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Burma JS, Roy MA, Kennedy CM, Labrecque L, Brassard P, Smirl JD. A systematic review, meta-analysis and meta-regression amalgamating the driven approaches used to quantify dynamic cerebral autoregulation. J Cereb Blood Flow Metab 2024; 44:1271-1297. [PMID: 38635887 PMCID: PMC11342731 DOI: 10.1177/0271678x241235878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 12/29/2023] [Accepted: 01/16/2024] [Indexed: 04/20/2024]
Abstract
Numerous driven techniques have been utilized to assess dynamic cerebral autoregulation (dCA) in healthy and clinical populations. The current review aimed to amalgamate this literature and provide recommendations to create greater standardization for future research. The PubMed database was searched with inclusion criteria consisting of original research articles using driven dCA assessments in humans. Risk of bias were completed using Scottish Intercollegiate Guidelines Network and Methodological Index for Non-Randomized Studies. Meta-analyses were conducted for coherence, phase, and gain metrics at 0.05 and 0.10 Hz using deep-breathing, oscillatory lower body negative pressure (OLBNP), sit-to-stand maneuvers, and squat-stand maneuvers. A total of 113 studies were included, with 40 of these incorporating clinical populations. A total of 4126 participants were identified, with younger adults (18-40 years) being the most studied population. The most common techniques were squat-stands (n = 43), deep-breathing (n = 25), OLBNP (n = 20), and sit-to-stands (n = 16). Pooled coherence point estimates were: OLBNP 0.70 (95%CI:0.59-0.82), sit-to-stands 0.87 (95%CI:0.79-0.95), and squat-stands 0.98 (95%CI:0.98-0.99) at 0.05 Hz; and deep-breathing 0.90 (95%CI:0.81-0.99); OLBNP 0.67 (95%CI:0.44-0.90); and squat-stands 0.99 (95%CI:0.99-0.99) at 0.10 Hz. This review summarizes clinical findings, discusses the pros/cons of the 11 unique driven techniques included, and provides recommendations for future investigations into the unique physiological intricacies of dCA.
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Affiliation(s)
- Joel S Burma
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
- Integrated Concussion Research Program, University of Calgary, Calgary, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Canada
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Canada
| | - Marc-Antoine Roy
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Courtney M Kennedy
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
- Integrated Concussion Research Program, University of Calgary, Calgary, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Canada
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Canada
| | - Lawrence Labrecque
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Jonathan D Smirl
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
- Integrated Concussion Research Program, University of Calgary, Calgary, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Canada
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Canada
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2
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Desai SA, Mirza UA, Mueller PJ. Influence of sex and sedentary conditions on sympathetic burst characteristics in prepubertal, postpubertal, and young adult rats. J Appl Physiol (1985) 2024; 136:1170-1181. [PMID: 38511214 PMCID: PMC11368517 DOI: 10.1152/japplphysiol.00649.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 03/07/2024] [Accepted: 03/15/2024] [Indexed: 03/22/2024] Open
Abstract
Recent evidence indicates that sex-based differences in cardiovascular disease (CVD) begin early in life, particularly when associated with risk factors such as a sedentary lifestyle. CVD is associated with elevated sympathetic nerve activity (SNA), quantified as increased SNA burst activity in humans. Whether burst characteristics are influenced by sex or sedentary conditions at younger ages is unknown. The purpose of our study is to compare SNA bursts in active and sedentary female and male rats at ages including prepuberty and young adulthood. We hypothesized that burst characteristics and blood pressure are higher under sedentary conditions and lower in female rats compared with males. We analyzed splanchnic SNA (SpSNA) recordings from Inactin-anesthetized male and female rats at 4-, 8-, and 16-wk of age. Physically active and sedentary rats were each housed in separate, environmentally controlled chambers where physically active rats had free access to an in-cage running wheel. Sympathetic bursts were obtained by rectifying and integrating the raw SpSNA signal. Burst frequency, burst height, and burst width were calculated using the Peak Parameters extension in LabChart. Our results showed that sedentary conditions produced a greater burst width in 8- and 16-wk-old rats compared with 4-wk-old rats in both males and females (P < 0.001 for both). Burst frequency and incidence were both higher in 16-wk-old males compared with 16-wk-old females (P < 0.001 for both). Our results suggest that there are sedentary lifestyle- and sex-related mechanisms that impact sympathetic regulation of blood pressure at ages that range from prepuberty into young adulthood.NEW & NOTEWORTHY The mechanisms of decreased incidence of cardiovascular disease (CVD) in reproductive-age women compared with age-matched men are unknown. The strong association between elevated sympathetic activity and CVD led us to characterize splanchnic sympathetic bursts in female and male rats. Prepubescent males and females exhibited narrower sympathetic bursts, whereas young adult males had higher resting burst frequency compared with age-matched females. Sex-based regulation of sympathetic activity suggests a need for sex-dependent therapeutic strategies to combat CVD.
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Affiliation(s)
- Shivansh A Desai
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Umme Aiman Mirza
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Patrick J Mueller
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States
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Nardone M, Foster M, O'Brien MW, Coovadia Y, Xie S, Usselman CW, Kimmerly DS, Taylor CE, Millar PJ. Sympathetic determinants of resting blood pressure in males and females. Am J Physiol Heart Circ Physiol 2024; 326:H612-H622. [PMID: 38214907 DOI: 10.1152/ajpheart.00497.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/13/2024]
Abstract
Discharge of postganglionic muscle sympathetic nerve activity (MSNA) is related poorly to blood pressure (BP) in adults. Whether neural measurements beyond the prevailing level of MSNA can account for interindividual differences in BP remains unclear. The current study sought to evaluate the relative contributions of sympathetic-BP transduction and sympathetic baroreflex gain on resting BP in young adults. Data were analyzed from 191 (77 females) young adults (18-39 years) who underwent continuous measurement of beat-to-beat BP (finger photoplethysmography), heart rate (electrocardiography), and fibular nerve MSNA (microneurography). Linear regression analyses were computed to determine associations between sympathetic-BP transduction (signal-averaging) or sympathetic baroreflex gain (threshold technique) and resting BP, before and after controlling for age, body mass index, and MSNA burst frequency. K-mean clustering was used to explore sympathetic phenotypes of BP control and consequential influence on resting BP. Sympathetic-BP transduction was unrelated to BP in males or females (both R2 < 0.01; P > 0.67). Sympathetic baroreflex gain was positively associated with BP in males (R2 = 0.09, P < 0.01), but not in females (R2 < 0.01; P = 0.80), before and after controlling for age, body mass index, and MSNA burst frequency. K-means clustering identified a subset of participants with average resting MSNA, yet lower sympathetic-BP transduction and lower sympathetic baroreflex gain. This distinct subgroup presented with elevated BP in males (P < 0.02), but not in females (P = 0.10). Sympathetic-BP transduction is unrelated to resting BP, while the association between sympathetic baroreflex gain and resting BP in males reveals important sex differences in the sympathetic determination of resting BP.NEW & NOTEWORTHY In a sample of 191 normotensive young adults, we confirm that resting muscle sympathetic nerve activity is a poor predictor of resting blood pressure and now demonstrate that sympathetic baroreflex gain is associated with resting blood pressure in males but not females. In contrast, signal-averaged measures of sympathetic-blood pressure transduction are unrelated to resting blood pressure. These findings highlight sex differences in the neural regulation of blood pressure.
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Affiliation(s)
- Massimo Nardone
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Monique Foster
- School of Health Sciences, Western Sydney University, Sydney, New South Wales, Australia
| | - Myles W O'Brien
- Division of Kinesiology, School of Health and Human Performance, Faculty of Health, Dalhousie University, Halifax, Nova Scotia, Canada
- School of Physiotherapy (Faculty of Health) and Division of Geriatric Medicine (Faculty of Medicine), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Yasmine Coovadia
- Cardiovascular Health and Autonomic Regulation Laboratory, Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
| | - Shengkun Xie
- Global Management Studies, Ted Rogers School of Management, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Charlotte W Usselman
- Cardiovascular Health and Autonomic Regulation Laboratory, Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
| | - Derek S Kimmerly
- Division of Kinesiology, School of Health and Human Performance, Faculty of Health, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Chloe E Taylor
- School of Health Sciences, Western Sydney University, Sydney, New South Wales, Australia
| | - Philip J Millar
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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Controls of Central and Peripheral Blood Pressure and Hemorrhagic/Hypovolemic Shock. J Clin Med 2023; 12:jcm12031108. [PMID: 36769755 PMCID: PMC9917827 DOI: 10.3390/jcm12031108] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/17/2023] [Accepted: 01/23/2023] [Indexed: 02/04/2023] Open
Abstract
The pressure exerted on the heart and blood vessels because of blood flow is considered an essential parameter for cardiovascular function. It determines sufficient blood perfusion, and transportation of nutrition, oxygen, and other essential factors to every organ. Pressure in the primary arteries near the heart and the brain is known as central blood pressure (CBP), while that in the peripheral arteries is known as peripheral blood pressure (PBP). Usually, CBP and PBP are correlated; however, various types of shocks and cardiovascular disorders interfere with their regulation and differently affect the blood flow in vital and accessory organs. Therefore, understanding blood pressure in normal and disease conditions is essential for managing shock-related cardiovascular implications and improving treatment outcomes. In this review, we have described the control systems (neural, hormonal, osmotic, and cellular) of blood pressure and their regulation in hemorrhagic/hypovolemic shock using centhaquine (Lyfaquin®) as a resuscitative agent.
