiliation(s)
- Masaaki Nishihara
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Ko Takesue
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Yoshitaka Hirooka
- Department of Advanced Cardiovascular Regulation and Therapeutics for Cardiovascular Diseases, Kyushu University Center for Disruptive Cardiovascular Medicine, Fukuoka, Japan.
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Machado NL, Silva FC, Chianca DA, de Menezes RC. Nitric oxide modulates blood pressure through NMDA receptors in the rostral ventrolateral medulla of conscious rats. Brain Res 2016; 1643:159-67. [DOI: 10.1016/j.brainres.2016.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 04/26/2016] [Accepted: 05/01/2016] [Indexed: 02/06/2023]
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Rajapakse NW, Head GA, Kaye DM. Say NO to Obesity-Related Hypertension: Role of the L-Arginine-Nitric Oxide Pathway. Hypertension 2016; 67:813-9. [PMID: 27021014 DOI: 10.1161/hypertensionaha.116.06778] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Niwanthi W Rajapakse
- From the Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia (N.W.R., G.A.H., D.M.K.); Department of Medicine, Monash University, Melbourne, VIC, Australia (D.M.K.); and Department of Physiology, Monash University, Melbourne, VIC, Australia (N.W.R.).
| | - Geoffrey A Head
- From the Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia (N.W.R., G.A.H., D.M.K.); Department of Medicine, Monash University, Melbourne, VIC, Australia (D.M.K.); and Department of Physiology, Monash University, Melbourne, VIC, Australia (N.W.R.)
| | - David M Kaye
- From the Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia (N.W.R., G.A.H., D.M.K.); Department of Medicine, Monash University, Melbourne, VIC, Australia (D.M.K.); and Department of Physiology, Monash University, Melbourne, VIC, Australia (N.W.R.)
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29
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Cavalcanti CDO, Alves RR, de Oliveira AL, Cruz JDC, de França-Silva MDS, Braga VDA, Balarini CDM. Inhibition of PDE5 Restores Depressed Baroreflex Sensitivity in Renovascular Hypertensive Rats. Front Physiol 2016; 7:15. [PMID: 26858657 PMCID: PMC4729906 DOI: 10.3389/fphys.2016.00015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 01/11/2016] [Indexed: 01/05/2023] Open
Abstract
Renal artery stenosis is frequently associated with resistant hypertension, which is defined as failure to normalize blood pressure (BP) even when combined drugs are used. Inhibition of PDE5 by sildenafil has been shown to increase endothelial function and decrease blood pressure in experimental models. However, no available study evaluated the baroreflex sensitivity nor autonomic balance in renovascular hypertensive rats treated with sildenafil. In a translational medicine perspective, our hypothesis is that sildenafil could improve autonomic imbalance and baroreflex sensitivity, contributing to lower blood pressure. Renovascular hypertensive 2-kidney-1-clip (2K1C) and sham rats were treated with sildenafil (45 mg/Kg/day) during 7 days. At the end of treatment, BP and heart rate (HR) were recorded in conscious rats after a 24-h-recovery period. Spontaneous and drug-induced baroreflex sensitivity and autonomic tone were evaluated; in addition, lipid peroxidation was measured in plasma samples. Treatment was efficient in increasing both spontaneous and induced baroreflex sensitivity in treated hypertensive animals. Inhibition of PDE5 was also capable of ameliorating autonomic imbalance in 2K1C rats and decreasing systemic oxidative stress. Taken together, these beneficial effects resulted in significant reductions in BP without affecting HR. We suggest that sildenafil could be considered as a promising alternative to treat resistant hypertension.
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Affiliation(s)
| | - Rafael R Alves
- Centro de Ciências Médicas, Universidade Federal da ParaíbaJoao Pessoa, Brazil; Centro de Ciências da Saúde, Universidade Federal da ParaíbaJoao Pessoa, Brazil
| | - Alessandro L de Oliveira
- Centro de Ciências Médicas, Universidade Federal da ParaíbaJoao Pessoa, Brazil; Centro de Ciências da Saúde, Universidade Federal da ParaíbaJoao Pessoa, Brazil
| | | | | | | | - Camille de Moura Balarini
- Centro de Biotecnologia, Universidade Federal da ParaíbaJoao Pessoa, Brazil; Centro de Ciências da Saúde, Universidade Federal da ParaíbaJoao Pessoa, Brazil
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Xu B, Li H. Brain mechanisms of sympathetic activation in heart failure: Roles of the renin‑angiotensin system, nitric oxide and pro‑inflammatory cytokines (Review). Mol Med Rep 2015; 12:7823-9. [PMID: 26499491 PMCID: PMC4758277 DOI: 10.3892/mmr.2015.4434] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 09/10/2015] [Indexed: 12/14/2022] Open
Abstract
Patients with chronic heart failure (CHF) have an insufficient perfusion to the peripheral tissues due to decreased cardiac output. The compensatory mechanisms are triggered even prior to the occurrence of clinical symptoms, which include activation of the sympathetic nervous system (SNS) and other neurohumoral factors. However, the long‑term activation of the SNS contributes to progressive cardiac dysfunction and has toxic effects on the cardiomyocytes. The mechanisms leading to the activation of SNS include changes in peripheral baroreceptor and chemoreceptor reflexes and the abnormal regulation of sympathetic nerve activity (SNA) in the central nervous system (CNS). Recent studies have focused on the role of brain mechanisms in the regulation of SNA and the progression of CHF. The renin‑angiotensin system, nitric oxide and pro‑inflammatory cytokines were shown to be involved in the abnormal regulation of SNA in the CNS. The alteration of these neurohumoral factors during CHF influences the activity of neurons in the autonomic regions and finally increase the sympathetic outflow. The present review summarizes the brain mechanisms contributing to sympathoexcitation in CHF.
