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Jama HA, Muralitharan RR, Xu C, O'Donnell JA, Bertagnolli M, Broughton BRS, Head GA, Marques FZ. Rodent models of hypertension. Br J Pharmacol 2021; 179:918-937. [PMID: 34363610 DOI: 10.1111/bph.15650] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 01/03/2023] Open
Abstract
Elevated blood pressure (BP), or hypertension, is the main risk factor for cardiovascular disease. As a multifactorial and systemic disease that involves multiple organs and systems, hypertension remains a challenging disease to study. Models of hypertension are invaluable to support the discovery of the specific genetic, cellular and molecular mechanisms underlying essential hypertension, as well as to test new possible treatments to lower BP. Rodent models have proven to be an invaluable tool for advancing the field. In this review, we discuss the strengths and weaknesses of rodent models of hypertension through a systems approach. We highlight the ways how target organs and systems including the kidneys, vasculature, the sympathetic nervous system (SNS), immune system and the gut microbiota influence BP in each rodent model. We also discuss often overlooked hypertensive conditions such as pulmonary hypertension and hypertensive-pregnancy disorders, providing an important resource for researchers.
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Affiliation(s)
- Hamdi A Jama
- Hypertension Research Laboratory, School of Biological Sciences, Faculty of Science, Monash University, Melbourne, Australia.,Heart Failure Research Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Rikeish R Muralitharan
- Hypertension Research Laboratory, School of Biological Sciences, Faculty of Science, Monash University, Melbourne, Australia.,Institute for Medical Research, Ministry of Health Malaysia, Kuala Lumpur, Malaysia
| | - Chudan Xu
- Hypertension Research Laboratory, School of Biological Sciences, Faculty of Science, Monash University, Melbourne, Australia
| | - Joanne A O'Donnell
- Hypertension Research Laboratory, School of Biological Sciences, Faculty of Science, Monash University, Melbourne, Australia
| | - Mariane Bertagnolli
- Laboratory of Maternal-child Health, Hospital Sacre-Coeur Research Center, CIUSSS Nord-de-l'Île-de-Montréal, Montreal, Canada.,School of Physical and Occupational Therapy, Faculty of Medicine, McGill University, Montreal, Canada
| | - Bradley R S Broughton
- Department of Pharmacology, Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Geoffrey A Head
- Department of Pharmacology, Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, Australia.,Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Francine Z Marques
- Hypertension Research Laboratory, School of Biological Sciences, Faculty of Science, Monash University, Melbourne, Australia.,Heart Failure Research Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia
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2
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Abstract
For the majority of hypertensive patients, the etiology of their disease is unknown. The hypothalamus is a central structure of the brain which provides an adaptive, integrative, autonomic, and neuroendocrine response to any fluctuations in physiological conditions of the external or internal environment. Hypothalamic insufficiency leads to severe metabolic and functional disorders, including persistent increase in blood pressure. Here, we discuss alterations in the neurochemical organization of the paraventricular and suprachiasmatic nucleus in the hypothalamus of patients who suffered from essential hypertension and died suddenly due to acute coronary failure. The changes observed are hypothesized to contribute to the pathogenesis of disease.
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Affiliation(s)
- Valeri D Goncharuk
- A.L. Myasnikov Research Institute of Clinical Cardiology, Russian Cardiology Research Center, Ministry of Health of the Russian Federation, Moscow, Russia; Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands.
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3
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Head GA, Jackson KL, Gueguen C. Potential Therapeutic Use of Neurosteroids for Hypertension. Front Physiol 2019; 10:1477. [PMID: 31920690 PMCID: PMC6920208 DOI: 10.3389/fphys.2019.01477] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 11/18/2019] [Indexed: 12/20/2022] Open
Abstract
The sympathetic nervous system (SNS) contribution to long-term setting of blood pressure (BP) and hence hypertension has been a continuing controversy over many decades. However, the contribution of increased sympathetic vasomotor tone to the heart, kidney, and blood vessels has been suggested as a major influence on the development of high BP which affects 30-40% of the population. This is relevant to hypertension associated with chronic stress, being overweight or obese as well to chronic kidney disease. Treatments that have attempted to block the peripheral aspects of the SNS contribution have included surgery to cut the sympathetic nerves as well as agents to block α- and β-adrenoceptors. Other treatments, such as centrally acting drugs like clonidine, rilmenidine, or moxonidine, activate receptors within the ventrolateral medulla to reduce the vasomotor tone overall but have side effects that limit their use. None of these treatments target the cause of the enhanced sympathetic tone. Recently we have identified an antihypertensive action of the neurosteroid allopregnanolone in a mouse model of neurogenic hypertension. Allopregnanolone is known to facilitate high-affinity extra-synaptic γ-aminobutyric acid A receptors (GABAAR) through allosteric modulation and transcriptional upregulation. The antihypertensive effect was specific for increased expression of δ subunits in the amygdala and hypothalamus. This focused review examines the possibility that neurosteroids may be a novel therapeutic approach to address the neurogenic contribution to hypertension. We discuss the causes and prevalence of neurogenic hypertension, current therapeutic approaches, and the applicability of using neurosteroids as antihypertensive therapy.