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Elsaafien K, Harden SW, Johnson DN, Kimball AK, Sheng W, Smith JA, Scott KA, Frazier CJ, de Kloet AD, Krause EG. A Novel Organ-Specific Approach to Selectively Target Sensory Afferents Innervating the Aortic Arch. Front Physiol 2022; 13:841078. [PMID: 35399269 PMCID: PMC8987286 DOI: 10.3389/fphys.2022.841078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/16/2022] [Indexed: 12/02/2022] Open
Abstract
The brain maintains cardiovascular homeostasis, in part, via the arterial baroreflex which senses changes in blood pressure (BP) at the level of the aortic arch. Sensory afferents innervating the aortic arch employ baroreceptors to convert stretch exerted on the arterial wall into action potentials carried by the vagus nerve to second order neurons residing within the nucleus of the solitary tract (NTS). Although the baroreflex was described more than 80 years ago, the specific molecular, structural, and functional phenotype of the baroreceptors remain uncharacterized. This is due to the lack of tools that provide the genetic and target organ specificity that is required to selectively characterize baroreceptor afferents. Here, we use a novel approach to selectively target baroreceptors. Male mice on a C57BL/6J background were anesthetized with isoflurane, intubated, and artificially ventilated. Following sternotomy, the aortic arch was exposed, and a retrograde adeno-associated virus was applied to the aortic arch to direct the expression of channelrhoropsin-2 (ChR2) and/or tdTomato (tdTom) to sensory afferents presumably functioning as baroreceptors. Consistent with the structural characteristics of arterial baroreceptors, robust tdTom expression was observed in nerve endings surrounding the aortic arch, within the fibers of the aortic depressor and vagus nerves, cell bodies of the nodose ganglia (NDG), and neural projections to the caudal NTS (cNTS). Additionally, the tdTom labeled cell bodies within the NDG also expressed mRNAs coding for the mechanically gated ion channels, PIEZO-1 and PIEZO-2. In vitro electrophysiology revealed that pulses of blue light evoked excitatory post-synaptic currents in a subset of neurons within the cNTS, suggesting a functional connection between the labeled aortic arch sensory afferents and second order neurons. Finally, the in vivo optogenetic stimulation of the cell bodies of the baroreceptor expressing afferents in the NDG produced robust depressor responses. Together, these results establish a novel approach for selectively targeting sensory neurons innervating the aortic arch. This approach may be used to investigate arterial baroreceptors structurally and functionally, and to assess their role in the etiology or reversal of cardiovascular disease.
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Affiliation(s)
- Khalid Elsaafien
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, United States
| | - Scott W. Harden
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, United States
| | - Dominique N. Johnson
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Aecha K. Kimball
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Wanhui Sheng
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, United States
| | - Justin A. Smith
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Karen A. Scott
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, United States
| | - Charles J. Frazier
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, United States
| | - Annette D. de Kloet
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, United States
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, United States
- Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- Annette D. de Kloet,
| | - Eric G. Krause
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, United States
- Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- *Correspondence: Eric G. Krause,
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Tumanova TS, Кokurina TN, Rybakova GI, Aleksandrov VG. Dexamethasone attenuates the modulatory effect of the insular cortex on the baroreflex in anesthetized rat. Can J Physiol Pharmacol 2021; 100:334-340. [PMID: 34644509 DOI: 10.1139/cjpp-2021-0385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The arterial baroreflex (BR) is an important neural mechanism for the stabilization of arterial pressure (AP). It is known that the insular cortex (IC) and other parts of the central autonomic network (CAN) are able to modulate the BR arc, altering baroreflex sensitivity (BRS). In addition, the sensitivity of the BR changes under the influence of hormones, in particular glucocorticoids (GC). It has been suggested that GC may influence BRS by altering the ability of the IC to modulate the BR. This hypothesis has been tested in experiments on rats anesthetized with urethane. It was found that microelectrostimulation of the visceral area in the left IC causes a short-term drop in AP, which is accompanied by bradycardia, and impairs BRS. The synthetic GC dexamethasone (DEX) did not significantly affect the magnitude of depressor responses but increased BRS and impaired the effect of IC stimulation on the BR. The results obtained confirm the hypothesis put forward and suggest that GC can attenuate the inhibitory effects of the IC on the BR arc, thereby enhancing the sensitivity of the BR.
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Affiliation(s)
- Tatiana Sergeevna Tumanova
- Pavlov Institute of Physiology RAS, 68594, Sankt Peterburg, Russian Federation.,Herzen State Pedagogical University of Russia, 104720, Biology, Sankt-Peterburg, Russian Federation;
| | | | | | - Viacheslav G Aleksandrov
- Pavlov Institute of Physiology RAS, 68594, 6, nab. Makarova, Sankt Peterburg, Russian Federation, 199034;
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7
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Yan X, Zhang S, Zhao H, Liu P, Huang H, Niu W, Wang W, Zhang C. ASIC2 Synergizes with TRPV1 in the Mechano-Electrical Transduction of Arterial Baroreceptors. Neurosci Bull 2021; 37:1381-1396. [PMID: 34215968 DOI: 10.1007/s12264-021-00737-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 03/09/2021] [Indexed: 11/24/2022] Open
Abstract
Mechanosensitive ion channels (MSCs) are key molecules in the mechano-electrical transduction of arterial baroreceptors. Among them, acid-sensing ion channel 2 (ASIC2) and transient receptor potential vanilloid subfamily member 1 (TRPV1) have been studied extensively and documented to play important roles. In this study, experiments using aortic arch-aortic nerve preparations isolated from rats revealed that both ASIC2 and TRPV1 are functionally necessary, as blocking either abrogated nearly all pressure-dependent neural discharge. However, whether ASIC2 and TRPV1 work in coordination remained unclear. So we carried out cell-attached patch-clamp recordings in HEK293T cells co-expressing ASIC2 and TRPV1 and found that inhibition of ASIC2 completely blocked stretch-activated currents while inhibition of TRPV1 only partially blocked these currents. Immunofluorescence staining of aortic arch-aortic adventitia from rats showed that ASIC2 and TRPV1 are co-localized in the aortic nerve endings, and co-immunoprecipitation assays confirmed that the two proteins form a compact complex in HEK293T cells and in baroreceptors. Moreover, protein modeling analysis, exogenous co-immunoprecipitation assays, and biotin pull-down assays indicated that ASIC2 and TRPV1 interact directly. In summary, our research suggests that ASIC2 and TRPV1 form a compact complex and function synergistically in the mechano-electrical transduction of arterial baroreceptors. The model of synergism between MSCs may have important biological significance beyond ASIC2 and TRPV1.
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Affiliation(s)
- Xiaodong Yan
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China
| | - Sitao Zhang
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China
| | - Haiyan Zhao
- Yanjing Medical College, Capital Medical University, Beijing, 101300, China
| | - Ping Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China
| | - Haixia Huang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China
| | - Weizhen Niu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China
| | - Wei Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China. .,Beijing Laboratory for Cardiovascular Precision Medicine, Capital Medical University, Beijing, 100069, China.
| | - Chen Zhang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100069, China.
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8
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Suarez-Roca H, Mamoun N, Sigurdson MI, Maixner W. Baroreceptor Modulation of the Cardiovascular System, Pain, Consciousness, and Cognition. Compr Physiol 2021; 11:1373-1423. [PMID: 33577130 DOI: 10.1002/cphy.c190038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Baroreceptors are mechanosensitive elements of the peripheral nervous system that maintain cardiovascular homeostasis by coordinating the responses to external and internal environmental stressors. While it is well known that carotid and cardiopulmonary baroreceptors modulate sympathetic vasomotor and parasympathetic cardiac neural autonomic drive, to avoid excessive fluctuations in vascular tone and maintain intravascular volume, there is increasing recognition that baroreceptors also modulate a wide range of non-cardiovascular physiological responses via projections from the nucleus of the solitary tract to regions of the central nervous system, including the spinal cord. These projections regulate pain perception, sleep, consciousness, and cognition. In this article, we summarize the physiology of baroreceptor pathways and responses to baroreceptor activation with an emphasis on the mechanisms influencing cardiovascular function, pain perception, consciousness, and cognition. Understanding baroreceptor-mediated effects on cardiac and extra-cardiac autonomic activities will further our understanding of the pathophysiology of multiple common clinical conditions, such as chronic pain, disorders of consciousness (e.g., abnormalities in sleep-wake), and cognitive impairment, which may result in the identification and implementation of novel treatment modalities. © 2021 American Physiological Society. Compr Physiol 11:1373-1423, 2021.
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Affiliation(s)
- Heberto Suarez-Roca
- Department of Anesthesiology, Center for Translational Pain Medicine, Duke University, Durham, North Carolina, USA
| | - Negmeldeen Mamoun
- Department of Anesthesiology, Division of Cardiothoracic Anesthesia and Critical Care Medicine, Duke University, Durham, North Carolina, USA
| | - Martin I Sigurdson
- Department of Anesthesiology and Critical Care Medicine, Landspitali, University Hospital, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - William Maixner
- Department of Anesthesiology, Center for Translational Pain Medicine, Duke University, Durham, North Carolina, USA
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Lu HJ, Nguyen TL, Hong GS, Pak S, Kim H, Kim H, Kim DY, Kim SY, Shen Y, Ryu PD, Lee MO, Oh U. Tentonin 3/TMEM150C senses blood pressure changes in the aortic arch. J Clin Invest 2021; 130:3671-3683. [PMID: 32484458 DOI: 10.1172/jci133798] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/24/2020] [Indexed: 01/09/2023] Open
Abstract
The baroreceptor reflex is a powerful neural feedback that regulates arterial pressure (AP). Mechanosensitive channels transduce pulsatile AP to electrical signals in baroreceptors. Here we show that tentonin 3 (TTN3/TMEM150C), a cation channel activated by mechanical strokes, is essential for detecting AP changes in the aortic arch. TTN3 was expressed in nerve terminals in the aortic arch and nodose ganglion (NG) neurons. Genetic ablation of Ttn3 induced ambient hypertension, tachycardia, AP fluctuations, and impaired baroreflex sensitivity. Chemogenetic silencing or activation of Ttn3+ neurons in the NG resulted in an increase in AP and heart rate, or vice versa. More important, overexpression of Ttn3 in the NG of Ttn3-/- mice reversed the cardiovascular changes observed in Ttn3-/- mice. We conclude that TTN3 is a molecular component contributing to the sensing of dynamic AP changes in baroreceptors.