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Affiliation(s)
- Bin Xu
- Department of Cardiology, Shanghai First People's Hospital, College of Medicine, Shanghai Jiaotong University, Shanghai 200080, P.R. China
| | - Hongli Li
- Department of Cardiology, Shanghai First People's Hospital, College of Medicine, Shanghai Jiaotong University, Shanghai 200080, P.R. China
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31
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Chertok VM, Kotsyuba AE, Kotsyuba EP, Startseva MS. Two pools of interneurons in the bulbar region of the cardiovascular center of rats. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2015; 463:178-82. [PMID: 26335965 DOI: 10.1134/s0012496615040079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Indexed: 11/23/2022]
Abstract
Wistar rats were subjected to renovascular hypertension. Then, we studied two pools of neurons: intranuclear neurons located in projection area of the solitary tract nucleus and reticular, magnocellular, and parvicellular nuclei; and two groups of internuclear neurons, which included both small neurons 50-300 µm(2) in size and large neurons more than 350 µm(2) in size. Immunohistochemical methods with antisera against neuronal nitric oxide synthase, cystathionine-β-synthase, and heme oxygenase-2 were used. The studies were performed 8, 16, and 24 weeks after the development of renovascular hypertension. We have found that at least two pools of interneurons, intra- and internuclear cells, may be involved in the mechanisms of regulation of hemodynamics. These pools of interneurons differ in some topochemical and functional features, including different resistances to an increased blood pressure.
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Affiliation(s)
- V M Chertok
- Pacific State Medical University, Vladivostok, Russia,
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32
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Sousa LE, Magalhães WG, Bezerra FS, Santos RAS, Campagnole-Santos MJ, Isoldi MC, Alzamora AC. Exercise training restores oxidative stress and nitric oxide synthases in the rostral ventrolateral medulla of renovascular hypertensive rats. Free Radic Res 2015; 49:1335-43. [DOI: 10.3109/10715762.2015.1069291] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Abstract
Neurogenic pulmonary edema (NPE) is a life-threatening complication of central nervous system (CNS) injuries. This review summarizes current knowledge about NPE etiology and pathophysiology with an emphasis on its experimental models, including our spinal cord compression model. NPE may develop as a result of activation of specific CNS trigger zones located in the brainstem, leading to a rapid sympathetic discharge, rise in systemic blood pressure, baroreflex-induced bradycardia, and enhanced venous return resulting in pulmonary vascular congestion characterized by interstitial edema, intra-alveolar accumulation of transudate, and intra-alveolar hemorrhages. The potential etiological role of neurotransmitter changes in NPE trigger zones leading to enhanced sympathetic nerve activity is discussed. Degree of anesthesia is a crucial determinant for the extent of NPE development in experimental models because of its influence on sympathetic nervous system activity. Sympathetic hyperactivity is based on the major activation of either ascending spinal pathways by spinal cord injury or NPE trigger zones by increased intracranial pressure. Attenuation of sympathetic nerve activity or abolition of reflex bradycardia completely prevent NPE development in our experimental model. Suggestions for future research into NPE pathogenesis as well as therapeutic potential of particular drugs and interventions are discussed.
