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Biomarkers and Hemodynamic Parameters in the Diagnosis and Treatment of Children with Postural Tachycardia Syndrome and Vasovagal Syncope. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19126974. [PMID: 35742222 PMCID: PMC9222341 DOI: 10.3390/ijerph19126974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/02/2022] [Accepted: 06/04/2022] [Indexed: 12/02/2022]
Abstract
In children, vasovagal syncope and postural tachycardia syndrome constitute the major types of orthostatic intolerance. The clinical characteristics of postural tachycardia syndrome and vasovagal syncope are similar but their treatments differ. Therefore, their differential diagnosis is important to guide the correct treatment. Therapeutic methods vary in patients with the same diagnosis because of different pathomechanisms. Hence, in patients with vasovagal syncope or postural tachycardia syndrome, routine treatments have an unsatisfactory efficacy. However, biomarkers could increase the therapeutic efficacy significantly, allowing for an accurate and detailed assessment of patients and leading to improved therapeutic effects. In the present review, we aimed to summarize the current state of research into biomarkers for distinguishing the diagnosis of pediatric vasovagal syncope from that of postural tachycardia syndrome. We also discuss the biomarkers that predict treatment outcomes during personalized therapy for each subtype.
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Renz-Polster H, Tremblay ME, Bienzle D, Fischer JE. The Pathobiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: The Case for Neuroglial Failure. Front Cell Neurosci 2022; 16:888232. [PMID: 35614970 PMCID: PMC9124899 DOI: 10.3389/fncel.2022.888232] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 04/13/2022] [Indexed: 12/20/2022] Open
Abstract
Although myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) has a specific and distinctive profile of clinical features, the disease remains an enigma because causal explanation of the pathobiological matrix is lacking. Several potential disease mechanisms have been identified, including immune abnormalities, inflammatory activation, mitochondrial alterations, endothelial and muscular disturbances, cardiovascular anomalies, and dysfunction of the peripheral and central nervous systems. Yet, it remains unclear whether and how these pathways may be related and orchestrated. Here we explore the hypothesis that a common denominator of the pathobiological processes in ME/CFS may be central nervous system dysfunction due to impaired or pathologically reactive neuroglia (astrocytes, microglia and oligodendrocytes). We will test this hypothesis by reviewing, in reference to the current literature, the two most salient and widely accepted features of ME/CFS, and by investigating how these might be linked to dysfunctional neuroglia. From this review we conclude that the multifaceted pathobiology of ME/CFS may be attributable in a unifying manner to neuroglial dysfunction. Because the two key features - post exertional malaise and decreased cerebral blood flow - are also recognized in a subset of patients with post-acute sequelae COVID, we suggest that our findings may also be pertinent to this entity.
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Affiliation(s)
- Herbert Renz-Polster
- Division of General Medicine, Center for Preventive Medicine and Digital Health Baden-Württemberg (CPD-BW), University Medicine Mannheim, Heidelberg University, Mannheim, Germany
| | - Marie-Eve Tremblay
- Axe Neurosciences, Centre de recherche du CHU de Québec, Université Laval, Quebec, QC, Canada
- Département de Médecine Moléculaire, Université Laval, Quebec, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Center for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
| | - Dorothee Bienzle
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Joachim E. Fischer
- Division of General Medicine, Center for Preventive Medicine and Digital Health Baden-Württemberg (CPD-BW), University Medicine Mannheim, Heidelberg University, Mannheim, Germany
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3
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Fatty acids as biomodulators of Piezo1 mediated glial mechanosensitivity in Alzheimer's disease. Life Sci 2022; 297:120470. [DOI: 10.1016/j.lfs.2022.120470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/09/2021] [Accepted: 03/06/2022] [Indexed: 11/18/2022]
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Wang S, Zou R, Cai H, Wang Y, Ding Y, Tan C, Yang M, Li F, Wang C. Heart Rate and Heart Rate Difference Predicted the Efficacy of Metoprolol on Postural Tachycardia Syndrome in Children and Adolescents. J Pediatr 2020; 224:110-114. [PMID: 32464225 DOI: 10.1016/j.jpeds.2020.05.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/08/2020] [Accepted: 05/13/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To evaluate the ability of heart rate (HR) and HR difference during head-up tilt test (HUTT) and to predict clinical improvement related to metoprolol treatment in children and adolescents with postural tachycardia syndrome (POTS). STUDY DESIGN This was a retrospective cohort study. A total of 53 subjects (27 male, aged 6-12 years old, mean age 11.79 ± 1.50 years old) with POTS treated with metoprolol were involved from July 2012 to September 2019. In total, 52 subjects who underwent health examination during the same period were matched as the control group. Subjects in both groups underwent HUTT. The HR distance between 5 minutes and 0 minutes (HR difference 5) and between 10 minutes and 0 minutes (HR difference 10) during HUTT was calculated. RESULTS The POTS group was significantly greater than the control group in HR 5, HR 10, HR difference 5, and HR difference 10 (P < .01). There was no statistical difference in HR 0 between the 2 groups (P > .05). In total, 53 subjects with POTS were followed up for 96.0 (IQR, 40.5, 134.5) days during treatment with metoprolol. HUTT results demonstrated that 58.49% of subjects with POTS had a response and symptom scores were reduced after intervention. HR and HR difference were useful in predicting the efficacy of metoprolol on POTS. When HR 5, HR 10, HR difference 5, and HR difference 10, respectively, were ≥110, 112, 34, and 37 beats/min, the sensitivity and specificity were 82.50% and 69.23%, 84.62% and 69.70%, 85.29% and 89.47%, and 97.56% and 64.86%, respectively. CONCLUSIONS HR and HR difference are helpful to predict the efficacy of metoprolol on POTS in children and adolescents.
