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Xue B, Johnson AK. Sensitization of Hypertension: The Impact of Earlier Life Challenges: Excellence Award for Hypertension Research 2021. Hypertension 2023; 80:1-12. [PMID: 36069195 DOI: 10.1161/hypertensionaha.122.18550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Hypertension affects over 1 billion individuals worldwide. Because the cause of hypertension is known only in a small fraction of patients, most individuals with high blood pressure are diagnosed as having essential hypertension. Elevated sympathetic nervous system activity has been identified in a large portion of hypertensive patients. However, the root cause for this sympathetic overdrive is unknown. A more complete understanding of the breadth of the functional capabilities of the sympathetic nervous system may lead to new insights into the cause of essential hypertension. By employing a unique experimental paradigm, we have recently discovered that the neural network controlling sympathetic drive is more reactive after rats are exposed to mild challenges (stressors) and that the hypertensive response can be sensitized (ie, hypertensive response sensitization [HTRS]). We have also found that the induction of HTRS involves plasticity in the neural network controlling sympathetic drive. The induction and maintenance of the latent HTRS state also require the functional integrity of the brain renin-angiotensin-aldosterone system and the presence of several central inflammatory factors. In this review, we will discuss the induction and expression of HTRS in adult animals and in the progeny of mothers with prenatal obesity/overnutrition or with maternal gestational hypertension. Also, interventions that reverse the effects of stressor-induced HTRS will be reviewed. Understanding the mechanisms underlying HTRS and identifying the beneficial effects of maternal or offspring early-life interventions that prevent or reverse the sensitized state can provide insights into therapeutic strategies for interrupting the vicious cycle of transgenerational hypertension.
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Affiliation(s)
- Baojian Xue
- Department of Psychological and Brain Sciences (B.X., A.K.J.), University of Iowa, Iowa City
| | - Alan Kim Johnson
- Department of Psychological and Brain Sciences (B.X., A.K.J.), University of Iowa, Iowa City.,Neuroscience and Pharmacology (A.K.J.), University of Iowa, Iowa City.,Health and Human Physiology (A.K.J.), University of Iowa, Iowa City.,François M. Abboud Cardiovascular Research Center (A.K.J.), University of Iowa, Iowa City
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Xue B, Xue J, Yu Y, Wei SG, Beltz TG, Felder RB, Johnson AK. Predator Scent-Induced Sensitization of Hypertension and Anxiety-like Behaviors. Cell Mol Neurobiol 2022; 42:1141-1152. [PMID: 33201417 PMCID: PMC8126575 DOI: 10.1007/s10571-020-01005-y] [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: 07/13/2020] [Accepted: 11/11/2020] [Indexed: 12/15/2022]
Abstract
Post-traumatic stress disorder (PTSD), an anxiety-related syndrome, is associated with increased risk for cardiovascular diseases. The present study investigated whether predator scent (PS) stress, a model of PTSD, induces sensitization of hypertension and anxiety-like behaviors and underlying mechanisms related to renin-angiotensin systems (RAS) and inflammation. Coyote urine, as a PS stressor, was used to model PTSD. After PS exposures, separate cohorts of rats were studied for hypertensive response sensitization (HTRS), anxiety-like behaviors, and changes in plasma levels and mRNA expression of several components of the RAS and proinflammatory cytokines (PICs) in the lamina terminalis (LT), paraventricular nucleus (PVN), and amygdala (AMY). Rats exposed to PS as compared to control animals exhibited (1) a significantly greater hypertensive response (i.e., HTRS) when challenged with a slow-pressor dose of angiotensin (ANG) II, (2) significant decrease in locomotor activity and increase in time spent in the closed arms of a plus maze as well as general immobility (i.e., behavioral signs of increased anxiety), (3) upregulated plasma levels of ANG II and interleukin-6, and (4) increased expression of message for components of the RAS and PICs in key brain nuclei. All the PS-induced adverse effects were blocked by pretreatment with either an angiotensin-converting enzyme antagonist or a tumor necrosis factor-α inhibitor. The results suggest that PS, used as an experimental model of PTSD, sensitizes ANG II-induced hypertension and produces behavioral signs of anxiety, probably through upregulation of RAS components and inflammatory markers in plasma and brain areas associated with anxiety and blood pressure control.
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Affiliation(s)
- Baojian Xue
- Department of Psychological and Brain Sciences, University of Iowa, PBSB, 340 Iowa Ave, Iowa City, IA, 52242, USA.