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Affiliation(s)
- Jiří Šedý
- Institute of Physiology , Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jaroslav Kuneš
- Institute of Physiology , Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Josef Zicha
- Institute of Physiology , Academy of Sciences of the Czech Republic, Prague, Czech Republic
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34
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Duan XC, Guo R, Liu SY, Xiao L, Xue HM, Guo Q, Jin S, Wu YM. Gene transfer of cystathionine β-synthase into RVLM increases hydrogen sulfide-mediated suppression of sympathetic outflow via KATP channel in normotensive rats. Am J Physiol Heart Circ Physiol 2015; 308:H603-11. [PMID: 25599573 DOI: 10.1152/ajpheart.00693.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hydrogen sulfide has been shown to have a sympathoinhibitory effect in the rostral ventrolateral medulla (RVLM). The present study examined the function of cystathionine β-synthase (CBS)/hydrogen sulfide system in the RVLM, which plays a crucial role in the control of blood pressure and sympathetic nerve activity. Adenovirus vectors encoding CBS (AdCBS) or enhanced green fluorescent protein (AdEGFP) were transfected into the RVLM in normotensive rats. Identical microinjection of AdCBS into the RVLM had no effect on systolic blood pressure and heart rate (HR) in conscious rats. Acute experiments were performed at day 7 after gene transfer in anesthetized rats. Microinjection of the CBS inhibitors hydroxylamine (HA) or amino-oxyacetate into the RVLM produced an increase in the renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP), and HR. There was a potentiation of the increases in RSNA, MAP, and HR because of the CBS inhibitors in AdCBS-injected rats compared with AdEGFP-injected rats. Pretreatment with pinacidil, a ATP-sensitive potassium (KATP) channel activator, abolished the effects of HA in two groups. Microinjection of glibenclamide, a KATP channel blocker, produced increases in RSNA, MAP, and HR in AdCBS-injected rats. No changes in behavior were observed in AdEGFP-injected rats. Furthermore, Western blot analysis indicated an increase in the expression of sulfonylurea receptor 2 and inward rectifier K(+) 6.1 in AdCBS-injected rats. These results suggest that the increase in KATP channels in the RVLM may be responsible for the greater sympathetic outflow and pressor effect of HA in AdCBS-injected rats compared with AdEGFP-injected rats.
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Affiliation(s)
- Xiao-cui Duan
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang, China; Hebei Key Lab of Laboratory Animal Science, Department of Laboratory Animal Science, Hebei Medical University, Shijiazhuang, China; and
| | - Rong Guo
- Dean's Office of the Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Shang-yu Liu
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang, China
| | - Lin Xiao
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang, China
| | - Hong-mei Xue
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang, China
| | - Qi Guo
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang, China
| | - Sheng Jin
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang, China
| | - Yu-ming Wu
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang, China;
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35
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Pro-inflammatory cytokines in paraventricular nucleus mediate the cardiac sympathetic afferent reflex in hypertension. Auton Neurosci 2014; 186:54-61. [DOI: 10.1016/j.autneu.2014.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 09/02/2014] [Accepted: 10/10/2014] [Indexed: 02/07/2023]
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36
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Geraldes V, Goncalves-Rosa N, Liu B, Paton JF, Rocha I. Essential role of RVL medullary neuronal activity in the long term maintenance of hypertension in conscious SHR. Auton Neurosci 2014; 186:22-31. [DOI: 10.1016/j.autneu.2014.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 08/14/2014] [Accepted: 09/05/2014] [Indexed: 02/07/2023]
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Abstract
Lung ventilation fluctuates widely with behavior but arterial PCO2 remains stable. Under normal conditions, the chemoreflexes contribute to PaCO2 stability by producing small corrective cardiorespiratory adjustments mediated by lower brainstem circuits. Carotid body (CB) information reaches the respiratory pattern generator (RPG) via nucleus solitarius (NTS) glutamatergic neurons which also target rostral ventrolateral medulla (RVLM) presympathetic neurons thereby raising sympathetic nerve activity (SNA). Chemoreceptors also regulate presympathetic neurons and cardiovagal preganglionic neurons indirectly via inputs from the RPG. Secondary effects of chemoreceptors on the autonomic outflows result from changes in lung stretch afferent and baroreceptor activity. Central respiratory chemosensitivity is caused by direct effects of acid on neurons and indirect effects of CO2 via astrocytes. Central respiratory chemoreceptors are not definitively identified but the retrotrapezoid nucleus (RTN) is a particularly strong candidate. The absence of RTN likely causes severe central apneas in congenital central hypoventilation syndrome. Like other stressors, intense chemosensory stimuli produce arousal and activate circuits that are wake- or attention-promoting. Such pathways (e.g., locus coeruleus, raphe, and orexin system) modulate the chemoreflexes in a state-dependent manner and their activation by strong chemosensory stimuli intensifies these reflexes. In essential hypertension, obstructive sleep apnea and congestive heart failure, chronically elevated CB afferent activity contributes to raising SNA but breathing is unchanged or becomes periodic (severe CHF). Extreme CNS hypoxia produces a stereotyped cardiorespiratory response (gasping, increased SNA). The effects of these various pathologies on brainstem cardiorespiratory networks are discussed, special consideration being given to the interactions between central and peripheral chemoreflexes.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia
