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Shin H, Sharma R, Neupane C, Pham TL, Park SE, Lee SY, Kim HW, Bae YM, Stern JE, Park JB. Tonic NMDAR Currents of NR2A-Containing NMDARs Represent Altered Ambient Glutamate Concentration in the Supraoptic Nucleus. eNeuro 2024; 11:ENEURO.0279-23.2023. [PMID: 38176904 PMCID: PMC10863629 DOI: 10.1523/eneuro.0279-23.2023] [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: 07/26/2023] [Revised: 12/03/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024] Open
Abstract
NMDA receptors (NMDARs) modulate glutamatergic excitatory tone in the brain via two complementary modalities: a phasic excitatory postsynaptic current and a tonic extrasynaptic modality. Here, we demonstrated that the tonic NMDAR-current (I NMDA) mediated by NR2A-containing NMDARs is an efficient biosensor detecting the altered ambient glutamate level in the supraoptic nucleus (SON). I NMDA of magnocellular neurosecretory cells (MNCs) measured by nonselective NMDARs antagonist, AP5, at holding potential (V holding) -70 mV in low concentration of ECF Mg2+ ([Mg2+]o) was transiently but significantly increased 1-week post induction of a DOCA salt hypertensive model rat which was compatible with that induced by a NR2A-selective antagonist, PEAQX (I PEAQX) in both DOCA-H2O and DOCA-salt groups. In agreement, NR2B antagonist, ifenprodil, or NR2C/D antagonist, PPDA, did not affect the holding current (I holding) at V holding -70 mV. Increased ambient glutamate by exogenous glutamate (10 mM) or excitatory amino acid transporters (EAATs) antagonist (TBOA, 50 mM) abolished the I PEAQX difference between two groups, suggesting that attenuated EAATs activity increased ambient glutamate concentration, leading to the larger I PEAQX in DOCA-salt rats. In contrast, only ifenprodil but not PEAQX and PPDA uncovered I NMDA at V holding +40 mV under 1.2 mM [Mg2+]o condition. I ifenprodil was not different in DOCA-H2O and DOCA-salt groups. Finally, NR2A, NR2B, and NR2D protein expression were not different in the SON of the two groups. Taken together, NR2A-containing NMDARs efficiently detected the increased ambient glutamate concentration in the SON of DOCA-salt hypertensive rats due to attenuated EAATs activity.
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Affiliation(s)
- Hyunjin Shin
- Department of Physiology & Medical Science, College of Medicine & Brain Research Institute, Chungnam National University, Daejeon 35015, South Korea
| | - Ramesh Sharma
- Department of Physiology & Medical Science, College of Medicine & Brain Research Institute, Chungnam National University, Daejeon 35015, South Korea
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Chiranjivi Neupane
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Thuy Linh Pham
- Department of Physiology & Medical Science, College of Medicine & Brain Research Institute, Chungnam National University, Daejeon 35015, South Korea
| | - Su Eun Park
- Department of Physiology & Medical Science, College of Medicine & Brain Research Institute, Chungnam National University, Daejeon 35015, South Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyun-Woo Kim
- Department of Physiology & Medical Science, College of Medicine & Brain Research Institute, Chungnam National University, Daejeon 35015, South Korea
| | - Young Min Bae
- Department of Physiology, Konkuk University School of Medicine, Chungju 27478, Republic of Korea
| | - Javier E Stern
- Neuroscience Institute and Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30302
| | - Jin Bong Park
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
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Grobe CC, Reho JJ, Brown-Williams D, Ziegler AA, Mathieu NM, Lawton SB, Fekete EM, Brozoski DT, Wackman KK, Burnett CM, Nakagawa P, Sigmund CD, Segar JL, Grobe JL. Cardiometabolic Effects of DOCA-Salt in Mice Depend on Ambient Temperature. Hypertension 2023; 80:1871-1880. [PMID: 37470185 PMCID: PMC10528934 DOI: 10.1161/hypertensionaha.122.20415] [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: 10/04/2022] [Accepted: 07/10/2023] [Indexed: 07/21/2023]
Abstract
BACKGROUND Mice prefer warmer environments than humans. For this reason, behavioral and physiological thermoregulatory responses are engaged by mice in response to a standard room temperature of 22 to 24 °C. Autonomic mechanisms mediating thermoregulatory responses overlap with mechanisms activated in hypertension, and, therefore, we hypothesized that housing at thermoneutral temperatures (TNs; 30 °C) would modify the cardiometabolic effects of deoxycorticosterone acetate (DOCA)-salt in mice. METHODS The effects of DOCA-salt treatment upon ingestive behaviors, energy expenditure, blood pressure, heart rate (HR), and core temperature were assessed in C57BL/6J mice housed at room temperature or TN. RESULTS Housing at TN reduced food intake, energy expenditure, blood pressure, and HR and attenuated HR responses to acute autonomic blockade by chlorisondamine. At room temperature, DOCA-salt caused expected increases in fluid intake, sodium retention in osmotically inactive pools, blood pressure, core temperature, and also caused expected decreases in fat-free mass, total body water, and HR. At TN, the effects of DOCA-salt upon fluid intake, fat gains, hydration, and core temperature were exaggerated, but effects on energy expenditure and HR were blunted. Effects of DOCA-salt upon blood pressure were similar for 3 weeks and exaggerated by TN housing in the fourth week. CONCLUSIONS Ambient temperature robustly influences behavioral and physiological functions in mice, including metabolic and cardiovascular phenotype development in response to DOCA-salt treatment. Studying cardiometabolic responses of mice at optimal ambient temperatures promises to improve the translational relevance of rodent models.
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Affiliation(s)
- Connie C. Grobe
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226
| | - John J. Reho
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, WI 53226
| | | | - Alisha A. Ziegler
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Natalia M. Mathieu
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Samuel B.R. Lawton
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Eva M. Fekete
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Daniel T. Brozoski
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Kelsey K. Wackman
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Colin M.L. Burnett
- Department of Medicine, Division of Cardiovascular Medicine, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Pablo Nakagawa
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Curt D. Sigmund
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Jeffrey L. Segar
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Justin L. Grobe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, WI 53226
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI 53226
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI 53226
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3
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Mathieu NM, Fekete EM, Muskus PC, Brozoski DT, Lu KT, Wackman KK, Gomez J, Fang S, Reho JJ, Grobe CC, Vazirabad I, Mouradian GC, Hodges MR, Segar JL, Grobe JL, Sigmund CD, Nakagawa P. Genetic Ablation of Prorenin Receptor in the Rostral Ventrolateral Medulla Influences Blood Pressure and Hydromineral Balance in Deoxycorticosterone-Salt Hypertension. FUNCTION 2023; 4:zqad043. [PMID: 37609445 PMCID: PMC10440998 DOI: 10.1093/function/zqad043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/24/2023] Open
Abstract
Non-enzymatic activation of renin via its interaction with prorenin receptor (PRR) has been proposed as a key mechanism of local renin-angiotensin system (RAS) activation. The presence of renin and angiotensinogen has been reported in the rostral ventrolateral medulla (RVLM). Overactivation of bulbospinal neurons in the RVLM is linked to hypertension (HTN). Previous studies have shown that the brain RAS plays a role in the pathogenesis of the deoxycorticosterone (DOCA)-salt HTN model. Thus, we hypothesized that PRR in the RVLM is involved in the local activation of the RAS, facilitating the development of DOCA-salt HTN. Selective PRR ablation targeting the RVLM (PRRRVLM-Null mice) resulted in an unexpected sex-dependent and biphasic phenotype in DOCA-salt HTN. That is, PRRRVLM-Null females (but not males) exhibited a significant delay in achieving maximal pressor responses during the initial stage of DOCA-salt HTN. Female PRRRVLM-Null subsequently showed exacerbated DOCA-salt-induced pressor responses during the "maintenance" phase with a maximal peak at 13 d on DOCA-salt. This exacerbated response was associated with an increased sympathetic drive to the resistance arterioles and the kidney, exacerbated fluid and sodium intake and output in response to DOCA-salt, and induced mobilization of fluids from the intracellular to extracellular space concomitant with elevated vasopressin. Ablation of PRR suppressed genes involved in RAS activation and catecholamine synthesis in the RVLM but also induced expression of genes involved in inflammatory responses. This study illustrates complex and sex-dependent roles of PRR in the neural control of BP and hydromineral balance through autonomic and neuroendocrine systems. Graphical abstract.
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Affiliation(s)
- Natalia M Mathieu
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Eva M Fekete
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Patricia C Muskus
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Daniel T Brozoski
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Ko-Ting Lu
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Kelsey K Wackman
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Javier Gomez
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Shi Fang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - John J Reho
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Connie C Grobe
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Ibrahim Vazirabad
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Gary C Mouradian
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Matthew R Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jeffrey L Segar
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Justin L Grobe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Curt D Sigmund
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Pablo Nakagawa
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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Wagner VA, Deng G, Claflin KE, Ritter ML, Cui H, Nakagawa P, Sigmund CD, Morselli LL, Grobe JL, Kwitek AE. Cell-specific transcriptome changes in the hypothalamic arcuate nucleus in a mouse deoxycorticosterone acetate-salt model of hypertension. Front Cell Neurosci 2023; 17:1207350. [PMID: 37293629 PMCID: PMC10244568 DOI: 10.3389/fncel.2023.1207350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 05/08/2023] [Indexed: 06/10/2023] Open
Abstract
A common preclinical model of hypertension characterized by low circulating renin is the "deoxycorticosterone acetate (DOCA)-salt" model, which influences blood pressure and metabolism through mechanisms involving the angiotensin II type 1 receptor (AT1R) in the brain. More specifically, AT1R within Agouti-related peptide (AgRP) neurons of the arcuate nucleus of the hypothalamus (ARC) has been implicated in selected effects of DOCA-salt. In addition, microglia have been implicated in the cerebrovascular effects of DOCA-salt and angiotensin II. To characterize DOCA-salt effects upon the transcriptomes of individual cell types within the ARC, we used single-nucleus RNA sequencing (snRNAseq) to examine this region from male C57BL/6J mice that underwent sham or DOCA-salt treatment. Thirty-two unique primary cell type clusters were identified. Sub-clustering of neuropeptide-related clusters resulted in identification of three distinct AgRP subclusters. DOCA-salt treatment caused subtype-specific changes in gene expression patterns associated with AT1R and G protein signaling, neurotransmitter uptake, synapse functions, and hormone secretion. In addition, two primary cell type clusters were identified as resting versus activated microglia, and multiple distinct subtypes of activated microglia were suggested by sub-cluster analysis. While DOCA-salt had no overall effect on total microglial density within the ARC, DOCA-salt appeared to cause a redistribution of the relative abundance of activated microglia subtypes. These data provide novel insights into cell-specific molecular changes occurring within the ARC during DOCA-salt treatment, and prompt increased investigation of the physiological and pathophysiological significance of distinct subtypes of neuronal and glial cell types.
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Affiliation(s)
- Valerie A. Wagner
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Genetics Graduate Program, University of Iowa, Iowa City, IA, United States
| | - Guorui Deng
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, United States
| | - Kristin E. Claflin
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, United States
| | - McKenzie L. Ritter
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Huxing Cui
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, United States
- Obesity Research and Education Initiative, University of Iowa, Iowa City, IA, United States
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, United States
| | - Pablo Nakagawa
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Curt D. Sigmund
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Lisa L. Morselli
- Department of Medicine, Division of Endocrinology and Molecular Medicine, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Justin L. Grobe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, United States
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Anne E. Kwitek
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, United States
- Linda T. and John A. Mellowes Center for Genomic Sciences and Precision Medicine, Medical College of Wisconsin, Milwaukee, WI, United States
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5
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De Silva TM, Faraci FM. The DOCA-Salt Model of Hypertension for Studies of Cerebrovascular Function, Stroke, and Brain Health. Methods Mol Biol 2023; 2616:481-487. [PMID: 36715955 DOI: 10.1007/978-1-0716-2926-0_34] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The brain renin-angiotensin-aldosterone system (RAAS) regulates many physiological processes including fluid and electrolyte balance, vascular structure and function, blood pressure, cognition, and other aspects of brain function. Treatment with the mineralocorticoid deoxycorticosterone acetate and salt stimulates the local RAAS within the brain. In this chapter, we describe the surgical procedures used to induce activation of the brain RAAS with deoxycorticosterone acetate and salt. This technique can be used for studies of hypertension, cerebrovascular biology and dysfunction, and other diseases that impact brain health.
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Affiliation(s)
- T Michael De Silva
- Department of Microbiology, Anatomy, Physiology and Pharmacology, Centre for Cardiovascular Biology and Disease Research, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC, Australia.
| | - Frank M Faraci
- Department of Internal Medicine, and Department of Neuroscience and Pharmacology, Francois M. Abboud Cardiovascular Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
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Renin-a in the Subfornical Organ Plays a Critical Role in the Maintenance of Salt-Sensitive Hypertension. Biomolecules 2022; 12:biom12091169. [PMID: 36139008 PMCID: PMC9496084 DOI: 10.3390/biom12091169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/20/2022] [Accepted: 08/22/2022] [Indexed: 11/17/2022] Open
Abstract
The brain renin-angiotensin system plays important roles in blood pressure and cardiovascular regulation. There are two isoforms of prorenin in the brain: the classic secreted form (prorenin/sREN) encoded by renin-a, and an intracellular form (icREN) encoded by renin-b. Emerging evidence indicates the importance of renin-b in cardiovascular and metabolic regulation. However, the role of endogenous brain prorenin in the development of salt-sensitive hypertension remains undefined. In this study, we test the hypothesis that renin-a produced locally in the brain contributes to the pathogenesis of hypertension. Using RNAscope, we report for the first time that renin mRNA is expressed in several regions of the brain, including the subfornical organ (SFO), the paraventricular nucleus of the hypothalamus (PVN), and the brainstem, where it is found in glutamatergic, GABAergic, cholinergic, and tyrosine hydroxylase-positive neurons. Notably, we found that renin mRNA was significantly elevated in the SFO and PVN in a mouse model of DOCA-salt–induced hypertension. To examine the functional importance of renin-a in the SFO, we selectively ablated renin-a in the SFO in renin-a–floxed mice using a Cre-lox strategy. Importantly, renin-a ablation in the SFO attenuated the maintenance of DOCA-salt–induced hypertension and improved autonomic function without affecting fluid or sodium intake. Molecularly, ablation of renin-a prevented the DOCA-salt–induced elevation in NADPH oxidase 2 (NOX2) in the SFO without affecting NOX4 or angiotensin II type 1 and 2 receptors. Collectively, our findings demonstrate that endogenous renin-a within the SFO is important for the pathogenesis of salt-sensitive hypertension.