| | - Jiarui Xue
- Department of Psychological and Brain Sciences, University of Iowa, PBSB, 340 Iowa Ave, Iowa City, IA, 52242, USA
| | - Yang Yu
- Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Shun-Guang Wei
- Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA
- The Franҫois M. Abboud Cardiovascular Research Center University of Iowa, Iowa City, IA, 52242, USA
| | - Terry G Beltz
- Department of Psychological and Brain Sciences, University of Iowa, PBSB, 340 Iowa Ave, Iowa City, IA, 52242, USA
| | - Robert B Felder
- Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA
- The Franҫois M. Abboud Cardiovascular Research Center University of Iowa, Iowa City, IA, 52242, USA
| | - Alan Kim Johnson
- Department of Psychological and Brain Sciences, University of Iowa, PBSB, 340 Iowa Ave, Iowa City, IA, 52242, USA
- Health and Human Physiology, University of Iowa, Iowa City, IA, 52242, USA
- Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, 52242, USA
- The Franҫois M. Abboud Cardiovascular Research Center University of Iowa, Iowa City, IA, 52242, USA
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Sharma NM, Haibara AS, Katsurada K, Nandi SS, Liu X, Zheng H, Patel KP. Central Ang II (Angiotensin II)-Mediated Sympathoexcitation: Role for HIF-1α (Hypoxia-Inducible Factor-1α) Facilitated Glutamatergic Tone in the Paraventricular Nucleus of the Hypothalamus. Hypertension 2020; 77:147-157. [PMID: 33296248 PMCID: PMC7720881 DOI: 10.1161/hypertensionaha.120.16002] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Central infusion of Ang II (angiotensin II) has been associated with increased sympathetic outflow resulting in neurogenic hypertension. In the present study, we appraised whether the chronic increase in central Ang II activates the paraventricular nucleus of the hypothalamus (PVN) resulting in elevated sympathetic tone and altered baro- and chemoreflexes. Further, we evaluated the contribution of HIF-1α (hypoxia-inducible factor-1α), a transcription factor involved in enhancing the expression of N-methyl-D-aspartate receptors and thus glutamatergic-mediated sympathetic tone from the PVN. Ang II infusion (20 ng/minute, intracerebroventricular, 14 days) increased mean arterial pressure (126±9 versus 84±4 mm Hg), cardiac sympathetic tone (96±7 versus 75±6 bpm), and decreased cardiac parasympathetic tone (16±2 versus 36±3 versus bpm) compared with saline-infused controls in conscious rats. The Ang II-infused group also showed an impaired baroreflex control of heart rate (-1.50±0.1 versus -2.50±0.3 bpm/mm Hg), potentiation of the chemoreflex pressor response (53±7 versus 30±7 mm Hg) and increased number of FosB-labeled cells (53±3 versus 19±4) in the PVN. Concomitant with the activation of the PVN, there was an increased expression of HIF-1α and N-Methyl-D-Aspartate-type1 receptors in the PVN. Further, Ang II-infusion showed increased renal sympathetic nerve activity (20.5±2.3% versus 6.4±1.9% of Max) and 3-fold enhanced renal sympathetic nerve activity responses to microinjection of N-methyl-D-aspartate (200 pmol) into the PVN of anesthetized rats. Further, silencing of HIF-1α in NG108 cells abrogated the expression of N-methyl-D-aspartate-N-methyl-D-aspartate-type1 induced by Ang II. Taken together, our studies suggest a novel Ang II-HIF-1α-N-methyl-D-aspartate receptor-mediated activation of preautonomic neurons in the PVN, resulting in increased sympathetic outflow and alterations in baro- and chemoreflexes.
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Affiliation(s)
- Neeru M Sharma
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha (N.M.S., A.S.H., K.K., S.S.N., K.P.P.)
| | - Andréa S Haibara
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha (N.M.S., A.S.H., K.K., S.S.N., K.P.P.)
| | - Kenichi Katsurada
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha (N.M.S., A.S.H., K.K., S.S.N., K.P.P.)
| | - Shyam S Nandi
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha (N.M.S., A.S.H., K.K., S.S.N., K.P.P.)
| | - Xuefei Liu
- Division of Basic Biomedical Sciences, Sanford School of Medicine of the University of South Dakota, Vermillion (X.L., H.Z.)
| | - Hong Zheng
- Division of Basic Biomedical Sciences, Sanford School of Medicine of the University of South Dakota, Vermillion (X.L., H.Z.)
| | - Kaushik P Patel
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha (N.M.S., A.S.H., K.K., S.S.N., K.P.P.)
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DeLalio LJ, Sved AF, Stocker SD. Sympathetic Nervous System Contributions to Hypertension: Updates and Therapeutic Relevance. Can J Cardiol 2020; 36:712-720. [PMID: 32389344 DOI: 10.1016/j.cjca.2020.03.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 12/15/2022] Open
Abstract
The sympathetic nervous system plays a pivotal role in the long-term regulation of arterial blood pressure through the ability of the central nervous system to integrate neurohumoral signals and differentially regulate sympathetic neural input to specific end organs. Part 1 of this review will discuss neural mechanisms of salt-sensitive hypertension, obesity-induced hypertension, and the ability of prior experiences to sensitize autonomic networks. Part 2 of this review focuses on new therapeutic advances to treat resistant hypertension including renal denervation and carotid baroactivation. Both advances lower arterial blood pressure by reducing sympathetic outflow. We discuss potential mechanisms and areas of future investigation to target the sympathetic nervous system.
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Affiliation(s)
- Leon J DeLalio
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Alan F Sved
- Department of Neuroscience, University of Pittsburgh, Pennsylvania, USA
| | - Sean D Stocker
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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Zhang Z, Zhang Y, Wang Y, Ding S, Wang C, Gao L, Johnson A, Xue B. Genetic knockdown of brain-derived neurotrophic factor in the nervous system attenuates angiotensin II-induced hypertension in mice. J Renin Angiotensin Aldosterone Syst 2019; 20:1470320319834406. [PMID: 30894041 PMCID: PMC6429654 DOI: 10.1177/1470320319834406] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Introduction: Brain-derived neurotropic factor (BDNF) is expressed throughout the central nervous system and peripheral organs involved in the regulation of blood pressure, but the systemic effects of BDNF in the control of blood pressure are not well elucidated. Materials and methods: We utilized loxP flanked BDNF male mice to cross with nestin-Cre female mice to generate nerve system BDNF knockdown mice, nestin-BDNF (+/–), or injected Cre adenovirus into the subfornical organ to create subfornical organ BDNF knockdown mice. Histochemistry was used to verify injection location. Radiotelemetry was employed to determine baseline blood pressure and pressor response to angiotensin II (1000 ng/kg/min). Real-time polymerase chain reaction was used to measure the expression of renin–angiotensin system components in the laminal terminalis and peripheral organs. Results: Nestin-BDNF (+/–) mice had lower renin–angiotensin system expression in the laminal terminalis and peripheral organs including the gonadal fat pad, and a lower basal blood pressure. They exhibited an attenuated hypertensive response and a weak or similar modification of renin–angiotensin system component expression to angiotensin II infusion. Subfornical organ BDNF knockdown was sufficient for the attenuation of angiotensin II-induced hypertension. Conclusion: Central BDNF, especially subfornical organ BDNF is involved in the maintenance of basal blood pressure and in augmentation of hypertensive response to angiotensin II through systemic regulation of the expression of renin–angiotensin system molecules.