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38
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Towiwat P, Phattanarudee S, Maher TJ, Ally A. Modulation of inducible nitric oxide synthase (iNOS) expression and cardiovascular responses during static exercise following iNOS antagonism within the ventrolateral medulla. Mol Cell Biochem 2014; 398:185-94. [PMID: 25234194 DOI: 10.1007/s11010-014-2218-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 09/12/2014] [Indexed: 10/24/2022]
Abstract
Previous reports indicate that inducible nitric oxide synthase (iNOS) blockade within the rostral ventrolateral medulla (RVLM) and caudal ventrolateral medulla (CVLM) differentially modulated cardiovascular responses, medullary glutamate, and GABA concentrations during static skeletal muscle contraction. In the current study, we determined the role of iNOS antagonism within the RVLM and CVLM on cardiovascular responses and iNOS protein expression during the exercise pressor reflex in anesthetized rats. Following 120 min of bilateral microdialysis of a selective iNOS antagonist, aminoguanidine (AGN; 10 µM), into the RVLM, the pressor responses were attenuated by 72 % and changes in heart rate were reduced by 38 % during a static muscle contraction. Furthermore, western blot analysis of iNOS protein abundance within the RVLM revealed a significant attenuation when compared to control animals. In contrast, bilateral administration of AGN (10 µM) into the CVLM augmented the increases in mean arterial pressure by 60 % and potentiated changes in heart rate by 61 % during muscle contractions, but did not alter expression of the iNOS protein within the CVLM. These results demonstrate that iNOS protein expression within the ventrolateral medulla is differentially regulated by iNOS blockade that may, in part, contribute to the modulation of cardiovascular responses during static exercise.
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Affiliation(s)
- Pasarapa Towiwat
- Department of Pharmacology and Physiology, Chulalongkorn University, Bangkok, 10330, Thailand
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39
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Ferguson SK, Hirai DM, Copp SW, Holdsworth CT, Allen JD, Jones AM, Musch TI, Poole DC. Dose dependent effects of nitrate supplementation on cardiovascular control and microvascular oxygenation dynamics in healthy rats. Nitric Oxide 2014; 39:51-8. [PMID: 24769046 DOI: 10.1016/j.niox.2014.04.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 04/11/2014] [Accepted: 04/13/2014] [Indexed: 01/21/2023]
Abstract
High dose nitrate (NO3(-)) supplementation via beetroot juice (BR, 1 mmol/kg/day) lowers mean arterial blood pressure (MAP) and improves skeletal muscle blood flow and O2 delivery/utilization matching thereby raising microvascular O2 pressure (PO2mv). We tested the hypothesis that a low dose of NO3(-) supplementation, consistent with a diet containing NO3(-) rich vegetables (BRLD, 0.3 mmol/kg/day), would be sufficient to cause these effects. Male Sprague-Dawley rats were administered a low dose of NO3(-) (0.3 mmol/kg/day; n=12), a high dose (1 mmol/kg/day; BRHD, n=6) or tap water (control, n=10) for 5 days. MAP, heart rate (HR), blood flow (radiolabeled microspheres) and vascular conductance (VC) were measured during submaximal treadmill exercise (20 m/min, 5% grade, equivalent to ~60% of maximal O2 uptake). Subsequently, PO2mv (phosphorescence quenching) was measured at rest and during 180 s of electrically-induced twitch contractions (1 Hz, ~6 V) of the surgically-exposed spinotrapezius muscle. BRLD and BRHD lowered resting (control: 139 ± 4, BRLD: 124 ± 5, BRHD: 128 ± 9 mmHg, P<0.05, BRLD vs. control) and exercising (control: 138 ± 3, BRLD: 126 ± 4, BRHD: 125 ± 5 mmHg, P<0.05) MAP to a similar extent. For BRLD this effect occurred in the absence of altered exercising hindlimb muscle(s) blood flow or spinotrapezius PO2mv (rest and across the transient response at the onset of contractions, all P>0.05), each of which increased significantly for the BRHD condition (all P<0.05). Whereas BRHD slowed the PO2mv kinetics significantly (i.e., >mean response time, MRT; control: 16.6 ± 2.1, BRHD: 23.3 ± 4.7s) following the onset of contractions compared to control, in the BRLD group this effect did not reach statistical significance (BRLD: 20.9 ± 1.9s, P=0.14). These data demonstrate that while low dose NO3(-) supplementation lowers MAP during exercise it does so in the absence of augmented muscle blood flow, VC and PO2mv; all of which are elevated at a higher dose. Thus, in healthy animals, a high dose of NO3(-) supplementation seems necessary to elicit significant changes in exercising skeletal muscle O2 delivery/utilization.
