keyword
MENU ▼
Read by QxMD icon Read
search

Microneurography

keyword
https://www.readbyqxmd.com/read/28100923/reductions-in-central-arterial-compliance-with-age-are-related-to-sympathetic-vasoconstrictor-nerve-activity-in-healthy-men
#1
Hirofumi Tanaka, Frank A Dinenno, Douglas R Seals
The compliance of large elastic arteries in the cardiothoracic circulation declines, whereas sympathetic nervous system activity increases markedly with advancing age in adult humans. We tested the hypothesis that the reduction in compliance of the large elastic arteries with age is associated with elevations in sympathetic tone to vascular smooth muscle in 16 young and 17 older adults. Carotid arterial compliance (via ultrasonography) was 45% lower in healthy older compared with young men (P<0.001), and was inversely related to sympathetic nerve activity (via microneurography) (r=-0...
January 19, 2017: Hypertension Research: Official Journal of the Japanese Society of Hypertension
https://www.readbyqxmd.com/read/28077660/muscle-spindles-in-human-tibialis-anterior-encode-muscle-fascicle-length-changes
#2
James Thomas Day, Leah R Bent, Ingvars Birznieks, Vaughan G Macefield, Andrew G Cresswell
Muscle spindles provide exquisitely sensitive proprioceptive information regarding joint position and movement. Through passively driven length changes in the muscle-tendon unit (MTU), muscle spindles detect joint rotations because of their in-parallel mechanical linkage to muscle fascicles. In human microneurography studies, muscle fascicles are assumed to follow the MTU and, as such, fascicle length is not measured in such studies. However, under certain mechanical conditions compliant structures can act to decouple the fascicles, and therefore the spindles, from the MTU...
January 11, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28057441/non-invasive-approach-for-the-assessment-of-sympathetic-baroreflex-function-a-feasibility-study
#3
Bartłomiej Paleczny, Agnieszka Siennicka, Piotr Ponikowski, Beata Ponikowska
BACKGROUND: Evaluation of sympathetic baroreflex (sBR) function in humans requires intra-neural recording of muscle sympathetic nerve activity (MSNA) by microneurography. AIMS: We proposed noninvasive approach for the evaluation of sBR function by applying the threshold-analysis (traditionally, based on MSNA) to systemic vascular resistance (SVR) measurement by photoplethysmography. METHODS & RESULTS: In nine healthy subjects (5M; age: 25±5y), the threshold-analysis was calculated twice: using MSNA and SVR...
December 29, 2016: Autonomic Neuroscience: Basic & Clinical
https://www.readbyqxmd.com/read/28055999/-role-of-the-sympathetic-nervous-system-in-vasovagal-syncope-and-rationale-for-beta-blockers-and-norepinephrine-transporter-inhibitors
#4
Manlio F Márquez, Jorge Rafael Gómez-Flores, Jesús A González-Hermosillo, Teresita de Jesús Ruíz-Siller, Manuel Cárdenas
Vasovagal or neurocardiogenic syncope is a common clinical situation and, as with other entities associated with orthostatic intolerance, the underlying condition is a dysfunction of the autonomic nervous system. This article reviews various aspects of vasovagal syncope, including its relationship with orthostatic intolerance and the role of the autonomic nervous system in it. A brief history of the problem is given, as well as a description of how the names and associated concepts have evolved. The response of the sympathetic system to orthostatic stress, the physiology of the baroreflex system and the neurohumoral changes that occur with standing are analyzed...
December 29, 2016: Medwave
https://www.readbyqxmd.com/read/28029639/sleep-disordered-breathing-exacerbates-muscle-vasoconstriction-and-sympathetic-neural-activation-in-patients-with-systolic-heart-failure
#5
Denise M L Lobo, Patricia F Trevizan, Edgar Toschi-Dias, Patricia A Oliveira, Rafael B Piveta, Dirceu R Almeida, Charles Mady, Edimar A Bocchi, Geraldo Lorenzi-Filho, Holly R Middlekauff, Carlos E Negrão
BACKGROUND: Sleep-disordered breathing (SDB) is common in patients with heart failure (HF), and hypoxia and hypercapnia episodes activate chemoreceptors stimulating autonomic reflex responses. We tested the hypothesis that muscle vasoconstriction and muscle sympathetic nerve activity (MSNA) in response to hypoxia and hypercapnia would be more pronounced in patients with HF and SDB than in patients with HF without SDB (NoSBD). METHODS AND RESULTS: Ninety consecutive patients with HF, New York Heart Association functional class II-III, and left ventricular ejection fraction ≤40% were screened for the study...