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Patil CN, Ritter ML, Wackman KK, Oliveira V, Balapattabi K, Grobe CC, Brozoski DT, Reho JJ, Nakagawa P, Mouradian GC, Kriegel AJ, Kwitek AE, Hodges MR, Segar JL, Sigmund CD, Grobe JL. Cardiometabolic effects of DOCA-salt in male C57BL/6J mice are variably dependent on sodium and nonsodium components of diet. Am J Physiol Regul Integr Comp Physiol 2022; 322:R467-R485. [PMID: 35348007 PMCID: PMC9054347 DOI: 10.1152/ajpregu.00017.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/14/2022] [Accepted: 03/23/2022] [Indexed: 01/22/2023]
Abstract
Hypertension characterized by low circulating renin activity accounts for roughly 25%-30% of primary hypertension in humans and can be modeled experimentally via deoxycorticosterone acetate (DOCA)-salt treatment. In this model, phenotypes develop in progressive phases, although the timelines and relative contributions of various mechanisms to phenotype development can be distinct between laboratories. To explore interactions among environmental influences such as diet formulation and dietary sodium (Na) content on phenotype development in the DOCA-salt paradigm, we examined an array of cardiometabolic endpoints in young adult male C57BL/6J mice during sham or DOCA-salt treatments when mice were maintained on several common, commercially available laboratory rodent "chow" diets including PicoLab 5L0D (0.39% Na), Envigo 7913 (0.31% Na), Envigo 2920x (0.15% Na), or a customized version of Envigo 2920x (0.4% Na). Energy balance (weight gain, food intake, digestive efficiency, and energy efficiency), fluid and electrolyte homeostasis (fluid intake, Na intake, fecal Na content, hydration, and fluid compartmentalization), renal functions (urine production rate, glomerular filtration rate, urine Na excretion, renal expression of renin, vasopressin receptors, aquaporin-2 and relationships among markers of vasopressin release, aquaporin-2 shedding, and urine osmolality), and blood pressure, all exhibited changes that were subject to interactions between diet and DOCA-salt. Interestingly, some of these phenotypes, including blood pressure and hydration, were dependent on nonsodium dietary components, as Na-matched diets resulted in distinct phenotype development. These findings provide a broad and robust illustration of an environment × treatment interaction that impacts the use and interpretation of a common rodent model of low-renin hypertension.
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Affiliation(s)
- Chetan N Patil
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - McKenzie L Ritter
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Kelsey K Wackman
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Vanessa Oliveira
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | | | - Connie C Grobe
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Daniel T Brozoski
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - John J Reho
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Pablo Nakagawa
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Gary C Mouradian
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Alison J Kriegel
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cancer Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Center of Systems Molecular Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Anne E Kwitek
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Center of Systems Molecular Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Matthew R Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Jeffrey L Segar
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Curt D Sigmund
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Center of Systems Molecular Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Justin L Grobe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Center of Systems Molecular Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin
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8
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Jin X, Kim WB, Kim MN, Jung WW, Kang HK, Hong EH, Kim YS, Shim WJ, Han HC, Colwell CS, Kim YB, Kim YI. Oestrogen inhibits salt-dependent hypertension by suppressing GABAergic excitation in magnocellular AVP neurons. Cardiovasc Res 2021; 117:2263-2274. [PMID: 32960965 PMCID: PMC10616626 DOI: 10.1093/cvr/cvaa271] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/24/2020] [Accepted: 09/08/2020] [Indexed: 12/25/2022] Open
Abstract
AIMS Abundant evidence indicates that oestrogen (E2) plays a protective role against hypertension. Yet, the mechanism underlying the antihypertensive effect of E2 is poorly understood. In this study, we sought to determine the mechanism through which E2 inhibits salt-dependent hypertension. METHODS AND RESULTS To this end, we performed a series of in vivo and in vitro experiments employing a rat model of hypertension that is produced by deoxycorticosterone acetate (DOCA)-salt treatment after uninephrectomy. We found that E2 prevented DOCA-salt treatment from inducing hypertension, raising plasma arginine-vasopressin (AVP) level, enhancing the depressor effect of the V1a receptor antagonist (Phenylac1,D-Tyr(Et)2,Lys6,Arg8,des-Gly9)-vasopressin, and converting GABAergic inhibition to excitation in hypothalamic magnocellular AVP neurons. Moreover, we obtained results indicating that the E2 modulation of the activity and/or expression of NKCC1 (Cl- importer) and KCC2 (Cl- extruder) underpins the effect of E2 on the transition of GABAergic transmission in AVP neurons. Lastly, we discovered that, in DOCA-salt-treated hypertensive ovariectomized rats, CLP290 (prodrug of the KCC2 activator CLP257, intraperitoneal injections) lowered blood pressure, and plasma AVP level and hyperpolarized GABA equilibrium potential to prevent GABAergic excitation from emerging in the AVP neurons of these animals. CONCLUSION Based on these results, we conclude that E2 inhibits salt-dependent hypertension by suppressing GABAergic excitation to decrease the hormonal output of AVP neurons.
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Affiliation(s)
- Xiangyan Jin
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Woong Bin Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Mi-Na Kim
- Department of Internal Medicine, Cardiovascular Section, Korea University Anam Hospital, Seoul 136-705, Republic of Korea
| | - Won Woo Jung
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Hyung Kyung Kang
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Eun-Hwa Hong
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Yoon Sik Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Wan Joo Shim
- Department of Internal Medicine, Cardiovascular Section, Korea University Anam Hospital, Seoul 136-705, Republic of Korea
| | - Hee Chul Han
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Christopher S Colwell
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, USA
| | - Young-Beom Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
| | - Yang In Kim
- Department of Physiology and Neuroscience Research Institute, Korea University College of Medicine, 126-1 Anam-dong 5-ga, Seoul 136-705, Republic of Korea
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9
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Li Y, Shen M, Ferens D, Broughton BRS, Murthi P, Saini S, Widdop RE, Ricardo SD, Pinar AA, Samuel CS. Combining mesenchymal stem cells with serelaxin provides enhanced renoprotection against 1K/DOCA/salt-induced hypertension. Br J Pharmacol 2021; 178:1164-1181. [PMID: 33450051 DOI: 10.1111/bph.15361] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/21/2020] [Accepted: 12/26/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE Fibrosis is a hallmark of chronic kidney disease (CKD) that significantly contributes to renal dysfunction, and impairs the efficacy of stem cell-based therapies. This study determined whether combining bone marrow-derived mesenchymal stem cells (BM-MSCs) with the renoprotective effects of recombinant human relaxin (serelaxin) could therapeutically reduce renal fibrosis in mice with one kidney/deoxycorticosterone acetate/salt (1K/DOCA/salt)-induced hypertension, compared with the effects of the ACE inhibitor, perindopril. EXPERIMENTAL APPROACH Adult male C57BL/6 mice were uni-nephrectomised and received deoxycorticosterone acetate and saline to drink (1K/DOCA/salt) for 21 days. Control mice were uni-nephrectomised but received water over the same time period. Sub-groups of 1K/DOCA/salt-injured mice (n = 5-8 per group) were treated with either serelaxin (0.5 mg·kg-1 ·day-1 ) or BM-MSCs (1 × 106 per mouse) alone; both treatments combined (with 0.5 × 106 or 1 × 106 BM-MSCs per mouse); or perindopril (2 mg·kg-1 ·day-1 ) from days 14-21. KEY RESULTS 1K/DOCA/salt-injured mice developed elevated BP and hypertension-induced renal damage, inflammation and fibrosis. BM-MSCs alone reduced the injury-induced fibrosis and attenuated BP to a similar extent as perindopril. Serelaxin alone modestly reduced renal fibrosis and effectively reduced tubular injury. Strikingly, the combined effects of BM-MSCs (at both doses) with serelaxin significantly inhibited renal fibrosis and proximal tubular epithelial injury while restoring renal architecture, to a greater extent than either therapy alone, and over the effects of perindopril. CONCLUSION AND IMPLICATIONS Combining BM-MSCs and serelaxin provided broader renoprotection over either therapy alone or perindopril and might represent a novel treatment for hypertensive CKD.
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Affiliation(s)
- Yifang Li
- Cardiovascular Disease Program, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Matthew Shen
- Cardiovascular Disease Program, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Dorota Ferens
- Cardiovascular Disease Program, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Brad R S Broughton
- Cardiovascular Disease Program, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Padma Murthi
- Cardiovascular Disease Program, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Sheetal Saini
- Cardiovascular Disease Program, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Robert E Widdop
- Cardiovascular Disease Program, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Sharon D Ricardo
- Cardiovascular Disease Program, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Anita A Pinar
- Cardiovascular Disease Program, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Chrishan S Samuel
- Cardiovascular Disease Program, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia.,Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia
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10
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Ye C, Zheng F, Wang JX, Wang XL, Chen Q, Li YH, Kang YM, Zhu GQ. Dysregulation of the Excitatory Renal Reflex in the Sympathetic Activation of Spontaneously Hypertensive Rat. Front Physiol 2021; 12:673950. [PMID: 34149454 PMCID: PMC8209386 DOI: 10.3389/fphys.2021.673950] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/08/2021] [Indexed: 11/20/2022] Open
Abstract
Excessive sympathetic activation plays crucial roles in the pathogenesis of hypertension. Chemical stimulation of renal afferents increases the sympathetic activity and blood pressure in normal rats. This study investigated the excitatory renal reflex (ERR) in the development of hypertension in the spontaneously hypertensive rat (SHR). Experiments were performed in the Wistar-Kyoto rat (WKY) and SHR aged at 4, 12, and 24 weeks under anesthesia. Renal infusion of capsaicin was used to stimulate renal afferents, and thus, to induce ERR. The ERR was evaluated by the changes in the contralateral renal sympathetic nerve activity and mean arterial pressure. At the age of 4 weeks, the early stage with a slight or moderate hypertension, the ERR was more enhanced in SHR compared with WKY. The pressor response was greater than the sympathetic activation response in the SHR. At the age of 12 weeks, the development stage with severe hypertension, there was no significant difference in the ERR between the WKY and SHR. At the age of 24 weeks, the later stage of hypertension with long-term several hypertensions, the ERR was more attenuated in the SHR compared with the WKY. On the other hand, the pressor response to sympathetic activation due to the ERR was smaller at the age of 12 and 24 weeks than those at the age of 4 weeks. These results indicate that ERR is enhanced in the early stage of hypertension, and attenuated in the later stage of hypertension in the SHR. Abnormal ERR is involved in the sympathetic activation and the development of hypertension.
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Affiliation(s)
- Chao Ye
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Fen Zheng
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Jing-Xiao Wang
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Xiao-Li Wang
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Qi Chen
- Department of Pathophysiology, Nanjing Medical University, Nanjing, China
| | - Yue-Hua Li
- Department of Pathophysiology, Nanjing Medical University, Nanjing, China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Cardiovascular Research Center, Xi'an Jiaotong University School of Medicine, Xi'an, China
| | - Guo-Qing Zhu
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China.,Department of Pathophysiology, Nanjing Medical University, Nanjing, China
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11
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Bigalke JA, Gao H, Chen QH, Shan Z. Activation of Orexin 1 Receptors in the Paraventricular Nucleus Contributes to the Development of Deoxycorticosterone Acetate-Salt Hypertension Through Regulation of Vasopressin. Front Physiol 2021; 12:641331. [PMID: 33633591 PMCID: PMC7902066 DOI: 10.3389/fphys.2021.641331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/13/2021] [Indexed: 12/13/2022] Open
Abstract
Salt-sensitivity is a major factor in the development of hypertension. The brain orexin system has been observed to play a role in numerous hypertensive animal models. However, orexin’s role in the pathology of salt-sensitive hypertension (SSH) remains to be adequately explored. We assessed the impact of orexin hyperactivity in the pathogenesis of the deoxycorticosterone acetate (DOCA) – salt rat model, specifically through modulation of Arginine Vasopressin (AVP). Adult male rats were separated into three groups: vehicle control, DOCA-salt, and DOCA-salt+OX1R-shRNA. DOCA-salt rats received subcutaneous implantation of a 21-day release, 75 mg DOCA pellet in addition to saline drinking water (1% NaCl and 0.2% KCl). DOCA-salt+OX1R-shRNA rats received bilateral microinjection of AAV2-OX1R-shRNA into the paraventricular nucleus (PVN) to knockdown function of the Orexin 1-Receptor (OX1R) within that area. Following 2-week to allow full transgene expression, a DOCA pellet was administered in addition to saline drinking solution. Vehicle controls received sham DOCA implantation but were given normal water. During the 3-week DOCA-salt or sham treatment period, mean arterial pressure (MAP) and heart rate (HR) were monitored utilizing tail-cuff plethysmography. Following the 3-week period, rat brains were collected for either PCR mRNA analysis, as well as immunostaining. Plasma samples were collected and subjected to ELISA analysis. In line with our hypothesis, OX1R expression was elevated in the PVN of DOCA-salt treated rats when compared to controls. Furthermore, following chronic knockdown of OX1R, the hypertension development normally induced by DOCA-salt treatment was significantly diminished in the DOCA-salt+OX1R-shRNA group. A concurrent reduction in PVN OX1R and AVP mRNA was observed in concert with the reduced blood pressure following AAV2-OX1R-shRNA treatment. Similarly, plasma AVP concentrations appeared to be reduced in the DOCA-salt+OX1R-shRNA group when compared to DOCA-salt rats. These results indicate that orexin signaling, specifically through the OX1R in the PVN are critical for the onset and maintenance of hypertension in the DOCA-salt model. This relationship is mediated, at least in part, through orexin activation of AVP producing neurons, and the subsequent release of AVP into the periphery. Our results outline a promising mechanism underlying the development of SSH through interactions with the brain orexin system.