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Affiliation(s)
- Zhongming Zhang
- 1 Zhang Zhongjing College of Chinese Medicine, Henan Key Laboratory of Zhang Zhongjing's Formulea for Immunoregulation, Nanyang Institute of Technology, China
| | - Yijing Zhang
- 1 Zhang Zhongjing College of Chinese Medicine, Henan Key Laboratory of Zhang Zhongjing's Formulea for Immunoregulation, Nanyang Institute of Technology, China
| | - Yan Wang
- 1 Zhang Zhongjing College of Chinese Medicine, Henan Key Laboratory of Zhang Zhongjing's Formulea for Immunoregulation, Nanyang Institute of Technology, China
| | - Shengchen Ding
- 1 Zhang Zhongjing College of Chinese Medicine, Henan Key Laboratory of Zhang Zhongjing's Formulea for Immunoregulation, Nanyang Institute of Technology, China
| | - Chenhui Wang
- 1 Zhang Zhongjing College of Chinese Medicine, Henan Key Laboratory of Zhang Zhongjing's Formulea for Immunoregulation, Nanyang Institute of Technology, China
| | - Li Gao
- 1 Zhang Zhongjing College of Chinese Medicine, Henan Key Laboratory of Zhang Zhongjing's Formulea for Immunoregulation, Nanyang Institute of Technology, China
| | - Alan Johnson
- 2 Department of Psychological and Brain Sciences, University of Iowa, USA
| | - Baojian Xue
- 2 Department of Psychological and Brain Sciences, University of Iowa, USA
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Abstract
The causes of essential hypertension remain an enigma. Interactions between genetic and external factors are generally recognized to act as aetiological mechanisms that trigger the pathogenesis of high blood pressure. However, the questions of which genes and factors are involved, and when and where such interactions occur, remain unresolved. Emerging evidence indicates that the hypertensive response to pressor stimuli, like many other physiological and behavioural adaptations, can become sensitized to particular stimuli. Studies in animal models show that, similarly to other response systems controlled by the brain, hypertensive response sensitization (HTRS) is mediated by neuroplasticity. The brain circuitry involved in HTRS controls the sympathetic nervous system. This Review outlines evidence supporting the phenomenon of HTRS and describes the range of physiological and psychosocial stressors that can produce a sensitized hypertensive state. Also discussed are the cellular and molecular changes in the brain neural network controlling sympathetic tone involved in long-term storage of information relating to stressors, which could serve to maintain a sensitized state. Finally, this Review concludes with a discussion of why a sensitized hypertensive response might previously have been beneficial and increased biological fitness under some environmental conditions and why today it has become a health-related liability.
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Affiliation(s)
- Alan Kim Johnson
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, USA.
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA.
- Department of Pharmacology, University of Iowa, Iowa City, IA, USA.
- The François M. Abboud Cardiovascular Center, Iowa City, IA, USA.
| | - Baojian Xue
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, USA
- The François M. Abboud Cardiovascular Center, Iowa City, IA, USA
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Farmer GE, Balapattabi K, Bachelor ME, Little JT, Cunningham JT. AT 1a influences GABAA-mediated inhibition through regulation of KCC2 expression. Am J Physiol Regul Integr Comp Physiol 2018; 315:R972-R982. [PMID: 30156863 PMCID: PMC6295501 DOI: 10.1152/ajpregu.00105.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 08/27/2018] [Accepted: 08/27/2018] [Indexed: 11/22/2022]
Abstract
The median preoptic nucleus (MnPO) is an integrative site involved in body fluid homeostasis, cardiovascular control, thermoregulation, and sleep homeostasis. Angiotensin II (ANG II), a neuropeptide shown to have excitatory effects on MnPO neurons, is of particular interest with regard to its role in body fluid homeostasis and cardiovascular control. The present study investigated the role of angiotensin type 1a (AT1a) receptor activation on neuronal excitability in the MnPO. Male Sprague-Dawley rats were infused with an adeno-associated virus with an shRNA against the AT1a receptor or a scrambled control. In vitro loose-patch voltage-clamp recordings of spontaneous action potential activity were made from labeled MnPO neurons in response to brief focal application of ANG II or the GABAA receptor agonist muscimol. Additionally, tissue punches from MnPO were taken to asses mRNA and protein expression. AT1a receptor knockdown neurons were insensitive to ANG II and showed a marked reduction in GABAA-mediated inhibition. The reduction in GABAA-mediated inhibition was not associated with reductions in mRNA or protein expression of GABAA β-subunits. Knockdown of the AT1a receptor was associated with a reduction in the potassium-chloride cotransporter KCC2 mRNA as well as a reduction in pS940 KCC2 protein. The impaired GABAA-mediated inhibition in AT1a knockdown neurons was recovered by bath application of phospholipase C and protein kinase C activators. The following study indicates that AT1a receptor activation mediates the excitability of MnPO neurons, in part, through the regulation of KCC2. The regulation of KCC2 influences the intracellular [Cl-] and the subsequent efficacy of GABAA-mediated currents.
