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muscle sympathetic nerve activity

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https://www.readbyqxmd.com/read/29676616/laboratory-practical-to-study-the-differential-innervation-pathways-of-urinary-tract-smooth-muscle
#1
Benjamin E Rembetski, Caroline A Cobine, Bernard T Drumm
In the mammalian lower urinary tract, there is a reciprocal relationship between the contractile state of the bladder and urethra. As the bladder fills with urine, it remains relaxed to accommodate increases in volume, while the urethra remains contracted to prevent leakage of urine from the bladder to the exterior. Disruptions to the normal contractile state of the bladder and urethra can lead to abnormal micturition patterns and urinary incontinence. While both the bladder and urethra are smooth-muscle organs, they are differentially contracted by input from cholinergic and sympathetic nerves, respectively...
June 1, 2018: Advances in Physiology Education
https://www.readbyqxmd.com/read/29672226/high-intensity-muscle-metaboreflex-activation-attenuates-cardiopulmonary-baroreflex-mediated-inhibition-of-muscle-sympathetic-nerve-activity
#2
Keisho Katayama, Jasdeep Kaur, Benjamin E Young, Thales C Barbosa, Shigehiko Ogoh, Paul J Fadel
Previous studies have shown that muscle sympathetic nerve activity (MSNA) is reduced during low- and mild-intensity dynamic leg exercise. It has been suggested that such inhibition is mediated by loading of the cardiopulmonary baroreceptors and that this effect is overridden by muscle metaboreflex activation with higher intensity exercise. However, limited data are available regarding the interaction between the cardiopulmonary baroreflex and the muscle metaboreflex. Therefore, we tested the hypothesis that cardiopulmonary baroreflex-mediated inhibition of MSNA is attenuated during high intensity muscle metaboreflex activation...
April 19, 2018: Journal of Applied Physiology
https://www.readbyqxmd.com/read/29668378/editorial-focus-on-relative-burst-amplitude-of-muscle-sympathetic-nerve-activity-is-an-indicator-of-altered-sympathetic-outflow-in-chronic-anxiety
#3
Nisha Charkoudian
No abstract text is available yet for this article.
April 18, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29668322/time-course-of-compensatory-physiological-responses-to-central-hypovolemia-in-high-and-low-tolerant-human-subjects
#4
Lusha Xiang, Carmen Hinojosa-Laborde, Kathy L Ryan, Caroline A Rickards, Victor A Convertino
Lower body negative pressure (LBNP) simulates hemorrhage in humans. Most subjects (67%) exhibited high tolerance (HT) to hypovolemia, while the remainder (33%) has low tolerance (LT). To investigate the mechanisms for decompensation to hypovolemia in HT and LT subjects, we characterized the time course of total peripheral resistance (TPR), heart rate (HR) and muscle sympathetic nerve activity (MSNA) during LBNP to tolerance determined by the onset of decompensation (presyncope, PS). We hypothesized that 1) maximum (max) TPR, HR, and MSNA would coincide, and 2) PS results from simultaneous decreases in TPR, HR and MSNA in LT and HT, but occur earlier in LT versus HT subjects...
April 18, 2018: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/29652544/acute-effects-of-device-guided-slow-breathing-on-sympathetic-nerve-activity-and-baroreflex-sensitivity-in-posttraumatic-stress-disorder
#5
Ida Fonkoue, Paul J Marvar, Seth D Norrholm, Melanie L Kankam, Yunxiao Li, Dana DaCosta, Barbara O Rothbaum, Jeanie Park
Posttraumatic stress disorder (PTSD) patients have elevated sympathetic nervous system (SNS) reactivity and impaired sympathetic and cardiovagal baroreflex sensitivity (BRS). Device-guided slow breathing (DGB) has been shown to lower blood pressure (BP) and sympathetic activity in other patient populations. We hypothesized that DGB acutely lowers BP, heart rate (HR), and improves BRS in PTSD. In 23 prehypertensive veterans with PTSD, we measured continuous BP, EKG, and muscle sympathetic nerve activity (MSNA) at rest, and during 15 minutes of device-guided slow breathing at 5 breaths/min (DGB; n=13) or identical sham device breathing at normal rates of 14 breaths/min (SHAM; n=10)...