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Affiliation(s)
- Geoffrey A Head
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Kristy L Jackson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Cindy Gueguen
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
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Jackson KL, Head GA, Gueguen C, Stevenson ER, Lim K, Marques FZ. Mechanisms Responsible for Genetic Hypertension in Schlager BPH/2 Mice. Front Physiol 2019; 10:1311. [PMID: 31681017 PMCID: PMC6813185 DOI: 10.3389/fphys.2019.01311] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 09/30/2019] [Indexed: 01/18/2023] Open
Abstract
It has been 45 years since Gunther Schlager used a cross breeding program in mice to develop inbred strains with high, normal, and low blood pressure (BPH/2, BPN/3, and BPL/1 respectively). Thus, it is timely to gather together the studies that have characterized and explored the mechanisms associated with the hypertension to take stock of exactly what is known and what remains to be determined. Growing evidence supports the notion that the mechanism of hypertension in BPH/2 mice is predominantly neurogenic with some of the early studies showing aberrant brain noradrenaline levels in BPH/2 compared with BPN/3. Analysis of the adrenal gland using microarray suggested an association with the activity of the sympathetic nervous system. Indeed, in support of this, there is a larger depressor response to ganglion blockade, which reduced blood pressure in BPH/2 mice to the same level as BPN/3 mice. Greater renal tyrosine hydroxylase staining and greater renal noradrenaline levels in BPH/2 mice suggest sympathetic hyperinnervation of the kidney. Renal denervation markedly reduced the blood pressure in BPH/2 but not BPN/3 mice, confirming the importance of renal sympathetic nervous activity contributing to the hypertension. Further, there is an important contribution to the hypertension from miR-181a and renal renin in this strain. BPH/2 mice also display greater neuronal activity of amygdalo-hypothalamic cardiovascular regulatory regions. Lesions of the medial nucleus of the amygdala reduced the hypertension in BPH/2 mice and abolished the strain difference in the effect of ganglion blockade, suggesting a sympathetic mechanism. Further studies suggest that aberrant GABAergic inhibition may play a role since BPH/2 mice have low GABAA receptor δ, α4 and β2 subunit mRNA expression in the hypothalamus, which are predominantly involved in promoting tonic neuronal inhibition. Allopregnanolone, an allosteric modulator of GABAA receptors, which increase the expression of these subunits in the amygdala and hypothalamus, is shown to reduce the hypertension and sympathetic nervous system contribution in BPH/2 mice. Thus far, evidence suggests that BPH/2 mice have aberrant GABAergic inhibition, which drives neuronal overactivity within amygdalo-hypothalamic brain regions. This overactivity is responsible for the greater sympathetic contribution to the hypertension in BPH/2 mice, thus making this an ideal model of neurogenic hypertension.