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Affiliation(s)
- Shuo Wang
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China; Department of Graduate Management, Jishou University School of Medicine, Jishou, Hunan, China; Department of Pediatrics, The First People's Hospital of Changde City, Changde, Hunan, China
| | - Runmei Zou
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hong Cai
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yuwen Wang
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yiyi Ding
- Department of Pediatrics, The First People's Hospital of Changde City, Changde, Hunan, China
| | - Chuanmei Tan
- Department of Graduate Management, Jishou University School of Medicine, Jishou, Hunan, China
| | - Maosheng Yang
- Department of Graduate Management, Jishou University School of Medicine, Jishou, Hunan, China
| | - Fang Li
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Cheng Wang
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
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Aiba I, Noebels JL. Adrenergic agonist induces rhythmic firing in quiescent cardiac preganglionic neurons in nucleus ambiguous via activation of intrinsic membrane excitability. J Neurophysiol 2019; 121:1266-1278. [PMID: 30699052 PMCID: PMC6485744 DOI: 10.1152/jn.00761.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Cholinergic vagal nerves projecting from neurons in the brain stem nucleus ambiguus (NAm) play a predominant role in cardiac parasympathetic pacemaking control. Central adrenergic signaling modulates the tone of this vagal output; however, the exact excitability mechanisms are not fully understood. We investigated responses of NAm neurons to adrenergic agonists using in vitro mouse brain stem slices. Preganglionic NAm neurons were identified by ChAT-tdTomato fluorescence in young adult transgenic mice, and their cardiac projection was confirmed by retrograde dye tracing. Juxtacellular recordings detected sparse or absent spontaneous action potentials (AP) in NAm neurons. However, bath application of epinephrine or norepinephrine strongly and reversibly activated most NAm neurons regardless of their basal firing rate. Epinephrine was more potent than norepinephrine, and this activation largely depends on α1-adrenoceptors. Interestingly, adrenergic activation of NAm neurons does not require an ionotropic synaptic mechanism, because postsynaptic excitatory or inhibitory receptor blockade did not occlude the excitatory effect, and bath-applied adrenergic agonists did not alter excitatory or inhibitory synaptic transmission. Instead, adrenergic agonists significantly elevated intrinsic membrane excitability to facilitate generation of recurrent action potentials. T-type calcium current and hyperpolarization-activated current are involved in this excitation pattern, although not required for spontaneous AP induction by epinephrine. In contrast, pharmacological blockade of persistent sodium current significantly inhibited the adrenergic effects. Our results demonstrate that central adrenergic signaling enhances the intrinsic excitability of NAm neurons and that persistent sodium current is required for this effect. This central balancing mechanism may counteract excessive peripheral cardiac excitation during increased sympathetic tone. NEW & NOTEWORTHY Cardiac preganglionic cholinergic neurons in the nucleus ambiguus (NAm) are responsible for slowing cardiac pacemaking. This study identified that adrenergic agonists can induce rhythmic action potentials in otherwise quiescent cholinergic NAm preganglionic neurons in brain stem slice preparation. The modulatory influence of adrenaline on central parasympathetic outflow may contribute to both physiological and deleterious cardiovascular regulation.