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Affiliation(s)
- Scott K Ferguson
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA.
| | - Daniel M Hirai
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA
| | - Steven W Copp
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA
| | - Clark T Holdsworth
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA
| | - Jason D Allen
- Department of Community and Family Medicine, Department of Medicine, Duke University, Durham, NC 27710, USA
| | - Andrew M Jones
- Sport and Health Sciences, University of Exeter, St. Luke's Campus, Exeter EX12LU, UK
| | - Timothy I Musch
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA; Department of Kinesiology, Kansas State University, Manhattan, KS 66506, USA
| | - David C Poole
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA; Department of Kinesiology, Kansas State University, Manhattan, KS 66506, USA
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Isegawa K, Hirooka Y, Kishi T, Yasukawa K, Utsumi H, Sunagawa K. Benefit of azilsartan on blood pressure elevation around rest-to-active phase in spontaneously hypertensive rats. Clin Exp Hypertens 2014; 37:45-50. [DOI: 10.3109/10641963.2014.897721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
| | - Yoshitaka Hirooka
- Department of Advanced Cardiovascular Regulation and Therapeutics, and
| | - Takuya Kishi
- Department of Advanced Therapeutics for Cardiovascular Diseases, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan,
| | - Keiji Yasukawa
- Department of Bio-Functional Science, Graduate School of Pharmaceutical Sciences, and
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan
| | - Hideo Utsumi
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, Japan
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41
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Penumarti A, Abdel-Rahman AA. The novel endocannabinoid receptor GPR18 is expressed in the rostral ventrolateral medulla and exerts tonic restraining influence on blood pressure. J Pharmacol Exp Ther 2014; 349:29-38. [PMID: 24431468 DOI: 10.1124/jpet.113.209213] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Systemic administration of the G-protein-coupled receptor 18 (GPR18) agonist abnormal cannabidiol (Abn CBD) lowers blood pressure (BP). Whether GPR18 is expressed in the central nervous system (CNS) and plays a role in BP control is not known despite the abundance of the GPR18 ligand N-arachidonoyl glycine (NAGly) in the CNS. Therefore, we first determined whether GPR18 is expressed in the presympathetic tyrosine hydroxylase (TH) immunoreactive (ir) neurons of the brainstem cardiovascular regulatory nuclei. Second, we investigated the impact of GPR18 activation and blockade on BP and heart rate (HR) and neurochemical modulators of sympathetic activity and BP. Immunofluorescence findings revealed GPR18 expression in TH-ir neurons in the rostral ventrolateral medulla (RVLM). Intra-RVLM GPR18 activation (Abn CBD) and blockade (O-1918, 1,3-dimethoxy-5-methyl-2-[(1R,6R)-3-methyl-6-(1-methylethenyl)-2-,cyclohexen-1-yl]benzene) elicited dose-dependent reductions and elevations in BP, respectively, along with respective increases and decreases in HR in conscious male Sprague-Dawley rats. RVLM GPR18 activation increased neuronal adiponectin (ADN) and NO and reduced reactive oxygen species (ROS) levels, and GPR18 blockade reduced neuronal ADN and increased oxidative stress (i.e., ROS) in the RVLM. Finally, we hypothesized that the negligible hypotensive effect caused by the endogenous GPR18 ligand NAGly could be due to concurrent activation of CB(1)R in the RVLM. Our findings support this hypothesis because NAGly-evoked hypotension was doubled after RVLM CB(1)R blockade (SR141716, rimonabant). These findings are the first to demonstrate GPR18 expression in the RVLM and to suggest a sympathoinhibitory role for this receptor. The findings yield new insight into the role of a novel cannabinoid receptor (GPR18) in central BP control.
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Affiliation(s)
- Anusha Penumarti
- Department of Pharmacology and Toxicology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
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Abstract
SIGNIFICANCE There is now compelling evidence to substantiate the notion that by depressing baroreflex regulation of blood pressure and augmenting central sympathetic outflow through their actions on the nucleus tractus solitarii (NTS) and rostral ventrolateral medulla (RVLM), brain stem nitric oxide synthase (NOS) and reactive oxygen species (ROS) are important contributing factors to neural mechanisms of hypertension. This review summarizes our contemporary views on the impact of NOS and ROS in the NTS and RVLM on neurogenic hypertension, and presents potential antihypertensive strategies that target brain stem NOS/ROS signaling. RECENT ADVANCES NO signaling in the brain stem may be pro- or antihypertensive depending on the NOS isoform that generates this gaseous moiety and the site of action. Elevation of the ROS level when its production overbalances its degradation in the NTS and RVLM underlies neurogenic hypertension. Interventional strategies with emphases on alleviating the adverse actions of these molecules on blood pressure regulation have been investigated. CRITICAL ISSUES The pathological roles of NOS in the RVLM and NTS in neural mechanisms of hypertension are highly complex. Likewise, multiple signaling pathways underlie the deleterious roles of brain-stem ROS in neurogenic hypertension. There are recent indications that interactions between brain stem ROS and NOS may play a contributory role. FUTURE DIRECTIONS Given the complicity of action mechanisms of brain-stem NOS and ROS in neural mechanisms of hypertension, additional studies are needed to identify the most crucial therapeutic target that is applicable not only in animal models but also in patients suffering from neurogenic hypertension.