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Affiliation(s)
- George E Farmer
- Department of Physiology and Anatomy, University of North Texas Health Science Center at Fort Worth , Fort Worth, Texas
| | - Kirthikaa Balapattabi
- Department of Physiology and Anatomy, University of North Texas Health Science Center at Fort Worth , Fort Worth, Texas
| | - Martha E Bachelor
- Department of Physiology and Anatomy, University of North Texas Health Science Center at Fort Worth , Fort Worth, Texas
| | - Joel T Little
- Department of Physiology and Anatomy, University of North Texas Health Science Center at Fort Worth , Fort Worth, Texas
| | - J Thomas Cunningham
- Department of Physiology and Anatomy, University of North Texas Health Science Center at Fort Worth , Fort Worth, Texas
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Kopf PG, Phelps LE, Schupbach CD, Johnson AK, Peuler JD. Differential effects of long-term slow-pressor and subpressor angiotensin II on contractile and relaxant reactivity of resistance versus conductance arteries. Physiol Rep 2018; 6:e13623. [PMID: 29504268 PMCID: PMC5835495 DOI: 10.14814/phy2.13623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/17/2018] [Accepted: 01/23/2018] [Indexed: 01/09/2023] Open
Abstract
Vascular reactivity was evaluated in three separate arteries isolated from rats after angiotensin II (Ang II) was infused chronically in two separate experiments, one using a 14-day high, slow-pressor dose known to produce hypertension and the other using a 7-day low, subpressor but hypertensive-sensitizing dose. There were three new findings. First, there was no evidence of altered vascular reactivity in resistance arteries that might otherwise explain the hypertension due to the high Ang II or the hypertensive-sensitizing effect of the low Ang II dose. Second, the high Ang II dose exerted a novel differential effect on arterial contractile responsiveness to the sympathetic neurotransmitter, norepinephrine, depending on the level of sympathetic innervation. It clearly enhanced that responsiveness in the sparsely innervated aorta but not in small mesenteric resistance arteries or the proximal (conductance) portion of the caudal artery, both of which are densely innervated. This suggests that the increased expression of alpha adrenergic receptors after long-term exposure to Ang II as previously reported for aortic smooth muscle, is prevented in densely innervated arteries, likely due to long-term Ang II-mediated increase in sympathetic neural traffic to those vessels. Third, the same high dose of Ang II impaired aortic relaxation in response to the nitric oxide (NO) donor nitroprusside without impairing aortic endothelium-dependent relaxation. NO is the main relaxing substance released by aortic endothelium. Accordingly, it is possible that this dose of Ang II is also associated with enhanced release of and/or enhanced smooth muscle responsiveness to other endothelial relaxing substances in a compensatory capacity.
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Affiliation(s)
- Phillip G. Kopf
- Department of PharmacologyMidwestern UniversityDowners GroveIllinois
| | - Laura E. Phelps
- Department of PharmacologyMidwestern UniversityDowners GroveIllinois
| | - Chad D. Schupbach
- Department of PharmacologyMidwestern UniversityDowners GroveIllinois
| | - Alan K. Johnson
- Departments of Psychological and Brain SciencesHealth and Human Physiology, and Pharmacologythe University of IowaIowa CityIowa
| | - Jacob D. Peuler
- Department of PharmacologyMidwestern UniversityDowners GroveIllinois
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Zubcevic J, Santisteban MM, Perez PD, Arocha R, Hiller H, Malphurs WL, Colon-Perez LM, Sharma RK, de Kloet A, Krause EG, Febo M, Raizada MK. A Single Angiotensin II Hypertensive Stimulus Is Associated with Prolonged Neuronal and Immune System Activation in Wistar-Kyoto Rats. Front Physiol 2017; 8:592. [PMID: 28912720 PMCID: PMC5583219 DOI: 10.3389/fphys.2017.00592] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/31/2017] [Indexed: 11/29/2022] Open
Abstract
Activation of autonomic neural pathways by chronic hypertensive stimuli plays a significant role in pathogenesis of hypertension. Here, we proposed that even a single acute hypertensive stimulus will activate neural and immune pathways that may be important in initiation of memory imprinting seen in chronic hypertension. We investigated the effects of acute angiotensin II (Ang II) administration on blood pressure, neural activation in cardioregulatory brain regions, and central and systemic immune responses, at 1 and 24 h post-injection. Administration of a single bolus intra-peritoneal (I.P.) injection of Ang II (36 μg/kg) resulted in a transient increase in the mean arterial pressure (MAP) (by 22 ± 4 mmHg vs saline), which returned to baseline within 1 h. However, in contrast to MAP, neuronal activity, as measured by manganese-enhanced magnetic resonance (MEMRI), remained elevated in several cardioregulatory brain regions over 24 h. The increase was predominant in autonomic regions, such as the subfornical organ (SFO; ~20%), paraventricular nucleus of the hypothalamus (PVN; ~20%) and rostral ventrolateral medulla (RVLM; ~900%), among others. Similarly, systemic and central immune responses, as evidenced by circulating levels of CD4+/IL17+ T cells, and increased IL17 levels and activation of microglia in the PVN, respectively, remained elevated at 24 h following Ang II challenge. Elevated Fos expression in the PVN was also present at 24 h (by 73 ± 11%) following Ang II compared to control saline injections, confirming persistent activation of PVN. Thus, even a single Ang II hypertensive stimulus will initiate changes in neuronal and immune cells that play a role in the developing hypertensive phenotype.