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Affiliation(s)
- Jeremy A Bigalke
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Department of Psychology, Montana State University, Bozeman, MT, United States
| | - Huanjia Gao
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Qing-Hui Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Health Research Institute, Michigan Technological University, Houghton, MI, United States
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Health Research Institute, Michigan Technological University, Houghton, MI, United States
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12
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Central endothelin ET B receptor activation reduces blood pressure and catecholaminergic activity in the olfactory bulb of deoxycorticosterone acetate-salt hypertensive rats. Eur J Pharmacol 2020; 885:173543. [PMID: 32896551 DOI: 10.1016/j.ejphar.2020.173543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 09/01/2020] [Accepted: 09/03/2020] [Indexed: 11/23/2022]
Abstract
Endothelins regulate catecholaminergic activity in the olfactory bulb (OB) in normotensive and hypertensive animals. Administration of an endothelin ETA receptor antagonist decreases blood pressure in deoxycorticosterone acetate-salt (DOCA-salt) rats along with a reduction in tyrosine hydroxylase (TH) activity and expression. In the present work, we sought to establish the role of brain endothelin ETB receptor on blood pressure regulation and its relationship with the catecholaminergic system within the OB of DOCA-Salt rats. Sprague-Dawley male rats were divided into control and DOCA-Salt groups. Blood pressure, heart rate and TH activity as well as neuronal nitric oxide synthase (nNOS) expression were assessed following IRL-1620 (selective endothelin ETB receptor agonist) applied to be brain. IRL-1620 significantly reduced systolic, diastolic, and mean arterial pressure in DOCA-Salt hypertensive rats. It also decreased TH activity, TH total and phosphorylated forms expression as well as its mRNA in the OB of hypertensive animals. The expression of phospho-Ser1417-nNOS, which reflects nNOS activation, was significantly decreased in the of OB of DOCA-salt rats, but it was enhanced by IRL-1620. These findings suggest that DOCA-Salt hypertension depends on endogenous central endothelin ETA receptor activity, rather than on ETB, and that low endothelin ETB stimulation is essential for blood pressure elevation in this animal model. The effect of endothelin ETA receptor antagonism may also result from endothelin ETB receptor overstimulation. The present study shows that endothelin receptors are involved in the regulation of TH in the OB and that such changes are likely implicated in the hemodynamic control and sympathetic outflow.
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13
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Guil MJ, Schöller MI, Cassinotti LR, Biancardi VC, Pitra S, Bianciotti LG, Stern JE, Vatta MS. Role of endothelin receptor type A on catecholamine regulation in the olfactory bulb of DOCA-salt hypertensive rats: Hemodynamic implications. Biochim Biophys Acta Mol Basis Dis 2019; 1865:165527. [PMID: 31398465 DOI: 10.1016/j.bbadis.2019.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 07/18/2019] [Accepted: 08/05/2019] [Indexed: 01/09/2023]
Abstract
Increasing evidence shows that the olfactory bulb is involved in blood pressure regulation in health and disease. Enhanced noradrenergic transmission in the olfactory bulb was reported in hypertension. Given that endothelins modulate catecholamines and are involved in the pathogenesis of hypertension, in the present study we sought to establish the role of the endothelin receptor type A on tyrosine hydroxylase, the rate limiting enzyme in catecholamine biosynthesis, in the olfactory bulb of DOCA-salt hypertensive rats. Sprague-Dawley male rats, randomly divided into Control and DOCA-Salt hypertensive groups, were used to assess endothelin receptors by Western blot and confocal microscopy, and their co-localization with tyrosine hydroxylase in the olfactory bulb. Blood pressure and heart rate as well as tyrosine hydroxylase expression and activity were assessed following BQ610 (ETA antagonist) applied to the brain. DOCA-Salt hypertensive rats showed enhanced ETA and decreased ETB expression. ETA co-localized with tyrosine hydroxylase positive neurons. Acute ETA blockade reduced blood pressure and heart rate and decreased the expression of total tyrosine hydroxylase and its phosphorylated forms. Furthermore, it also diminished mRNA tyrosine hydroxylase expression and accelerated the enzyme degradation through the proteasome pathway as shown by pretreatment with MG132, (20s proteasome inhibitor) intracerebroventricularly applied. Present findings support that the brain endothelinergic system plays a major role through ETA activation in the increase of catecholaminergic activity in the olfactory bulb of DOCA-Salt hypertensive rats. They provide rationale evidence that this telencephalic structure contributes in a direct or indirect way to the hemodynamic regulation in salt dependent hypertension.
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Affiliation(s)
- María J Guil
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Fisiología, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA), Buenos Aires, Argentina
| | - Mercedes I Schöller
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Fisiología, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA), Buenos Aires, Argentina
| | - Luis R Cassinotti
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Fisiología, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA), Buenos Aires, Argentina
| | | | - Soledad Pitra
- Department of Physiology, Augusta University, Augusta, GA, USA
| | - Liliana G Bianciotti
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Fisiopatología, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - Javier E Stern
- Department of Physiology, Augusta University, Augusta, GA, USA
| | - Marcelo S Vatta
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Fisiología, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA), Buenos Aires, Argentina.
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14
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Souza LAC, Worker CJ, Li W, Trebak F, Watkins T, Gayban AJB, Yamasaki E, Cooper SG, Drumm BT, Feng Y. (Pro)renin receptor knockdown in the paraventricular nucleus of the hypothalamus attenuates hypertension development and AT 1 receptor-mediated calcium events. Am J Physiol Heart Circ Physiol 2019; 316:H1389-H1405. [PMID: 30925093 DOI: 10.1152/ajpheart.00780.2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Activation of the brain renin-angiotensin system (RAS) is a pivotal step in the pathogenesis of hypertension. The paraventricular nucleus (PVN) of the hypothalamus is a critical part of the angiotensinergic sympatho-excitatory neuronal network involved in neural control of blood pressure and hypertension. However, the importance of the PVN (pro)renin receptor (PVN-PRR)-a key component of the brain RAS-in hypertension development has not been examined. In this study, we investigated the involvement and mechanisms of the PVN-PRR in DOCA-salt-induced hypertension, a mouse model of hypertension. Using nanoinjection of adeno-associated virus-mediated Cre recombinase expression to knock down the PRR specifically in the PVN, we report here that PVN-PRR knockdown attenuated the enhanced blood pressure and sympathetic tone associated with hypertension. Mechanistically, we found that PVN-PRR knockdown was associated with reduced activation of ERK (extracellular signal-regulated kinase)-1/2 in the PVN and rostral ventrolateral medulla during hypertension. In addition, using the genetically encoded Ca2+ biosensor GCaMP6 to monitor Ca2+-signaling events in the neurons of PVN brain slices, we identified a reduction in angiotensin II type 1 receptor-mediated Ca2+ activity as part of the mechanism by which PVN-PRR knockdown attenuates hypertension. Our study demonstrates an essential role of the PRR in PVN neurons in hypertension through regulation of ERK1/2 activation and angiotensin II type 1 receptor-mediated Ca2+ activity. NEW & NOTEWORTHY PRR knockdown in PVN neurons attenuates the development of DOCA-salt hypertension and autonomic dysfunction through a decrease in ERK1/2 activation in the PVN and RVLM during hypertension. In addition, PRR knockdown reduced AT1aR expression and AT1R-mediated calcium activity during hypertension. Furthermore, we characterized the neuronal targeting specificity of AAV serotype 2 in the mouse PVN and validated the advantages of the genetically encoded calcium biosensor GCaMP6 in visualizing neuronal calcium activity in the PVN.
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Affiliation(s)
- Lucas A C Souza
- Department of Pharmacology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Center for Cardiovascular Research, University of Nevada, Reno, School of Medicine , Reno, Nevada
| | - Caleb J Worker
- Department of Pharmacology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Center for Cardiovascular Research, University of Nevada, Reno, School of Medicine , Reno, Nevada
| | - Wencheng Li
- Department of Pathology, Wake Forest University , Winston-Salem, North Carolina
| | - Fatima Trebak
- Department of Pharmacology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Center for Cardiovascular Research, University of Nevada, Reno, School of Medicine , Reno, Nevada
| | - Trevor Watkins
- Department of Pharmacology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Center for Cardiovascular Research, University of Nevada, Reno, School of Medicine , Reno, Nevada
| | - Ariana Julia B Gayban
- Department of Pharmacology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Center for Cardiovascular Research, University of Nevada, Reno, School of Medicine , Reno, Nevada
| | - Evan Yamasaki
- Department of Pharmacology, University of Nevada, Reno, School of Medicine , Reno, Nevada
| | - Silvana G Cooper
- Department of Pharmacology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Center for Cardiovascular Research, University of Nevada, Reno, School of Medicine , Reno, Nevada
| | - Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine , Reno, Nevada
| | - Yumei Feng
- Department of Pharmacology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine , Reno, Nevada.,Center for Cardiovascular Research, University of Nevada, Reno, School of Medicine , Reno, Nevada
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15
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Li D, Paterson DJ. Pre-synaptic sympathetic calcium channels, cyclic nucleotide-coupled phosphodiesterases and cardiac excitability. Semin Cell Dev Biol 2019; 94:20-27. [PMID: 30658154 DOI: 10.1016/j.semcdb.2019.01.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/07/2019] [Accepted: 01/14/2019] [Indexed: 12/20/2022]
Abstract
In sympathetic neurons innervating the heart, action potentials activate voltage-gated Ca2+ channels and evoke Ca2+ entry into presynaptic terminals triggering neurotransmitter release. Binding of transmitters to specific receptors stimulates signal transduction pathways that cause changes in cardiac function. The mechanisms contributing to presynaptic Ca2+ dynamics involve regulation of endogenous Ca2+ buffers, in particular the endoplasmic reticulum, mitochondria and cyclic nucleotide targeted pathways. The purpose of this review is to summarize and highlight recent findings about Ca2+ homeostasis in cardiac sympathetic neurons and how modulation of second messengers can drive neurotransmission and affect myocyte excitability in cardiovascular disease. Moreover, we discuss the underlying mechanism of abnormal intracellular Ca2+ homeostasis and signaling in these neurons, and speculate on the role of phosphodiesterases as a therapeutic target to restore normal autonomic transmission in disease states of overactivity.
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Affiliation(s)
- Dan Li
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.
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16
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Nomura K, Hiyama TY, Sakuta H, Matsuda T, Lin CH, Kobayashi K, Kobayashi K, Kuwaki T, Takahashi K, Matsui S, Noda M. [Na +] Increases in Body Fluids Sensed by Central Na x Induce Sympathetically Mediated Blood Pressure Elevations via H +-Dependent Activation of ASIC1a. Neuron 2018; 101:60-75.e6. [PMID: 30503172 DOI: 10.1016/j.neuron.2018.11.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 10/08/2018] [Accepted: 11/08/2018] [Indexed: 02/07/2023]
Abstract
Increases in sodium concentrations ([Na+]) in body fluids elevate blood pressure (BP) by enhancing sympathetic nerve activity (SNA). However, the mechanisms by which information on increased [Na+] is translated to SNA have not yet been elucidated. We herein reveal that sympathetic activation leading to BP increases is not induced by mandatory high salt intakes or the intraperitoneal/intracerebroventricular infusions of hypertonic NaCl solutions in Nax-knockout mice in contrast to wild-type mice. We identify Nax channels expressed in specific glial cells in the organum vasculosum lamina terminalis (OVLT) as the sensors detecting increases in [Na+] in body fluids and show that OVLT neurons projecting to the paraventricular nucleus (PVN) are activated via acid-sensing ion channel 1a (ASIC1a) by H+ ions exported from Nax-positive glial cells. The present results provide an insight into the neurogenic mechanisms responsible for salt-induced BP elevations.
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Affiliation(s)
- Kengo Nomura
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan
| | - Takeshi Y Hiyama
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan; School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan
| | - Hiraki Sakuta
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan; School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan
| | - Takashi Matsuda
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan
| | - Chia-Hao Lin
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
| | - Kazuto Kobayashi
- Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Tomoyuki Kuwaki
- Department of Physiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Kunihiko Takahashi
- Department of Biostatistics, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Shigeyuki Matsui
- Department of Biostatistics, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Masaharu Noda
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi 444-8787, Japan; School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan; Research Center for Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan.
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17
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Qin C, Li J, Tang K. The Paraventricular Nucleus of the Hypothalamus: Development, Function, and Human Diseases. Endocrinology 2018; 159:3458-3472. [PMID: 30052854 DOI: 10.1210/en.2018-00453] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 07/16/2018] [Indexed: 02/08/2023]
Abstract
The paraventricular nucleus of the hypothalamus (PVH), located in the ventral diencephalon adjacent to the third ventricle, is a highly conserved brain region present in species from zebrafish to humans. The PVH is composed of three main types of neurons, magnocellular, parvocellular, and long-projecting neurons, which play imperative roles in the regulation of energy balance and various endocrinological activities. In this review, we focus mainly on recent findings about the early development of the hypothalamus and the PVH, the functions of the PVH in the modulation of energy homeostasis and in the hypothalamus-pituitary system, and human diseases associated with the PVH, such as obesity, short stature, hypertension, and diabetes insipidus. Thus, the investigations of the PVH will benefit not only understanding of the development of the central nervous system but also the etiology of and therapy for human diseases.
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Affiliation(s)
- Cheng Qin
- Queen Mary School, Medical Department, Nanchang University, Nanchang, Jiangxi, China
- Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Jiaheng Li
- Queen Mary School, Medical Department, Nanchang University, Nanchang, Jiangxi, China
- Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Ke Tang
- Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, Guangdong, China
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18
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Sandgren JA, Linggonegoro DW, Zhang SY, Sapouckey SA, Claflin KE, Pearson NA, Leidinger MR, Pierce GL, Santillan MK, Gibson-Corley KN, Sigmund CD, Grobe JL. Angiotensin AT 1A receptors expressed in vasopressin-producing cells of the supraoptic nucleus contribute to osmotic control of vasopressin. Am J Physiol Regul Integr Comp Physiol 2018; 314:R770-R780. [PMID: 29364700 PMCID: PMC6032302 DOI: 10.1152/ajpregu.00435.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/03/2018] [Accepted: 01/17/2018] [Indexed: 11/22/2022]
Abstract
Angiotensin II (ANG) stimulates the release of arginine vasopressin (AVP) from the neurohypophysis through activation of the AT1 receptor within the brain, although it remains unclear whether AT1 receptors expressed on AVP-expressing neurons directly mediate this control. We explored the hypothesis that ANG acts through AT1A receptors expressed directly on AVP-producing cells to regulate AVP secretion. In situ hybridization and transgenic mice demonstrated localization of AVP and AT1A mRNA in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN), but coexpression of both AVP and AT1A mRNA was only observed in the SON. Mice harboring a conditional allele for the gene encoding the AT1A receptor (AT1Aflox) were then crossed with AVP-Cre mice to generate mice that lack AT1A in all cells that express the AVP gene (AT1AAVP-KO). AT1AAVP-KO mice exhibited spontaneously increased plasma and serum osmolality but no changes in fluid or salt-intake behaviors, hematocrit, or total body water. AT1AAVP-KO mice exhibited reduced AVP secretion (estimated by measurement of copeptin) in response to osmotic stimuli such as acute hypertonic saline loading and in response to chronic intracerebroventricular ANG infusion. However, the effects of these receptors on AVP release were masked by complex stimuli such as overnight dehydration and DOCA-salt treatment, which simultaneously induce osmotic, volemic, and pressor stresses. Collectively, these data support the expression of AT1A in AVP-producing cells of the SON but not the PVN, and a role for AT1A receptors in these cells in the osmotic regulation of AVP secretion.