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Affiliation(s)
- Kristy L Jackson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Geoffrey A Head
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Cindy Gueguen
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Emily R Stevenson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Kyungjoon Lim
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, VIC, Australia
| | - Francine Z Marques
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Hypertension Research Laboratory, School of Biological Sciences, Monash University, Clayton, VIC, Australia
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Positive allosteric modulation of GABAA receptors attenuates high blood pressure in Schlager hypertensive mice. J Hypertens 2017; 35:546-557. [PMID: 28009705 DOI: 10.1097/hjh.0000000000001210] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Blood pressure high Schlager (BPH/2J) mice have neurogenic hypertension associated with differences in hypothalamic GABAA receptors compared with their normotensive counterparts (BPN/3J). Allopregnanolone is an endogenous neurosteroid reduced in chronic stress, and when administered, decreases anxiety by positive allosteric modulation of GABAA receptors. METHODS To determine if allopregnanolone could be a viable therapeutic for neurogenic hypertension, male BPH/2J (n = 6-7) and BPN/3J (n = 8-9) mice were equipped with radiotelemetry probes to compare cardiovascular variables before and after implantation of subcutaneous minipumps delivering allopregnanolone (5 mg/kg per day), or its vehicle, for a period of 2 weeks. In addition to baseline recordings, the response to stress and ganglionic blockade with pentolinium was recorded, before and 7-14 days after minipump implantation. Following treatment, brains were processed for c-Fos immunohistochemistry and quantitative real-time polymerase chain reaction. RESULTS Administration of allopregnanolone selectively reduced mean arterial pressure (-8.0 ± 2.7 mmHg; P = 0.02) and the depressor response to pentolinium (-15.3 ± 3.2 mmHg; P = 0.001) in BPH/2J mice, with minimal effects observed in BPN/3J mice. Following allopregnanolone treatment, the diminished expression of GABAA δ, α4 and β2 subunits in the hypothalamus (-1.6 to 4.8-fold; Pstrain < 0.05) was abolished. Furthermore, in BPH/2J mice, allopregnanolone treatment reduced the pressor response to dirty cage switch stress (-26.7 ± 4.5%; P < 0.001) and abolished the elevated c-Fos expression in pre-sympathetic nuclei. CONCLUSION The selective antihypertensive and stress inhibitory effects of allopregnanolone in BPH/2J mice suggest that allosteric modulation of GABAA receptors, in amygdalo-hypothalamic pathways, may contribute to the development of hypertension in this model and may offer a potential new therapeutic avenue.
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Hinton AO, Yang Y, Quick AP, Xu P, Reddy CL, Yan X, Reynolds CL, Tong Q, Zhu L, Xu J, Wehrens XHT, Xu Y, Reddy AK. SRC-1 Regulates Blood Pressure and Aortic Stiffness in Female Mice. PLoS One 2016; 11:e0168644. [PMID: 28006821 PMCID: PMC5179266 DOI: 10.1371/journal.pone.0168644] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 12/05/2016] [Indexed: 12/11/2022] Open
Abstract
Framingham Heart Study suggests that dysfunction of steroid receptor coactivator-1 may be involved in the development of hypertension. However, there is no functional evidence linking steroid receptor coactivator-1 to the regulation of blood pressure. We used immunohistochemistry to map the expression of steroid receptor coactivator-1 protein in mouse brain, especially in regions implicated in the regulation of blood pressure. Steroid receptor coactivator-1 protein was found in central amygdala, medial amygdala, supraoptic nucleus, arcuate nucleus, ventromedial, dorsomedial, paraventricular hypothalamus, and nucleus of the solitary tract. To determine the effects of steroid receptor coactivator-1 protein on cardiovascular system we measured blood pressures, blood flow velocities, echocardiographic parameters, and aortic input impedance in female steroid receptor coactivator-1 knockout mice and their wild type littermates. Steroid receptor coactivator-1 knockout mice had higher blood pressures and increased aortic stiffness when compared to female wild type littermates. Additionally, the hearts of steroid receptor coactivator-1 knockout mice seem to consume higher energy as evidenced by increased impedance and higher heart rate pressure product when compared to female wild type littermates. Our results demonstrate that steroid receptor coactivator-1 may be functionally involved in the regulation of blood pressure and aortic stiffness through the regulation of sympathetic activation in various neuronal populations.
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Affiliation(s)
- Antentor Othrell Hinton
- Pediatrics-Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yongjie Yang
- Pediatrics-Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ann P. Quick
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Pingwen Xu
- Pediatrics-Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Chitra L. Reddy
- Debakey High School for Health Professions, Houston, Texas, United States of America
| | - Xiaofeng Yan
- Pediatrics-Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Corey L. Reynolds
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Advanced Technology/Core Laboratory, Baylor College of Medicine, Houston, Texas, United States of America
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Liangru Zhu
- Department of Gastroenterology, Union Hospital, Tongji Medical College and Huazhong University of Science and Technology, Wuhan, China
| | - Jianming Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Xander H. T. Wehrens
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yong Xu
- Pediatrics-Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (AKR); (YX)
| | - Anilkumar K. Reddy
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Section of Cardiovascular Research, Department Medicine and DeBakey Heart Center, Baylor College of Medicine, Houston, Texas, United States of America
- Indus Instruments, Webster, Texas, United States of America
- * E-mail: (AKR); (YX)
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Hinton AO, He Y, Xia Y, Xu P, Yang Y, Saito K, Wang C, Yan X, Shu G, Henderson A, Clegg DJ, Khan SA, Reynolds C, Wu Q, Tong Q, Xu Y. Estrogen Receptor-α in the Medial Amygdala Prevents Stress-Induced Elevations in Blood Pressure in Females. Hypertension 2016; 67:1321-30. [PMID: 27091896 DOI: 10.1161/hypertensionaha.116.07175] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/16/2016] [Indexed: 11/16/2022]
Abstract
Psychological stress contributes to the development of hypertension in humans. The ovarian hormone, estrogen, has been shown to prevent stress-induced pressor responses in females by unknown mechanisms. Here, we showed that the antihypertensive effects of estrogen during stress were blunted in female mice lacking estrogen receptor-α in the brain medial amygdala. Deletion of estrogen receptor-α in medial amygdala neurons also resulted in increased excitability of these neurons, associated with elevated ionotropic glutamate receptor expression. We further demonstrated that selective activation of medial amygdala neurons mimicked effects of stress to increase blood pressure in mice. Together, our results support a model where estrogen acts on estrogen receptor-α expressed by medial amygdala neurons to prevent stress-induced activation of these neurons, and therefore prevents pressor responses to stress.