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Affiliation(s)
- Isamu Aiba
- Department of Neurology, Baylor College of Medicine , Houston, Texas
| | - Jeffrey L Noebels
- Department of Neurology, Baylor College of Medicine , Houston, Texas
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Lo Martire V, Silvani A, Alvente S, Bastianini S, Berteotti C, Valli A, Zoccoli G. Modulation of sympathetic vasoconstriction is critical for the effects of sleep on arterial pressure in mice. J Physiol 2018; 596:591-608. [PMID: 29266348 DOI: 10.1113/jp275353] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/15/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS While values of arterial pressure during sleep are predictive of cardiovascular risk, the autonomic mechanisms underlying the cardiovascular effects of sleep remain poorly understood. Here, we assess the autonomic mechanisms of the cardiovascular effects of sleep in C57Bl/6J mice, taking advantage of a novel technique for continuous intraperitoneal infusion of autonomic blockers. Our results indicate that non-REM sleep decreases arterial pressure by decreasing sympathetic vasoconstriction, decreases heart rate by balancing parasympathetic activation and sympathetic withdrawal, and increases cardiac baroreflex sensitivity mainly by increasing fluctuations in parasympathetic activity. Our results also indicate that REM sleep increases arterial pressure by increasing sympathetic activity to the heart and blood vessels, and increases heart rate, at least in part, by increasing cardiac sympathetic activity. These results provide a framework for generating and testing hypotheses on cardiovascular derangements during sleep in mouse models and human patients. ABSTRACT The values of arterial pressure (AP) during sleep predict cardiovascular risk. Sleep exerts similar effects on cardiovascular control in human subjects and mice. We aimed to determine the underlying autonomic mechanisms in 12 C57Bl/6J mice with a novel technique of intraperitoneal infusion of autonomic blockers, while monitoring the electroencephalogram, electromyogram, AP and heart period (HP, i.e. 1/heart rate). In different sessions, we administered atropine methyl nitrate, atenolol and prazosin to block muscarinic cholinergic, β1 -adrenergic and α1 -adrenergic receptors, respectively, and compared each drug infusion with a matched vehicle infusion. The decrease in AP from wakefulness to non-rapid-eye-movement sleep (N) was abolished by prazosin but was not significantly affected by atropine and atenolol, which, however, blunted the accompanying increase in HP to a similar extent. On passing from N to rapid-eye-movement sleep (R), the increase in AP was significantly blunted by prazosin and atenolol, whereas the accompanying decrease in HP was blunted by atropine and abolished by atenolol. Cardiac baroreflex sensitivity (cBRS, sequence technique) was dramatically decreased by atropine and slightly increased by prazosin. These data indicate that in C57Bl/6J mice, N decreases mean AP by decreasing sympathetic vasoconstriction, increases HP by balancing parasympathetic activation and sympathetic withdrawal, and increases cBRS mainly by increasing fluctuations in parasympathetic activity. R increases mean AP by increasing sympathetic vasoconstriction and cardiac sympathetic activity, which also explains, at least in part, the concomitant decrease in HP. These data represent the first comprehensive assessment of the autonomic mechanisms of cardiovascular control during sleep in mice.
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Affiliation(s)
- Viviana Lo Martire
- Laboratory of Physiological Regulation in Sleeping Mice (PRISM), Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Alessandro Silvani
- Laboratory of Physiological Regulation in Sleeping Mice (PRISM), Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Sara Alvente
- Laboratory of Physiological Regulation in Sleeping Mice (PRISM), Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Stefano Bastianini
- Laboratory of Physiological Regulation in Sleeping Mice (PRISM), Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Chiara Berteotti
- Laboratory of Physiological Regulation in Sleeping Mice (PRISM), Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Alice Valli
- Laboratory of Physiological Regulation in Sleeping Mice (PRISM), Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Giovanna Zoccoli
- Laboratory of Physiological Regulation in Sleeping Mice (PRISM), Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
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Grzelka K, Kurowski P, Gawlak M, Szulczyk P. Noradrenaline Modulates the Membrane Potential and Holding Current of Medial Prefrontal Cortex Pyramidal Neurons via β 1-Adrenergic Receptors and HCN Channels. Front Cell Neurosci 2017; 11:341. [PMID: 29209170 PMCID: PMC5701640 DOI: 10.3389/fncel.2017.00341] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/16/2017] [Indexed: 12/27/2022] Open
Abstract