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Affiliation(s)
- Huan-Jun Lu
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea.,College of Pharmacy
| | - Thien-Luan Nguyen
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea.,College of Pharmacy
| | - Gyu-Sang Hong
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | - Sungmin Pak
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | - Hyesu Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | - Hyungsup Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | | | - Sung-Yon Kim
- Institute of Molecular Biology and Genetics, and
| | - Yiming Shen
- College of Veterinary Medicine, Seoul National University, Seoul, Korea
| | - Pan Dong Ryu
- College of Veterinary Medicine, Seoul National University, Seoul, Korea
| | | | - Uhtaek Oh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
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10
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Huo L, Gao Y, Zhang D, Wang S, Han Y, Men H, Yang Z, Qin X, Wang R, Kong D, Bai H, Zhang H, Zhang W, Jia Z. Piezo2 channel in nodose ganglia neurons is essential in controlling hypertension in a pathway regulated directly by Nedd4-2. Pharmacol Res 2021; 164:105391. [PMID: 33352230 DOI: 10.1016/j.phrs.2020.105391] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/25/2020] [Accepted: 12/12/2020] [Indexed: 11/24/2022]
Abstract
Baroreflex plays a crucial role in regulation of arterial blood pressure (BP). Recently, Piezo1 and Piezo2, the mechanically-activated (MA) ion channels, have been identified as baroreceptors. However, the underlying molecular mechanism for regulating these baroreceptors in hypertension remains unknown. In this study, we used spontaneously hypertensive rats (SHR) and NG-Nitro-l-Arginine (L-NNA)- and Angiotensin II (Ang II)-induced hypertensive model rats to determine the role and mechanism of Piezo1 and Piezo2 in hypertension. We found that Piezo2 was dominantly expressed in baroreceptor nodose ganglia (NG) neurons and aortic nerve endings in Wistar-Kyoto (WKY) rats. The expression of Piezo2 not Piezo1 was significantly downregulated in these regions in SHR and hypertensive model rats. Electrophysiological results showed that the rapidly adapting mechanically-activated (RA-MA) currents and the responsive neuron numbers were significantly reduced in baroreceptor NG neurons in SHR. In WKY rats, the arterial BP was elevated by knocking down the expression of Piezo2 or inhibiting MA channel activity by GsMTx4 in NG. Knockdown of Piezo2 in NG also attenuated the baroreflex and increased serum norepinephrine (NE) concentration in WKY rats. Co-immunoprecipitation experiment suggested that Piezo2 interacted with Neural precursor cell-expressed developmentally downregulated gene 4 type 2 (Nedd4-2, also known as Nedd4L); Electrophysiological results showed that Nedd4-2 inhibited Piezo2 MA currents in co-expressed HEK293T cells. Additionally, Nedd4-2 was upregulated in NG baroreceptor neurons in SHR. Collectively, our results demonstrate that Piezo2 not Piezo1 may act as baroreceptor to regulate arterial BP in rats. Nedd4-2 induced downregulation of Piezo2 in baroreceptor NG neurons leads to hypertension in rats. Our findings provide a novel insight into the molecular mechanism for the regulation of baroreceptor Piezo2 and its critical role in the pathogenesis of hypertension.
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Affiliation(s)
- Lifang Huo
- Department of Pharmacology of Chinese Materia Medica, Institution of Chinese Integrative Medicine, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China; Department of Pharmacology, Center of Innovative Drug Research and Evaluation, Institute of Medical Science and Health, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China
| | - Yiting Gao
- Department of Pharmacology, Center of Innovative Drug Research and Evaluation, Institute of Medical Science and Health, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China
| | - Dongfang Zhang
- Department of Pharmacology, Center of Innovative Drug Research and Evaluation, Institute of Medical Science and Health, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China
| | - Shengnan Wang
- Department of Pharmacology, Center of Innovative Drug Research and Evaluation, Institute of Medical Science and Health, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China
| | - Yu Han
- Department of Pharmacology, Center of Innovative Drug Research and Evaluation, Institute of Medical Science and Health, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China; Department of Pharmacy, Children's Hospital of Hebei Province, China
| | - Hongchao Men
- Department of Pharmacology, Center of Innovative Drug Research and Evaluation, Institute of Medical Science and Health, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China
| | - Zuxiao Yang
- Department of Pharmacology of Chinese Materia Medica, Institution of Chinese Integrative Medicine, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China
| | - Xia Qin
- Department of Pharmacology of Chinese Materia Medica, Institution of Chinese Integrative Medicine, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China
| | - Ri Wang
- Department of Pharmacology of Chinese Materia Medica, Institution of Chinese Integrative Medicine, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China
| | - Dezhi Kong
- Department of Pharmacology of Chinese Materia Medica, Institution of Chinese Integrative Medicine, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China
| | - Hui Bai
- Department of Cardiac Ultrasound, The Second Hospital of Hebei Medical University, China
| | - Hailin Zhang
- Department of Pharmacology, Center of Innovative Drug Research and Evaluation, Institute of Medical Science and Health, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China
| | - Wei Zhang
- Department of Pharmacology of Chinese Materia Medica, Institution of Chinese Integrative Medicine, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China.
| | - Zhanfeng Jia
- Department of Pharmacology, Center of Innovative Drug Research and Evaluation, Institute of Medical Science and Health, The Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of New Drug Pharmacology and Toxicology, Hebei Medical University, Shijiazhuang, Hebei Province, 050017, China.
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11
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Gu JG, Berkowitz DE. Tentonin 3 as a baroreceptor mechanosensor: not a stretch. J Clin Invest 2021; 130:3412-3415. [PMID: 32484454 DOI: 10.1172/jci138120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Mechanical stretch of baroreceptors in the wall of the aortic arch and carotid sinus initiates autonomic reflexes to change heart rate and blood pressure for cardiovascular homeostasis. In this issue of the JCI, Lu et al. show that tentonin 3 (TTN3), a recently identified stretch-sensitive ion channel, was present at the vagus afferent nerve endings innervating the aortic arch to function as a baroreceptor. This study expands the molecular profiles of baroreceptors and provides new insights into molecular mechanisms underlying the regulation of cardiovascular functions through baroreceptor function.
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12
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Yu SQ, Ma S, Wang DH. TRPV1 Activation Prevents Renal Ischemia-Reperfusion Injury-Induced Increase in Salt Sensitivity by Suppressing Renal Sympathetic Nerve Activity. Curr Hypertens Rev 2020; 16:148-155. [PMID: 31721716 PMCID: PMC7499355 DOI: 10.2174/1573402115666191112122339] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 11/23/2022]
Abstract
Abstract: Background Salt sensitivity is increased following renal Ischemia-Reperfusion (I/R) injury. We tested the hypothesis that high salt intake induced increase in Renal Sympathetic Nerve Activity (RSNA) after renal I/R can be prevented by activation of Transient Receptor Potential Vanilloid 1 (TRPV1). Methods Rats were fed a 0.4% NaCl diet for 5 weeks after renal I/R, followed by a 4% NaCl diet for 4 more weeks in four groups: sham, I/R, I/R +High Dose Capsaicin (HDC), and I/R+Low Dose Capsaicin (LDC). The low (1mg/kg) or high (100mg/kg) dose of capsaicin was injected subcutaneously before I/R to activate or desensitize TRPV1, respectively. Results Systolic blood pressure was gradually elevated after fed on a high-salt diet in the I/R and I/R+HDC groups but not in the I/R+LDC group, with a greater increase in the I/R+HDC group. Renal function was impaired in the I/R group and was further deteriorated in the I/R+HDC group but was unchanged in the I/R+LDC group. At the end of high salt treatment, afferent renal nerve activity in response to unilateral intra-pelvic administration of capsaicin was decreased in the I/R group and was further suppressed in the I/R+HDC group but was unchanged in the I/R+LDC group. RSNA in response to intrathecal administration of muscimol, a selective agonist of GABA-A receptors, was augmented in the I/R group and further intensified in the I/R+HDC group but was unchanged in the I/R+LDC group. Similarly, urinary norepinephrine levels were increased in the I/R group and were further elevated in the I/R+HDC group but unchanged in the I/R+LDC group. Conclusion These data suggest that TRPV1 activation prevents renal I/R injury-induced increase in salt sensitivity by suppressing RSNA.
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Affiliation(s)
- Shuang-Quan Yu
- Division of Nanomedicine and Molecular Intervention, Department of Medicine Michigan State University, East Lansing, Michigan, MI 48824, United States
| | - Shuangtao Ma
- Division of Nanomedicine and Molecular Intervention, Department of Medicine Michigan State University, East Lansing, Michigan, MI 48824, United States
| | - Donna H Wang
- Division of Nanomedicine and Molecular Intervention, Department of Medicine Michigan State University, East Lansing, Michigan, MI 48824, United States
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13
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Damianaki K, Burnier M, Dimitriadis K, Tsioufis C, Petras D. Renal Functional Reserve Is Related to the Nondipping Phenotype and to the Exercise Heart Rate Response in Patients with Essential Hypertension and Preserved Renal Function. Kidney Blood Press Res 2020; 45:737-747. [PMID: 32784307 DOI: 10.1159/000508939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 05/25/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Renal functional reserve (RFR), defined as the difference between stress and resting glomerular filtration rate (GFR), may constitute a diagnostic tool to identify patients at higher risk of developing acute kidney injury or chronic kidney disease. Blunted RFR has been demonstrated in early stages of hypertension and has been attributed to impaired vascular reactivity due to an overactive sympathetic nervous system (SNS). OBJECTIVE The purpose of this study was to investigate whether RFR correlates with other phenotypes expressing overactivity of the SNS in patients with essential hypertension and preserved renal function. METHODS Thirty-six patients with untreated essential hypertension and a GFR >60 mL/min/1.73 m2 were enrolled. The following parameters were measured: RFR, 24-h ambulatory blood pressure (BP) profile, a treadmill stress test, and an echocardiographic examination. Urine and venous samples were obtained at specific time points for the determination of clinical parameters, and both resting and stress GFR were calculated by using endogenous creatinine clearance for the measurement of RFR after an acute oral protein load (1 g/kg). RESULTS Twenty-one patients had a RFR <30 mL/min/1.73 m2 and 15 had a RFR above this cutoff. A nondipping pattern of 24-h BP was significantly more frequent in patients with low RFR (57.1 vs. 25.0%, p < 0.05 for systolic BP and 52.3 vs. 10.0%, p < 0.02 for diastolic BP). Moreover, patients with lower RFR values showed a blunted heart rate (HR) response to exercise during treadmill test (r = 0.439, p < 0.05). None of the echocardiographic parameters differed between the two groups of patients. CONCLUSIONS In hypertensive patients with preserved GFR, reduced RFR is related to nondipping BP phenotype as well as to attenuated exercise HR response. Overactivity of the SNS may be a common pathway. Since loss of RFR may represent a risk factor for acute or chronic kidney injury, hypertensive patients with blunted RFR might need a more careful renal follow-up.