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Affiliation(s)
- Jasenka Zubcevic
- Department of Physiological Sciences, College of Veterinary Medicine, University of FloridaGainesville, FL, United States
| | - Monica M Santisteban
- Department of Physiology and Functional Genomics, College of Medicine, University of FloridaGainesville, FL, United States
| | - Pablo D Perez
- Department of Psychiatry, College of Medicine, University of FloridaGainesville, FL, United States
| | - Rebeca Arocha
- Department of Physiological Sciences, College of Veterinary Medicine, University of FloridaGainesville, FL, United States
| | - Helmut Hiller
- Department of Pharmacodynamics, College of Medicine, University of FloridaGainesville, FL, United States
| | - Wendi L Malphurs
- Department of Physiological Sciences, College of Veterinary Medicine, University of FloridaGainesville, FL, United States
| | - Luis M Colon-Perez
- Department of Psychiatry, College of Medicine, University of FloridaGainesville, FL, United States
| | - Ravindra K Sharma
- Department of Physiology and Functional Genomics, College of Medicine, University of FloridaGainesville, FL, United States
| | - Annette de Kloet
- Department of Physiology and Functional Genomics, College of Medicine, University of FloridaGainesville, FL, United States
| | - Eric G Krause
- Department of Pharmacodynamics, College of Medicine, University of FloridaGainesville, FL, United States
| | - Marcelo Febo
- Department of Psychiatry, College of Medicine, University of FloridaGainesville, FL, United States
| | - Mohan K Raizada
- Department of Physiology and Functional Genomics, College of Medicine, University of FloridaGainesville, FL, United States
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Stocker SD, Kinsman BJ, Sved AF. Recent Advances in Neurogenic Hypertension: Dietary Salt, Obesity, and Inflammation. Hypertension 2017; 70:HYPERTENSIONAHA.117.08936. [PMID: 28739972 PMCID: PMC5783795 DOI: 10.1161/hypertensionaha.117.08936] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neurally-mediated hypertension results from a dysregulation of sympathetic and/or neuroendocrine mechanisms to increase ABP. Multiple factors may exert multiple central effects to alter neural circuits and produce unique sympathetic signatures and elevate ABP. In this brief review, we have discussed novel observations regarding three contributing factors: dietary salt intake, obesity, and inflammation. However, the interaction among these and other factors is likely much more complex; recent studies suggest a prior exposure to one stimulus may sensitize the response to a subsequent hypertensive stimulus. Insight into the central mechanisms by which these factors selectively alter SNA or cooperatively interact to impact hypertension may represent a platform for novel therapeutic treatment strategies.
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Affiliation(s)
- Sean D Stocker
- From the Department of Medicine, Renal-Electrolyte Division (S.D.S., B.J.K.), Department of Neuroscience (A.F.S.), and University of Pittsburgh Hypertension Center (S.D.S.), University of Pittsburgh, PA.
| | - Brian J Kinsman
- From the Department of Medicine, Renal-Electrolyte Division (S.D.S., B.J.K.), Department of Neuroscience (A.F.S.), and University of Pittsburgh Hypertension Center (S.D.S.), University of Pittsburgh, PA
| | - Alan F Sved
- From the Department of Medicine, Renal-Electrolyte Division (S.D.S., B.J.K.), Department of Neuroscience (A.F.S.), and University of Pittsburgh Hypertension Center (S.D.S.), University of Pittsburgh, PA
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11
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Becker BK, Wang H, Zucker IH. Central TrkB blockade attenuates ICV angiotensin II-hypertension and sympathetic nerve activity in male Sprague-Dawley rats. Auton Neurosci 2017; 205:77-86. [PMID: 28549782 DOI: 10.1016/j.autneu.2017.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 05/17/2017] [Accepted: 05/17/2017] [Indexed: 02/07/2023]
Abstract
Increased sympathetic nerve activity and the activation of the central renin-angiotensin system are commonly associated with cardiovascular disease states such as hypertension and heart failure, yet the precise mechanisms contributing to the long-term maintenance of this sympatho-excitation are incompletely understood. Due to the established physiological role of neurotrophins contributing toward neuroplasticity and neuronal excitability along with recent evidence linking the renin-angiotensin system and brain-derived neurotrophic factor (BDNF) along with its receptor (TrkB), it is likely the two systems interact to promote sympatho-excitation during cardiovascular disease. However, this interaction has not yet been fully demonstrated, in vivo. Thus, we hypothesized that central angiotensin II (Ang II) treatment will evoke a sympatho-excitatory state mediated through the actions of BDNF/TrkB. We infused Ang II (20ng/min) into the right lateral ventricle of male Sprague-Dawley rats for twelve days with or without the TrkB receptor antagonist, ANA-12 (50ng/h). We found that ICV infusion of Ang II increased mean arterial pressure (+40.4mmHg), increased renal sympathetic nerve activity (+19.4% max activity), and induced baroreflex dysfunction relative to vehicle. Co-infusion of ANA-12 attenuated the increase in blood pressure (-20.6mmHg) and prevented the increase in renal sympathetic nerve activity (-22.2% max) and baroreflex dysfunction relative to Ang II alone. Ang II increased thirst and decreased food consumption, and Ang II+ANA-12 augmented the thirst response while attenuating the decrease in food consumption. We conclude that TrkB signaling is a mediator of the long-term blood pressure and sympathetic nerve activity responses to central Ang II activity. These findings demonstrate the involvement of neurotrophins such as BDNF in promoting Ang II-induced autonomic dysfunction and further implicate TrkB signaling in modulating presympathetic autonomic neurons during cardiovascular disease.
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Affiliation(s)
- Bryan K Becker
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Hanjun Wang
- Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE, USA.; Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Irving H Zucker
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA..
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Marchese NA, Paz MC, Caeiro X, Dadam FM, Baiardi G, Perez MF, Bregonzio C. Angiotensin II AT 1 receptors mediate neuronal sensitization and sustained blood pressure response induced by a single injection of amphetamine. Neuroscience 2016; 340:521-529. [PMID: 27856342 DOI: 10.1016/j.neuroscience.2016.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/27/2016] [Accepted: 08/25/2016] [Indexed: 11/28/2022]
Abstract
A single exposure to amphetamine induces neurochemical sensitization in striatal areas. The neuropeptide angiotensin II, through AT1 receptors (AT1-R) activation, is involved in these responses. However, amphetamine-induced alterations can be extended to extra-striatal areas involved in blood pressure control and their physiological outcomes. Our aim for the present study was to analyze the possible role for AT1-R in these events using a two-injection protocol and to further characterize the proposed AT1-R antagonism protocol. Central effect of orally administered AT1-R blocker (Candesartan, 3mg/kg p.o.×5days) in male Wistar rats was analyzed by spontaneous activity of neurons within locus coeruleus. In another group of animals pretreated with the AT1-R blocker or vehicle, sensitization was achieved by a single administration of amphetamine (5mg/kg i.p. - day 6) followed by a 3-week period off drug. On day 27, after receiving an amphetamine challenge (0.5mg/kg i.p.), we evaluated: (1) the sensitized c-Fos expression in locus coeruleus (LC), nucleus of the solitary tract (NTS), caudal ventrolateral medulla (A1) and central amygdala (CeAmy); and (2) the blood pressure response. AT1-R blockade decreased LC neurons' spontaneous firing rate. Moreover, sensitized c-Fos immunoreactivity in TH+neurons was found in LC and NTS; and both responses were blunted by the AT1-R blocker pretreatment. Meanwhile, no differences were found neither in CeAmy nor A1. Sensitized blood pressure response was observed as sustained changes in mean arterial pressure and was effectively prevented by AT1-R blockade. Our results extend AT1-R role in amphetamine-induced sensitization over noradrenergic nuclei and their cardiovascular output.