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Affiliation(s)
- Samuel H H Chan
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital , Kaohsiung, Taiwan, Republic of China
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Jia LL, Kang YM, Wang FX, Li HB, Zhang Y, Yu XJ, Qi J, Suo YP, Tian ZJ, Zhu Z, Zhu GQ, Qin DN. Exercise training attenuates hypertension and cardiac hypertrophy by modulating neurotransmitters and cytokines in hypothalamic paraventricular nucleus. PLoS One 2014; 9:e85481. [PMID: 24482680 PMCID: PMC3901693 DOI: 10.1371/journal.pone.0085481] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 11/28/2013] [Indexed: 02/05/2023] Open
Abstract
AIMS Regular exercise as an effective non-pharmacological antihypertensive therapy is beneficial for prevention and control of hypertension, but the central mechanisms are unclear. In this study, we hypothesized that chronic exercise training (ExT) delays the progression of hypertension and attenuates cardiac hypertrophy by up-regulating anti-inflammatory cytokines, reducing pro-inflammatory cytokines (PICs) and restoring the neurotransmitters balance in the hypothalamic paraventricular nucleus (PVN) in young spontaneously hypertensive rats (SHR). In addition, we also investigated the involvement of nuclear factor-κB (NF-κB) p65 and NAD(P)H oxidase in exercise-induced effects. METHODS AND RESULTS Moderate-intensity ExT was administrated to young normotensive Wistar-Kyoto (WKY) and SHR rats for 16 weeks. SHR rats had a significant increase in mean arterial pressure and cardiac hypertrophy. SHR rats also had higher levels of glutamate, norepinephrine (NE), phosphorylated IKKβ, NF-κB p65 activity, NAD(P)H oxidase subunit gp91(phox), PICs and the monocyte chemokine protein-1 (MCP-1), and lower levels of gamma-aminobutyric acid (GABA) and interleukin-10 (IL-10) in the PVN. These SHR rats also exhibited higher renal sympathetic nerve activity (RSNA), and higher plasma levels of PICs, and lower plasma IL-10. However, ExT ameliorates all these changes in SHR rats. CONCLUSION These findings suggest that there are the imbalances between excitatory and inhibitory neurotransmitters and between pro- and anti-inflammatory cytokines in the PVN of SHR rats, which at least partly contributing to sympathoexcitation, hypertension and cardiac hypertrophy; chronic exercise training attenuates hypertension and cardiac hypertrophy by restoring the balances between excitatory and inhibitory neurotransmitters and between pro- and anti-inflammatory cytokines in the PVN; NF-κB and oxidative stress in the PVN may be involved in these exercise-induced effects.
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Affiliation(s)
- Lin-Lin Jia
- Department of Physiology and Pathophysiology, Xi’an Jiaotong University Cardiovascular Research Center, Xi’an Jiaotong University School of Medicine, Xi’an, China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Xi’an Jiaotong University Cardiovascular Research Center, Xi’an Jiaotong University School of Medicine, Xi’an, China
- * E-mail: (JMK); (DNQ)
| | - Fu-Xin Wang
- Department of Neurology, The First Affiliated Hospital of Jiamusi University, Jiamusi, China
| | - Hong-Bao Li
- Department of Physiology and Pathophysiology, Xi’an Jiaotong University Cardiovascular Research Center, Xi’an Jiaotong University School of Medicine, Xi’an, China
| | - Yan Zhang
- Department of Physiology and Pathophysiology, Xi’an Jiaotong University Cardiovascular Research Center, Xi’an Jiaotong University School of Medicine, Xi’an, China
| | - Xiao-Jing Yu
- Department of Physiology and Pathophysiology, Xi’an Jiaotong University Cardiovascular Research Center, Xi’an Jiaotong University School of Medicine, Xi’an, China
| | - Jie Qi
- Department of Physiology and Pathophysiology, Xi’an Jiaotong University Cardiovascular Research Center, Xi’an Jiaotong University School of Medicine, Xi’an, China
| | - Yu-Ping Suo
- Department of Obstetrics and Gynecology, Shanxi Provincial People’s Hospital, Taiyuan, China
| | - Zhen-Jun Tian
- Institute of Sports and Exercise Biology, School of Physical Education, Shaanxi Normal University, Xi’an, China
| | - Zhiming Zhu
- Department of Hypertension and Endocrinology, Center for Hypertension and Metabolic Diseases, Daping Hospital, The Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, China
| | - Guo-Qing Zhu
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Da-Nian Qin
- Department of Physiology, Shantou University Medical College, Shantou, China
- * E-mail: (JMK); (DNQ)