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MESH Headings
- Angiotensin II/administration & dosage
- Angiotensin II/pharmacology
- Animals
- Body Water
- Feeding Behavior
- Injections, Intraventricular
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Osmosis
- Paraventricular Hypothalamic Nucleus/metabolism
- Receptor, Angiotensin, Type 1/biosynthesis
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/physiology
- Sodium, Dietary
- Supraoptic Nucleus/metabolism
- Supraoptic Nucleus/physiology
- Vasoconstrictor Agents/administration & dosage
- Vasoconstrictor Agents/pharmacology
- Vasopressins/biosynthesis
- Vasopressins/physiology
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Affiliation(s)
| | | | - Shao Yang Zhang
- Department of Pharmacology, University of Iowa , Iowa City, Iowa
| | | | | | - Nicole A Pearson
- Department of Pharmacology, University of Iowa , Iowa City, Iowa
| | | | - Gary L Pierce
- Department of Health and Human Physiology, University of Iowa , Iowa City, Iowa
- Center for Hypertension Research, University of Iowa , Iowa City, Iowa
- François M. Abboud Cardiovascular Research Center, University of Iowa , Iowa City, Iowa
| | - Mark K Santillan
- Department of Obstetrics and Gynecology, University of Iowa , Iowa City, Iowa
- Center for Hypertension Research, University of Iowa , Iowa City, Iowa
| | - Katherine N Gibson-Corley
- Department of Pathology, University of Iowa , Iowa City, Iowa
- Center for Hypertension Research, University of Iowa , Iowa City, Iowa
- Fraternal Order of Eagles' Diabetes Research Center, University of Iowa , Iowa City, Iowa
| | - Curt D Sigmund
- Department of Pharmacology, University of Iowa , Iowa City, Iowa
- Center for Hypertension Research, University of Iowa , Iowa City, Iowa
- François M. Abboud Cardiovascular Research Center, University of Iowa , Iowa City, Iowa
| | - Justin L Grobe
- Department of Pharmacology, University of Iowa , Iowa City, Iowa
- Center for Hypertension Research, University of Iowa , Iowa City, Iowa
- François M. Abboud Cardiovascular Research Center, University of Iowa , Iowa City, Iowa
- Iowa Neuroscience Institute, University of Iowa , Iowa City, Iowa
- Obesity Research and Education Initiative, University of Iowa , Iowa City, Iowa
- Fraternal Order of Eagles' Diabetes Research Center, University of Iowa , Iowa City, Iowa
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19
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Li C, Chang Q, Zhang J, Chai W. Effects of slow breathing rate on heart rate variability and arterial baroreflex sensitivity in essential hypertension. Medicine (Baltimore) 2018; 97:e0639. [PMID: 29718876 PMCID: PMC6392805 DOI: 10.1097/md.0000000000010639] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
This study is to investigate the effects of slow breathing on heart rate variability (HRV) and arterial baroreflex sensitivity in essential hypertension.We studied 60 patients with essential hypertension and 60 healthy controls. All subjects underwent controlled breathing at 8 and 16 breaths per minute. Electrocardiogram, respiratory, and blood pressure signals were recorded simultaneously. We studied effects of slow breathing on heart rate, blood pressure and respiratory peak, high-frequency (HF) power, low-frequency (LF) power, and LF/HF ratio of HRV with traditional and corrected spectral analysis. Besides, we tested whether slow breathing was capable of modifying baroreflex sensitivity in hypertensive subjects.Slow breathing, compared with 16 breaths per minute, decreased the heart rate and blood pressure (all P < .05), and shifted respiratory peak toward left (P < .05). Compared to 16 breaths/minute, traditional spectral analysis showed increased LF power and LF/HF ratio, decreased HF power of HRV at 8 breaths per minute (P < .05). As breathing rate decreased, corrected spectral analysis showed increased HF power, decreased LF power, LF/HF ratio of HRV (P < .05). Compared to controls, resting baroreflex sensitivity decreased in hypertensive subjects. Slow breathing increased baroreflex sensitivity in hypertensive subjects (from 59.48 ± 6.39 to 78.93 ± 5.04 ms/mm Hg, P < .05) and controls (from 88.49 ± 6.01 to 112.91 ± 7.29 ms/mm Hg, P < .05).Slow breathing can increase HF power and decrease LF power and LF/HF ratio in essential hypertension. Besides, slow breathing increased baroreflex sensitivity in hypertensive subjects. These demonstrate slow breathing is indeed capable of shifting sympatho-vagal balance toward vagal activities and increasing baroreflex sensitivity, suggesting a safe, therapeutic approach for essential hypertension.
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Affiliation(s)
| | - Qinghua Chang
- Cardiovascular Institute, the First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning Province, China
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20
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Xie A, Song Z, Liu H, Zhou A, Shi G, Wang Q, Gu L, Liu M, Xie LH, Qu Z, Dudley SC. Mitochondrial Ca 2+ Influx Contributes to Arrhythmic Risk in Nonischemic Cardiomyopathy. J Am Heart Assoc 2018; 7:JAHA.117.007805. [PMID: 29627768 PMCID: PMC6015427 DOI: 10.1161/jaha.117.007805] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background Heart failure (HF) is associated with increased arrhythmia risk and triggered activity. Abnormal Ca2+ handling is thought to underlie triggered activity, and mitochondria participate in Ca2+ homeostasis. Methods and Results A model of nonischemic HF was induced in C57BL/6 mice by hypertension. Computer simulations were performed using a mouse ventricular myocyte model of HF. Isoproterenol‐induced premature ventricular contractions and ventricular fibrillation were more prevalent in nonischemic HF mice than sham controls. Isolated myopathic myocytes showed decreased cytoplasmic Ca2+ transients, increased mitochondrial Ca2+ transients, and increased action potential duration at 90% repolarization. The alteration of action potential duration at 90% repolarization was consistent with in vivo corrected QT prolongation and could be explained by augmented L‐type Ca2+ currents, increased Na+‐Ca2+ exchange currents, and decreased total K+ currents. Of myopathic ventricular myocytes, 66% showed early afterdepolarizations (EADs) compared with 17% of sham myocytes (P<0.05). Intracellular application of 1 μmol/L Ru360, a mitochondrial Ca2+ uniporter–specific antagonist, could reduce mitochondrial Ca2+ transients, decrease action potential duration at 90% repolarization, and ameliorate EADs. Furthermore, genetic knockdown of mitochondrial Ca2+ uniporters inhibited mitochondrial Ca2+ uptake, reduced Na+‐Ca2+ exchange currents, decreased action potential duration at 90% repolarization, suppressed EADs, and reduced ventricular fibrillation in nonischemic HF mice. Computer simulations showed that EADs promoted by HF remodeling could be abolished by blocking either the mitochondrial Ca2+ uniporter or the L‐type Ca2+ current, consistent with the experimental observations. Conclusions Mitochondrial Ca2+ handling plays an important role in EADs seen with nonischemic cardiomyopathy and may represent a therapeutic target to reduce arrhythmic risk in this condition.
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Affiliation(s)
- An Xie
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Zhen Song
- Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA
| | - Hong Liu
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Anyu Zhou
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Guangbin Shi
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Qiongying Wang
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Lianzhi Gu
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Man Liu
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School Rutgers, The State University of New Jersey, Newark, NJ
| | - Zhilin Qu
- Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA
| | - Samuel C Dudley
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
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21
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Abstract
Hypertension is a multifaceted disease that is involved in ∼40% of cardiovascular mortalities and is the result of both genetic and environmental factors. Because of its complexity, hypertension has been studied by using various models and approaches, each of which tends to focus on individual organs or tissues to isolate the most critical and treatable causes of hypertension and the related damage to end-organs. Animal models of hypertension have ranged from Goldblatt's kidney clip models in which the origin of the disease is clearly renal to animals that spontaneously develop hypertension either through targeted genetic manipulations, such as the TGR(mRen2)27, or selective breeding resulting in more enigmatic origins, as exemplified by the spontaneously hypertensive rat (SHR). These two genetically derived models simulate the less-common human primary hypertension in which research has been able to define a Mendelian linkage. Several models are more neurogenic or endocrine in nature and illustrate that crosstalk between the nervous system and hormones can cause a significant rise in blood pressure (BP). This review will examine one of these neurogenic models of hypertension, i.e., the deoxycorticosterone acetate (DOCA), reduced renal mass, and high-salt diet (DOCA-salt) rodent model, one of the most common experimental models used today. Although the DOCA-salt model is mainly believed to be neurogenic and has been shown to impact the central and peripheral nervous systems, it also significantly involves many other body organs.
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Affiliation(s)
- Tyler Basting
- Department of Pharmacology and Experimental Therapeutics, School of Medicine, Louisiana State University Health Sciences Center, 1901 Perdido Street, Room 5218, New Orleans, LA, 70112, USA.,Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Eric Lazartigues
- Department of Pharmacology and Experimental Therapeutics, School of Medicine, Louisiana State University Health Sciences Center, 1901 Perdido Street, Room 5218, New Orleans, LA, 70112, USA. .,Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, USA. .,Neurosciences Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, USA.
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22
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Chronic Blockade of Brain Endothelin Receptor Type-A (ET A) Reduces Blood Pressure and Prevents Catecholaminergic Overactivity in the Right Olfactory Bulb of DOCA-Salt Hypertensive Rats. Int J Mol Sci 2018; 19:ijms19030660. [PMID: 29495426 PMCID: PMC5877521 DOI: 10.3390/ijms19030660] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/05/2018] [Accepted: 02/08/2018] [Indexed: 01/06/2023] Open
Abstract
Overactivity of the sympathetic nervous system and central endothelins (ETs) are involved in the development of hypertension. Besides the well-known brain structures involved in the regulation of blood pressure like the hypothalamus or locus coeruleus, evidence suggests that the olfactory bulb (OB) also modulates cardiovascular function. In the present study, we evaluated the interaction between the endothelinergic and catecholaminergic systems in the OB of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Following brain ET receptor type A (ETA) blockade by BQ610 (selective antagonist), transcriptional, traductional, and post-traductional changes in tyrosine hydroxylase (TH) were assessed in the OB of normotensive and DOCA-salt hypertensive rats. Time course variations in systolic blood pressure and heart rate were also registered. Results showed that ETA blockade dose dependently reduced blood pressure in hypertensive rats, but it did not change heart rate. It also prevented the increase in TH activity and expression (mRNA and protein) in the right OB of hypertensive animals. However, ETA blockade did not affect hemodynamics or TH in normotensive animals. Present results support that brain ETA are not involved in blood pressure regulation in normal rats, but they significantly contribute to chronic blood pressure elevation in hypertensive animals. Changes in TH activity and expression were observed in the right but not in the left OB, supporting functional asymmetry, in line with previous studies regarding cardiovascular regulation. Present findings provide further evidence on the role of ETs in the regulation of catecholaminergic activity and the contribution of the right OB to DOCA-salt hypertension.
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23
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Mui RK, Fernandes RN, Garver HG, Van Rooijen N, Galligan JJ. Macrophage-dependent impairment of α 2-adrenergic autoreceptor inhibition of Ca 2+ channels in sympathetic neurons from DOCA-salt but not high-fat diet-induced hypertensive rats. Am J Physiol Heart Circ Physiol 2018; 314:H863-H877. [PMID: 29351460 DOI: 10.1152/ajpheart.00536.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
DOCA-salt and obesity-related hypertension are associated with inflammation and sympathetic nervous system hyperactivity. Prejunctional α2-adrenergic receptors (α2ARs) provide negative feedback to norepinephrine release from sympathetic nerves through inhibition of N-type Ca2+ channels. Increased neuronal norepinephrine release in DOCA-salt and obesity-related hypertension occurs through impaired α2AR signaling; however, the mechanisms involved are unclear. Mesenteric arteries are resistance arteries that receive sympathetic innervation from the superior mesenteric and celiac ganglia (SMCG). We tested the hypothesis that macrophages impair α2AR-mediated inhibition of Ca2+ channels in SMCG neurons from DOCA-salt and high-fat diet (HFD)-induced hypertensive rats. Whole cell patch-clamp methods were used to record Ca2+ currents from SMCG neurons maintained in primary culture. We found that DOCA-salt, but not HFD-induced, hypertension caused macrophage accumulation in mesenteric arteries, increased SMCG mRNA levels of monocyte chemoattractant protein-1 and tumor necrosis factor-α, and impaired α2AR-mediated inhibition of Ca2+ currents in SMCG neurons. α2AR dysfunction did not involve changes in α2AR expression, desensitization, or downstream signaling factors. Oxidative stress impaired α2AR-mediated inhibition of Ca2+ currents in SMCG neurons and resulted in receptor internalization in human embryonic kidney-293T cells. Systemic clodronate-induced macrophage depletion preserved α2AR function and lowered blood pressure in DOCA-salt rats. HFD caused hypertension without obesity in Sprague-Dawley rats and hypertension with obesity in Dahl salt-sensitive rats. HFD-induced hypertension was not associated with inflammation in SMCG and mesenteric arteries or α2AR dysfunction in SMCG neurons. These results suggest that macrophage-mediated α2AR dysfunction in the mesenteric circulation may only be relevant to mineralocorticoid-salt excess. NEW & NOTEWORTHY Here, we identify a contribution of macrophages to hypertension development through impaired α2-adrenergic receptor (α2AR)-mediated inhibition of sympathetic nerve terminal Ca2+ channels in DOCA-salt hypertensive rats. Impaired α2AR function may involve oxidative stress-induced receptor internalization. α2AR dysfunction may be unique to mineralocorticoid-salt excess, as it does not occur in obesity-related hypertension.