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Affiliation(s)
- N A Marchese
- Instituto de Farmacología Experimental Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas Universidad Nacional de Córdoba, Córdoba, Argentina
| | - M C Paz
- Instituto de Farmacología Experimental Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas Universidad Nacional de Córdoba, Córdoba, Argentina
| | - X Caeiro
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC-CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - F M Dadam
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC-CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - G Baiardi
- Laboratorio de Neurofarmacología, (IIBYT-CONICET) Universidad Nacional de Córdoba, Córdoba, Argentina
| | - M F Perez
- Instituto de Farmacología Experimental Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas Universidad Nacional de Córdoba, Córdoba, Argentina
| | - C Bregonzio
- Instituto de Farmacología Experimental Córdoba (IFEC-CONICET), Departamento de Farmacología, Facultad de Ciencias Químicas Universidad Nacional de Córdoba, Córdoba, Argentina.
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Asirvatham-Jeyaraj N, Fink GD. Possible role for brain prostanoid pathways in the development of angiotensin II-salt hypertension in rats. Am J Physiol Regul Integr Comp Physiol 2016; 311:R232-42. [PMID: 27225954 DOI: 10.1152/ajpregu.00535.2015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 05/19/2016] [Indexed: 11/22/2022]
Abstract
Prostanoids generated by the cyclooxygenase (COX) pathway appear to contribute to the neurogenic hypertension (HTN) in rats. The first goal of this study was to establish the time frame during which prostanoids participate in ANG II-salt HTN. We induced HTN using ANG II (150 ng·kg(-1)·min(-1) sc) infusion for 14 days in rats on a high-salt (2% NaCl) diet. When ketoprofen pretreatment was combined with treatment during the first 7 days of ANG II infusion, development of HTN and increased neurogenic pressor activity (indexed by the depressor response to ganglion blockade) were significantly attenuated for the entire ANG II infusion period. This suggests that prostanoid generation caused by administration of ANG II and salt leads to an increase in neurogenic pressor activity and blood pressure (BP) via a mechanism that persists without the need for continuing prostanoid input. The second goal of this study was to determine whether prostanoid products specifically in the brain contribute to HTN development. Expression of prostanoid pathway genes was measured in brain regions known to affect neurogenic BP regulation. ANG II-treated rats exhibited changes in gene expression of phospholipase A2 (upregulated in organum vasculosum of the lamina terminalis, paraventricular nucleus, nucleus of the solitary tract, and middle cerebral artery) and lipocalin-type prostaglandin D synthase (upregulated in the organum vasculosum of the lamina terminalis). On the basis of our results, we propose that activation of the brain prostanoid synthesis pathway both upstream and downstream from COX at early stages plays an important role in the development of the neurogenic component of ANG II-salt HTN.
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Affiliation(s)
| | - Gregory D Fink
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
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Abstract
OBJECTIVE The purpose of the study was to determine whether exposure to chronic mild stress (CMS) affects expression of angiotensin II Type 1a receptor (AT1aR) messenger RNA (mRNA) in the brain and kidney. METHODS Male Sprague-Dawley rats were divided into an unchallenged control group, which remained at rest, and an experimental group, exposed to CMS produced by a series of unexpected, disturbing stimuli applied at random over a period of 4 weeks. After sacrificing the animals, samples of the septal/accumbal and hypothalamic/thalamic diencephalon, brain medulla, cerebellum, and the renal medulla were harvested for determination of AT1aR mRNA. RESULTS Expression of AT1a receptor mRNA was significantly greater in the rats in the CMS condition than in the controls (septal/accumbal diencephalon: 1.689 [0.205] versus 0.027 [0.004], hypothalamic/thalamic diencephalon: 1.239 [0.101] versus 0.003 [0.001], brain medulla: 2.694 [0.295] versus 0.028 [0.003], cerebellum: 0.013 [0.002] versus 0.005 [0.001; p < .001 for all comparisons], and renal medulla: 409.92 [46.92] versus 208.06 [30.56; p < .01]). There was a significant positive correlation between AT1a mRNA expression in the septal/accumbal diencephalon and brain medulla (p < .025). CONCLUSIONS The results provide evidence that CMS significantly enhances expression of the AT1aR gene in the brain and kidney and indicate that changes in expression of AT1aR mRNA in different brain regions during CMS may be causally related. It is suggested that the up-regulation of AT1a receptors by chronic stress may potentiate negative effects of angiotensin II in pathologies associated with activation of the renin-angiotensin system.