November 2016: Circulation. Heart Failure
https://www.readbyqxmd.com/read/27956555/the-influence-of-aetiology-on-the-benefits-of-exercise-training-in-patients-with-heart-failure
#6
Ligia M Antunes-Correa, Linda M Ueno-Pardi, Patricia F Trevizan, Marcelo R Santos, Carlos Henrique P da Silva, Fábio Gm Franco, Maria Janieire Nn Alves, Maria Urbana Pb Rondon, Carlos E Negrao
BACKGROUND: Exercise training improves neurovascular control and functional capacity in heart failure (HF) patients. However, the influence of the aetiology on these benefits is unknown. We compared the effects of exercise training on neurovascular control and functional capacity in idiopathic, ischaemic and hypertensive HF patients. DESIGN: Subjects consisted of 45 exercise-trained HF patients from our database (2000-2015), aged 40-70 years old, functional class II/III and ejection fraction ≤40%, and they were divided into three groups: idiopathic (n = 11), ischaemic (n = 18) and hypertensive (n = 16)...
December 12, 2016: European Journal of Preventive Cardiology
https://www.readbyqxmd.com/read/27891612/neurovascular-mechanisms-underlying-augmented-cold-induced-reflex-cutaneous-vasoconstriction-in-human-hypertension
#7
Jody L Greaney, W Larry Kenney, Lacy M Alexander
Despite ample evidence of dysregulated sympathetic control of the peripheral vasculature in hypertension, no studies have examined integrated neurovascular function during cold stress in hypertensive adults (HTN). We hypothesized that (1) whole-body cooling would elicit greater cutaneous vasoconstriction and greater increases in skin sympathetic nervous system activity (SSNA) in HTN (n = 14; 56 ± 2 yrs) compared to age-matched normotensive adults (NTN; n = 14; 55 ± 2 yrs) and (2) augmented reflex vasoconstriction in HTN would be mediated by an increase in cutaneous vascular adrenergic sensitivity and a greater contribution of non-adrenergic sympathetic co-transmitters...
November 28, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27861895/effects-of-postural-change-from-supine-to-head-up-tilt-on-the-skin-sympathetic-nerve-activity-component-synchronised-with-the-cardiac-cycle-in-warmed-men
#8
Yu Ogawa, Yoshi-Ichiro Kamijo, Shigeki Ikegawa, Shizue Masuki, Hiroshi Nose
KEY POINTS: Humans are unique in controlling body temperature in a hot environment by a large amount of skin blood flow; however, the decrease in total peripheral resistance due to systemic cutaneous vasodilatation and the reduction of venous return to the heart due to blood pooling in the cutaneous vein threatens blood pressure maintenance in the upright position, and occasionally causes heat syncope. Against this condition, cutaneous vasodilatation is reportedly suppressed to maintain arterial pressure; however, the nerve activity responsible for this phenomenon has not been identified...
November 8, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27857694/comparable-attenuation-of-sympathetic-nervous-system-activity-in-obese-subjects-with-normal-glucose-tolerance-impaired-glucose-tolerance-and-treatment-na%C3%A3-ve-type-2-diabetes-following-equivalent-weight-loss
#9
Nora E Straznicky, Mariee T Grima, Carolina I Sari, Elisabeth A Lambert, Sarah E Phillips, Nina Eikelis, Justin A Mariani, Daisuke Kobayashi, Dagmara Hering, John B Dixon, Gavin W Lambert
Background and Purpose: Elevated sympathetic nervous system (SNS) activity is a characteristic of obesity and type 2 diabetes (T2D) that contributes to target organ damage and cardiovascular risk. In this study we examined whether baseline metabolic status influences the degree of sympathoinhibition attained following equivalent dietary weight loss. Methods: Un-medicated obese individuals categorized as normal glucose tolerant (NGT, n = 15), impaired glucose tolerant (IGT, n = 24), and newly-diagnosed T2D (n = 15) consumed a hypocaloric diet (29% fat, 23% protein, 45% carbohydrate) for 4-months...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27789772/blunted-increases-in-skin-sympathetic-nerve-activity-are-related-to-attenuated-reflex-vasodilation-in-aged-human-skin
#10
Anna E Stanhewicz, Jody L Greaney, Lacy M Alexander, W Larry Kenney
Reflex cutaneous vasodilation in response to passive heating is attenuated in human aging. This diminished response is mediated, in part, by age-associated reductions in endothelial function; however, the contribution of altered skin sympathetic nervous system activity (SSNA) is unknown. We hypothesized that 1) healthy older adults would demonstrate blunted SSNA responses to increased core temperature compared with young adults and 2) the decreased SSNA response would be associated with attenuated cutaneous vasodilation...