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Affiliation(s)
- Antentor Othrell Hinton
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Yanlin He
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Yan Xia
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Pingwen Xu
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Yongjie Yang
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Kenji Saito
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Chunmei Wang
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Xiaofeng Yan
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Gang Shu
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Alexander Henderson
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Deborah J Clegg
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Sohaib A Khan
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Corey Reynolds
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Qi Wu
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Qingchun Tong
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.)
| | - Yong Xu
- From the Department of Pediatrics, Children's Nutrition Research Center (A.O.H., Y.H., Y.X., P.X., Y.Y., K.S., C.W., X.Y., G.S., A.H., Q.W., Y.X.), Advanced Technology/Core Laboratory (C.R.), and Department of Molecular and Cellular Biology (Y.X.), Baylor College of Medicine, One Baylor Plaza, Houston, TX; Department of Biomedical Research, Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA (D.J.C.); Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, OH (S.A.K.); and Center for Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston (Q.T.).
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Maternal hypomagnesemia alters renal function but does not program changes in the cardiovascular physiology of adult offspring. J Dev Orig Health Dis 2016; 7:473-480. [PMID: 27019320 DOI: 10.1017/s2040174416000106] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Maternal undernutrition is known to adversely impact fetal health and development. Insults experienced in utero alter development of the fetus as it adapts to microenvironment stressors, leading to growth restriction and subsequent low birth weight. Infants born small for gestational age have significantly increased risk of developing cardiovascular and renal disease in later life, an effect that is often characterized by hypertension and reduced glomerular number. Maternal magnesium (Mg2+) deficiency during pregnancy impairs fetal growth, however, the long-term health consequences for the offspring remain unknown. Here, we used a mouse model of dietary Mg2+ deficiency before and during pregnancy to investigate cardiovascular and renal outcomes in male and female adult offspring at 6 months of age. There were no differences between groups in 24-h mean arterial pressure or heart rate as measured by radiotelemetry. Cardiovascular responses to aversive (restraint, dirty cage switch) and non-aversive (feeding response) stressors were also similar in all groups. There were no differences in nephron number, however, Mg2+-deficient offspring had increased urine flow (in both males and females) and reduced Mg2+ excretion (in males only). Despite evidence suggesting that maternal nutrient restriction programs for hypertension in adult offspring, we found that a moderate level of maternal dietary Mg2+ deficiency did not program for a nephron deficit, or alter cardiovascular function at 6 months of age. These data suggest there are no long-term adverse outcomes for the cardiovascular health of offspring of Mg2+ deficient mothers.