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Affiliation(s)
- Ryan K Mui
- Department of Physiology, Michigan State University , East Lansing, Michigan
| | - Roxanne N Fernandes
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
| | - Hannah G Garver
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
| | - Nico Van Rooijen
- Department of Molecular Cell Biology, Vrije Universiteit Medical Center , Amsterdam , The Netherlands
| | - James J Galligan
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan.,Neuroscience Program, Michigan State University , East Lansing, Michigan
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24
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Abstract
PURPOSE OF REVIEW The central nervous system plays a pivotal role in the regulation of extracellular fluid volume and consequently arterial blood pressure. Key hypothalamic regions sense and integrate neurohumoral signals to subsequently alter intake (thirst and salt appetite) and output (renal excretion via neuroendocrine and autonomic function). Here, we review recent findings that provide new insight into such mechanisms that may represent new therapeutic targets. RECENT FINDINGS Implementation of cutting edge neuroscience approaches such as opto- and chemogenetics highlight pivotal roles of circumventricular organs to impact body fluid homeostasis. Key signaling mechanisms within these areas include the N-terminal variant of transient receptor potential vannilloid type-1, NaX, epithelial sodium channel, brain electroneutral transporters, and non-classical actions of vasopressin. Despite the identification of several new mechanisms, future studies need to better define the neurochemical phenotype and molecular profiles of neurons within circumventricular organs for future therapeutic potential.
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25
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Zhang M, Stern JE. Altered NMDA receptor-evoked intracellular Ca 2+ dynamics in magnocellular neurosecretory neurons of hypertensive rats. J Physiol 2017; 595:7399-7411. [PMID: 29034474 DOI: 10.1113/jp275169] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/03/2017] [Indexed: 01/03/2023] Open
Abstract
KEY POINTS NMDA receptor (NMDAR)-mediated Ca2+ signalling plays a critical role in modulating hypothalamic neurosecretory function. However, whether an altered NMDAR-evoked changes in Ca2+ (NMDAR-ΔCa2+ ) signalling in magnocellular neurosecretory cells (MNCs) may contribute to neurohumoral activation during disease states is unknown. We show that activation of NMDARs evoked similar inward currents in MNCs of sham and renovascular hypertensive (RVH) rats. Despite this, a prolonged and larger NMDAR-ΔCa2+ response was observed in the latter. The exacerbated NMDAR-ΔCa2+ responses in MNCs of RVH rats affected both somatic and dendritic compartments. Inhibition of the endoplasmic reticulum sarcoendoplasmic reticulum calcium trasport ATPase (SERCA) pump prolonged NMDAR-ΔCa2+ responses in sham rats, but not in RVH rats. Our study supports an altered spatiotemporal dynamic of NMDAR-ΔCa2+ signalling in MNCs from RVH rats, partly due to blunted endoplasmic reticulum Ca2+ buffering capacity. ABSTRACT A growing body of evidence supports an elevated NMDA receptor (NMDAR)-mediated glutamate excitatory function in the supraoptic nucleus and paraventricular nucleus of hypertensive rats that contributes to neurohumoral activation in this disease. However, the precise mechanisms underlying altered NMDAR signalling in hypertension remain to be elucidated. In this study, we performed simultaneous electrophysiology and fast confocal Ca2+ imaging to determine whether altered NMDAR-mediated changes in intracellular Ca2+ levels (NMDAR-ΔCa2+ ) occurred in hypothalamic magnocellular neurosecretory cells (MNCs) in renovascular hypertensive (RVH) rats. We found that despite evoking a similar excitatory inward current, activation of NMDARs resulted in a larger and prolonged ΔCa2+ in MNCs from RVH rats. Changes in NMDAR-ΔCa2+ dynamics were observed both in somatic and dendritic compartments. Inhibition of the sarcoendoplasmic reticulum calcium trasport ATPase (SERCA) pump activity with thapsigargin prolonged NMDAR-ΔCa2+ responses in MNCs of sham rats, but this effect was occluded in RVH rats, thus equalizing the magnitude and time course of the NMDA-ΔCa2+ responses between the two experimental groups. Taken together, our results support (1) an exacerbated NMDAR-ΔCa2+ response in somatodendritic compartments of MNCs of RVH rats, and (2) that a blunted ER Ca2+ buffering capacity contributes to the altered NMDAR-ΔCa2+ dynamics in this condition. Thus, altered spatiotemporal dynamics of the NMDAR-ΔCa2+ response stands as an underlying mechanism contributing to neurohumoral activation in neurogenic hypertension.
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Affiliation(s)
- Meng Zhang
- Department of Physiology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
| | - Javier E Stern
- Department of Physiology, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA
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26
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Prager-Khoutorsky M, Choe KY, Levi DI, Bourque CW. Role of Vasopressin in Rat Models of Salt-Dependent Hypertension. Curr Hypertens Rep 2017; 19:42. [PMID: 28451854 DOI: 10.1007/s11906-017-0741-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW Dietary salt intake increases both plasma sodium and osmolality and therefore increases vasopressin (VP) release from the neurohypophysis. Although this effect could increase blood pressure by inducing fluid reabsorption and vasoconstriction, acute activation of arterial baroreceptors inhibits VP neurons via GABAA receptors to oppose high blood pressure. Here we review recent findings demonstrating that this protective mechanism fails during chronic high salt intake in rats. RECENT FINDINGS Two recent studies showed that chronic high sodium intake causes an increase in intracellular chloride concentration in VP neurons. This effect causes GABAA receptors to become excitatory and leads to the emergence of VP-dependent hypertension. One study showed that the increase in intracellular chloride was provoked by a decrease in the expression of the chloride exporter KCC2 mediated by local secretion of brain-derived neurotrophic factor and activation of TrkB receptors. Prolonged high dietary salt intake can cause pathological plasticity in a central homeostatic circuit that controls VP secretion and thereby contribute to peripheral vasoconstriction and hypertension.
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Affiliation(s)
- Masha Prager-Khoutorsky
- Department of Physiology, McGill University, McIntyre Medical Sciences Bldg., 3655 Promenade Sir-William Osler, Montreal, QC, H3G 1Y6, Canada
| | - Katrina Y Choe
- 2309 Gonda Neuroscience and Genetics Research Center, UCLA Department of Neurology, 695 Charles E. Young Dr. South, Los Angeles, CA, 90095, USA
| | - David I Levi
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Center, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC, H3G 1A4, Canada
| | - Charles W Bourque
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Center, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC, H3G 1A4, Canada.
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27
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Zhang M, Biancardi VC, Stern JE. An increased extrasynaptic NMDA tone inhibits A-type K + current and increases excitability of hypothalamic neurosecretory neurons in hypertensive rats. J Physiol 2017; 595:4647-4661. [PMID: 28378360 PMCID: PMC5509869 DOI: 10.1113/jp274327] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 03/31/2017] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS A functional coupling between extrasynaptic NMDA receptors (eNMDARs) and the A-type K+ current (IA ) influences homeostatic firing responses of magnocellular neurosecretory cells (MNCs) to a physiological challenge. However, whether an altered eNMDAR-IA coupling also contributes to exacerbated MNC activity and neurohumoral activation during disease states is unknown. We show that activation of eNMDARs by exogenously applied NMDA inhibited IA in MNCs obtained from sham, but not in MNCs from renovascular hypertensive (RVH) rats. Neither the magnitude of the exogenously evoked NMDA current nor the expression of NMDAR subunits were altered in RVH rats. Conversely, we found that a larger endogenous glutamate tone, which was not due to blunted glutamate transport activity, led to the sustained activation of eNMDARs that tonically inhibited IA , contributing in turn to higher firing activity in RVH rats. Our studies show that exacerbated activation of eNMDARs by endogenous glutamate contributes to tonic inhibition of IA and enhanced MNC excitability in RVH rats. ABSTRACT We recently showed that a functional coupling between extrasynaptic NMDA receptors (eNMDARs) and the A-type K+ current (IA ) influences the firing activity of hypothalamic magnocellular neurosecretory neurons (MNCs), as well as homeostatic adaptive responses to a physiological challenge. Here, we aimed to determine whether changes in the eNMDAR-IA coupling also contributed to exacerbated MNC activity during disease states. We used a combination of patch-clamp electrophysiology and real-time PCR in MNCs in sham and renovascular hypertensive (RVH) rats. Activation of eNMDARs by exogenously applied NMDA inhibited IA in sham rats, but this effect was largely blunted in RVH rats. The blunted response was not due to changes in eNMDAR expression and/or function, since neither NMDA current magnitude or reversal potential, nor the levels of NR1-NR2A-D subunit expression were altered in RVH rats. Conversely, we found a larger endogenous glutamate tone, resulting in the sustained activation of eNMDARs that tonically inhibited IA and contributed also to higher ongoing firing activity in RVH rats. The enhanced endogenous glutamate tone in RVH rats was not due to blunted glutamate transporter activity. Rather, a higher transporter activity was observed, which possibly acted as a compensatory mechanism in the face of the elevated endogenous tone. In summary, our studies indicate that an elevated endogenous glutamate tone results in an exacerbated activation of eNMDARs, which in turn contributes to diminished IA magnitude and increased firing activity of MNCs from hypertensive rats.
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Affiliation(s)
- Meng Zhang
- Department of PhysiologyMedical College of GeorgiaAugusta University1120 15th StreetAugustaGA30912USA
| | - Vinicia C. Biancardi
- Department of PhysiologyMedical College of GeorgiaAugusta University1120 15th StreetAugustaGA30912USA
| | - Javier E. Stern
- Department of PhysiologyMedical College of GeorgiaAugusta University1120 15th StreetAugustaGA30912USA
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28
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Prayitnaningsih S, Sujuti H, Effendi M, Abdullah A, Anandita NW, Yohana F, Permatasari N, Widodo MA. Neuropathy optic glaucomatosa induced by systemic hypertension through activation endothelin-1 signaling pathway in central retinal artery in rats. Int J Ophthalmol 2016; 9:1568-1577. [PMID: 27990358 DOI: 10.18240/ijo.2016.11.06] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 05/30/2016] [Indexed: 12/14/2022] Open
Abstract
AIM To evaluate effect of hypertension on retinal ganglion cell (RGC) apoptosis, intraocular pressure (IOP), and the activation of endothelin-1 (ET-1) signaling pathway in central retinal artery (CRA) in rats. METHODS The experimental study was performed on 20 male Sprague Dawley rats that were divided into control group, and hypertension groups. The hypertension was induced by subcutaneous deoxycorticoacetate (DOCA) 10 mg/kg twice a week and administered 0.9% NaCl solution daily for 2, 6, and 10wk. Blood pressure (BP) was measured using animal BP analyzer. IOP was measured by handheld tonometry. Retinal tissue preparations by paraffin blocks were made after enucleation. The expression of ET-1, eNOS, ET-1 receptor A (ETRA), ET-1 receptor B (ETRB), and phosphorylated myosin light chain kinase (MLCK), and caldesmon (CaD) in CRA and RGC apoptosis were evaluated through immunofluorescent staining method then observed using laser scanning confocal microscopy. RESULTS BP significantly increased in all of the hypertension groups compared to control (P=0.001). Peak IOP elevation (7.78±4.14 mm Hg) and RGC apoptosis (576.15±33.28 Au) occurred on 2wk of hypertension. ET-1 expression (1238.6±55.1 Au) and eNOS expression (2814.2±70.7 Au) were found highest in 2wk of hypertension, although the ratio of ET-1/eNOS decreased since 2wk. ETRA reached peak expression in 10wk of hypertension (1219.4±6.3 Au), while ETRB significantly increased only in 2 weeks group (1069.2±9.6 Au). The highest MLCK expression (1190.09±58.32 Au), CaD (1670.28±18.36 Au) were also found in 2wk of hypertension. CONCLUSION Hypertension effects to activation of ET-1 signaling pathway significantly in CRA, elevation of IOP, and RGC apoptosis. The highest value was achieved at 2wk, which is the development phase of hypertension.
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Affiliation(s)
| | - Hidayat Sujuti
- Department of Ophthalmology, Faculty of Medicine, Brawijaya University, Malang 65145, Indonesia
| | - Maksum Effendi
- Department of Ophthalmology, Faculty of Medicine, Brawijaya University, Malang 65145, Indonesia
| | - Aulia Abdullah
- Department of Ophthalmology, Faculty of Medicine, Brawijaya University, Malang 65145, Indonesia
| | - Nanda Wahyu Anandita
- Department of Ophthalmology, Faculty of Medicine, Brawijaya University, Malang 65145, Indonesia
| | - Febriani Yohana
- Department of Ophthalmology, Faculty of Medicine, Brawijaya University, Malang 65145, Indonesia
| | - Nur Permatasari
- Pharmacology Laboratory, Faculty of Medicine, Brawijaya University, Malang 65145, Indonesia
| | - Mohamad Aris Widodo
- Pharmacology Laboratory, Faculty of Medicine, Brawijaya University, Malang 65145, Indonesia
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Xu J, Mukerjee S, Silva-Alves CRA, Carvalho-Galvão A, Cruz JC, Balarini CM, Braga VA, Lazartigues E, França-Silva MS. A Disintegrin and Metalloprotease 17 in the Cardiovascular and Central Nervous Systems. Front Physiol 2016; 7:469. [PMID: 27803674 PMCID: PMC5067531 DOI: 10.3389/fphys.2016.00469] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 09/30/2016] [Indexed: 01/19/2023] Open
Abstract
ADAM17 is a metalloprotease and disintegrin that lodges in the plasmatic membrane of several cell types and is able to cleave a wide variety of cell surface proteins. It is somatically expressed in mammalian organisms and its proteolytic action influences several physiological and pathological processes. This review focuses on the structure of ADAM17, its signaling in the cardiovascular system and its participation in certain disorders involving the heart, blood vessels, and neural regulation of autonomic and cardiovascular modulation.