December 1, 2016: Journal of Applied Physiology
https://www.readbyqxmd.com/read/27784689/central-vs-peripheral-determinants-of-sympathetic-neural-recruitment-insights-from-static-handgrip-exercise-and-postexercise-circulatory-occlusion
#11
Mark B Badrov, T Dylan Olver, J Kevin Shoemaker
Sympathetic outflow is modified during acute homeostatic stress through increased firing of low-threshold axons, recruitment of latent axons, and synaptic delay modifications. However, the role of central mechanisms versus peripheral reflex control over sympathetic recruitment remains unknown. Here, we examined sympathetic discharge patterns during fatiguing static handgrip (SHG) exercise and postexercise circulatory occlusion (PECO) to study the central vs. peripheral reflex elements of sympathetic neural coding...
December 1, 2016: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/27781142/pathological-nociceptors-in-two-patients-with-erythromelalgia-like-symptoms-and-rare-genetic-nav-1-9-variants
#12
Inge P Kleggetveit, Roland Schmidt, Barbara Namer, Hugh Salter, Tormod Helås, Martin Schmelz, Ellen Jørum
INTRODUCTION: The sodium channel Nav 1.9 is expressed in peripheral nociceptors and has recently been linked to human pain conditions, but the exact role of Nav 1.9 for human nociceptor excitability is still unclear. METHODS: C-nociceptors from two patients with late onset of erythromelalgia-like pain, signs of small fiber neuropathy, and rare genetic variants of Nav 1.9 (N1169S, I1293V) were assessed by microneurography. RESULTS: Compared with patients with comparable pain phenotypes (erythromelalgia-like pain without Nav-mutations and painful polyneuropathy), there was a tendency toward more activity-dependent slowing of conduction velocity in mechanoinsensitive C-nociceptors...
October 2016: Brain and Behavior
https://www.readbyqxmd.com/read/27676142/post-exercise-neurovascular-control-in-chronic-heart-failure-patients
#13
T S Nobre, R V Groehs, L F Azevedo, L M Antunes-Correa, D G Martinez, M J N N Alves, C E Negrao
It remains unknown whether or not a reduction in muscle sympathetic nerve activity in heart failure patients is associated over time with the effects of long- or short-term repeated exercise. 10 chronic heart failure patients, age 49±3 years old, functional class I-III NYHA, ejection fraction <40% were randomly submitted to either an acute bout of moderate continuous exercise OR high-intensity interval exercise. Muscle sympathetic nerve activity (microneurography) and forearm blood flow (venous occlusion plethysmography) were evaluated pre- and post-exercise sessions...
December 2016: International Journal of Sports Medicine
https://www.readbyqxmd.com/read/27639906/sympathetic-activity-in-patients-with%C3%A2-secondary-symptomatic-mitral%C3%A2-regurgitation-or-end-stage-systolic%C3%A2-heart-failure
#14
Can Öztürk, Robert Schueler, Marcel Weber, Armin Welz, Nikos Werner, Georg Nickenig, Christoph Hammerstingl
OBJECTIVES: This study shows the impact of secondary mitral regurgitation (sMR) and transcatheter mitral valve repair (TMVR) with the MitraClip system on sympathetic nerve activity (SNA). BACKGROUND: An increase in SNA is associated with worse outcomes and limited survival in patients with chronic heart failure (CHF). METHODS: Twenty CHF-patients without relevant sMR and 30 CHF patients with symptomatic sMR were enrolled prospectively. All patients underwent standardized laboratory testing and microneurography...
October 10, 2016: JACC. Cardiovascular Interventions
https://www.readbyqxmd.com/read/27598514/scn10a-mutation-in-a-patient-with-erythromelalgia-enhances-c-fiber-activity-dependent-slowing
#15
Andreas M Kist, Dagrun Sagafos, Anthony M Rush, Cristian Neacsu, Esther Eberhardt, Roland Schmidt, Lars Kristian Lunden, Kristin Ørstavik, Luisa Kaluza, Jannis Meents, Zhiping Zhang, Thomas Hedley Carr, Hugh Salter, David Malinowsky, Patrik Wollberg, Johannes Krupp, Inge Petter Kleggetveit, Martin Schmelz, Ellen Jørum, Angelika Lampert, Barbara Namer
Gain-of-function mutations in the tetrodotoxin (TTX) sensitive voltage-gated sodium channel (Nav) Nav1.7 have been identified as a key mechanism underlying chronic pain in inherited erythromelalgia. Mutations in TTX resistant channels, such as Nav1.8 or Nav1.9, were recently connected with inherited chronic pain syndromes. Here, we investigated the effects of the p.M650K mutation in Nav1.8 in a 53 year old patient with erythromelalgia by microneurography and patch-clamp techniques. Recordings of the patient's peripheral nerve fibers showed increased activity dependent slowing (ADS) in CMi and less spontaneous firing compared to a control group of erythromelalgia patients without Nav mutations...