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Affiliation(s)
- Katerina Damianaki
- Service of Nephrology, University Hospital of Athens, Hippokration Hospital, Athens, Greece,
| | - Michel Burnier
- Service of Nephrology and Hypertension, University Hospital of Lausanne, Lausanne, Switzerland
| | - Kyriakos Dimitriadis
- First Cardiology Clinic, National and Kapodistrian University of Athens, Medical School, Hippokration Hospital, Athens, Greece
| | - Costas Tsioufis
- First Cardiology Clinic, National and Kapodistrian University of Athens, Medical School, Hippokration Hospital, Athens, Greece
| | - Dimitrios Petras
- Service of Nephrology, University Hospital of Athens, Hippokration Hospital, Athens, Greece
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14
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Lord RN, Wakeham DJ, Pugh CJA, Simpson LL, Talbot JS, Lodge FM, Curry BA, Dawkins TG, Shave RE, Moore JP. The influence of barosensory vessel mechanics on the vascular sympathetic baroreflex: insights into aging and blood pressure homeostasis. Am J Physiol Heart Circ Physiol 2020; 319:H370-H376. [PMID: 32648822 DOI: 10.1152/ajpheart.00265.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Changes in the arterial baroreflex arc contribute to elevated sympathetic outflow and altered reflex control of blood pressure with human aging. Using ultrasound and sympathetic microneurography (muscle sympathetic nerve activity, MSNA) we investigated the relationships between aortic and carotid artery wall tension (indices of baroreceptor activation) and the vascular sympathetic baroreflex operating point (OP; MSNA burst incidence) in healthy, normotensive young (n = 27, 23 ± 3 yr) and middle-aged men (n = 22, 55 ± 4 yr). In young men, the OP was positively related to the magnitude and rate of unloading and time spent unloaded in the aortic artery (r = 0.56, 0.65, and 0.51, P = 0.02, 0.003, and 0.03), but not related to the magnitude or rate of unloading or time spent unloaded in the carotid artery (r = -0.32, -0.07, and 0.06, P = 0.25, 0.81, and 0.85). In contrast, in middle-aged men, the OP was not related to either the magnitude or rate of unloading or time spent unloaded in the aortic (r = 0.22, 0.21, and 0.27, P = 0.41, 0.43, and 0.31) or carotid artery (r = 0.06, 0.28, and -0.01; P = 0.48, 0.25, and 0.98). In conclusion, in young men, aortic unloading mechanics may play a role in determining the vascular sympathetic baroreflex OP. In contrast, in middle-aged men, barosensory vessel unloading mechanics do not appear to determine the vascular sympathetic baroreflex OP and, therefore, do not contribute to age-related arterial baroreflex resetting and increased resting MSNA.NEW & NOTEWORTHY We assessed the influence of barosensory vessel mechanics (magnitude and rate of unloading and time spent unloaded) as a surrogate for baroreceptor unloading. In young men, aortic unloading mechanics are important in regulating the operating point of the vascular sympathetic baroreflex, whereas in middle-aged men, these arterial mechanics do not influence this operating point. The age-related increase in resting muscle sympathetic nerve activity does not appear to be driven by altered baroreceptor input from stiffer barosensory vessels.
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Affiliation(s)
- Rachel N Lord
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Denis J Wakeham
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Christopher J A Pugh
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Lydia L Simpson
- Physical Activity for Health and Well-Being Centre, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom
| | - Jack S Talbot
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Freya M Lodge
- Cardiff and Vale University Health Board, University Hospital of Wales, Cardiff, United Kingdom
| | - Bryony A Curry
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Tony G Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Rob E Shave
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom.,Centre for Heart, Lung, and Vascular Health, University of British Columbia Okanagan, Kelowna, Canada
| | - Jonathan P Moore
- Physical Activity for Health and Well-Being Centre, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom
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15
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Thieme K, Meller T, Evermann U, Malinowski R, Mathys MG, Graceley RH, Maixner W, Turk DC. Efficacy of Systolic Extinction Training in Fibromyalgia Patients With Elevated Blood Pressure Response to Stress: A Tailored Randomized Controlled Trial. Arthritis Care Res (Hoboken) 2020; 71:678-688. [PMID: 29882635 DOI: 10.1002/acr.23615] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 06/05/2018] [Indexed: 01/19/2023]
Abstract
OBJECTIVE An intrinsic pain regulatory system is modulated by both cardiovascular dynamics that influence baroreflex sensitivity (BRS) and is diminished in fibromyalgia (FM). Baroreceptors relay cardiovascular output to the dorsal medial nucleus tractus solitarius reflex arcs that regulate pain, sleep, anxiety, and blood pressure. The aim of this study was to evaluate the effects of systolic extinction training (SET), which combines operant treatment (OT) with baroreflex training (BRT). BRT delivers peripheral electrical stimulation within a few milliseconds of the systolic or diastolic peak in the cardiac cycle. In addition, we compared SET to OT-transcutaneous electrical stimulation (TENS) independent of the cardiac cycle and aerobic exercise (AE)-BRT in FM patients with elevated blood pressure responses to stress. METHODS Sixty-two female patients with FM were randomized to receive either SET (n = 21), OT-TENS (n = 20), or AE-BRT (n = 21). Outcome assessments were performed before treatment (T1), after 5 weeks of treatment (T2), and after the 12-month follow-up (T3). RESULTS In contrast to patients receiving OT-TENS or AE-BRT, those receiving SET reported a significantly greater reduction in pain and pain interference (all P < 0.01) that was maintained at the 12-month follow-up. Clinically meaningful pain reduction at T3 was achieved in 82% of patients in the SET group, 39% of those in the OT-TENS group, and only 14% of those in the AE-BRT group. Patients in the SET group showed a significant increase (57%) in BRS following treatment, while neither the AE-BRT group or the OT-TENS group showed significant changes over time. CONCLUSION SET resulted in statistically significant, clinically meaningful, and long-lasting pain remission and interference compared to OT-TENS and AE-BRT. These results suggest that BRS modification is the primary mechanism of improvement. Replication of our results using larger samples and extension to other chronic pain conditions appear to be warranted.
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Affiliation(s)
- Kati Thieme
- Institute of Medical Psychology at Philipps-University Marburg, Marburg, Germany
| | - Tina Meller
- Institute of Medical Psychology at Philipps-University Marburg, Marburg, Germany
| | - Ulrika Evermann
- Institute of Medical Psychology at Philipps-University Marburg, Marburg, Germany
| | - Robert Malinowski
- Institute of Medical Psychology at Philipps-University Marburg, Marburg, Germany
| | - Marc G Mathys
- Institute of Medical Psychology at Philipps-University Marburg, Marburg, Germany
| | - Richard H Graceley
- Center for Pain Research and Innovation, University of North Carolina, Chapel Hill
| | - William Maixner
- Center for Translational Sciences, Duke University, Durham, North Carolina
| | - Dennis C Turk
- Center for Pain Research on Impact, Measurement, and Effectiveness, University of Washington, Seattle
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16
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Sible IJ, Nation DA. Long-Term Blood Pressure Variability Across the Clinical and Biomarker Spectrum of Alzheimer's Disease. J Alzheimers Dis 2020; 77:1655-1669. [PMID: 32925032 PMCID: PMC8054661 DOI: 10.3233/jad-200221] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Elevated blood pressure is linked to cognitive impairment and Alzheimer's disease (AD) biomarker abnormality. However, blood pressure levels vary over time. Less is known about the role of long-term blood pressure variability in cognitive impairment and AD pathophysiology. OBJECTIVE Determine whether long-term blood pressure variability is elevated across the clinical and biomarker spectrum of AD. METHODS Alzheimer's Disease Neuroimaging Initiative participants (cognitively normal, mild cognitive impairment, AD [n = 1,421]) underwent baseline exam, including blood pressure measurement at 0, 6, and 12 months. A subset (n = 318) underwent baseline lumbar puncture to determine cerebrospinal fluid amyloid-β and phosphorylated tau levels. Clinical groups and biomarker-confirmed AD groups were compared on blood pressure variability over 12 months. RESULTS Systolic blood pressure variability was elevated in clinically diagnosed AD dementia (VIM: F2,1195 = 6.657, p = 0.001, η2 = 0.01) compared to cognitively normal participants (p = 0.001), and in mild cognitive impairment relative to cognitively normal participants (p = 0.01). Findings were maintained in biomarker-confirmed AD (VIM: F2,850 = 5.216, p = 0.006, η2 = 0.01), such that systolic blood pressure variability was elevated in biomarker-confirmed dementia due to AD relative to cognitively normal participants (p = 0.005) and in biomarker-confirmed mild cognitive impairment due to AD compared to cognitively normal participants (p = 0.04). CONCLUSION Long-term systolic blood pressure variability is elevated in cognitive impairment due to AD. Blood pressure variability may represent an understudied aspect of vascular dysfunction in AD with potential clinical implications.