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Johnson AK, Zhang Z, Clayton SC, Beltz TG, Hurley SW, Thunhorst RL, Xue B. The roles of sensitization and neuroplasticity in the long-term regulation of blood pressure and hypertension. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1309-25. [PMID: 26290101 PMCID: PMC4698407 DOI: 10.1152/ajpregu.00037.2015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/18/2015] [Indexed: 01/01/2023]
Abstract
After decades of investigation, the causes of essential hypertension remain obscure. The contribution of the nervous system has been excluded by some on the basis that baroreceptor mechanisms maintain blood pressure only over the short term. However, this point of view ignores one of the most powerful contributions of the brain in maintaining biological fitness-specifically, the ability to promote adaptation of behavioral and physiological responses to cope with new challenges and maintain this new capacity through processes involving neuroplasticity. We present a body of recent findings demonstrating that prior, short-term challenges can induce persistent changes in the central nervous system to result in an enhanced blood pressure response to hypertension-eliciting stimuli. This sensitized hypertensinogenic state is maintained in the absence of the inducing stimuli, and it is accompanied by sustained upregulation of components of the brain renin-angiotensin-aldosterone system and other molecular changes recognized to be associated with central nervous system neuroplasticity. Although the heritability of hypertension is high, it is becoming increasingly clear that factors beyond just genes contribute to the etiology of this disease. Life experiences and attendant changes in cellular and molecular components in the neural network controlling sympathetic tone can enhance the hypertensive response to recurrent, sustained, or new stressors. Although the epigenetic mechanisms that allow the brain to be reprogrammed in the face of challenges to cardiovascular homeostasis can be adaptive, this capacity can also be maladaptive under conditions present in different evolutionary eras or ontogenetic periods.
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Affiliation(s)
- Alan Kim Johnson
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, Iowa; Department of Health and Human Physiology, The University of Iowa, Iowa City, Iowa; Department of Pharmacology, The University of Iowa, Iowa City, Iowa; François M. Abboud Cardiovascular Center, The University of Iowa, Iowa City, Iowa; and
| | - Zhongming Zhang
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, Iowa; Nanyang Institute of Technology, Zhang Zhongjing College of Chinese Medicine, Nanyang, Henan Province, China
| | - Sarah C Clayton
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, Iowa
| | - Terry G Beltz
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, Iowa
| | - Seth W Hurley
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, Iowa
| | - Robert L Thunhorst
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, Iowa; François M. Abboud Cardiovascular Center, The University of Iowa, Iowa City, Iowa; and
| | - Baojian Xue
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, Iowa; François M. Abboud Cardiovascular Center, The University of Iowa, Iowa City, Iowa; and
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Xue B, Thunhorst RL, Yu Y, Guo F, Beltz TG, Felder RB, Johnson AK. Central Renin-Angiotensin System Activation and Inflammation Induced by High-Fat Diet Sensitize Angiotensin II-Elicited Hypertension. Hypertension 2015; 67:163-70. [PMID: 26573717 DOI: 10.1161/hypertensionaha.115.06263] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/27/2015] [Indexed: 01/11/2023]
Abstract
Obesity has been shown to promote renin-angiotensin system activity and inflammation in the brain and to be accompanied by increased sympathetic activity and blood pressure. Our previous studies demonstrated that administration of a subpressor dose of angiotensin (Ang) II sensitizes subsequent Ang II-elicited hypertension. The present study tested whether high-fat diet (HFD) feeding also sensitizes the Ang II-elicited hypertensive response and whether HFD-induced sensitization is mediated by an increase in renin-angiotensin system activity and inflammatory mechanisms in the brain. HFD did not increase baseline blood pressure, but enhanced the hypertensive response to Ang II compared with a normal-fat diet. The sensitization produced by the HFD was abolished by concomitant central infusions of either a tumor necrosis factor-α synthesis inhibitor, pentoxifylline, an Ang II type 1 receptor blocker, irbesartan, or an inhibitor of microglial activation, minocycline. Furthermore, central pretreatment with tumor necrosis factor-α mimicked the sensitizing action of a central subpressor dose of Ang II, whereas central pentoxifylline or minocycline abolished this Ang II-induced sensitization. Real-time quantitative reverse transcription-polymerase chain reaction analysis of lamina terminalis tissue indicated that HFD feeding, central tumor necrosis factor-α, or a central subpressor dose of Ang II upregulated mRNA expression of several components of the renin-angiotensin system and proinflammatory cytokines, whereas inhibition of Ang II type 1 receptor and of inflammation reversed these changes. The results suggest that HFD-induced sensitization of Ang II-elicited hypertension is mediated by upregulation of the brain renin-angiotensin system and of central proinflammatory cytokines.
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Affiliation(s)
- Baojian Xue
- From the Departments of Psychological and Brain Sciences (B.X., R.L.T., F.G., T.G.B., A.K.J.), Pharmacology (A.K.J.), Internal Medicine (Y.Y., R.B.F.), and the François M. Abboud Cardiovascular Research Center (B.X., R.B.F., A.K.J.), University of Iowa, Iowa City.