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Jackson KL, Dampney BW, Moretti JL, Stevenson ER, Davern PJ, Carrive P, Head GA. Contribution of Orexin to the Neurogenic Hypertension in BPH/2J Mice. Hypertension 2016; 67:959-69. [PMID: 26975709 DOI: 10.1161/hypertensionaha.115.07053] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 02/14/2016] [Indexed: 11/16/2022]
Abstract
BPH/2J mice are a genetic model of hypertension associated with an overactive sympathetic nervous system. Orexin is a neuropeptide which influences sympathetic activity and blood pressure. Orexin precursor mRNA expression is greater in hypothalamic tissue of BPH/2J compared with normotensive BPN/3J mice. To determine whether enhanced orexinergic signaling contributes to the hypertension, BPH/2J and BPN/3J mice were preimplanted with radiotelemetry probes to compare blood pressure 1 hour before and 5 hours after administration of almorexant, an orexin receptor antagonist. Mid frequency mean arterial pressure power and the depressor response to ganglion blockade were also used as indicators of sympathetic nervous system activity. Administration of almorexant at 100 (IP) and 300 mg/kg (oral) in BPH/2J mice during the dark-active period (2 hours after lights off) markedly reduced blood pressure (-16.1 ± 1.6 and -11.0 ± 1.1 mm Hg, respectively;P<0.001 compared with vehicle). However, when almorexant (100 mg/kg, IP) was administered during the light-inactive period (5 hours before lights off) no reduction from baseline was observed (P=0.64). The same dose of almorexant in BPN/3J mice had no effect on blood pressure during the dark (P=0.79) or light periods (P=0.24). Almorexant attenuated the depressor response to ganglion blockade (P=0.018) and reduced the mid frequency mean arterial pressure power in BPH/2J mice (P<0.001), but not BPN/3J mice (P=0.70). Immunohistochemical labeling revealed that BPH/2J mice have 29% more orexin neurons than BPN/3J mice which are preferentially located in the lateral hypothalamus. The results suggest that enhanced orexinergic signaling contributes to sympathetic overactivity and hypertension during the dark period in BPH/2J mice.
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Affiliation(s)
- Kristy L Jackson
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., J.-L.M., E.R.S., P.J.D., G.A.H.); Blood Pressure, Brain and Behavior Laboratory, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia (B.W.D., P.C.); and Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (G.A.H.)
| | - Bruno W Dampney
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., J.-L.M., E.R.S., P.J.D., G.A.H.); Blood Pressure, Brain and Behavior Laboratory, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia (B.W.D., P.C.); and Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (G.A.H.)
| | - John-Luis Moretti
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., J.-L.M., E.R.S., P.J.D., G.A.H.); Blood Pressure, Brain and Behavior Laboratory, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia (B.W.D., P.C.); and Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (G.A.H.)
| | - Emily R Stevenson
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., J.-L.M., E.R.S., P.J.D., G.A.H.); Blood Pressure, Brain and Behavior Laboratory, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia (B.W.D., P.C.); and Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (G.A.H.)
| | - Pamela J Davern
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., J.-L.M., E.R.S., P.J.D., G.A.H.); Blood Pressure, Brain and Behavior Laboratory, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia (B.W.D., P.C.); and Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (G.A.H.)
| | - Pascal Carrive
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., J.-L.M., E.R.S., P.J.D., G.A.H.); Blood Pressure, Brain and Behavior Laboratory, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia (B.W.D., P.C.); and Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (G.A.H.)
| | - Geoffrey A Head
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., J.-L.M., E.R.S., P.J.D., G.A.H.); Blood Pressure, Brain and Behavior Laboratory, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia (B.W.D., P.C.); and Department of Pharmacology, Monash University, Melbourne, Victoria, Australia (G.A.H.).
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Lambert EA, Chatzivlastou K, Schlaich M, Lambert G, Head GA. Morning surge in blood pressure is associated with reactivity of the sympathetic nervous system. Am J Hypertens 2014; 27:783-92. [PMID: 24436322 DOI: 10.1093/ajh/hpt273] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND An exaggerated morning surge in blood pressure (BP) closely relates to target organ damage and cardiovascular risk, but whether the causative mechanism involves greater reactivity of the sympathetic nervous system (SNS) is unknown. We determined whether the response of the SNS to a cold pressor test predicted the BP morning surge. METHODS Ambulatory BP recordings were obtained from 14 men and 19 women (age = 41±4 years), and the amplitude (day-night difference), rate of rise (RoR), rate by amplitude product (BPPower), and morning BP surge (MBPS; post-awake minus pre-awake) of morning mean arterial pressure (MAP) were determined. The reactivity of the SNS to CPT was assessed by recording of muscle sympathetic nerve activity (MSNA). RESULTS CPT induced a marked increase in MAP and all parameters of MSNA, including burst amplitude. Log-normalized BPPower positively correlated with the overall average CPT-induced increases in total MSNA (r = 0.38; P = 0.04) and burst amplitude (r = 0.43; P = 0.02) but was not related to the increase in MSNA frequency. Furthermore, a strong positive linear trend in the CPT-induced changes in burst amplitude across tertiles of BPPower and RoR was observed. BPPower and RoR were not related to CPT-induced hemodynamic changes. The MBPS did not correlate with any of the CPT-induced changes in vascular or MSNA variables. CONCLUSIONS These results suggest that the central nervous system mechanisms influencing the increase in MSNA burst amplitude during arousal may also be fundamental in determining the rate and power of BP rise during the morning period.