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Affiliation(s)
- Isabel J. Sible
- Department of Psychology, University of Southern California, Los Angeles, CA 90007, USA
| | - Daniel A. Nation
- Department of Psychological Science, University of California, Irvine, Irvine, CA 92697, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697, USA
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17
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Zhilyaev SY, Platonova TF, Alekseeva OS, Nikitina ER, Demchenko IT. Adaptive Mechanisms of Baroreflectory Regulation of the Cardiovascular System in Extreme Hyperoxia. J EVOL BIOCHEM PHYS+ 2019. [DOI: 10.1134/s002209301905003x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Torabi P, Ricci F, Hamrefors V, Melander O, Sutton R, Benditt DG, Fedorowski A. Impact of Cardiovascular Neurohormones on Onset of Vasovagal Syncope Induced by Head-up Tilt. J Am Heart Assoc 2019; 8:e012559. [PMID: 31208249 PMCID: PMC6645642 DOI: 10.1161/jaha.119.012559] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Background Vasovagal reflex is the most common form of syncope, but the pathophysiological mechanisms that initiate the reflex are not well understood. We aimed to study supine and early orthostatic levels of the neurohormones involved in control of circulatory homeostasis in relation to the onset of tilt‐induced vasovagal syncope (VVS). Methods and Results A total of 827 patients who were investigated for unexplained syncope with head‐up tilt test (HUT) and optional nitroglycerin provocation (Italian protocol) had blood samples collected while supine and after 3‐minutes of HUT. Of these, 173 (20.9%) patients developed VVS during drug‐free HUT, 161 of whom (males 44.7%; age 45±21 years) had complete data. We analyzed levels of epinephrine, norepinephrine, C‐terminal pro–arginine vasopressin, C‐terminal endothelin‐1, and midregional fragments of pro–atrial natriuretic peptide and pro‐adrenomedullin in relation to time from tilt‐up to onset of VVS. We applied a linear regression model adjusted for age and sex. The mean time to syncope was 11±7 minutes. Older age (β=0.13; SE=0.03, P<0.001), higher supine systolic blood pressure (β=0.06; SE=0.03, P=0.02), and higher supine midregional fragment of pro‐adrenomedullin predicted longer time to syncope (β=2.31; SE=0.77, P=0.003), whereas supine levels of other neurohormones were not associated with time to syncope. Among 151 patients who developed VVS later than 3 minutes of HUT, increase in epinephrine (β=−3.24; SE=0.78, P<0.001) and C‐terminal pro–arginine vasopressin (β=−2.07; SE=0.61, P=0.001) at 3 minutes of HUT were related to shorter time to syncope. Conclusions Older age, higher blood pressure, and higher level of pro‐adrenomedullin are associated with later onset of VVS during tilt testing, whereas greater increase of tilt‐induced epinephrine and vasopressin release correlate with shorter time to syncope. See Editorial Williford et al
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Affiliation(s)
- Parisa Torabi
- 1 Department of Clinical Sciences Lund University Malmö Sweden.,2 Department of Clinical Physiology Skåne University Hospital Malmö Sweden
| | - Fabrizio Ricci
- 1 Department of Clinical Sciences Lund University Malmö Sweden.,3 Department of Neuroscience, Imaging and Clinical Sciences "G. d'Annunzio" University Chieti Italy.,4 Fondazione Villa Serena per la Ricerca Città Sant'Angelo Italy
| | - Viktor Hamrefors
- 1 Department of Clinical Sciences Lund University Malmö Sweden.,5 Department of Internal Medicine Skåne University Hospital Malmö Sweden
| | - Olle Melander
- 1 Department of Clinical Sciences Lund University Malmö Sweden.,5 Department of Internal Medicine Skåne University Hospital Malmö Sweden
| | - Richard Sutton
- 6 National Heart and Lung Institute Imperial College Hammersmith Hospital Campus London United Kingdom
| | - David G Benditt
- 7 Cardiac Arrhythmia Center Cardiovascular Division University of Minnesota Minneapolis MN
| | - Artur Fedorowski
- 1 Department of Clinical Sciences Lund University Malmö Sweden.,8 Department of Cardiology Skåne University Hospital Malmö Sweden
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19
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Burke SD, Jordan J, Harrison DG, Karumanchi SA. Solving Baroreceptor Mystery: Role of PIEZO Ion Channels. J Am Soc Nephrol 2019; 30:911-913. [PMID: 31043433 DOI: 10.1681/asn.2019020160] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- Suzanne D Burke
- Center for Vascular Biology Research and Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Jens Jordan
- Institute of Aerospace Medicine, German Aerospace Center and Department of Aerospace Medicine, University of Cologne, Cologne, Germany
| | - David G Harrison
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - S Ananth Karumanchi
- Center for Vascular Biology Research and Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts; .,Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
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20
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Neuronal stretch reception – Making sense of the mechanosense. Exp Cell Res 2019; 378:104-112. [DOI: 10.1016/j.yexcr.2019.01.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/14/2019] [Accepted: 01/17/2019] [Indexed: 02/06/2023]
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21
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Haspula D, Clark MA. Neuroinflammation and sympathetic overactivity: Mechanisms and implications in hypertension. Auton Neurosci 2018; 210:10-17. [DOI: 10.1016/j.autneu.2018.01.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 01/02/2018] [Accepted: 01/08/2018] [Indexed: 02/07/2023]
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22
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Possible Breathing Influences on the Control of Arterial Pressure After Sino-aortic Denervation in Rats. Curr Hypertens Rep 2018; 20:2. [PMID: 29356918 DOI: 10.1007/s11906-018-0800-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
PURPOSE OF REVIEW Surgical removal of the baroreceptor afferents [sino-aortic denervation (SAD)] leads to a lack of inhibitory feedback to sympathetic outflow, which in turn is expected to result in a large increase in mean arterial pressure (MAP). However, few days after surgery, the sympathetic nerve activity (SNA) and MAP of SAD rats return to a range similar to that observed in control rats. In this review, we present experimental evidence suggesting that breathing contributes to control of SNA and MAP following SAD.The purpose of this review was to discuss studies exploring SNA and MAP regulation in SAD rats, highlighting the possible role of breathing in the neural mechanisms of this modulation of SNA. RECENT FINDINGS Recent studies show that baroreceptor afferent stimulation or removal (SAD) results in changes in the respiratory pattern. Changes in the neural respiratory network and in the respiratory pattern must be considered among mechanisms involved in the modulation of the MAP after SAD.
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23
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The effect of slow-loaded breathing training on the blood pressure response to handgrip exercise in patients with isolated systolic hypertension. Hypertens Res 2017; 40:885-891. [PMID: 28424510 DOI: 10.1038/hr.2017.54] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 02/12/2017] [Accepted: 03/03/2017] [Indexed: 11/08/2022]
Abstract
Isolated systolic hypertension (ISH) is the most common form of hypertension in older people. It is characterized by increased resting systolic blood pressure (sBP) and increased sBP in response to exercise. It has previously been shown that slow breathing training reduces resting sBP, and the objective of the present study was to determine whether it also reduced the blood pressure response to static handgrip exercise. ISH patients aged between 60 and 74 years were randomly divided into a control group (10 subjects, 4 of which were male) that breathed normally and a trained group (10 subjects, 4 of which were male) that trained daily for 8 weeks by slow breathing against an inspiratory resistance of 18 cmH2O. Before and immediately after training, subjects underwent a 2-min handgrip test (30% max) followed by 2 min of post-exercise circulatory occlusion (PECO) to assess metaboreflex activity. Training reduced sBP by 10.6 mm Hg (95% confidence interval (CI), -16 to -5 mm Hg, P=0.004), but changes were not observed in the control group. The peak exercise sBP was reduced by 23 mm Hg (95% CI, -16 to -31 mm Hg, P<0.001), while the increase in the sBP above resting was reduced by 12.6 mm Hg (95% CI, -6.9 to -18.2 mm Hg, P=0.002). The sBP during PECO was reduced by 8.9 mm Hg (95% CI, -4 to -14 mm Hg, P=0.008), which is indicative of reduced metaboreflex activity; no such change was observed in the control group. The results demonstrate that conventional treatment of older patients with ISH may be improved in two ways by slow breathing training: resting sBP may be reduced by 10 mm Hg, more than can be achieved by conventional pharmacological therapies, while the response to static exercise may be reduced by approximately twice this value.
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Abstract
The objective of this review is to provide an in-depth evaluation of how renal nerves regulate renal and cardiovascular function with a focus on long-term control of arterial pressure. We begin by reviewing the anatomy of renal nerves and then briefly discuss how the activity of renal nerves affects renal function. Current methods for measurement and quantification of efferent renal-nerve activity (ERNA) in animals and humans are discussed. Acute regulation of ERNA by classical neural reflexes as well and hormonal inputs to the brain is reviewed. The role of renal nerves in long-term control of arterial pressure in normotensive and hypertensive animals (and humans) is then reviewed with a focus on studies utilizing continuous long-term monitoring of arterial pressure. This includes a review of the effect of renal-nerve ablation on long-term control of arterial pressure in experimental animals as well as humans with drug-resistant hypertension. The extent to which changes in arterial pressure are due to ablation of renal afferent or efferent nerves are reviewed. We conclude by discussing the importance of renal nerves, relative to sympathetic activity to other vascular beds, in long-term control of arterial pressure and hypertension and propose directions for future research in this field. © 2017 American Physiological Society. Compr Physiol 7:263-320, 2017.
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Affiliation(s)
- John W Osborn
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jason D Foss
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
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Berg T. M-currents (Kv7.2-7.3/KCNQ2-KCNQ3) Are Responsible for Dysfunctional Autonomic Control in Hypertensive Rats. Front Physiol 2016; 7:584. [PMID: 27965589 PMCID: PMC5126116 DOI: 10.3389/fphys.2016.00584] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 11/14/2016] [Indexed: 01/19/2023] Open
Abstract
Autonomic dysfunctions play important roles in hypertension, heart failure and arrhythmia, often with a detrimental and fatal effect. The present study analyzed if these dysfunctions involved M-channels (members of the Kv7/KNCQ family) in spontaneously hypertensive rats (SHR). Cardiac output and heart rate (HR) were recorded by a flow probe on the ascending aorta in anesthetized SHR and normotensive rats (WKY), and blood pressure (BP) by a femoral artery catheter. Total peripheral vascular resistance (TPR) was calculated. XE-991 (Kv7.1-7.4-inhibitor) reduced resting HR in WKY but only after reserpine in SHR. XE-991 increased TPR and BP baseline in both strains. Retigabine (Kv7.2-7.5-opener) reduced HR, TPR and BP, also after reserpine. Depolarization induced by 3,4-diaminopyridine (3,4-DAP), a voltage-sensitive K+ channel (Kv) inhibitor, activated release of both acetylcholine and norepinephrine, thus activating an initial, cholinergic bradycardia in SHR, followed by sustained, norepinephrine-dependant tachycardia in both strains. XE-991 augmented the initial 3,4-DAP-induced bradycardia and eliminated the late tachycardia in SHR, but not in WKY. The increased bradycardia was eliminated by hexamethonium and methoctramine (M2muscarinic receptor antagonist) but not reserpine. Retigabine eliminated the increased bradycardia observed in reserpinized SHR. XE-991 also increased 3,4-DAP-stimulated catecholamine release, but not after hexamethonium or reserpine. Conclusions: M-currents hampered parasympathetic ganglion excitation and, through that, vagal control of HR, in SHR but not WKY. M-currents also opposed catecholamine release in SHR but not in WKY. M-currents represented a vasodilatory component in resting TPR-control, with no strain-related difference detected. Excessive M-currents may represent the underlying cause of autonomic dysfunctions in hypertension.
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Affiliation(s)
- Torill Berg
- Division of Physiology, Department of Molecular Medicine, Institute for Basic Medical Sciences, University of Oslo Oslo, Norway
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26
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Katta S, Krieg M, Goodman MB. Feeling force: physical and physiological principles enabling sensory mechanotransduction. Annu Rev Cell Dev Biol 2016; 31:347-71. [PMID: 26566115 DOI: 10.1146/annurev-cellbio-100913-013426] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Organisms as diverse as microbes, roundworms, insects, and mammals detect and respond to applied force. In animals, this ability depends on ionotropic force receptors, known as mechanoelectrical transduction (MeT) channels, that are expressed by specialized mechanoreceptor cells embedded in diverse tissues and distributed throughout the body. These cells mediate hearing, touch, and proprioception and play a crucial role in regulating organ function. Here, we attempt to integrate knowledge about the architecture of mechanoreceptor cells and their sensory organs with principles of cell mechanics, and we consider how engulfing tissues contribute to mechanical filtering. We address progress in the quest to identify the proteins that form MeT channels and to understand how these channels are gated. For clarity and convenience, we focus on sensory mechanobiology in nematodes, fruit flies, and mice. These themes are emphasized: asymmetric responses to applied forces, which may reflect anisotropy of the structure and mechanics of sensory mechanoreceptor cells, and proteins that function as MeT channels, which appear to have emerged many times through evolution.