The medial prefrontal cortex (mPFC) receives dense noradrenergic projections from the locus coeruleus. Adrenergic innervation of mPFC pyramidal neurons plays an essential role in both physiology (control of memory formation, attention, working memory, and cognitive behavior) and pathophysiology (attention deficit hyperactivity disorder, posttraumatic stress disorder, cognitive deterioration after traumatic brain injury, behavioral changes related to addiction, Alzheimer's disease and depression). The aim of this study was to elucidate the mechanism responsible for adrenergic receptor-mediated control of the resting membrane potential in layer V mPFC pyramidal neurons. The membrane potential or holding current of synaptically isolated layer V mPFC pyramidal neurons was recorded in perforated-patch and classical whole-cell configurations in slices from young rats. Application of noradrenaline (NA), a neurotransmitter with affinity for all types of adrenergic receptors, evoked depolarization or inward current in the tested neurons irrespective of whether the recordings were performed in the perforated-patch or classical whole-cell configuration. The effect of noradrenaline depended on β1- and not α1- or α2-adrenergic receptor stimulation. Activation of β1-adrenergic receptors led to an increase in inward Na+ current through hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which carry a mixed Na+/K+ current. The protein kinase A- and C-, glycogen synthase kinase-3β- and tyrosine kinase-linked signaling pathways were not involved in the signal transduction between β1-adrenergic receptors and HCN channels. The transduction system operated in a membrane-delimited fashion and involved the βγ subunit of G-protein. Thus, noradrenaline controls the resting membrane potential and holding current in mPFC pyramidal neurons through β1-adrenergic receptors, which in turn activate HCN channels via a signaling pathway involving the βγ subunit.
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Affiliation(s)
- Katarzyna Grzelka
- Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, Medical University of Warsaw, Warsaw, Poland
| | | | | | - Paweł Szulczyk
- Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, Medical University of Warsaw, Warsaw, Poland
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Gherghina FL, Tica AA, Deliu E, Abood ME, Brailoiu GC, Brailoiu E. Effects of VPAC1 activation in nucleus ambiguus neurons. Brain Res 2017; 1657:297-303. [PMID: 28043808 DOI: 10.1016/j.brainres.2016.12.026] [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] [Received: 11/11/2016] [Revised: 12/20/2016] [Accepted: 12/27/2016] [Indexed: 11/25/2022]
Abstract
The pituitary adenylyl cyclase-activating polypeptide (PACAP) and its G protein-coupled receptors, PAC1, VPAC1 and VPAC2 form a system involved in a variety of biological processes. Although some sympathetic stimulatory effects of this system have been reported, its central cardiovascular regulatory properties are poorly characterized. VPAC1 receptors are expressed in the nucleus ambiguus (nAmb), a key center controlling cardiac parasympathetic tone. In this study, we report that selective VPAC1 activation in rhodamine-labeled cardiac vagal preganglionic neurons of the rat nAmb produces inositol 1,4,5-trisphosphate receptor-mediated Ca2+ mobilization, membrane depolarization and activation of P/Q-type Ca2+ channels. In vivo, this pathway converges onto transient reduction in heart rate of conscious rats. Therefore we demonstrate a VPAC1-dependent mechanism in the central parasympathetic regulation of the heart rate, adding to the complexity of PACAP-mediated cardiovascular modulation.
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Affiliation(s)
| | - Andrei Adrian Tica
- Department of Pharmacology, University of Medicine and Pharmacy, Craiova, Romania
| | - Elena Deliu
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Mary E Abood
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - G Cristina Brailoiu
- Department of Pharmaceutical Sciences, Thomas Jefferson University, Jefferson College of Pharmacy, Philadelphia, PA 19107, USA
| | - Eugen Brailoiu
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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Shapoval LM, Dmytrenko OV, Naumenko AM, Davydovska TL, Sagach VF. Effects of Stereotactic Introduction of Baclofen in the Medullary Cardiovascular Nuclei of Rats. NEUROPHYSIOLOGY+ 2017. [DOI: 10.1007/s11062-017-9626-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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10
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Allen B, Friedman BH. Threatening the heart and mind of gender stereotypes: Can imagined contact influence the physiology of stereotype threat? Psychophysiology 2017; 53:105-12. [PMID: 26681622 DOI: 10.1111/psyp.12580] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Revised: 10/03/2015] [Accepted: 10/07/2015] [Indexed: 12/01/2022]
Abstract
Research shows that when a gender stereotype is made salient and the target of the stereotype is asked to perform in the stereotyped domain, targets of the stereotype often perform at a lower level compared to situations when the stereotype was not made salient. The noticeable absence of female faculty and students in math and science departments at coed universities throughout the United States may increase the belief in gender stereotypes and discourage women from pursuing careers in these fields. Contact with counterstereotypical exemplars, such as female science experts, decreases belief in gender stereotypes and increases women's motivation to pursue careers in science. Thus, the present study examined whether imagining an interpersonal interaction with a counterstereotypical exemplar removes the physiological and performance effects of stereotype threat. Subjects were asked to imagine either a nature scene or meeting a female math professor, and were also assigned to either a control or stereotype threat condition. Imagination was used because studies have shown it to be an effective method of simulating interpersonal contact. Subjects were 139 young women (mean age 19 years) recruited from a pool of undergraduates. Results showed that the stereotype threat manipulation elicited greater vagal withdrawal and poorer working memory capacity during the n-back, and that vagal withdrawal was attenuated when the stereotype threat manipulation was preceded by a brief imagined interaction with a counterstereotypical exemplar. This study provides novel evidence that exposure to counterstereotypical exemplars can diminish cardiovascular reactions to salient information about threatening gender stereotypes.