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Affiliation(s)
- Elisabeth A Lambert
- Human Neurotransmitters Laboratory, Baker IDI Heart & Diabetes Institute, Melbourne, Victoria, Australia
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Jackson KL, Palma-Rigo K, Nguyen-Huu TP, Davern PJ, Head GA. Major Contribution of the Medial Amygdala to Hypertension in BPH/2J Genetically Hypertensive Mice. Hypertension 2014; 63:811-8. [DOI: 10.1161/hypertensionaha.113.02020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Kristy L. Jackson
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., K.P.-R., T.-P.N.-H., P.J.D., G.A.H.); and Department of Pharmacology, Monash University, Clayton, Victoria, Australia (K.L.J., G.A.H.)
| | - Kesia Palma-Rigo
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., K.P.-R., T.-P.N.-H., P.J.D., G.A.H.); and Department of Pharmacology, Monash University, Clayton, Victoria, Australia (K.L.J., G.A.H.)
| | - Thu-Phuc Nguyen-Huu
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., K.P.-R., T.-P.N.-H., P.J.D., G.A.H.); and Department of Pharmacology, Monash University, Clayton, Victoria, Australia (K.L.J., G.A.H.)
| | - Pamela J. Davern
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., K.P.-R., T.-P.N.-H., P.J.D., G.A.H.); and Department of Pharmacology, Monash University, Clayton, Victoria, Australia (K.L.J., G.A.H.)
| | - Geoffrey A. Head
- From the Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, Melbourne, Victoria, Australia (K.L.J., K.P.-R., T.-P.N.-H., P.J.D., G.A.H.); and Department of Pharmacology, Monash University, Clayton, Victoria, Australia (K.L.J., G.A.H.)
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Actions of rilmenidine on neurogenic hypertension in BPH/2J genetically hypertensive mice. J Hypertens 2014; 32:575-86. [DOI: 10.1097/hjh.0000000000000036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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GABAA receptor dysfunction contributes to high blood pressure and exaggerated response to stress in Schlager genetically hypertensive mice. J Hypertens 2014; 32:352-62. [DOI: 10.1097/hjh.0000000000000015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Abegaz B, Davern PJ, Jackson KL, Nguyen-Huu TP, Bassi JK, Connelly A, Choong YT, Allen AM, Head GA. Cardiovascular role of angiotensin type1A receptors in the nucleus of the solitary tract of mice. Cardiovasc Res 2013; 100:181-91. [DOI: 10.1093/cvr/cvt183] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Marques FZ, Morris BJ. Neurogenic hypertension: revelations from genome-wide gene expression profiling. Curr Hypertens Rep 2013; 14:485-91. [PMID: 22639016 DOI: 10.1007/s11906-012-0282-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There is now good evidence for a role of the sympathetic nervous system in the etiology of essential hypertension in humans. Although genetic variation is expected to underlie the elevated sympathetic outflow in this complex polygenic condition, only limited information has emerged from classic molecular genetic studies. Recently, progress has been made in understanding neurogenic aspects by determination of global alterations in gene expression in key brain regions of animal models of neurogenic hypertension. Such genome-wide expression studies in the hypothalamus and brainstem support roles for factors such as neuronal nitric oxide synthase, inflammation and reactive oxygen species. A role for non-coding RNAs such as microRNAs, and epigenetic alterations await exploration. Ongoing novel approaches should provide a better understanding of the processes responsible for the increased sympathetic outflow in animal models, as well as essential hypertension in humans. Such information may lead to better therapies for neurogenic hypertension in humans.