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Affiliation(s)
- Samata Katta
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305;
| | - Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305;
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305;
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Terra DG, de Lima EM, do Nascimento AM, Brasil GA, Filete PF, Kalil IC, Lenz D, Endringer DC, Bissoli NS, de Andrade TU. Low dose of methyltestosterone in ovariectomised rats improves baroreflex sensitivity without geno- and cytotoxicity. Fundam Clin Pharmacol 2016; 30:316-26. [DOI: 10.1111/fcp.12203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 04/15/2016] [Accepted: 05/03/2016] [Indexed: 01/03/2023]
Affiliation(s)
- Denise G. Terra
- Department of Pharmaceutical Sciences; University Vila Velha; Av. Comissário José Dantas de Melo, n°21, Boa Vista Vila Velha Espirito Santo - ES CEP 29102-920 Brazil
| | - Ewelyne M. de Lima
- Department of Pharmaceutical Sciences; University Vila Velha; Av. Comissário José Dantas de Melo, n°21, Boa Vista Vila Velha Espirito Santo - ES CEP 29102-920 Brazil
| | - Andrews M. do Nascimento
- Department of Physiological Sciences; Health Sciences Center; Federal University of Espírito Santo; Av. Marechal Campos, n°1468 Vitória Espirito Santo - ES CEP 29042-755 Brazil
| | - Girlandia A. Brasil
- Department of Physiological Sciences; Health Sciences Center; Federal University of Espírito Santo; Av. Marechal Campos, n°1468 Vitória Espirito Santo - ES CEP 29042-755 Brazil
| | - Placielle F. Filete
- Department of Pharmaceutical Sciences; University Vila Velha; Av. Comissário José Dantas de Melo, n°21, Boa Vista Vila Velha Espirito Santo - ES CEP 29102-920 Brazil
| | - Ieda C. Kalil
- Department of Pharmaceutical Sciences; University Vila Velha; Av. Comissário José Dantas de Melo, n°21, Boa Vista Vila Velha Espirito Santo - ES CEP 29102-920 Brazil
| | - Dominik Lenz
- Department of Pharmaceutical Sciences; University Vila Velha; Av. Comissário José Dantas de Melo, n°21, Boa Vista Vila Velha Espirito Santo - ES CEP 29102-920 Brazil
| | - Denise C. Endringer
- Department of Pharmaceutical Sciences; University Vila Velha; Av. Comissário José Dantas de Melo, n°21, Boa Vista Vila Velha Espirito Santo - ES CEP 29102-920 Brazil
| | - Nazaré S. Bissoli
- Department of Physiological Sciences; Health Sciences Center; Federal University of Espírito Santo; Av. Marechal Campos, n°1468 Vitória Espirito Santo - ES CEP 29042-755 Brazil
| | - Tadeu U. de Andrade
- Department of Pharmaceutical Sciences; University Vila Velha; Av. Comissário José Dantas de Melo, n°21, Boa Vista Vila Velha Espirito Santo - ES CEP 29102-920 Brazil
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Kaur M, Chandran DS, Jaryal AK, Bhowmik D, Agarwal SK, Deepak KK. Baroreflex dysfunction in chronic kidney disease. World J Nephrol 2016; 5:53-65. [PMID: 26788464 PMCID: PMC4707168 DOI: 10.5527/wjn.v5.i1.53] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 10/04/2015] [Accepted: 11/25/2015] [Indexed: 02/06/2023] Open
Abstract
Chronic kidney disease (CKD) patients have high cardiovascular mortality and morbidity. The presence of traditional and CKD related risk factors results in exaggerated vascular calcification in these patients. Vascular calcification is associated with reduced large arterial compliance and thus impaired baroreflex sensitivity (BRS) resulting in augmented blood pressure (BP) variability and hampered BP regulation. Baroreflex plays a vital role in short term regulation of BP. This review discusses the normal baroreflex physiology, methods to assess baroreflex function, its determinants along with the prognostic significance of assessing BRS in CKD patients, available literature on BRS in CKD patients and the probable patho-physiology of baroreflex dysfunction in CKD.
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Berg T. Voltage-Sensitive K(+) Channels Inhibit Parasympathetic Ganglion Transmission and Vagal Control of Heart Rate in Hypertensive Rats. Front Neurol 2015; 6:260. [PMID: 26696959 PMCID: PMC4672051 DOI: 10.3389/fneur.2015.00260] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 11/25/2015] [Indexed: 01/19/2023] Open
Abstract
Parasympathetic withdrawal plays an important role in the autonomic dysfunctions in hypertension. Since hyperpolarizing, voltage-sensitive K+ channels (KV) hamper transmitter release, elevated KV-activity may explain the disturbed vagal control of heart rate (HR) in hypertension. Here, the KV inhibitor 3,4-diaminopyridine was used to demonstrate the impact of KV on autonomic HR control. Cardiac output and HR were recorded by a flow probe on the ascending aorta in anesthetized, normotensive (WKY), and spontaneously hypertensive rats (SHR), and blood pressure by a femoral artery catheter. 3,4-diaminopyridine induced an initial bradycardia, which was greater in SHR than in WKY, followed by sustained tachycardia in both strains. The initial bradycardia was eliminated by acetylcholine synthesis inhibitor (hemicholinium-3) and nicotinic receptor antagonist/ganglion blocker (hexamethonium), and reversed to tachycardia by muscarinic receptor (mAchR) antagonist (atropine). The latter was abolished by sympatho-inhibition (reserpine). Reserpine also eliminated the late, 3,4-diaminopyridine-induced tachycardia in WKY, but induced a sustained atropine-sensitive bradycardia in SHR. Inhibition of the parasympathetic component with hemicholinium-3, hexamethonium, or atropine enhanced the late tachycardia in SHR, whereas hexamethonium reduced the tachycardia in WKY. In conclusion, 3,4-diaminopyridine-induced acetylcholine release, and thus enhanced parasympathetic ganglion transmission, with subsequent mAchR activation and bradycardia. 3,4-diaminopyridine also activated tachycardia, initially by enhancing sympathetic ganglion transmission, subsequently by activation of norepinephrine release from sympathetic nerve terminals. The 3,4-diaminopyridine-induced parasympathetic activation was stronger and more sustained in SHR, demonstrating an enhanced inhibitory control of KV on parasympathetic ganglion transmission. This enhanced KV activity may explain the dysfunctional vagal HR control in SHR.
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Affiliation(s)
- Torill Berg
- Division of Physiology, Department of Molecular Medicine, Institute for Basic Medical Sciences, University of Oslo , Oslo , Norway
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Turner MJ, Kawada T, Shimizu S, Fukumitsu M, Sugimachi M. Differences in the dynamic baroreflex characteristics of unmyelinated and myelinated central pathways are less evident in spontaneously hypertensive rats. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1397-405. [DOI: 10.1152/ajpregu.00315.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/09/2015] [Indexed: 11/22/2022]
Abstract
The aim of the study was to identify the contribution of myelinated (A-fiber) and unmyelinated (C-fiber) baroreceptor central pathways to the baroreflex control of sympathetic nerve activity (SNA) and arterial pressure (AP) in anesthetized Wistar-Kyoto (WKY; n = 8) and spontaneously hypertensive rats (SHR; n = 8). The left aortic depressor nerve (ADN) was electrically stimulated with two types of binary white noise signals designed to preferentially activate A-fibers (A-BRx protocol) or C-fibers (C-BRx protocol). In WKY, the central arc transfer function from ADN stimulation to SNA estimated by A-BRx showed strong derivative characteristics with the slope of dynamic gain between 0.1 and 1 Hz ( Gslope) of 14.63 ± 0.89 dB/decade. In contrast, the central arc transfer function estimated by C-BRx exhibited nonderivative characteristics with Gslope of 0.64 ± 1.13 dB/decade. This indicates that A-fibers are important for rapid baroreflex regulation, whereas C-fibers are likely important for more sustained regulation of SNA and AP. In SHR, the central arc transfer function estimated by A-BRx showed higher Gslope (18.46 ± 0.75 dB/decade, P < 0.01) and that estimated by C-BRx showed higher Gslope (8.62 ± 0.64 dB/decade, P < 0.001) with significantly lower dynamic gain at 0.01 Hz (6.29 ± 0.48 vs. 2.80 ± 0.36%/Hz, P < 0.001) compared with WKY. In conclusion, the dynamic characteristics of the A-fiber central pathway are enhanced in the high-modulation frequency range (0.1–1 Hz) and those of the C-fiber central pathway are attenuated in the low-modulation frequency range (0.01–0.1 Hz) in SHR.
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Affiliation(s)
- Michael J. Turner
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan; and
| | - Toru Kawada
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan; and
| | - Shuji Shimizu
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan; and
| | - Masafumi Fukumitsu
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan; and
- Department of Artificial Organ Medicine, Faculty of Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Masaru Sugimachi
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan; and
- Department of Artificial Organ Medicine, Faculty of Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
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31
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Dias da Silva VJ, Tobaldini E, Rocchetti M, Wu MA, Malfatto G, Montano N, Zaza A. Modulation of sympathetic activity and heart rate variability by ivabradine. Cardiovasc Res 2015; 108:31-8. [DOI: 10.1093/cvr/cvv180] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 06/11/2015] [Indexed: 11/13/2022] Open
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Orthostatic response of cephalic blood flow using a mini laser Doppler blood flowmeter and hemodynamics of a new active standing test. Eur J Appl Physiol 2015; 115:2167-76. [PMID: 26040237 DOI: 10.1007/s00421-015-3197-6] [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: 02/11/2015] [Accepted: 05/27/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE Cephalic hemodynamic assessment is important in initial orthostatic hypotension. We sought to investigate cephalic blood flow (CBF) in the earlobe using a mini laser Doppler flowmeter (LDF) during orthostatic challenge. In addition, we clarified hemodynamic differences during a new active standing protocol using a footstool standing test (FST) with bending of the legs on the footstool in the sitting position to reduce the load of the squatting posture in the conventional squat standing test (SST). METHODS Ten healthy men (21 ± 0.5 years) performed the SST after a 1 min squat and the FST after a 1 min load consisting of bending the legs on a footstool in the sitting position. Earlobe CBF, beat-to-beat arterial blood pressure (ABP), mean arterial blood pressure (MAP), and heart rate (HR) were recorded during each test. RESULTS Earlobe CBF showed a transient fall synchronized with the ABP during each test. No significant differences in the recovery times (RTs) of CBF and MAP were observed during the SST (CBF 12.9 ± 0.6 s vs. MAP 12.1 ± 0.5 s, P = 0.313) and FST (CBF 10.6 ± 0.4 s vs. MAP 10.1 ± 0.8 s, P = 0.552). Although the CBF and ABP decreases were not different in each test, the HR increase was significantly lower with the FST (24 ± 2 bpm) than with the SST (31 ± 3 bpm, P < 0.005). CONCLUSIONS Earlobe CBF reflects the compensatory ABP regulatory response during standing and is potentially useful for estimating the orthostatic ABP response indirectly. Furthermore, the FST is a low-load protocol that can be an effective protocol for a standing test of cardiac function.