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Affiliation(s)
- Jiaxi Xu
- Department of Pharmacology and Experimental Therapeutics and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center New Orleans, LA, USA
| | - Snigdha Mukerjee
- Department of Pharmacology and Experimental Therapeutics and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center New Orleans, LA, USA
| | | | | | - Josiane C Cruz
- Centro de Biotecnologia, Universidade Federal da Paraíba João Pessoa, Brazil
| | - Camille M Balarini
- Centro de Ciências da Saúde, Universidade Federal da Paraíba João Pessoa, Brazil
| | - Valdir A Braga
- Centro de Biotecnologia, Universidade Federal da Paraíba João Pessoa, Brazil
| | - Eric Lazartigues
- Department of Pharmacology and Experimental Therapeutics and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center New Orleans, LA, USA
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Kalla M, Herring N, Paterson DJ. Cardiac sympatho-vagal balance and ventricular arrhythmia. Auton Neurosci 2016; 199:29-37. [PMID: 27590099 PMCID: PMC5334443 DOI: 10.1016/j.autneu.2016.08.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 12/11/2022]
Abstract
A hallmark of cardiovascular disease is cardiac autonomic dysregulation. The phenotype of impaired parasympathetic responsiveness and sympathetic hyperactivity in experimental animal models is also well documented in large scale human studies in the setting of heart failure and myocardial infarction, and is predictive of morbidity and mortality. Despite advances in emergency revascularisation strategies for myocardial infarction, device therapy for heart failure and secondary prevention pharmacotherapies, mortality from malignant ventricular arrhythmia remains high. Patients at highest risk or those with haemodynamically significant ventricular arrhythmia can be treated with catheter ablation and implantable cardioverter defibrillators, but the morbidity and reduction in quality of life due to the burden of ventricular arrhythmia and shock therapy persists. Therefore, future therapies must aim to target the underlying pathophysiology that contributes to the generation of ventricular arrhythmia. This review explores recent advances in mechanistic research in both limbs of the autonomic nervous system and potential avenues for translation into clinical therapy. In addition, we also discuss the relationship of these findings in the context of the reported efficacy of current neuromodulatory strategies in the management of ventricular arrhythmia. We review advances in mechanistic research in the cardiac autonomic nervous system. This is discussed in relation to neuromodulatory therapy for ventricular arrhythmia. Neuromodulation therapies can influence both neurotransmitters and co-transmitters. This may therefore improve on conventional medical treatment.
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Affiliation(s)
| | - Neil Herring
- Corresponding author at: Burdon Sanderson Cardiac Science Centre, Dept. of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, OX13PT, UK.Burdon Sanderson Cardiac Science CentreDept. of Physiology, Anatomy and GeneticsUniversity of OxfordParks RoadOX13PTUK
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31
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Li D, Paterson DJ. Cyclic nucleotide regulation of cardiac sympatho-vagal responsiveness. J Physiol 2016; 594:3993-4008. [PMID: 26915722 DOI: 10.1113/jp271827] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/17/2016] [Indexed: 12/22/2022] Open
Abstract
Cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) are now recognized as important intracellular signalling molecules that modulate cardiac sympatho-vagal balance in the progression of heart disease. Recent studies have identified that a significant component of autonomic dysfunction associated with several cardiovascular pathologies resides at the end organ, and is coupled to impairment of cyclic nucleotide targeted pathways linked to abnormal intracellular calcium handling and cardiac neurotransmission. Emerging evidence also suggests that cyclic nucleotide coupled phosphodiesterases (PDEs) play a key role limiting the hydrolysis of cAMP and cGMP in disease, and as a consequence this influences the action of the nucleotide on its downstream biological target. In this review, we illustrate the action of nitric oxide-CAPON signalling and brain natriuretic peptide on cGMP and cAMP regulation of cardiac sympatho-vagal transmission in hypertension and ischaemic heart disease. Moreover, we address how PDE2A is now emerging as a major target that affects the efficacy of soluble/particulate guanylate cyclase coupling to cGMP in cardiac dysautonomia.
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Affiliation(s)
- Dan Li
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
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Li X, Dai Y, Yan S, Shi Y, Li J, Liu J, Cha L, Mu J. Resveratrol lowers blood pressure in spontaneously hypertensive rats via calcium-dependent endothelial NO production. Clin Exp Hypertens 2016; 38:287-93. [PMID: 27018796 DOI: 10.3109/10641963.2015.1089882] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Resveratrol, a polyphenol of natural compounds, has beneficial cardiovascular effects, many of which are mediated by nitric oxide (NO). Resveratrol increases intracellular calcium and activates AMP-activated protein kinase (AMPK), all of which could increase NO production. We hypothesized that resveratrol via a calcium-dependent NO production lowers blood pressure (BP) in spontaneously hypertensive rats (SHR). METHODS Acetylcholine (Ach)-induced endothelium-dependent relaxations in rat aortas were examined by organ chamber. Blood pressures were determined by radiotelemetry methods. RESULTS Incubation of isolated aortas from SHR with resveratrol dramatically improved vasorelaxation induced by Ach. Preincubation of aortas with endothelial NO synthase (eNOS) inhibitor or calcium chelant blunted the effects of resveratrol on Ach-induced relaxation, as wells as NO production and eNOS phosphorylation. In animal studies, administration of resveratrol significantly lowered systemic BP in SHR. CONCLUSION Resveratrol increases endothelial NO production to improve endothelial dysfunction and lowers BP in hypertensive rats, which depends on calcium-eNOS activation.
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Affiliation(s)
- Xin Li
- a Department of Cardiology , The First Affiliated Hospital of Medical College, Xi'an Jiao Tong University , Xi'an , China.,b Department of Cardiology , The Fourth Affiliated Hospital of Harbin Medical University , Harbin , China
| | - Yingnan Dai
- b Department of Cardiology , The Fourth Affiliated Hospital of Harbin Medical University , Harbin , China
| | - Shujun Yan
- b Department of Cardiology , The Fourth Affiliated Hospital of Harbin Medical University , Harbin , China
| | - Yanli Shi
- b Department of Cardiology , The Fourth Affiliated Hospital of Harbin Medical University , Harbin , China
| | - Jingxiu Li
- b Department of Cardiology , The Fourth Affiliated Hospital of Harbin Medical University , Harbin , China
| | - Jinglu Liu
- b Department of Cardiology , The Fourth Affiliated Hospital of Harbin Medical University , Harbin , China
| | - Li Cha
- b Department of Cardiology , The Fourth Affiliated Hospital of Harbin Medical University , Harbin , China
| | - Jianjun Mu
- a Department of Cardiology , The First Affiliated Hospital of Medical College, Xi'an Jiao Tong University , Xi'an , China
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Thang LV, Demel SL, Crawford R, Kaminski NE, Swain GM, Van Rooijen N, Galligan JJ. Macrophage depletion lowers blood pressure and restores sympathetic nerve α2-adrenergic receptor function in mesenteric arteries of DOCA-salt hypertensive rats. Am J Physiol Heart Circ Physiol 2015; 309:H1186-97. [PMID: 26320034 DOI: 10.1152/ajpheart.00283.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/25/2015] [Indexed: 02/07/2023]
Abstract
We tested the hypothesis that vascular macrophage infiltration and O2 (-) release impairs sympathetic nerve α2-adrenergic autoreceptor (α2AR) function in mesenteric arteries (MAs) of DOCA-salt hypertensive rats. Male rats were uninephrectomized or sham operated (sham). DOCA pellets were implanted subcutaneously in uninephrectomized rats who were provided high-salt drinking water or high-salt water with apocynin. Sham rats received tap water. Blood pressure was measured using radiotelemetry. Treatment of sham and DOCA-salt rats with liposome-encapsulated clodronate was used to deplete macrophages. After 3-5, 10-13, and 18-21 days of DOCA-salt treatment, MAs and peritoneal fluid were harvested from euthanized rats. Norepinephrine (NE) release from periarterial sympathetic nerves was measured in vitro using amperometry with microelectrodes. Macrophage infiltration into MAs as well as TNF-α and p22(phox) were measured using immunohistochemistry. Peritoneal macrophage activation was measured by flow cytometry. O2 (-) was measured using dihydroethidium staining. Hypertension developed over 28 days, and apocynin reduced blood pressure on days 18-21. O2 (-) and macrophage infiltration were greater in DOCA-salt MAs compared with sham MAs after day 10. Peritoneal macrophage activation occurred after day 10 in DOCA-salt rats. Macrophages expressing TNF-α and p22(phox) were localized near sympathetic nerves. Impaired α2AR function and increased NE release from sympathetic nerves occurred in MAs from DOCA-salt rats after day 18. Macrophage depletion reduced blood pressure and vascular O2 (-) while restoring α2AR function in DOCA-salt rats. Macrophage infiltration into the vascular adventitia contributes to increased blood pressure in DOCA-salt rats by releasing O2 (-), which disrupts α2AR function, causing enhanced NE release from sympathetic nerves.
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Affiliation(s)
- Loc V Thang
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - Stacie L Demel
- Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Robert Crawford
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan
| | - Norbert E Kaminski
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan
| | - Greg M Swain
- Neuroscience Program, Michigan State University, East Lansing, Michigan; Department of Chemistry, Michigan State University, East Lansing, Michigan; and
| | - Nico Van Rooijen
- Department of Molecular Cell Biology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands
| | - James J Galligan
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; Neuroscience Program, Michigan State University, East Lansing, Michigan;
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de Queiroz TM, Xia H, Filipeanu CM, Braga VA, Lazartigues E. α-Lipoic acid reduces neurogenic hypertension by blunting oxidative stress-mediated increase in ADAM17. Am J Physiol Heart Circ Physiol 2015; 309:H926-34. [PMID: 26254330 DOI: 10.1152/ajpheart.00259.2015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/30/2015] [Indexed: 02/07/2023]
Abstract
We previously reported that type 2 angiotensin-converting enzyme (ACE2) compensatory activity is impaired by the disintegrin and metalloprotease 17 (ADAM17), and lack of ACE2 is associated with oxidative stress in neurogenic hypertension. To investigate the relationship between ADAM17 and oxidative stress, Neuro2A cells were treated with ANG II (100 nM) 24 h after vehicle or α-lipoic acid (LA, 500 μM). ADAM17 expression was increased by ANG II (120.5 ± 9.1 vs. 100.2 ± 0.8%, P < 0.05) and decreased after LA (69.0 ± 0.3 vs. 120.5 ± 9.1%, P < 0.05). In another set of experiments, LA reduced ADAM17 (92.9 ± 5.3 vs. 100.0 ± 11.2%, P < 0.05) following its overexpression. Moreover, ADAM17 activity was reduced by LA in ADAM17-overexpressing cells [109.5 ± 19.8 vs. 158.0 ± 20.0 fluorescence units (FU)·min(-1)·μg protein(-1), P < 0.05], in which ADAM17 overexpression increased oxidative stress (114.1 ± 2.5 vs. 101.0 ± 1.0%, P < 0.05). Conversely, LA-treated cells attenuated ADAM17 overexpression-induced oxidative stress (76.0 ± 9.1 vs. 114.1 ± 2.5%, P < 0.05). In deoxycorticosterone acetate (DOCA)-salt hypertensive mice, a model in which ADAM17 expression and activity are increased, hypertension was blunted by pretreatment with LA (119.0 ± 2.4 vs. 131.4 ± 2.2 mmHg, P < 0.05). In addition, LA improved dysautonomia and baroreflex sensitivity. Furthermore, LA blunted the increase in NADPH oxidase subunit expression, as well as the increase in ADAM17 and decrease in ACE2 activity in the hypothalamus of DOCA-salt hypertensive mice. Taken together, these data suggest that LA might preserve ACE2 compensatory activity by breaking the feedforward cycle between ADAM17 and oxidative stress, resulting in a reduction of neurogenic hypertension.
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Affiliation(s)
- Thyago M de Queiroz
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana; Department of Biotechnology, Federal University of Paraíba, João Pessoa, PB, Brazil
| | - Huijing Xia
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana; Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana; and
| | - Catalin M Filipeanu
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana; Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana; and
| | - Valdir A Braga
- Department of Biotechnology, Federal University of Paraíba, João Pessoa, PB, Brazil
| | - Eric Lazartigues
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana; Neurosciences Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana; Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana; and
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Sun GQ, Li YB, Du B, Meng Y. Resveratrol via activation of AMPK lowers blood pressure in DOCA-salt hypertensive mice. Clin Exp Hypertens 2015; 37:616-21. [DOI: 10.3109/10641963.2015.1036060] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Toczek M, Schlicker E, Grzęda E, Malinowska B. Enhanced function of inhibitory presynaptic cannabinoid CB1 receptors on sympathetic nerves of DOCA-salt hypertensive rats. Life Sci 2015; 138:78-85. [PMID: 25921770 DOI: 10.1016/j.lfs.2015.03.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 03/20/2015] [Accepted: 03/26/2015] [Indexed: 02/08/2023]
Abstract
AIMS This study was performed to examine whether hypertension affects the sympathetic transmission to resistance vessels of pithed rats via inhibitory presynaptic cannabinoid CB1 receptors and whether endocannabinoids are involved in this response. MATERIALS AND METHODS We compared uninephrectomised rats rendered hypertensive by high salt diet and deoxycorticosterone acetate (DOCA) injections with normotensive animals (uninephrectomy only). Experiments were performed on vagotomised and pithed animals. Increases in diastolic blood pressure (DBP) were induced four times (S1-S4) by electrical stimulation or phenylephrine injection. KEY FINDINGS Electrical stimulation (0.75Hz, 1ms, 50V, 5 impulses) of the preganglionic sympathetic nerve fibres innervating the blood vessels more strongly increased DBP in normotensive than in DOCA-salt rats. Phenylephrine (0.01μmol/kg) induced similar increases in DBP in both groups. The cannabinoid receptor agonist CP55940 (0.01-1μmol/kg) did not modify the rises in DBP induced by phenylephrine. However, it inhibited the electrically stimulated increases in DBP, more strongly in DOCA-salt than in normotensive animals (maximally by 50 and 30%, respectively). The effect of CP55940 was attenuated by the CB1 antagonist AM251 (3μmol/kg). AM251 enhanced the neurogenic vasopressor response during S4 by itself in hypertensive rats only. URB597 (3μmol/kg), which inhibits degradation of the endocannabinoid anandamide, did not modify the electrically stimulated increases in DBP. SIGNIFICANCE The function of inhibitory presynaptic CB1 receptors on sympathetic nerves is enhanced in DOCA-salt hypertensive rats. Thus, the CB1 receptor-mediated inhibition of noradrenaline release from the sympathetic nerve fibres innervating the resistance vessels might play a protective role in hypertension.
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Affiliation(s)
- Marek Toczek
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Mickiewicz Str. 2A, 15-222 Białystok, Poland
| | - Eberhard Schlicker
- Department of Pharmacology and Toxicology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
| | - Emilia Grzęda
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Mickiewicz Str. 2A, 15-222 Białystok, Poland
| | - Barbara Malinowska
- Department of Experimental Physiology and Pathophysiology, Medical University of Białystok, Mickiewicz Str. 2A, 15-222 Białystok, Poland.