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Affiliation(s)
- Ben Allen
- Department of Psychology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Bruce H Friedman
- Department of Psychology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
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Dyavanapalli J, Dergacheva O, Wang X, Mendelowitz D. Parasympathetic Vagal Control of Cardiac Function. Curr Hypertens Rep 2016; 18:22. [PMID: 26849575 DOI: 10.1007/s11906-016-0630-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This brief review focuses on four new topics, with novel and clinically significant consequences, concerning the powerful influence of parasympathetic activity on cardiac function. In this short summary, we will highlight very recent and important work, published in the last 3-4 years, that (1) challenges the paradigm that parasympathetic activity to the heart is involved in the control of heart rate but plays little role in other cardiac functions, (2) characterizes important long-range synaptic pathways to parasympathetic cardiac vagal neurons that are involved in "higher" brain functions (such as arousal and emotional challenges), (3) asks whether implantable chronic vagal nerve stimulation is a promising clinical tool for treating cardiovascular diseases, and (4) describes newly identified neuropeptides and other modulators that can influence the generation and maintenance of parasympathetic activity to the heart.
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Affiliation(s)
- Jhansi Dyavanapalli
- Department of Pharmacology and Physiology, The George Washington University, 2300 Eye St NW, Washington, DC, 20037, USA
| | - Olga Dergacheva
- Department of Pharmacology and Physiology, The George Washington University, 2300 Eye St NW, Washington, DC, 20037, USA
| | - Xin Wang
- Department of Pharmacology and Physiology, The George Washington University, 2300 Eye St NW, Washington, DC, 20037, USA
| | - David Mendelowitz
- Department of Pharmacology and Physiology, The George Washington University, 2300 Eye St NW, Washington, DC, 20037, USA.
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12
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Tallapragada VJ, Hildreth CM, Burke PGR, Raley DA, Hassan SF, McMullan S, Goodchild AK. Tonically Active cAMP-Dependent Signaling in the Ventrolateral Medulla Regulates Sympathetic and Cardiac Vagal Outflows. J Pharmacol Exp Ther 2015; 356:424-33. [PMID: 26578265 DOI: 10.1124/jpet.115.227488] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 11/13/2015] [Indexed: 01/24/2023] Open
Abstract
The ventrolateral medulla contains presympathetic and vagal preganglionic neurons that control vasomotor and cardiac vagal tone, respectively. G protein-coupled receptors influence the activity of these neurons. Gα s activates adenylyl cyclases, which drive cyclic adenosine monophosphate (cAMP)-dependent targets: protein kinase A (PKA), the exchange protein activated by cAMP (EPAC), and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. The aim was to determine the cardiovascular effects of activating and inhibiting these targets at presympathetic and cardiac vagal preganglionic neurons. Urethane-anesthetized rats were instrumented to measure splanchnic sympathetic nerve activity (sSNA), arterial pressure (AP), heart rate (HR), as well as baroreceptor and somatosympathetic reflex function, or were spinally transected and instrumented to measure HR, AP, and cardiac baroreflex function. All drugs were injected bilaterally. In the rostral ventrolateral medulla (RVLM), Sp-cAMPs and 8-Br-cAMP, which activate PKA, as well as 8-pCPT, which activates EPAC, increased sSNA, AP, and HR. Sp-cAMPs also facilitated the reflexes tested. Sp-cAMPs also increased cardiac vagal drive and facilitated cardiac baroreflex sensitivity. Blockade of PKA, using Rp-cAMPs or H-89 in the RVLM, increased sSNA, AP, and HR and increased HR when cardiac vagal preganglionic neurons were targeted. Brefeldin A, which inhibits EPAC, and ZD7288, which inhibits HCN channels, each alone had no effect. Cumulative, sequential blockade of all three inhibitors resulted in sympathoinhibition. The major findings indicate that Gα s-linked receptors in the ventral medulla can be recruited to drive both sympathetic and parasympathetic outflows and that tonically active PKA-dependent signaling contributes to the maintenance of both sympathetic vasomotor and cardiac vagal tone.