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Cossenza M, Socodato R, Portugal CC, Domith ICL, Gladulich LFH, Encarnação TG, Calaza KC, Mendonça HR, Campello-Costa P, Paes-de-Carvalho R. Nitric oxide in the nervous system: biochemical, developmental, and neurobiological aspects. VITAMINS AND HORMONES 2014; 96:79-125. [PMID: 25189385 DOI: 10.1016/b978-0-12-800254-4.00005-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nitric oxide (NO) is a very reactive molecule, and its short half-life would make it virtually invisible until its discovery. NO activates soluble guanylyl cyclase (sGC), increasing 3',5'-cyclic guanosine monophosphate levels to activate PKGs. Although NO triggers several phosphorylation cascades due to its ability to react with Fe II in heme-containing proteins such as sGC, it also promotes a selective posttranslational modification in cysteine residues by S-nitrosylation, impacting on protein function, stability, and allocation. In the central nervous system (CNS), NO synthesis usually requires a functional coupling of nitric oxide synthase I (NOS I) and proteins such as NMDA receptors or carboxyl-terminal PDZ ligand of NOS (CAPON), which is critical for specificity and triggering of selected pathways. NO also modulates CREB (cAMP-responsive element-binding protein), ERK, AKT, and Src, with important implications for nerve cell survival and differentiation. Differences in the regulation of neuronal death or survival by NO may be explained by several mechanisms involving localization of NOS isoforms, amount of NO being produced or protein sets being modulated. A number of studies show that NO regulates neurotransmitter release and different aspects of synaptic dynamics, such as differentiation of synaptic specializations, microtubule dynamics, architecture of synaptic protein organization, and modulation of synaptic efficacy. NO has also been associated with synaptogenesis or synapse elimination, and it is required for long-term synaptic modifications taking place in axons or dendrites. In spite of tremendous advances in the knowledge of NO biological effects, a full description of its role in the CNS is far from being completely elucidated.
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Affiliation(s)
- Marcelo Cossenza
- Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil; Departamento de Fisiologia e Farmacologia, Instituto Biomédico, Universidade Federal Fluminense, Rio de Janeiro, Brazil
| | - Renato Socodato
- Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Camila C Portugal
- Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Ivan C L Domith
- Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Luis F H Gladulich
- Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Thaísa G Encarnação
- Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Karin C Calaza
- Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil; Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Henrique R Mendonça
- Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Paula Campello-Costa
- Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil; Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Roberto Paes-de-Carvalho
- Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil; Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil.
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Features of GABAergic Cardiovascular Control Provided by Medullary Neurons in Rats. NEUROPHYSIOLOGY+ 2013. [DOI: 10.1007/s11062-013-9386-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Abstract
Statins (3-hydroxy-3-methylglutaryl-CoA reductase inhibitors) reduce plasma cholesterol and improve endothelium-dependent vasodilation, inflammation and oxidative stress. A ‘pleiotropic’ property of statins receiving less attention is their effect on the autonomic nervous system. Increased central sympathetic outflow and diminished cardiac vagal tone are disturbances characteristic of a range of cardiovascular conditions for which statins are now prescribed routinely to reduce cardiovascular events: following myocardial infarction, and in hypertension, chronic kidney disease, heart failure and diabetes. The purpose of the present review is to synthesize contemporary evidence that statins can improve autonomic circulatory regulation. In experimental preparations, high-dose lipophilic statins have been shown to reduce adrenergic outflow by attenuating oxidative stress in central brain regions involved in sympathetic and parasympathetic discharge induction and modulation. In patients with hypertension, chronic kidney disease and heart failure, lipophilic statins, such as simvastatin or atorvastatin, have been shown to reduce MNSA (muscle sympathetic nerve activity) by 12–30%. Reports concerning the effect of statin therapy on HRV (heart rate variability) are less consistent. Because of their implications for BP (blood pressure) control, insulin sensitivity, arrhythmogenesis and sudden cardiac death, these autonomic nervous system actions should be considered additional mechanisms by which statins lower cardiovascular risk.