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Abramoff T, Guil MJ, Morales VP, Hope SI, Höcht C, Bianciotti LG, Vatta MS. Involvement of endothelins in deoxycorticosterone acetate-salt hypertension through the modulation of noradrenergic transmission in the rat posterior hypothalamus. Exp Physiol 2015; 100:617-27. [PMID: 25809871 DOI: 10.1113/ep085230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 03/23/2015] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does ex vivo administration of endothelin-1 and endothelin-3 regulate noradrenergic transmission in the posterior hypothalamus of deoxycorticosterone acetate-salt hypertensive rats compared with normotensive rats? What is the main finding and its importance? Endothelin-1 and endothelin-3 enhanced diverse mechanisms leading to increased noradrenergic transmission in the posterior hypothalamus of deoxycorticosterone acetate-salt hypertensive rats. Unveiling the role of brain endothelins in hypertension would probably favour the development of new therapeutic targets for the treatment of essential hypertension, which still represents a challenging disease with high mortality. Brain catecholamines participate in diverse biological functions regulated by the hypothalamus. We have previously reported that endothelin-1 and endothelin-3 (ET-1 and ET-3) modulate catecholaminergic activity in the anterior and posterior hypothalamus of normotensive rats. The aim of the present study was to evaluate the interaction between endothelins and noradrenergic transmission in the posterior hypothalamus of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. We assessed the effects of ET-1 and ET-3 on tyrosine hydroxylase activity and expression, neuronal noradrenaline (NA) release, neuronal NA transporter (NAT) activity and expression, monoamine oxidase activity and NA endogenous content and utilization (as a marker of turnover) in the posterior hypothalamus of DOCA-salt hypertensive rats. In addition, levels of ETA and ETB receptors were assayed in normotensive and hypertensive rats. Results showed that tyrosine hydroxylase activity and total and phosphorylated levels, NAT activity and content, NA release, monoamine oxidase activity and NA utilization were increased in DOCA-salt rats. Both ET-1 and ET-3 further enhanced all noradrenergic parameters except for total tyrosine hydroxylase level and NA endogenous content and utilization. The expression of ETA receptors was increased in the posterior hypothalamus of DOCA-salt rats, but ETB receptors showed no changes. These results show that ET-1 and ET-3 upregulate noradrenergic activity in the posterior hypothalamus of DOCA-salt hypertensive rats. Our findings suggest that the interaction between noradrenergic transmission and the endothelinergic system in the posterior hypothalamus may be involved in the development and/or maintenance of hypertension in this animal model.
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Affiliation(s)
- Tamara Abramoff
- Cátedra de Fisiología, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
| | - María J Guil
- Cátedra de Fisiología, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
| | - Vanina P Morales
- Cátedra de Fisiología, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
| | - Sandra I Hope
- Cátedra de Fisiología, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
| | - Christian Höcht
- Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
| | - Liliana G Bianciotti
- Cátedra de Fisiopatología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires e Instituto de Inmunología, Genética y Metabolismo (INIGEM-CONICET), Argentina
| | - Marcelo S Vatta
- Cátedra de Fisiología, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
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Mendoza A, Lazartigues E. The compensatory renin-angiotensin system in the central regulation of arterial pressure: new avenues and new challenges. Ther Adv Cardiovasc Dis 2015; 9:201-8. [PMID: 25801471 DOI: 10.1177/1753944715578056] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hypertension is a widespread condition that affects millions of people around the world and has a major impact in public health. The classic renin-angiotensin system is a complex system comprised of multiple peptides and pathways that have been the driver of drug development over the years to control hypertension. However, there are still patients whose hypertension is very difficult to control with current drugs and strategies, thus motivating further research in this field. In the past two decades, important discoveries have expanded our knowledge of this system and new pathways are emerging that are helping us understand the complex interaction taking place not only in the periphery, but also in the central nervous system where the renin-angiotensin system is also very active. A new arm, called the ACE2/Ang-(1-7)/Mas receptor axis, was shown to exert antihypertensive properties and serve as a counterbalance to the classic ACE/angiotensin II/AT1 receptor axis, in this way modulating or even counteracting the negative effects of angiotensin II in blood pressure regulation and water retention. Modulation of this new axis through ACE2 activation, ADAM17 regulation or AT1 receptor internalization are some of the novel avenues and challenges that have the potential to become a target for new drug research and development for the treatment of hypertension.
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Affiliation(s)
- Alberto Mendoza
- Department of Pharmacology and Experimental Therapeutics, Neurosciences and Cardiovascular Centers of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Eric Lazartigues
- Louisiana State University Health Sciences Center, School of Medicine, Department of Pharmacology and Experimental Therapeutics, 1901 Perdido St, Rm 5218, New Orleans, LA 70112, USA
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Petersen-Jones HG, Johnson KB, Hitomi K, Tykocki NR, Thompson JM, Watts SW. Transglutaminase activity is decreased in large arteries from hypertensive rats compared with normotensive controls. Am J Physiol Heart Circ Physiol 2015; 308:H592-602. [PMID: 25599570 DOI: 10.1152/ajpheart.00402.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transglutaminases (TGs) catalyze the formation of covalent cross-links between glutamine residues and amine groups. This cross-linking activity has been implicated in arterial remodeling. Because hypertension is characterized by arterial remodeling, we hypothesized that TG activity, expression, and functionality would be increased in the aorta, but not in the vena cava (which does not undergo remodeling), from hypertensive rats relative to normotensive rats. Spontaneously hypertensive stroke-prone rats (SHRSP) and DOCA-salt rats as well as their respective normotensive Wistar-Kyoto or Sprague-Dawley counterparts were used. Immunohistochemistry and Western blot analysis measured the presence and expression of TG1 and TG2, in situ activity assays quantified active TGs, and isometric contractility was used to measure TG functionality. Contrary to our hypothesis, the activity (52% DOCA-salt vs. control rats and 56% SHRSP vs. control rats, P < 0.05), expression (TG1: 54% DOCA-salt vs. control rats, P > 0.05, and TG2: 77% DOCA-salt vs. control rats, P < 0.05), and functionality of TG1 and TG2 were decreased in the aorta, but not in the vena cava, from hypertensive rats. Mass spectrometry identified proteins uniquely amidated by TGs in the aorta that play roles in cytoskeletal regulation, redox regulation, and DNA/RNA/protein synthesis and regulation and in the vena cava that play roles in cytoskeletal regulation, coagulation regulation, and cell metabolism. Consistent with the idea that growing cells lose TG2 expression, vascular smooth muscle cells placed in culture lost TG2 expression. We conclude that the expression, activity, and functionality of TG1 and TG2 are decreased in the aorta, but not in the vena cava, from hypertensive rats compared with control rats.
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Affiliation(s)
| | - Kyle B Johnson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Kiyotaka Hitomi
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
| | - Nathan R Tykocki
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Janice M Thompson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Stephanie W Watts
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
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Sriramula S, Xia H, Xu P, Lazartigues E. Brain-targeted angiotensin-converting enzyme 2 overexpression attenuates neurogenic hypertension by inhibiting cyclooxygenase-mediated inflammation. Hypertension 2014; 65:577-86. [PMID: 25489058 DOI: 10.1161/hypertensionaha.114.04691] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Overactivity of the renin-angiotensin system, oxidative stress, and cyclooxygenases (COX) in the brain are implicated in the pathogenesis of hypertension. We previously reported that angiotensin-converting enzyme 2 (ACE2) overexpression in the brain attenuates the development of deoxycorticosterone acetate-salt hypertension, a neurogenic hypertension model with enhanced brain renin-angiotensin system and sympathetic activity. To elucidate the mechanisms involved, we investigated whether oxidative stress, mitogen-activated protein kinase signaling and cyclooxygenase (COX) activation in the brain are modulated by ACE2 in neurogenic hypertension. Deoxycorticosterone acetate-salt hypertension significantly increased expression of Nox-2 (+61±5%), Nox-4 (+50±13%), and nitrotyrosine (+89±32%) and reduced activity of the antioxidant enzymes, catalase (-29±4%) and superoxide dismutase (-31±7%), indicating increased oxidative stress in the brain of nontransgenic mice. This increased oxidative stress was attenuated in transgenic mice overexpressing ACE2 in the brain. Deoxycorticosterone acetate-salt-induced reduction of neuronal nitric oxide synthase expression (-26±7%) and phosphorylated endothelial nitric oxide synthase/total endothelial nitric oxide synthase (-30±3%), and enhanced phosphorylation of protein kinase B and extracellular signal-regulated kinase 1/2 in the paraventricular nucleus, were reversed by ACE2 overexpression. In addition, ACE2 overexpression blunted the hypertension-mediated increase in gene and protein expression of COX-1 and COX-2 in the paraventricular nucleus. Furthermore, gene silencing of either COX-1 or COX-2 in the brain, reduced microglial activation and accompanied neuroinflammation, ultimately attenuating Deoxycorticosterone acetate-salt hypertension. Together, these data provide evidence that brain ACE2 overexpression reduces oxidative stress and COX-mediated neuroinflammation, improves antioxidant and nitric oxide signaling, and thereby attenuates the development of neurogenic hypertension.
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Affiliation(s)
- Srinivas Sriramula
- Department of Pharmacology and Experimental Therapeutics, Neurosciences and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans
| | - Huijing Xia
- Department of Pharmacology and Experimental Therapeutics, Neurosciences and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans
| | - Ping Xu
- Department of Pharmacology and Experimental Therapeutics, Neurosciences and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans
| | - Eric Lazartigues
- Department of Pharmacology and Experimental Therapeutics, Neurosciences and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans.
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Hernandez ME, Hayward LF. Effect of DOCA/salt hypertension on CRF expression in the amygdala and the autonomic stress response in conscious rats. Auton Neurosci 2014; 185:83-92. [DOI: 10.1016/j.autneu.2014.07.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 07/29/2014] [Accepted: 07/31/2014] [Indexed: 12/26/2022]
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Kim YB, Kim YS, Kim WB, Shen FY, Lee SW, Chung HJ, Kim JS, Han HC, Colwell CS, Kim YI. GABAergic excitation of vasopressin neurons: possible mechanism underlying sodium-dependent hypertension. Circ Res 2013; 113:1296-307. [PMID: 24103391 DOI: 10.1161/circresaha.113.301814] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Increased arginine-vasopressin (AVP) secretion is a key physiological response to hyperosmotic stress and may be part of the mechanism by which high-salt diets induce or exacerbate hypertension. OBJECTIVE Using deoxycorticosterone acetate-salt hypertension model rats, we sought to test the hypothesis that changes in GABA(A) receptor-mediated inhibition in AVP-secreting magnocellular neurons contribute to the generation of Na(+)-dependent hypertension. METHODS AND RESULTS In vitro gramicidin-perforated recordings in the paraventricular and supraoptic nuclei revealed that the GABAergic inhibition in AVP-secreting neurons was converted into excitation in this model, because of the depolarization of GABA equilibrium potential. Meanwhile, in vivo extracellular recordings in the supraoptic nuclei showed that the GABAergic baroreflexive inhibition of magnocellular neurons was transformed to excitation, so that baroreceptor activation may increase AVP release. The depolarizing GABA equilibrium potential shift in AVP-secreting neurons occurred progressively over weeks of deoxycorticosterone acetate-salt treatment along with gradual increases in plasma AVP and blood pressure. Furthermore, the shift was associated with changes in chloride transporter expression and partially reversed by bumetanide (Na(+)-K(+)-2Cl(-) cotransporter inhibitor). Intracerebroventricular bumetanide administration during deoxycorticosterone acetate-salt treatment hindered the development of hypertension and rise in plasma AVP level. Muscimol (GABA(A) agonist) microinjection into the supraoptic nuclei in hypertensive rats increased blood pressure, which was prevented by previous intravenous V1a AVP antagonist injection. CONCLUSIONS We conclude that the inhibitory-to-excitatory switch of GABAA receptor-mediated transmission in AVP neurons contributes to the generation of Na(+)-dependent hypertension by increasing AVP release. We speculate that normalizing the GABA equilibrium potential may have some utility in treating Na(+)-dependent hypertension.
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Affiliation(s)
- Young-Beom Kim
- From the Department of Physiology (Y.-B.K., Y.S.K., W.B.K., F.-Y.S., S.W.L., H.J.C., H.C.H., Y.I.K.), and Neuroscience Research Institute (Y.-B.K., Y.S.K., W.B.K., F.-Y.S., S.W.L., H.J.C., H.C.H., Y.I.K.), Korea University College of Medicine, Seoul, Republic of Korea; Department of Physiology, Biomedical Science Institute and Brain Korea 21 Project Center, Kyung Hee University School of Medicine, Seoul, Republic of Korea (J.S.K.); and Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, CA (C.S.C.)
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Xia H, Sriramula S, Chhabra KH, Lazartigues E. Brain angiotensin-converting enzyme type 2 shedding contributes to the development of neurogenic hypertension. Circ Res 2013; 113:1087-1096. [PMID: 24014829 DOI: 10.1161/circresaha.113.301811] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RATIONALE Overactivity of the brain renin-angiotensin system is a major contributor to neurogenic hypertension. Although overexpression of angiotensin-converting enzyme type 2 (ACE2) has been shown to be beneficial in reducing hypertension by transforming angiotensin II into angiotensin-(1-7), several groups have reported decreased brain ACE2 expression and activity during the development of hypertension. OBJECTIVE We hypothesized that ADAM17-mediated ACE2 shedding results in decreased membrane-bound ACE2 in the brain, thus promoting the development of neurogenic hypertension. METHODS AND RESULTS To test this hypothesis, we used the deoxycorticosterone acetate-salt model of neurogenic hypertension in nontransgenic and syn-hACE2 mice overexpressing ACE2 in neurons. Deoxycorticosterone acetate-salt treatment in nontransgenic mice led to significant increases in blood pressure, hypothalamic angiotensin II levels, inflammation, impaired baroreflex sensitivity, and autonomic dysfunction, as well as decreased hypothalamic ACE2 activity and expression, although these changes were blunted or prevented in syn-hACE2 mice. In addition, reduction of ACE2 expression and activity in the brain paralleled an increase in ACE2 activity in the cerebrospinal fluid of nontransgenic mice after deoxycorticosterone acetate-salt treatment and were accompanied by enhanced ADAM17 expression and activity in the hypothalamus. Chronic knockdown of ADAM17 in the brain blunted the development of hypertension and restored ACE2 activity and baroreflex function. CONCLUSIONS Our data provide the first evidence that ADAM17-mediated shedding impairs brain ACE2 compensatory activity, thus contributing to the development of neurogenic hypertension.