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Affiliation(s)
- Vikram J Tallapragada
- Dept Biomedical Sciences, Faculty of Medicine, Macquarie University, Sydney, NSW, Australia
| | - Cara M Hildreth
- Dept Biomedical Sciences, Faculty of Medicine, Macquarie University, Sydney, NSW, Australia
| | - Peter G R Burke
- Dept Biomedical Sciences, Faculty of Medicine, Macquarie University, Sydney, NSW, Australia
| | - Darryl A Raley
- Dept Biomedical Sciences, Faculty of Medicine, Macquarie University, Sydney, NSW, Australia
| | - Sarah F Hassan
- Dept Biomedical Sciences, Faculty of Medicine, Macquarie University, Sydney, NSW, Australia
| | - Simon McMullan
- Dept Biomedical Sciences, Faculty of Medicine, Macquarie University, Sydney, NSW, Australia
| | - Ann K Goodchild
- Dept Biomedical Sciences, Faculty of Medicine, Macquarie University, Sydney, NSW, Australia
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Yuan H, Silberstein SD. Vagus Nerve and Vagus Nerve Stimulation, a Comprehensive Review: Part I. Headache 2015; 56:71-8. [DOI: 10.1111/head.12647] [Citation(s) in RCA: 179] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Hsiangkuo Yuan
- Jefferson Headache Center, Thomas Jefferson University; Philadelphia PA USA
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15
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Allen B, Jennings JR, Gianaros PJ, Thayer JF, Manuck SB. Resting high-frequency heart rate variability is related to resting brain perfusion. Psychophysiology 2014; 52:277-87. [PMID: 25174686 DOI: 10.1111/psyp.12321] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/28/2014] [Indexed: 12/13/2022]
Abstract
We examined the neural correlates of resting cardiac vagal activity in a sample of 432 participants (206 male; 61 African American; mean age 42 years). Pulsed arterial spin labeling was used to quantify whole brain and regional cerebral blood flow at rest. High-frequency heart rate variability (HF-HRV) was used to measure cardiac vagal activity at rest. The primary aim was to determine whether brain regions implicated in regulating cardiac vagal reactions were also related to cardiac vagal activity at rest, and whether these associations varied by sex or race. Brain areas previously related to vagal reactivity were related to resting HF-HRV. Directionality of relationships differed between overall and regional flows. Some relationships were only observed in women and African Americans. There appears to be communality between brain regions associated with task-induced vagal reactivity and those associated with resting cardiac vagal activity.
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Affiliation(s)
- Ben Allen
- Department of Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Optogenetic stimulation of locus ceruleus neurons augments inhibitory transmission to parasympathetic cardiac vagal neurons via activation of brainstem α1 and β1 receptors. J Neurosci 2014; 34:6182-9. [PMID: 24790189 DOI: 10.1523/jneurosci.5093-13.2014] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Locus ceruleus (LC) noradrenergic neurons are critical in generating alertness. In addition to inducing cortical arousal, the LC also orchestrates changes in accompanying autonomic system function that compliments increased attention, such as during stress, excitation, and/or exposure to averse or novel stimuli. Although the association between arousal and increased heart rate is well accepted, the neurobiological link between the LC and parasympathetic neurons that control heart rate has not been identified. In this study, we test directly whether activation of noradrenergic neurons in the LC influences brainstem parasympathetic cardiac vagal neurons (CVNs). CVNs were identified in transgenic mice that express channel-rhodopsin-2 (ChR2) in LC tyrosine hydroxylase neurons. Photoactivation evoked a rapid depolarization, increased firing, and excitatory inward currents in ChR2-expressing neurons in the LC. Photostimulation of LC neurons did not alter excitatory currents, but increased inhibitory neurotransmission to CVNs. Optogenetic activation of LC neurons increased the frequency of isolated glycinergic IPSCs by 27 ± 8% (p = 0.003, n = 26) and augmented GABAergic IPSCs in CVNs by 21 ± 5% (p = 0.001, n = 26). Inhibiting α1, but not α2, receptors blocked the evoked responses. Inhibiting β1 receptors prevented the increase in glycinergic, but not GABAergic, IPSCs in CVNs. This study demonstrates LC noradrenergic neurons inhibit the brainstem CVNs that generate parasympathetic activity to the heart. This inhibition of CVNs would increase heart rate and risks associated with tachycardia. The receptors activated within this pathway, α1 and/or β1 receptors, are targets for clinically prescribed antagonists that promote slower, cardioprotective heart rates during heightened vigilant states.