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Hirooka Y, Kishi T, Ito K, Sunagawa K. Potential clinical application of recently discovered brain mechanisms involved in hypertension. Hypertension 2013; 62:995-1002. [PMID: 24101665 DOI: 10.1161/hypertensionaha.113.00801] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Yoshitaka Hirooka
- Department of Advanced Cardiovascular Regulation and Therapeutics, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
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Kishi T. Regulation of the sympathetic nervous system by nitric oxide and oxidative stress in the rostral ventrolateral medulla: 2012 Academic Conference Award from the Japanese Society of Hypertension. Hypertens Res 2013; 36:845-51. [DOI: 10.1038/hr.2013.73] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 03/01/2013] [Accepted: 03/26/2013] [Indexed: 02/07/2023]
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Ogawa K, Hirooka Y, Kishi T, Ide T, Sunagawa K. Partially silencing brain toll-like receptor 4 prevents in part left ventricular remodeling with sympathoinhibition in rats with myocardial infarction-induced heart failure. PLoS One 2013; 8:e69053. [PMID: 23874864 PMCID: PMC3706428 DOI: 10.1371/journal.pone.0069053] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 06/04/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Left ventricular (LV) remodeling and activation of sympathetic nervous system (SNS) are cardinal features of heart failure. We previously demonstrated that enhanced central sympathetic outflow is associated with brain toll-like receptor 4 (TLR4) probably mediated by brain angiotensin II type 1 receptor in mice with myocardial infarction (MI)-induced heart failure. The purpose of the present study was to examine whether silencing brain TLR4 could prevent LV remodeling with sympathoinhibition in MI-induced heart failure. METHODOLOGY/PRINCIPAL FINDINGS MI-induced heart failure model rats were created by ligation of left coronary artery. The expression level of TLR4 in brainstem was significantly higher in MI-induced heart failure treated with intracerebroventricular (ICV) injection of hGAPDH-SiRNA than in sham. TLR4 in brainstem was significantly lower in MI-induced heart failure treated with ICV injection of TLR4-SiRNA than in that treated with ICV injection of hGAPDH-SiRNA. Lung weight, urinary norepinephrine excretion, and LV end-diastolic pressure were significantly lower and LV dimension was significantly smaller in MI-induced heart failure treated with TLR4-SiRNA than in that treated with hGAPDH-SiRNA for 2 weeks. CONCLUSIONS Partially silencing brain TLR4 by ICV injection of TLR4-SiRNA for 2 weeks could in part prevent LV remodeling with sympathoinhibition in rats with MI-induced heart failure. Brain TLR4 has a potential to be a target of the treatment for MI-induced heart failure.
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Affiliation(s)
- Kiyohiro Ogawa
- Departments of Cardiovascular Medicine, Kyushu University Graduate School of Medical Science, Fukuoka, Japan
| | - Yoshitaka Hirooka
- Advanced Cardiovascular Regulation and Therapeutics, Kyushu University Graduate School of Medical Science, Fukuoka, Japan
- * E-mail:
| | - Takuya Kishi
- Advanced Therapeutics for Cardiovascular Diseases, Kyushu University Graduate School of Medical Science, Fukuoka, Japan
| | - Tomomi Ide
- Departments of Cardiovascular Medicine, Kyushu University Graduate School of Medical Science, Fukuoka, Japan
| | - Kenji Sunagawa
- Departments of Cardiovascular Medicine, Kyushu University Graduate School of Medical Science, Fukuoka, Japan
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Tandai-Hiruma M, Kato K, Kemuriyama T, Ohta H, Tashiro A, Hagisawa K, Nishida Y. High blood pressure enhances brain stem neuronal nitric oxide synthase activity in Dahl salt-sensitive rats. Clin Exp Pharmacol Physiol 2013; 40:197-204. [PMID: 23278407 DOI: 10.1111/1440-1681.12049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 12/18/2012] [Indexed: 11/30/2022]
Abstract
The aims of the present study were to determine the mechanism underlying enhanced neuronal nitric oxide synthase (nNOS) activity in the brain of hypertensive Dahl salt-sensitive (DSS) rats and the consequences of enhanced nNOS activity. Male DSS rats were fed either a regular (0.4% NaCl) or high-salt (8% NaCl) diet, with or without 0.25% nifedipine, for 4 weeks. The effects of nifedipine, which lowers blood pressure peripherally, on central nNOS were determined by measuring nNOS activity, as well as the number of nNOS-positive neurons in the brain stem and diencephalon. The effects of chronic (12 days) infusion of 7 μg (0.5 μL/h, i.c.v.) S-methyl-L-thiocitrulline (SMTC; a stereoselective competitive nNOS inhibitor) on mean arterial pressure were assessed in conscious DSS rats using a radiotelemetry system. In addition, the number of central nNOS-positive neurons was compared between DSS and salt-insensitive Sprague-Dawley rats. Normalization of blood pressure by nifedipine attenuated the increase in nNOS activity in the brain stem of DSS rats. Chronic i.c.v. infusion of SMTC further enhanced hypertension in DSS rats. Feeding of a high-salt diet increased nNOS-positive neurons in the lateral parabrachial nucleus, rostral ventrolateral medulla and nucleus tractus solitarius of DSS compared with Sprague-Dawley rats, whereas nNOS-positive neurons in the paraventricular nucleus remained downregulated in DSS rats. The results of the present study suggest that hypertension, rather than a high-salt diet, increases central nNOS activity in hypertensive DSS rats to buffer high blood pressure. However, this compensatory response may be insufficient to relieve salt-induced hypertension.
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Affiliation(s)
- Megumi Tandai-Hiruma
- Department of Physiology, National Defense Medical College, Tokorozawa, Saitama, Japan.
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