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Affiliation(s)
- Huijing Xia
- Department of Pharmacology and Experimental Therapeutics and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Srinivas Sriramula
- Department of Pharmacology and Experimental Therapeutics and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Kavaljit H Chhabra
- Department of Pharmacology and Experimental Therapeutics and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Eric Lazartigues
- Department of Pharmacology and Experimental Therapeutics and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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Abramoff T, Guil MJ, Morales VP, Hope SI, Soria C, Bianciotti LG, Vatta MS. Enhanced assymetrical noradrenergic transmission in the olfactory bulb of deoxycorticosterone acetate-salt hypertensive rats. Neurochem Res 2013; 38:2063-71. [PMID: 23888389 DOI: 10.1007/s11064-013-1114-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 07/10/2013] [Accepted: 07/13/2013] [Indexed: 01/14/2023]
Abstract
The ablation of olfactory bulb induces critical changes in dopamine, and monoamine oxidase activity in the brain stem. Growing evidence supports the participation of this telencephalic region in the regulation blood pressure and cardiovascular activity but little is known about its contribution to hypertension. We have previously reported that in the olfactory bulb of normotensive rats endothelins enhance noradrenergic activity by increasing tyrosine hydroxylase activity and norepinephrine release. In the present study we sought to establish the status of noradrenergic activity in the olfactory bulb of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Different steps in norepinephrine transmission including tyrosine hydroxylase activity, neuronal norepinephrine release and uptake were assessed in the left and right olfactory bulb of DOCA-salt hypertensive rats. Increased tyrosine hydroxylase activity, and decreased neuronal norepinephrine uptake were observed in the olfactory bulb of DOCA-salt hypertensive rats. Furthermore the expression of tyrosine hydroxylase and its phosphorylated forms were also augmented. Intriguingly, asymmetrical responses between the right and left olfactory bulb of normotensive and hypertensive rats were observed. Neuronal norepinephrine release was increased in the right but not in the left olfactory bulb of DOCA-salt hypertensive rats, whereas non asymmetrical differences were observed in normotensive animals. Present findings indicate that the olfactory bulb of hypertensive rats show an asymmetrical increase in norepinephrine activity. The observed changes in noradrenergic transmission may likely contribute to the onset and/or progression of hypertension in this animal model.
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Affiliation(s)
- Tamara Abramoff
- Cátedra de Fisiología e Instituto de la Química y Metabolismo del Fármaco (IQUIMEFA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Piso 7, 1113AAD-CABA, Buenos Aires, Argentina
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Davis RP, Szasz T, Garver H, Burnett R, Tykocki NR, Watts SW. One-month serotonin infusion results in a prolonged fall in blood pressure in the deoxycorticosterone acetate (DOCA) salt hypertensive rat. ACS Chem Neurosci 2013; 4:141-8. [PMID: 23336053 DOI: 10.1021/cn300114a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 09/16/2012] [Indexed: 12/31/2022] Open
Abstract
A 7-day infusion of serotonin (5-hydroxytryptamine, 5-HT) causes a sustained fall in elevated blood pressure in the male deoxycorticosterone acetate (DOCA)-salt rat. As hypertension is a long-term disease, we presently test the hypothesis that a longer (30 day) 5-HT infusion could cause a sustained fall in blood pressure in the established hypertensive DOCA-salt rat. This time period (∼4 weeks) was also sufficient to test whether 5-HT could attenuate the development of DOCA-salt hypertension. 5-HT (25 μg/kg/min; sc) or vehicle (Veh) was delivered via osmotic pump to (1) established DOCA-salt rats for one month, (2) Sprague-Dawley rats prior to DOCA-salt administration for one month, and blood pressure and heart rate measured telemetrically. On the final day of 5-HT infusion, free platelet poor plasma 5-HT concentrations were significantly higher in 5-HT versus Veh-infused rats, and mean arterial pressure was significantly lower in 5-HT-infused (135 ± 4 mmHg vs Veh-infused 151 ± 7 mmHg) established DOCA-salt rats. By contrast, 5-HT-infusion did not prevent the development of DOCA-salt hypertension (144 ± 7 mmHg vs Veh = 156 ± 6 mmHg). Isometric contraction of aortic strips was measured, and neither the potency nor maximum contraction to the alpha adrenergic receptor agonist phenylephrine (PE) or 5-HT were modified by infusion of 5-HT (established or preventative infusion), and maximum aortic relaxation to acetylcholine (ACh) was modestly but not significantly enhanced (∼15% improvement). This study demonstrates 5-HT is capable of lowering blood pressure in established DOCA-salt hypertensive rats over the course of one month in a mechanism that does not significantly modify or is dependent on modified vascular responsiveness. This finding opens the possibility that elevation of 5-HT levels could be useful in the treatment of hypertension.
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Affiliation(s)
- Robert Patrick Davis
- Department of Pharmacology
and Toxicology, Michigan State University, East Lansing, Michigan,
United States
| | - Theodora Szasz
- Department of Pharmacology
and Toxicology, Michigan State University, East Lansing, Michigan,
United States
| | - Hannah Garver
- Department of Pharmacology
and Toxicology, Michigan State University, East Lansing, Michigan,
United States
| | - Robert Burnett
- Department of Pharmacology
and Toxicology, Michigan State University, East Lansing, Michigan,
United States
| | - Nathan R. Tykocki
- Department of Pharmacology
and Toxicology, Michigan State University, East Lansing, Michigan,
United States
| | - Stephanie W. Watts
- Department of Pharmacology
and Toxicology, Michigan State University, East Lansing, Michigan,
United States
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Hilzendeger AM, Cassell MD, Davis DR, Stauss HM, Mark AL, Grobe JL, Sigmund CD. Angiotensin type 1a receptors in the subfornical organ are required for deoxycorticosterone acetate-salt hypertension. Hypertension 2012; 61:716-22. [PMID: 23266541 DOI: 10.1161/hypertensionaha.111.00356] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although elevated renin-angiotensin system activity and angiotensinergic signaling within the brain are required for hypertension, polydipsia, and increased metabolic rate induced by deoxycorticosterone acetate (DOCA)-salt, the contribution of specific receptor subtypes and brain nuclei mediating these responses remains poorly defined. We hypothesized that angiotensin type 1a receptors (AT(1a)R) within the subfornical organ (SFO) mediate these responses. Transgenic mice carrying a conditional allele of the endogenous AT(1a)R (AT(1a)R(flox)) were administered an adenovirus encoding Cre-recombinase and enhanced green fluorescent protein (eGFP) or adenovirus encoding eGFP alone into the lateral cerebral ventricle. Adenovirus encoding Cre-recombinase reduced AT(1a)R mRNA and induced recombination in AT(1a)R(flox) genomic DNA specifically in the SFO, without significant effect in the paraventricular or arcuate nuclei, and also induced SFO-specific recombination in ROSA(TdTomato) reporter mice. The effect of SFO-targeted ablation of endogenous AT(1a)R was evaluated in AT(1a)R(flox) mice at 3 time points: (1) baseline, (2) 1 week after virus injection but before DOCA-salt, and (3) after 3 weeks of DOCA-salt. DOCA-salt-treated mice with deletion of AT(1a)R in SFO exhibited a blunted increase in arterial pressure. Increased sympathetic cardiac modulation and urine copeptin, a marker of vasopressin release, were both significantly reduced in DOCA-salt mice when AT(1a)R was deleted in the SFO. Additionally, deletion of AT(1a)R in the SFO significantly attenuated the polydipsia, polyuria, and sodium intake in response to DOCA-salt. Together, these data highlight the contribution of AT(1a)R in the SFO to arterial pressure regulation potentially through changes on sympathetic cardiac modulation, vasopressin release, and hydromineral balance in the DOCA-salt model of hypertension.
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Li D, Nikiforova N, Lu CJ, Wannop K, McMenamin M, Lee CW, Buckler KJ, Paterson DJ. Targeted neuronal nitric oxide synthase transgene delivery into stellate neurons reverses impaired intracellular calcium transients in prehypertensive rats. Hypertension 2012; 61:202-7. [PMID: 23172925 DOI: 10.1161/hypertensionaha.111.00105] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Hypertension is associated with the early onset of cardiac sympathetic hyperresponsiveness and enhanced intracellular Ca(2+) concentration [Ca(2+)](i) in sympathetic neurons from both prehypertensive and hypertensive, spontaneously hypertensive rats (SHRs). Oxidative stress is a hallmark of hypertension, therefore, we tested the hypothesis that the inhibitory action of the nitric oxide-cGMP pathway on [Ca(2+)](i) transients is impaired in cardiac sympathetic neurons from the SHR. Stellate ganglia were isolated from young prehypertensive SHRs and age-matched normotensive Wistar-Kyoto rats. [Ca(2+)](i) was measured by ratiometric fluorescence imaging. Neurons from the prehypertensive SHR ganglia had a significantly higher depolarization evoked [Ca(2+)](i) transient that was also associated with decreased expression of neuronal nitric oxide synthase (nNOS), β1 subunit of soluble guanylate cyclase and cGMP when compared with the Wistar-Kyoto rat ganglia. Soluble guanylate cyclase inhibition or nNOS inhibition increased [Ca(2+)](i) in the Wistar-Kyoto rats but had no effect in SHR neurons. A nitric oxide donor decreased [Ca(2+)](i) in both sets of neurons, although this was markedly less in the SHR. A novel noradrenergic cell specific vector (Ad.PRSx8-nNOS/Cherry) or its control vector (Ad.PRSx8-Cherry) was expressed in sympathetic neurons. In the SHR, Ad.PRSx8-nNOS/Cherry-treated neurons had a significantly reduced peak [Ca(2+)](i) transient that was associated with increased tissue levels of nNOS protein and cGMP concentration compared with gene transfer of Ad.PRSx8-Cherry alone. nNOS inhibition significantly increased [Ca(2+)](i) after Ad.PRSx8-nNOS/Cherry expression. We conclude that artificial upregulation of stellate sympathetic nNOS via targeted gene transfer can directly attenuate intracellular Ca(2+) and may provide a novel method for decreasing enhanced cardiac sympathetic neurotransmission.
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Affiliation(s)
- Dan Li
- Department of Physiology, Anatomy and Genetics, University of Oxford, Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Oxford, United Kingdom.
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Cardiac sympathetic hyperinnervation in deoxycorticosterone acetate-salt hypertensive rats. Clin Sci (Lond) 2012; 123:445-57. [PMID: 22507072 DOI: 10.1042/cs20120080] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sympathetic activities are elevated in the central SNSs (sympathetic nervous systems) of hypertensive animals, but it is not known whether sympathetic innervation is also elevated in the heart. Sympathetic hyper-responsiveness in hypertension may result from oxidative stress. The aim of the present study was to investigate sympathetic hyperinnervation in DOCA (deoxycorticosterone acetate)-salt hypertensive rats with established hypertension. At 4 weeks after the start of DOCA-salt treatment and uninephrectomization, male Wistar rats were randomized into three groups for 8 weeks: vehicle, NAC (N-acetylcysteine) and triple therapy (hydralazine, hydrochlorothiazide and reserpine). DOCA-salt was associated with increased oxidant release. DOCA-salt produced concentric left ventricular hypertrophy and cardiomyocyte hypertrophy. Sympathetic hyperinnervation was observed in DOCA-salt rats, as assessed by myocardial noradrenaline levels, immunofluorescent analysis of tyrosine hydroxylase, growth-associated factor 43 and neurofilament and Western blotting and real-time quantitative RT-PCR (reverse transcription-PCR) of NGF (nerve growth factor). Arrhythmic scores during programmed stimulation in DOCA-salt rats were significantly higher than those in the control rats. Triple therapy, despite being effective on BP (blood pressure), offered neither attenuated cardiomyocyte hypertrophy nor anti-arrhythmia. The effects of DOCA-salt treatment on NGF expression, sympathetic hyperinnervation and arrhythmias were attenuated by NAC. Furthermore, the effects of NAC on NGF were abolished by administering BSO (L-buthionine sulfoximine), an inhibitor of glutamate-cysteine ligase. In conclusion, DOCA-salt treatment contributes to up-regulation of NGF proteins probably through a free radical-dependent pathway in a BP-independent manner. DOCA-salt rats treated with NAC attenuate sympathetic hyperinnervation and thus show a beneficial effect on arrhythmogenic response to programmed electrical stimulation.
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'Volume-expanded' hypertension: the effect of fluid overload and the role of the sympathetic nervous system in salt-dependent hypertension. J Hypertens 2012; 30:655-9. [PMID: 22227820 DOI: 10.1097/hjh.0b013e32834f6de1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
It is widely believed that salt-dependent hypertension is induced and maintained by expansion of intravascular fluid volume resulting from excessive retention of sodium. The purpose of this brief article is to present a series of arguments in support of the thesis that volume overload per se does not raise the arterial blood pressure. Several investigators in the 1960s and 1970s reported that excessive retention of salt - regardless of cause - leads to sympathetic activation mediated by the effects of the Na ion on α(2)-adrenergic receptors located mostly in the brainstem. In recent years, the cloning and characterization of α(2)-adrenergic receptors subtypes permitted differentiation of their hemodynamic effects via use of salt loading of nephrectomized animals submitted to genetic engineering or gene treatment. These studies indicate that sodium alters the balance between the sympathoinhibitory α(2A)-adrenergic receptors and the sympathoexcitatory α(2B)-adrenergic receptors, leading to a hyperadrenergic hypertensive state unrelated to volume overload.
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50
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Ando K, Fujita M. Reactive oxygen species and the central nervous system in salt-sensitive hypertension: possible relationship with obesity-induced hypertension. Clin Exp Pharmacol Physiol 2012; 39:111-6. [PMID: 21388436 DOI: 10.1111/j.1440-1681.2011.05510.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. There are multiple and complex mechanisms of salt-induced hypertension; however, central sympathoexcitation plays an important role. In addition, the production of reactive oxygen species (ROS) is increased in salt-sensitive hypertensive humans and animals. Thus, we hypothesized that brain ROS overproduction may increase blood pressure (BP) by central sympathostimulation. 2. Recently, we demonstrated that ROS levels were elevated in the hypothalamus of salt-sensitive hypertensive animals. Moreover, intracerebroventricular anti-oxidants suppressed BP and renal sympathetic nerve activity more in salt-sensitive than non-salt-sensitive hypertensive rats. Thus, brain ROS overproduction increased BP through central sympathoexcitation in salt-sensitive hypertension. 3. Salt sensitivity of BP is enhanced in obesity and metabolic syndrome. Interestingly, it is also suggested that, in obesity-induced hypertension models, increases in BP are caused by brain ROS-induced central sympathoexcitation. 4. Recent studies suggest that increased ROS production in the brain and central sympathoexcitation may share a common pathway that increases BP in both salt- and obesity-induced hypertension.
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Affiliation(s)
- Katsuyuki Ando
- Department of Nephrology and Endocrinology, University of Tokyo Graduate School of Medicine, Tokyo, Japan.
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