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Drenjancevic I, Grizelj I, Harsanji-Drenjancevic I, Cavka A, Selthofer-Relatic K. The interplay between sympathetic overactivity, hypertension and heart rate variability (review, invited). ACTA ACUST UNITED AC 2014; 101:129-42. [PMID: 24901074 DOI: 10.1556/aphysiol.101.2014.2.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The control of arterial pressure is a complex interaction of the long- and short-term influences of hormones, local vascular factors, and neural mechanisms. The autonomic nervous system and its sympathetic arm play important roles in the regulation of blood pressure, and overactivity of sympathetic nerves may have an important role in the development of hypertension and related cardiovascular disorders. The baroreceptor system opposes either increases or decreases in arterial pressure, and the primary purpose of the arterial baroreflex is to keep blood pressure close to a particular set point over a relatively short period of time. The ability of the baroreflex to powerfully buffer acute changes in arterial pressure is well established, but the role of the arterial baroreceptor reflex in long-term control of arterial pressure has been a topic of many debate and controversy for decades. The sympathetic nervous system and arterial baroreceptor reflex control of renal sympathetic nerve activity has been proposed to play a role in long-term control of arterial pressure. The aim of this paper has been to review the postulated role of sympathetic activation.
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Affiliation(s)
- Ines Drenjancevic
- University of Osijek Department of Physiology and Immunology, Faculty of Medicine J. Huttlera 4 31000 Osijek Croatia University of Pécs Pécs Hungary
| | - I Grizelj
- University of Osijek Department of Physiology and Immunology, Faculty of Medicine J. Huttlera 4 31000 Osijek Croatia
| | - I Harsanji-Drenjancevic
- Clinical Hospital Center Osijek Department of Anesthesiology, Reanimatology and Intensive Care Unit Osijek Croatia
| | - A Cavka
- University of Osijek Department of Physiology and Immunology, Faculty of Medicine J. Huttlera 4 31000 Osijek Croatia
| | - K Selthofer-Relatic
- Clinical Hospital Center Osijek Department of Cardiology, Clinic of Internal Medicine Osijek Croatia University of Osijek Department of Internal Medicine, Medical Ethic and History of Medicine, Faculty of Medicine Osijek Croatia
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Alnima T, Kroon AA, de Leeuw PW. Baroreflex activation therapy for patients with drug-resistant hypertension. Expert Rev Cardiovasc Ther 2014; 12:955-62. [PMID: 25017430 DOI: 10.1586/14779072.2014.931226] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Uncontrolled or resistant hypertension is still a major problem facing many physicians daily in the clinic. Several new therapies are being developed to help those patients whose blood pressure does not respond sufficiently to regular antihypertensive medication. One of these promising therapies is electrical activation of the carotid sinus baroreflex. In this overview, the authors predominantly summarize the background, efficacy and safety of this promising treatment with its latest achievements in patients with resistant hypertension. The authors also discuss certain issues that need further clarification before this therapy can be added to the common treatment guidelines of hypertension.
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Affiliation(s)
- Teba Alnima
- Maastricht University Medical Center, Department of Internal Medicine, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
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35
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Sleight P. A historical perspective on peripheral reflex cardiovascular control from animals to man. Exp Physiol 2014; 99:1017-26. [PMID: 24986973 DOI: 10.1113/expphysiol.2014.079434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although drug treatment of human hypertension has greatly improved, there is renewed interest in non-drug methods of blood pressure reduction. Animal experiments have now shown that arterial baroreflexes do control long-term blood pressure levels, particularly by nervously mediated renal excretion of sodium and water. This Paton Lecture provides a review of the historical development of knowledge of peripheral circulatory control in order to supplement prior Paton Lectures concerned with cerebral cortical and other areas of influence. I also discuss how improved understanding of nervous control of the circulation has led to current methods of non-drug blood pressure control in man by implanted carotid baroreceptor pacemakers or by renal denervation. Finally, the role of other therapy, particularly listening to music, is reviewed.
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Turner MJ, Kawada T, Shimizu S, Sugimachi M. Sustained reduction in blood pressure from electrical activation of the baroreflex is mediated via the central pathway of unmyelinated baroreceptors. Life Sci 2014; 106:40-9. [PMID: 24780319 DOI: 10.1016/j.lfs.2014.04.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 03/27/2014] [Accepted: 04/17/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Michael J Turner
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan.
| | - Toru Kawada
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Shuji Shimizu
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Masaru Sugimachi
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
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Arterial stiffening provides sufficient explanation for primary hypertension. PLoS Comput Biol 2014; 10:e1003634. [PMID: 24853828 PMCID: PMC4031054 DOI: 10.1371/journal.pcbi.1003634] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 04/09/2014] [Indexed: 02/07/2023] Open
Abstract
Hypertension is one of the most common age-related chronic disorders, and by predisposing individuals for heart failure, stroke, and kidney disease, it is a major source of morbidity and mortality. Its etiology remains enigmatic despite intense research efforts over many decades. By use of empirically well-constrained computer models describing the coupled function of the baroreceptor reflex and mechanics of the circulatory system, we demonstrate quantitatively that arterial stiffening seems sufficient to explain age-related emergence of hypertension. Specifically, the empirically observed chronic changes in pulse pressure with age and the impaired capacity of hypertensive individuals to regulate short-term changes in blood pressure arise as emergent properties of the integrated system. The results are consistent with available experimental data from chemical and surgical manipulation of the cardio-vascular system. In contrast to widely held opinions, the results suggest that primary hypertension can be attributed to a mechanogenic etiology without challenging current conceptions of renal and sympathetic nervous system function.
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Hayat A, Whittam D. Baroreceptor failure related to bilateral carotid artery disease: an uncommon cause of labile hypertension. Intern Med J 2014; 44:105-6. [DOI: 10.1111/imj.12324] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 08/25/2013] [Indexed: 11/28/2022]
Affiliation(s)
- A. Hayat
- Department of Medicine and Nephrology; Taranaki Base Hospital; New Plymouth New Zealand
| | - D. Whittam
- Department of Medicine and Nephrology; Taranaki Base Hospital; New Plymouth New Zealand
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Demchenko IT, Zhilyaev SY, Moskvin AN, Krivchenko AI, Piantadosi CA, Allen BW. Baroreflex-mediated cardiovascular responses to hyperbaric oxygen. J Appl Physiol (1985) 2013; 115:819-28. [PMID: 23823147 DOI: 10.1152/japplphysiol.00625.2013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The cardiovascular system responds to hyperbaric hyperoxia (HBO2) with vasoconstriction, hypertension, bradycardia, and reduced cardiac output (CO). We tested the hypothesis that these responses are linked by a common mechanism-activation of the arterial baroreflex. Baroreflex function in HBO2 was assessed in anesthetized and conscious rats after deafferentation of aortic or carotid baroreceptors or both. Cardiovascular and autonomic responses to HBO2 in these animals were compared with those in intact animals at 2.5 ATA for conscious rats and at 3 ATA for anesthetized rats. During O2 compression, hypertension was greater after aortic or carotid baroreceptor deafferentation and was significantly more severe if these procedures were combined. Similarly, the hyperoxic bradycardia observed in intact animals was diminished after aortic or carotid baroreceptor deafferentation and replaced by a slight tachycardia after complete baroreceptor deafferentation. We found that hypertension, bradycardia, and reduced CO--the initial cardiovascular responses to moderate levels of HBO2--are coordinated through a baroreflex-mediated mechanism initiated by HBO2-induced vasoconstriction. Furthermore, we have shown that baroreceptor activation in HBO2 inhibits sympathetic outflow and can partially reverse an O2-dependent increase in arterial pressure.
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Affiliation(s)
- Ivan T Demchenko
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, North Carolina
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Regulation of blood pressure by the arterial baroreflex and autonomic nervous system. HANDBOOK OF CLINICAL NEUROLOGY 2013; 117:89-102. [DOI: 10.1016/b978-0-444-53491-0.00008-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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41
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The treatment with pyridostigmine improves the cardiocirculatory function in rats with chronic heart failure. Auton Neurosci 2013; 173:58-64. [DOI: 10.1016/j.autneu.2012.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 10/26/2012] [Accepted: 11/12/2012] [Indexed: 11/24/2022]
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Sustained acute voltage-dependent blood pressure decrease with prolonged carotid baroreflex activation in therapy-resistant hypertension. J Hypertens 2012; 30:1665-70. [DOI: 10.1097/hjh.0b013e3283551f10] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hosokawa K, Ide T, Tobushi T, Sakamoto K, Onitsuka K, Sakamoto T, Fujino T, Saku K, Sunagawa K. Bionic baroreceptor corrects postural hypotension in rats with impaired baroreceptor. Circulation 2012; 126:1278-85. [PMID: 22851542 DOI: 10.1161/circulationaha.112.108357] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Impairment of the arterial baroreflex causes orthostatic hypotension. Arterial baroreceptor sensitivity degrades with age. Thus, an impaired baroreceptor plays a pivotal role in orthostatic hypotension in most elderly patients. There is no effective treatment for orthostatic hypotension. The aims of this investigation were to develop a bionic baroreceptor (BBR) and to verify whether it corrects postural hypotension. METHODS AND RESULTS The BBR consists of a pressure sensor, a regulator, and a neurostimulator. In 35 Sprague-Dawley rats, we vascularly and neurally isolated the baroreceptor regions and attached electrodes to the aortic depressor nerve for stimulation. To mimic impaired baroreceptors, we maintained intracarotid sinus pressure at 60 mm Hg during activation of the BBR. Native baroreflex was reproduced by matching intracarotid sinus pressure to the instantaneous pulsatile aortic pressure. The encoding rule for translating intracarotid sinus pressure into stimulation of the aortic depressor nerve was identified by a white noise technique and applied to the regulator. The open-loop arterial pressure response to intracarotid sinus pressure (n=7) and upright tilt-induced changes in arterial pressure (n=7) were compared between native baroreceptor and BBR conditions. The intracarotid sinus pressure-arterial pressure relationships were comparable. Compared with the absence of baroreflex, the BBR corrected tilt-induced hypotension as effectively as under native baroreceptor conditions (native, -39±5 mm Hg; BBR, -41±5 mm Hg; absence, -63±5 mm Hg; P<0.05). CONCLUSIONS The BBR restores the pressure buffering function. Although this research demonstrated feasibility of the BBR, further research is needed to verify its long-term effect and safety in larger animal models and humans.
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Affiliation(s)
- Kazuya Hosokawa
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Fukuoka, 812-8582, Japan.