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Palma-Rigo K, Bassi JK, Nguyen-Huu TP, Jackson KL, Davern PJ, Chen D, Elghozi JL, Thomas WG, Allen AM, Head GA. Angiotensin 1A receptors transfected into caudal ventrolateral medulla inhibit baroreflex gain and stress responses. Cardiovasc Res 2012; 96:330-9. [PMID: 22869618 DOI: 10.1093/cvr/cvs252] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
AIMS The caudal ventrolateral medulla (CVLM) is important for autonomic regulation and is rich in angiotensin II type 1A receptors (AT(1A)R). To determine their function, we examined whether the expression of AT(1A)R in the CVLM of mice lacking AT(1A)R (AT(1A)(-/-)) alters baroreflex sensitivity and cardiovascular responses to stress. METHODS AND RESULTS Bilateral microinjections into the CVLM of AT(1A)(-/-) mice of lentivirus with the phox-2 selective promoter (PRSx8) were made to express either AT(1A)R (Lv-PRSx8-AT(1A)) or green fluorescent protein (Lv-PRSx8-GFP) as a control. Radiotelemetry was used to record mean arterial pressure (MAP), heart rate (HR), and locomotor activity. Following injection of Lv-PRSx8-GFP, robust neuronal expression of GFP was observed with ∼60% of the GFP-positive cells also expressing the catecholamine-synthetic enzyme tyrosine hydroxylase. After 5 weeks, there were no differences in MAP or HR between groups, but the Lv-PRSx8-AT(1A)- injected mice showed reduced baroreflex sensitivity (-25%, P = 0.003) and attenuated pressor responses to cage-switch and restraint stress compared with the Lv-PRSx8-GFP-injected mice. Reduced MAP mid-frequency power during cage-switch stress reflected attenuated sympathetic activation (Pgroup × stress = 0.04). Fos-immunohistochemistry indicated greater activation of forebrain and hypothalamic neurons in the Lv-PRSx8-AT(1A) mice compared with the control. CONCLUSION The expression of AT(1A)R in CVLM neurons, including A1 neurons, while having little influence on the basal blood pressure or HR, may play a tonic role in inhibiting cardiac vagal baroreflex sensitivity. However, they strongly facilitate the forebrain response to aversive stress, yet reduce the pressor response presumably through greater sympatho-inhibition. These findings outline novel and specific roles for angiotensin II in the CVLM in autonomic regulation.
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Affiliation(s)
- Kesia Palma-Rigo
- Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Research Institute, 75 Commercial Road, PO Box 6492 St Kilda Road Central, Melbourne, VIC 8008, Australia
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Renin-angiotensin and sympathetic nervous system contribution to high blood pressure in Schlager mice. J Hypertens 2012; 29:2156-66. [PMID: 21941207 DOI: 10.1097/hjh.0b013e32834bbb6b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Schlager hypertensive (BPH/2J) mice have been suggested to have high blood pressure (BP) due to an overactive sympathetic nervous system (SNS), but the contribution of the renin-angiotensin system (RAS) is unclear. In the present study, we examined the cardiovascular effects of chronically blocking the RAS in BPH/2J mice. METHODS Schlager normotensive (BPN/3J, n = 6) and BPH/2J mice (n = 8) received the angiotensin AT 1A-receptor antagonist losartan (150 mg/kg per day) in drinking water for 2 weeks. Pre-implanted telemetry devices were used to record mean arterial pressure (MAP), heart rate (HR) and locomotor activity. RESULTS MAP was reduced by losartan treatment in BPN/3J (-23 mmHg, P < 0.01) and in BPH/2J mice (-25 mmHg, P < 0.001), whereas HR was increased. Losartan had little effect on initial pressor responses to feeding or to stress, but did attenuate the sustained pressor response to cage-switch stress. During the active period, the hypotension to sympathetic blockade with pentolinium was greater in BPH/2J than BPN/3J (suggesting neurogenic hypertension), but was not affected by losartan. During the inactive period, a greater depressor response to pentolinium was observed in losartan-treated animals. CONCLUSION The hypotensive actions of losartan suggest that although the RAS provides an important contribution to BP, it contributes little, if at all, to the hypertension-induced or the greater stress-induced pressor responses in Schlager mice. The effects of pentolinium suggest that the SNS is mainly responsible for hypertension in BPH/2J mice. However, the RAS inhibits sympathetic vasomotor tone during inactivity and prolongs sympathetic activation during periods of adverse stress, indicating an important sympatho-modulatory role.
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Marques FZ, Campain AE, Davern PJ, Yang YHJ, Head GA, Morris BJ. Global identification of the genes and pathways differentially expressed in hypothalamus in early and established neurogenic hypertension. Physiol Genomics 2011; 43:766-71. [DOI: 10.1152/physiolgenomics.00009.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The hypothalamus has an important etiological role in the onset and maintenance of hypertension and stress responses in the Schlager high blood pressure (BP) (BPH/2J) mouse, a genetic model of neurogenic hypertension. Using Affymetrix GeneChip Mouse Gene 1.0 ST Arrays we identified 1,019 hypothalamic genes whose expression differed between 6 wk old BPH/2J and normal BP (BPN/3J) strains, and 466 for 26 wk old mice. Of these, 459 were in 21 mouse BP quantitative trait loci. We validated 46 genes by qPCR. Gene changes that would increase sympathetic outflow at both ages were: Dynll1 encoding dynein light chain LC8-type 1, which physically destabilizes neuronal nitric oxide synthase, decreasing neuronal nitric oxide, and Hcrt encoding hypocretin and Npsr1 encoding neuropeptide S receptor 1, each involved in sympathetic response to stress. At both ages we identified genes for inflammation, such as CC-chemokine ligand 19 ( Ccl19), and oxidative stress. Via reactive oxygen species generation, these could contribute to oxidative damage. Other genes identified could be responding to such perturbations. Atp2b1, the major gene from genome-wide association studies of BP variation, was underexpressed in the early phase. Comparison of profiles of young and adult BPH/2J mice, after adjusting for maturation genes, pointed to the proopiomelanocortin-α gene ( Pomc) and neuropeptide Y gene ( Npy), among others, as potentially causative. The present study has identified a diversity of genes and possible mechanisms involved in hypertension etiology and maintenance in the hypothalamus of BPH/2J mice, highlighting both common and divergent processes in each phase of the condition.