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Nasse JS, Travers JB. Adrenoreceptor modulation of oromotor pathways in the rat medulla. J Neurophysiol 2014; 112:580-93. [PMID: 24805080 DOI: 10.1152/jn.00091.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Regulation of feeding behavior involves the integration of multiple physiological and neurological pathways that control both nutrient-seeking and consummatory behaviors. The consummatory phase of ingestion includes stereotyped oromotor movements of the tongue and jaw that are controlled through brain stem pathways. These pathways encompass not only cranial nerve sensory and motor nuclei for processing feeding-related afferent signals and supplying the oromotor musculature but also reticular neurons for orchestrating ingestion and coordinating it with other behaviors that utilize the same musculature. Based on decerebrate studies, this circuit should be sensitive to satiety mechanisms mediated centrally by A2 noradrenergic neurons in the caudal nucleus of the solitary tract (cNST) that are potently activated during satiety. Because the first observable phase of satiety is inhibition of oromotor movements, we hypothesized that norepinephrine (NE) would act to inhibit prehypoglossal neurons in the medullary reticular formation. Using patch-clamp electrophysiology of retrogradely labeled prehypoglossal neurons and calcium imaging to test this hypothesis, we demonstrate that norepinephrine can influence both pre- and postsynaptic properties of reticular neurons through both α1- and α2-adrenoreceptors. The α1-adrenoreceptor agonist phenylephrine (PE) activated an inward current in the presence of TTX and increased the frequency of both inhibitory and excitatory miniature postsynaptic currents. The α2-adrenoreceptor agonist dexmedetomidine (DMT) inhibited cNST-evoked excitatory currents as well as spontaneous and miniature excitatory currents through presynaptic mechanisms. The diversity of adrenoreceptor modulation of these prehypoglossal neurons may reflect their role in a multifunctional circuit coordinating both ingestive and respiratory lingual function.
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Affiliation(s)
- Jason S Nasse
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, Ohio
| | - Joseph B Travers
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, Ohio
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Craigmyle NA. The beneficial effects of meditation: contribution of the anterior cingulate and locus coeruleus. Front Psychol 2013; 4:731. [PMID: 24137145 PMCID: PMC3797386 DOI: 10.3389/fpsyg.2013.00731] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 09/22/2013] [Indexed: 12/11/2022] Open
Abstract
During functional magnetic resonance imaging studies of meditation the cortical salience detecting and executive networks become active during "awareness of mind wandering," "shifting," and "sustained attention." The anterior cingulate (AC) is activated during "awareness of mind wandering." The AC modulates both the peripheral sympathetic nervous system (SNS) and the central locus coeruleus (LC) norepinephrine systems, which form the principal neuromodulatory system, regulating in multiple ways both neuronal and non-neuronal cells to maximize adaptation in changing environments. The LC is the primary source of central norepinephrine (C-NE) and nearly the exclusive source of cortical norepinephrine. Normally activated by novel or salient stimuli, the AC initially inhibits the SNS reflexively, lowering peripheral norepinephrine and activates the LC, increasing C-NE. Moderate levels of C-NE enhance working memory through alpha 2 adrenergic receptors, while higher levels of C-NE, acting on alpha 1 and beta receptors, enhance other executive network functions such as the stopping of ongoing behavior, attentional set-shifting, and sustained attention. The actions of the AC on both the central and peripheral noradrenergic systems are implicated in the beneficial effects of meditation. This paper will explore some of the known functions and interrelationships of the AC, SNS, and LC with respect to their possible relevance to meditation.