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Baroreflex activation therapy for the treatment of drug-resistant hypertension: new developments. Cardiol Res Pract 2012; 2012:587194. [PMID: 22762007 PMCID: PMC3384947 DOI: 10.1155/2012/587194] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 04/23/2012] [Indexed: 02/07/2023] Open
Abstract
In the past few years, novel accomplishments have been obtained in carotid baroreflex activation therapy (BAT) for the treatment of resistant hypertension. In addition, this field is still evolving with promising results in the reduction of blood pressure and heart rate. This overview addresses the latest developments in BAT for the treatment of drug-resistant hypertension. Although not totally understood considering the working mechanisms of BAT, it appeared to be possible to achieve at least as much efficacy of single-sided as bilateral stimulation. Therefore unlike the first-generation Rheos system, the second-generation Barostim neo operates by unilateral baroreflex activation, using a completely different carotid electrode. Also significant improvements in several cardiac parameters have been shown by BAT in hypertensive patients, which set the basis for further research to evaluate BAT as a therapy for systolic heart failure. Yet important uncertainties need to be clarified to guarantee beneficial effects; hence not all participants seem to respond to BAT.
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Zamir M, Kimmerly DS, Shoemaker JK. Cardiac mechanoreceptor function implicated during premature ventricular contraction. Auton Neurosci 2012; 167:50-5. [PMID: 22226888 DOI: 10.1016/j.autneu.2011.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 12/07/2011] [Accepted: 12/10/2011] [Indexed: 11/15/2022]
Abstract
In a premature ventricular contraction (PVC), a systolic blood pressure peak is missing during the affected cardiac cycle, leading to a prolonged reduction in blood pressure which is then followed by a large burst of sympathetic outflow. In a normal ventricular contraction, it is generally believed that peak carotid and aortic distensions associated with systolic pressure is the neural feedback that terminates sympathetic outflow through a baroreflex mechanism. Yet, the characteristically large sympathetic burst following a PVC is terminated without a systolic pressure and evidently without this mechanism. To address this anomaly, we examined the possible role of cardiac receptors in providing an alternative mechanism for the termination of sympathetic outflow in a PVC. For this purpose, recordings of electrocardiogram (ECG), arterial blood pressure (ABP), and muscle sympathetic neural activity (MSNA) were made in a human subject during repeated PVC episodes. The time intervals, or "latencies", from key events within the PVC to the peak of the associated MSNA burst were calculated and compared with the latency in a normal ventricular contraction which is associated with central baroreceptor function. It was found that the only event in a PVC that corresponds with a physiologically plausible latency is that which marks the end of ventricular filling. We conclude with the hypothesis that in the unique circumstances of a PVC, where the systolic pressure peak required to trigger arterial baroreceptors to terminate sympathetic outflow is absent, mechanoreceptors in the heart appear to "step in" to perform this sympathoinhibitory function.
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Affiliation(s)
- M Zamir
- Neurovascular Research Laboratory, The University of Western Ontario, London, Canada.
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Berg T, Jensen J. Simultaneous parasympathetic and sympathetic activation reveals altered autonomic control of heart rate, vascular tension, and epinephrine release in anesthetized hypertensive rats. Front Neurol 2011; 2:71. [PMID: 22131984 PMCID: PMC3222849 DOI: 10.3389/fneur.2011.00071] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 10/29/2011] [Indexed: 12/20/2022] Open
Abstract
Sympathetic hyperactivity and parasympathetic insufficiency characterize blood pressure (BP) control in genetic hypertension. This shift is difficult to investigate in anesthetized rats. Here we present a pharmacological approach to simultaneously provoke sympathetic and parasympathetic transmitter release, and identify their respective roles in the concomitant cardiovascular response. To stimulate transmitter release in anesthetized normotensive (WKY) and spontaneously hypertensive rats (SHR), we injected intravenously 4-aminopyridine (4-AP), a voltage-sensitive K+ channel (KV) inhibitor. A femoral artery catheter monitored BP, an ascending aorta flow-probe recorded cardiac output and heart rate (HR). Total peripheral vascular resistance (TPVR) was calculated. 4-AP-induced an immediate, atropine (muscarinic antagonist)- and hexamethonium (ganglion blocker)-sensitive bradycardia in WKY, and in both strains, a subsequent, sustained tachycardia, and norepinephrine but not epinephrine release. Reserpine (sympatholytic), nadolol (β-adrenoceptor antagonist) or right vagal nerve stimulation eliminated the late tachycardia, adrenalectomy, scopolamine (central muscarinic antagonist) or hexamethonium did not. 4-AP increased TPVR, transiently in WKY but sustained in SHR. Yohimbine (α2-adrenoceptor antagonist) prevented the TPVR down-regulation in WKY. Reserpine and prazosin (α1-adrenoceptor antagonist) eliminated the late vasoconstriction in SHR. Plasma epinephrine overflow increased in nadolol-treated SHR. Through inhibition of KV, 4-AP activated parasympathetic ganglion transmission and peripheral, neuronal norepinephrine release. The sympathetic component dominated the 4-AP–HR-response in SHR. α2-adrenoceptor-dependent vasodilatation opposed norepinephrine-induced α1-adrenergic vasoconstriction in WKY, but not SHR. A βAR-activated, probably vagal afferent mechanism, hampered epinephrine secretion in SHR. Thus, 4-AP activated the autonomic system and exposed mechanisms relevant to hypertensive disease.
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Affiliation(s)
- Torill Berg
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo Oslo, Norway
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Sauzeau V, Carvajal-González JM, Riolobos AS, Sevilla MA, Menacho-Márquez M, Román AC, Abad A, Montero MJ, Fernández-Salguero P, Bustelo XR. Transcriptional factor aryl hydrocarbon receptor (Ahr) controls cardiovascular and respiratory functions by regulating the expression of the Vav3 proto-oncogene. J Biol Chem 2010; 286:2896-909. [PMID: 21115475 DOI: 10.1074/jbc.m110.187534] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Aryl hydrocarbon receptor (Ahr) is a transcriptional factor involved in detoxification responses to pollutants and in intrinsic biological processes of multicellular organisms. We recently described that Vav3, an activator of Rho/Rac GTPases, is an Ahr transcriptional target in embryonic fibroblasts. These results prompted us to compare the Ahr(-/-) and Vav3(-/-) mouse phenotypes to investigate the implications of this functional interaction in vivo. Here, we show that Ahr is important for Vav3 expression in kidney, lung, heart, liver, and brainstem regions. This process is not affected by the administration of potent Ahr ligands such as benzo[a]pyrene. We also report that Ahr- and Vav3-deficient mice display hypertension, tachypnea, and sympathoexcitation. The Ahr gene deficiency also induces the GABAergic transmission defects present in the Vav3(-/-) ventrolateral medulla, a main cardiorespiratory brainstem center. However, Ahr(-/-) mice, unlike Vav3-deficient animals, display additional defects in fertility, perinatal growth, liver size and function, closure, spleen size, and peripheral lymphocytes. These results demonstrate that Vav3 is a bona fide Ahr target that is in charge of a limited subset of the developmental and physiological functions controlled by this transcriptional factor. Our data also reveal the presence of sympathoexcitation and new cardiorespiratory defects in Ahr(-/-) mice.
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Affiliation(s)
- Vincent Sauzeau
- Centro de Investigación del Cáncer, Consejo Superior de Investigaciones Científicas-Salamanca University, 37007 Salamanca, Spain
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Sauzeau V, Horta-Junior JAC, Riolobos AS, Fernández G, Sevilla MA, López DE, Montero MJ, Rico B, Bustelo XR. Vav3 is involved in GABAergic axon guidance events important for the proper function of brainstem neurons controlling cardiovascular, respiratory, and renal parameters. Mol Biol Cell 2010; 21:4251-63. [PMID: 20926682 PMCID: PMC2993752 DOI: 10.1091/mbc.e10-07-0639] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Vav3 is a phosphorylation-dependent activator of Rho/Rac GTPases that has been implicated in hematopoietic, bone, cerebellar, and cardiovascular roles. Consistent with the latter function, Vav3-deficient mice develop hypertension, tachycardia, and renocardiovascular dysfunctions. The cause of those defects remains unknown as yet. Here, we show that Vav3 is expressed in GABAegic neurons of the ventrolateral medulla (VLM), a brainstem area that modulates respiratory rates and, via sympathetic efferents, a large number of physiological circuits controlling blood pressure. On Vav3 loss, GABAergic cells of the caudal VLM cannot innervate properly their postsynaptic targets in the rostral VLM, leading to reduced GABAergic transmission between these two areas. This results in an abnormal regulation of catecholamine blood levels and in improper control of blood pressure and respiration rates to GABAergic signals. By contrast, the reaction of the rostral VLM to excitatory signals is not impaired. Consistent with those observations, we also demonstrate that Vav3 plays important roles in axon branching and growth cone morphology in primary GABAergic cells. Our study discloses an essential and nonredundant role for this Vav family member in axon guidance events in brainstem neurons that control blood pressure and respiratory rates.
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Affiliation(s)
- Vincent Sauzeau
- Centro de Investigación del Cáncer, CSIC-Salamanca University, Instituto de Neurociencias de Castilla y León and Departamento de Fisiología y Farmacología, Salamanca University, 37007 Salamanca, Spain
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Castrop H, Höcherl K, Kurtz A, Schweda F, Todorov V, Wagner C. Physiology of Kidney Renin. Physiol Rev 2010; 90:607-73. [PMID: 20393195 DOI: 10.1152/physrev.00011.2009] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The protease renin is the key enzyme of the renin-angiotensin-aldosterone cascade, which is relevant under both physiological and pathophysiological settings. The kidney is the only organ capable of releasing enzymatically active renin. Although the characteristic juxtaglomerular position is the best known site of renin generation, renin-producing cells in the kidney can vary in number and localization. (Pro)renin gene transcription in these cells is controlled by a number of transcription factors, among which CREB is the best characterized. Pro-renin is stored in vesicles, activated to renin, and then released upon demand. The release of renin is under the control of the cAMP (stimulatory) and Ca2+(inhibitory) signaling pathways. Meanwhile, a great number of intrarenally generated or systemically acting factors have been identified that control the renin secretion directly at the level of renin-producing cells, by activating either of the signaling pathways mentioned above. The broad spectrum of biological actions of (pro)renin is mediated by receptors for (pro)renin, angiotensin II and angiotensin-( 1 – 7 ).
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Affiliation(s)
- Hayo Castrop
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Klaus Höcherl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Vladimir Todorov
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Regensburg, Germany
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Bie P, Damkjaer M. Renin secretion and total body sodium: Pathways of integrative control. Clin Exp Pharmacol Physiol 2010; 37:e34-42. [DOI: 10.1111/j.1440-1681.2009.05316.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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