| | - Robert L Thunhorst
- From the Departments of Psychological and Brain Sciences (B.X., R.L.T., F.G., T.G.B., A.K.J.), Pharmacology (A.K.J.), Internal Medicine (Y.Y., R.B.F.), and the François M. Abboud Cardiovascular Research Center (B.X., R.B.F., A.K.J.), University of Iowa, Iowa City
| | - Yang Yu
- From the Departments of Psychological and Brain Sciences (B.X., R.L.T., F.G., T.G.B., A.K.J.), Pharmacology (A.K.J.), Internal Medicine (Y.Y., R.B.F.), and the François M. Abboud Cardiovascular Research Center (B.X., R.B.F., A.K.J.), University of Iowa, Iowa City
| | - Fang Guo
- From the Departments of Psychological and Brain Sciences (B.X., R.L.T., F.G., T.G.B., A.K.J.), Pharmacology (A.K.J.), Internal Medicine (Y.Y., R.B.F.), and the François M. Abboud Cardiovascular Research Center (B.X., R.B.F., A.K.J.), University of Iowa, Iowa City
| | - Terry G Beltz
- From the Departments of Psychological and Brain Sciences (B.X., R.L.T., F.G., T.G.B., A.K.J.), Pharmacology (A.K.J.), Internal Medicine (Y.Y., R.B.F.), and the François M. Abboud Cardiovascular Research Center (B.X., R.B.F., A.K.J.), University of Iowa, Iowa City
| | - Robert B Felder
- From the Departments of Psychological and Brain Sciences (B.X., R.L.T., F.G., T.G.B., A.K.J.), Pharmacology (A.K.J.), Internal Medicine (Y.Y., R.B.F.), and the François M. Abboud Cardiovascular Research Center (B.X., R.B.F., A.K.J.), University of Iowa, Iowa City
| | - Alan Kim Johnson
- From the Departments of Psychological and Brain Sciences (B.X., R.L.T., F.G., T.G.B., A.K.J.), Pharmacology (A.K.J.), Internal Medicine (Y.Y., R.B.F.), and the François M. Abboud Cardiovascular Research Center (B.X., R.B.F., A.K.J.), University of Iowa, Iowa City
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Sayk F, Wobbe I, Twesten C, Meusel M, Wellhöner P, Derad I, Dodt C. Prolonged blood pressure elevation following continuous infusion of angiotensin II-a baroreflex study in healthy humans. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1406-14. [PMID: 26400183 DOI: 10.1152/ajpregu.00111.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 09/22/2015] [Indexed: 02/07/2023]
Abstract
ANG II interacts with the sympathetic nervous system at central nervous blood pressure-regulating structures, including the baroreflex. It is unknown whether prolonged BP elevation mediated by high ANG II plasma levels could induce a persistent shift of the central nervous baroreflex setpoint, lasting beyond the short ANG II plasmatic half time of a few seconds, thereby consolidating elevated BP and/or increased SNA in healthy humans. In a blinded crossover design, ANG II or placebo (saline) was infused for a 6-h period in 12 resting normotensive students (6 males, 6 females) raising BP to borderline hypertensive levels. Between 60 and 120 min after the infusion period, muscle sympathetic nerve activity (MSNA) was assessed microneurographically and correlated with oscillometric BP measurements and heart rate at supine rest (baseline) and during pharmacologic baroreceptor challenge. Infusion of ANG II increased BP to borderline-hypertensive levels, as intended, whereas heart rate remained unaltered. At baroreflex assessment (i.e., 60-120 min after end of infusion period), systolic BP was significantly higher compared with placebo (Δ8.4 ± 3.1 mmHg; P < 0.05), whereas diastolic values were nearly equal between conditions. Baseline MSNA was neither decreased nor increased, and baroreflex sensitivity to vasoactive drug challenge was not altered. Our results show that elevation of ANG II plasma levels over 6 h was able to increase systolic, but not diastolic, BP far beyond blood-mediated ANG II effects. MSNA or heart rate did not counter-regulate this BP elevation, indicating that ANG II had sustainably reset the central nervous BP threshold of sympathetic baroreflex function to accept elevated BP input signals without counter-regulatory response.
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Affiliation(s)
- Friedhelm Sayk
- Department of Internal Medicine I, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany; Department of Internal Medicine II, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany;
| | - Isabel Wobbe
- Institute of Radiology, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany; and
| | - Christoph Twesten
- Department of Internal Medicine I, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Moritz Meusel
- Department of Internal Medicine II, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Peter Wellhöner
- Department of Internal Medicine I, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Inge Derad
- Department of Internal Medicine I, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Christoph Dodt
- Department of Emergency Medicine, München-Bogenhausen Hospital, München, Germany
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Xue B, Zhang Z, Beltz TG, Guo F, Hay M, Johnson AK. Estrogen regulation of the brain renin-angiotensin system in protection against angiotensin II-induced sensitization of hypertension. Am J Physiol Heart Circ Physiol 2014; 307:H191-8. [PMID: 24858844 DOI: 10.1152/ajpheart.01012.2013] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
This study investigated sex differences in the sensitization of angiotensin (ANG) II-induced hypertension and the role of central estrogen and ANG-(1-7) in this process. Male and female rats were implanted for telemetered blood pressure (BP) recording. A subcutaneous subpressor dose of ANG II was given alone or concurrently with intracerebroventricular estrogen, ANG-(1-7), an ANG-(1-7) receptor antagonist A-779 or vehicle for 1 wk (induction). After a 1-wk rest (delay), a pressor dose of ANG II was given for 2 wk (expression). In males and ovariectomized females, subpressor ANG II had no sustained effect on BP during induction, but produced an enhanced hypertensive response to the subsequent pressor dose of ANG II during expression. Central administration of estrogen or ANG-(1-7) during induction blocked ANG II-induced sensitization. In intact females, subpressor ANG II treatment produced a decrease in BP during induction and delay, and subsequent pressor ANG II treatment given during expression produced only a slight but significant increase in BP. However, central blockade of ANG-(1-7) by intracerebroventricular infusion of A-779 during induction restored the decreased BP observed in females during induction and enhanced the pressor response to the ANG II treatment during expression. RT-PCR analyses indicated that estrogen given during induction upregulated mRNA expression of the renin-angiotensin system (RAS) antihypertensive components, whereas both central estrogen and ANG-(1-7) downregulated mRNA expression of RAS hypertensive components in the lamina terminalis. The results indicate that females are protected from ANG II-induced sensitization through central estrogen and its regulation of brain RAS.
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Affiliation(s)
- Baojian Xue
- Department of Psychology, University of Iowa, Iowa City, Iowa;
| | - Zhongming Zhang
- Zhang Zhongjing College of Chinese Medicine, Nanyang Institute of Technology, Henan, China
| | - Terry G Beltz
- Department of Psychology, University of Iowa, Iowa City, Iowa
| | - Fang Guo
- Department of Psychology, University of Iowa, Iowa City, Iowa
| | - Meredith Hay
- Department of Physiology, University of Arizona, Tucson, Arizona; Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, Arizona; and
| | - Alan Kim Johnson
- Department of Psychology, University of Iowa, Iowa City, Iowa; Department of Pharmacology, University of Iowa, Iowa City, Iowa; Francois M. Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
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