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Abstract
The central noradrenergic neurone, like the peripheral sympathetic neurone, is characterized by a diffusely arborizing terminal axonal network. The central neurones aggregate in distinct brainstem nuclei, of which the locus coeruleus (LC) is the most prominent. LC neurones project widely to most areas of the neuraxis, where they mediate dual effects: neuronal excitation by α₁-adrenoceptors and inhibition by α₂-adrenoceptors. The LC plays an important role in physiological regulatory networks. In the sleep/arousal network the LC promotes wakefulness, via excitatory projections to the cerebral cortex and other wakefulness-promoting nuclei, and inhibitory projections to sleep-promoting nuclei. The LC, together with other pontine noradrenergic nuclei, modulates autonomic functions by excitatory projections to preganglionic sympathetic, and inhibitory projections to preganglionic parasympathetic neurones. The LC also modulates the acute effects of light on physiological functions ('photomodulation'): stimulation of arousal and sympathetic activity by light via the LC opposes the inhibitory effects of light mediated by the ventrolateral preoptic nucleus on arousal and by the paraventricular nucleus on sympathetic activity. Photostimulation of arousal by light via the LC may enable diurnal animals to function during daytime. LC neurones degenerate early and progressively in Parkinson's disease and Alzheimer's disease, leading to cognitive impairment, depression and sleep disturbance.
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Affiliation(s)
- Elemer Szabadi
- Division of Psychiatry, University of Nottingham, Nottingham, UK.
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Dyavanapalli J, Byrne P, Mendelowitz D. Activation of D2-like dopamine receptors inhibits GABA and glycinergic neurotransmission to pre-motor cardiac vagal neurons in the nucleus ambiguus. Neuroscience 2013; 247:213-26. [PMID: 23727508 DOI: 10.1016/j.neuroscience.2013.05.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Revised: 05/17/2013] [Accepted: 05/21/2013] [Indexed: 12/16/2022]
Abstract
The parasympathetic control of heart rate arises from premotor cardiac vagal neurons (CVNs) located in the nucleus ambiguus (NA). Previous microinjection studies in NA show that dopamine evokes a decrease in heart rate, but the underlying mechanisms responsible for these responses were not identified. This study tested whether dopamine modulates inhibitory GABAergic and glycinergic and/or excitatory glutamatergic neurotransmission to CVNs. Retrogradely labeled CVNs were identified in an in vitro rat brainstem slice preparation and synaptic events were recorded using whole cell voltage clamp techniques. Bath application of dopamine (100 μM) had no effect on excitatory synaptic events, but reversibly inhibited the frequency (but not amplitude) of GABAergic inhibitory postsynaptic currents (IPSCs) in CVNs. Similarly, dopamine (10 μM and 100 μM) inhibited glycinergic IPSC frequency by ~50% and 70% respectively. The reduction in inhibitory neurotransmission to CVNs by dopamine was prevented by the sodium channel blocker TTX (1μM) indicating that the dopamine mediated effects were action potential dependent. Dopamine evoked responses were mimicked by the D2-like receptor agonist, Quinpirole but not D1-like receptor agonist, SKF 38393. In addition, the dopamine mediated depression of inhibitory synaptic responses were prevented by the D2-like receptor antagonist sulpiride, but not by D1-like or adrenergic or serotonergic receptor antagonists, suggesting that these responses were D2-like receptor mediated and not D1-like or adrenergic or 5-HT receptor mediated. These data suggest that dopamine acts via dis-inhibition, and diminishes inhibitory GABAergic and glycinergic neurotransmission to CVNs, which would be predicted to increase parasympathetic activity to the heart and evoke a bradycardia.
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Affiliation(s)
- J Dyavanapalli
- Department of Pharmacology & Physiology, The George Washington University, 2300 Eye Street NW, Washington, DC 20037, USA.
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Garcia AJ, Koschnitzky JE, Dashevskiy T, Ramirez JM. Cardiorespiratory coupling in health and disease. Auton Neurosci 2013; 175:26-37. [PMID: 23497744 DOI: 10.1016/j.autneu.2013.02.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 01/21/2013] [Accepted: 02/08/2013] [Indexed: 10/27/2022]
Abstract
Cardiac and respiratory activities are intricately linked both functionally as well as anatomically through highly overlapping brainstem networks controlling these autonomic physiologies that are essential for survival. Cardiorespiratory coupling (CRC) has many potential benefits creating synergies that promote healthy physiology. However, when such coupling deteriorates autonomic dysautonomia may ensue. Unfortunately there is still an incomplete mechanistic understanding of both normal and pathophysiological interactions that respectively give rise to CRC and cardiorespiratory dysautonomia. Moreover, there is also a need for better quantitative methods to assess CRC. This review addresses the current understanding of CRC by discussing: (1) the neurobiological basis of respiratory sinus arrhythmia (RSA); (2) various disease states involving cardiorespiratory dysautonomia; and (3) methodologies measuring heart rate variability and RSA.
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Affiliation(s)
- Alfredo J Garcia
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
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