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Affiliation(s)
- Francine Z. Marques
- Basic & Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, and
| | - Anna E. Campain
- School of Mathematics and Statistics, The University of Sydney, Sydney, New South Wales; and
| | - Pamela J. Davern
- the Neuropharmacology Laboratory, Baker IDI Heart Research Institute, Melbourne, Victoria, Australia
| | - Yee Hwa J. Yang
- School of Mathematics and Statistics, The University of Sydney, Sydney, New South Wales; and
| | - Geoffrey A. Head
- the Neuropharmacology Laboratory, Baker IDI Heart Research Institute, Melbourne, Victoria, Australia
| | - Brian J. Morris
- Basic & Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, and
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Marques FZ, Campain AE, Davern PJ, Yang YHJ, Head GA, Morris BJ. Genes influencing circadian differences in blood pressure in hypertensive mice. PLoS One 2011; 6:e19203. [PMID: 21541337 PMCID: PMC3082552 DOI: 10.1371/journal.pone.0019203] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 03/29/2011] [Indexed: 01/11/2023] Open
Abstract
Essential hypertension is a common multifactorial heritable condition in which increased sympathetic outflow from the central nervous system is involved in the elevation in blood pressure (BP), as well as the exaggerated morning surge in BP that is a risk factor for myocardial infarction and stroke in hypertensive patients. The Schlager BPH/2J mouse is a genetic model of hypertension in which increased sympathetic outflow from the hypothalamus has an important etiological role in the elevation of BP. Schlager hypertensive mice exhibit a large variation in BP between the active and inactive periods of the day, and also show a morning surge in BP. To investigate the genes responsible for the circadian variation in BP in hypertension, hypothalamic tissue was collected from BPH/2J and normotensive BPN/3J mice at the ‘peak’ (n = 12) and ‘trough’ (n = 6) of diurnal BP. Using Affymetrix GeneChip® Mouse Gene 1.0 ST Arrays, validation by quantitative real-time PCR and a statistical method that adjusted for clock genes, we identified 212 hypothalamic genes whose expression differed between ‘peak’ and ‘trough’ BP in the hypertensive strain. These included genes with known roles in BP regulation, such as vasopressin, oxytocin and thyrotropin releasing hormone, as well as genes not recognized previously as regulators of BP, including chemokine (C-C motif) ligand 19, hypocretin and zinc finger and BTB domain containing 16. Gene ontology analysis showed an enrichment of terms for inflammatory response, mitochondrial proton-transporting ATP synthase complex, structural constituent of ribosome, amongst others. In conclusion, we have identified genes whose expression differs between the peak and trough of 24-hour circadian BP in BPH/2J mice, pointing to mechanisms responsible for diurnal variation in BP. The findings may assist in the elucidation of the mechanism for the morning surge in BP in essential hypertension.
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Affiliation(s)
- Francine Z. Marques
- Basic and Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, The University of Sydney, Sydney, Australia
| | - Anna E. Campain
- School of Mathematics and Statistics, The University of Sydney, Sydney, Australia
| | - Pamela J. Davern
- Neuropharmacology Laboratory, Baker IDI Heart Research Institute, Melbourne, Australia
| | - Yee Hwa J. Yang
- School of Mathematics and Statistics, The University of Sydney, Sydney, Australia
| | - Geoffrey A. Head
- Neuropharmacology Laboratory, Baker IDI Heart Research Institute, Melbourne, Australia
| | - Brian J. Morris
- Basic and Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, The University of Sydney, Sydney, Australia
- * E-mail:
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Burke SL, Lambert E, Head GA. New Approaches to Quantifying Sympathetic Nerve Activity. Curr Hypertens Rep 2011; 13:249-57. [DOI: 10.1007/s11906-011-0196-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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