2016: PloS One
https://www.readbyqxmd.com/read/27591218/exercise-training-improves-neurovascular-control-and-calcium-cycling-gene-expression-in-heart-failure-patients-with-cardiac-resynchronization-therapy
#16
Thais S Nobre, Ligia M Antunes-Correa, Raphaela V Groehs, Maria-Janieire N N Alves, Adriana O Sarmento, Aline Villa Nova Bacurau, Ursula Urias, Guilherme Barreto Alves, Maria Urbana P B Rondon, Patricia C Brum, Martino Martinelli, Holly R Middlekauff, Carlos E Negrao
Heart failure(HF) is characterized by decreased exercise capacity, attributable to neurocirculatory and skeletal muscle factors. Cardiac resynchronization therapy(CRT) and exercise training have each been shown to decrease muscle sympathetic nerve activity(MSNA) and increase exercise capacity in patients with HF. We hypothesized that exercise training in the setting of CRT would further reduce MSNA and vasoconstriction and would increase Ca(2+) handling gene expression in skeletal muscle in chronic systolic HF patients...
September 2, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27542408/effects-of-aging-and-coronary-artery-disease-on-sympathetic-neural-recruitment-strategies-during-end-inspiratory-and-end-expiratory-apnea
#17
Mark B Badrov, Sophie Lalande, T Dylan Olver, Neville Suskin, J Kevin Shoemaker
In response to acute physiological stress, the sympathetic nervous system modifies neural outflow through increased firing frequency of lower-threshold axons, recruitment of latent subpopulations of higher-threshold axons, and/or acute modifications of synaptic delays. Aging and coronary artery disease (CAD) often modify efferent muscle sympathetic nerve activity (MSNA). Therefore, we investigated whether CAD (n = 14; 61 ± 10 yr) and/or healthy aging without CAD (OH; n = 14; 59 ± 9 yr) modified these recruitment strategies that normally are observed in young healthy (YH; n = 14; 25 ± 3 yr) individuals...
October 1, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27542313/exercise-training-induced-modification-in-autonomic-nervous-system-an-update-for-cardiac-patients
#18
REVIEW
Florent Besnier, Marc Labrunée, Atul Pathak, Anne Pavy-Le Traon, Céline Galès, Jean-Michel Sénard, Thibaut Guiraud
Patients with cardiovascular disease show autonomic dysfunction, including sympathetic activation and vagal withdrawal, which leads to fatal events. This review aims to place sympathovagal balance as an essential element to be considered in management for cardiovascular disease patients who benefit from a cardiac rehabilitation program. Many studies showed that exercise training, as non-pharmacologic treatment, plays an important role in enhancing sympathovagal balance and could normalize levels of markers of sympathetic flow measured by microneurography, heart rate variability or plasma catecholamine levels...
August 16, 2016: Annals of Physical and Rehabilitation Medicine
https://www.readbyqxmd.com/read/27508821/-op-7b-02-metabolic-syndrome-is-associated-with-increased-sympathetic-nervous-system-activity-and-arterial-stiffness-in-resistant-hypertensive-patients
#19
K Dimitriadis, C Tsioufis, E Andrikou, A Kasiakogias, K Kyriazopoulos, A Frantzeskakis, T Kalos, I Liatakis, E Koutra, D Tousoulis
OBJECTIVE: Resistant hypertension is related to sympathetic overdrive and arterial stiffening, while there are scarce data whether metabolic syndrome further potentiates sympathetic activity and vascular abnormalities in this setting. The aim of this study was to assess the effect of the metabolic syndrome on muscle sympathetic nerve activity (MSNA) and arterial stiffness in resistant hypertensive patients. DESIGN AND METHOD: We studied 36 patients with resistant hypertension [age: 59 ± 10 years, 24 males, office blood pressure (BP): 178/93 ± 14/11 mmHg, 24-hour BP: 146/84 ± 13/11 mmHg, under 4...
September 2016: Journal of Hypertension
https://www.readbyqxmd.com/read/27278369/obstructive-sleep-apnoea-and-hypertension-the-role-of-the-central-nervous-system
#20
REVIEW
Luke A Henderson, Vaughan G Macefield
PURPOSE OF REVIEW: Obstructive sleep apnoea (OSA) is associated with both nocturnal and daytime hypertensions which increase cardiovascular morbidity and mortality. It is thought that the repeated episodes of hypoxia and hypercapnia during nocturnal airway obstructions that characterise OSA result in increased sympathetic drive that persists during wakefulness. Although the underlying mechanisms responsible for this hypertension remain to be elucidated, several neural and humoral mechanisms have been proposed and recent evidence suggesting changes in the central nervous system may play a significant role...
July 2016: Current Hypertension Reports
keyword
keyword
53662
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"