April 13, 2018: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29649477/involvement-of-prostatic-interstitial-cells-of-cajal-in-inflammatory-cytokines-elicited-catecholamines-production-implications-for-the-pathophysiology-of-chronic-prostatitis-chronic-pelvic-pain-syndrome-cp-cpps
#6
Jiangping Wang, Bo Zhang, Yong Jiao, Zhibin Xu, Biao Qian, Qinzhang Wang
In a previous work using guinea pig prostate, we have identified a novel interstitial cells of Cajal (ICCs) which possess close contacts between sympathetic nerve bundles and smooth muscle cells. The ability of prostatic ICCs in mediating excitatory neural inputs was therefore studied using isolated murine prostate ICCs by collagenase digestion combined with FACS method. RT-PCR and Western blotting analyses revealed that prostatic ICCs under a quiescent state expressed abundantly the rate-limiting enzymes essential for catecholamine synthesis...
April 9, 2018: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/29603444/femoral-vascular-conductance-and-peroneal-muscle-sympathetic-nerve-activity-responses-to-acute-epidural-spinal-cord-stimulation-in-humans
#7
Seth W Holwerda, Marshall T Holland, Chandan G Reddy, Gary L Pierce
Clinical cases have reported increased peripheral blood flow following continuous epidural spinal cord stimulation (SCS), and that reduced muscle sympathetic nerve activity (MSNA) may be a potential mechanism. However, no studies in humans have directly examined the effects of acute SCS (< 60 min) on vascular conductance and MSNA. In study 1, we tested the hypothesis that acute SCS (< 60 min) of the thoracic spine would lead to increased common femoral vascular conductance, but not brachial vascular conductance, in 11 patients that previously underwent surgical SCS implantation for management of neuropathic pain...
March 30, 2018: Experimental Physiology
https://www.readbyqxmd.com/read/29588339/selective-prostacyclin-receptor-agonist-selexipag-in-contrast-to-prostacyclin-analogs-does-not-evoke-paradoxical-vasoconstriction-of-rat-femoral-artery
#8
Keith Morrison, Franck Haag, Roland Ernst, Marc Iglarz, Martine Clozel
Selexipag is a selective non-prostanoid prostacyclin (PGI2 ) receptor (IP receptor) agonist that is approved for the treatment of pulmonary arterial hypertension (PAH). In contrast to selexipag, PGI2 analogs used in the clinic are non-selective agonists at prostanoid receptors and can also activate contractile EP3 receptors. Leg pain is a common side effect in patients receiving treatment with PGI2 analogs and peripheral vasoconstriction can be responsible for side effects related to muscular ischemia. This study tested the hypothesis that PGI2 analogs could cause paradoxical vasoconstriction of the femoral artery via EP3 receptor activation but that only vasorelaxation would be observed in response to selexipag and its active metabolite ACT-333679...
March 27, 2018: Journal of Pharmacology and Experimental Therapeutics
https://www.readbyqxmd.com/read/29541532/muscle-sympathetic-nerve-activity-coupled-changes-in-brain-activity-during-sustained-muscle-pain
#9
Sophie Kobuch, Azharuddin Fazalbhoy, Rachael Brown, Vaughan G Macefield, Luke A Henderson
Introduction: Long-lasting experimental muscle pain elicits divergent muscle sympathetic responses, with some individuals exhibiting a persistent increase in muscle sympathetic nerve activity (MSNA), and others a decrease. These divergent responses are thought to result from sustained functional changes in specific brain regions that modulate the cardiovascular responses to pain. Aim: The aim of this study was to investigate brain regions that are functionally coupled to the generation of an MSNA burst at rest and to determine their behavior during tonic muscle pain...
March 2018: Brain and Behavior
https://www.readbyqxmd.com/read/29537916/relative-burst-amplitude-of-muscle-sympathetic-nerve-activity-is-an-indicator-of-altered-sympathetic-outflow-in-chronic-anxiety
#10
Seth W Holwerda, Rachel E Luehrs, Allene L Gremaud, Nealy A Wooldridge, Amy K Stroud, Jess G Fiedorowicz, Francois M Abboud, Gary L Pierce
Relative burst amplitude of muscle sympathetic nerve activity (MSNA) is an indicator of augmented sympathetic outflow and contributes to greater vasoconstrictor responses. Evidence suggests anxiety-induced augmentation of relative MSNA burst amplitude in patients with panic disorder, thus we hypothesized that acute stress would result in augmented relative MSNA burst amplitude and vasoconstriction in individuals with chronic anxiety. Eighteen participants with chronic anxiety (ANX, 8 men/10 women, 32{plus minus}2 years) and 18 healthy controls with low/no anxiety (CON, 8 men/10 women, 39{plus minus}3 years) were studied...
March 14, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29488839/pharmacological-assessment-of-the-contribution-of-the-arterial-baroreflex-to-sympathetic-discharge-patterns-in-healthy-humans
#11
Jacqueline K Limberg, Elizabeth P Ott, Walter W Holbein, Sarah Elizabeth Baker, Timothy B Curry, Wayne T Nicholson, Michael J Joyner, J Kevin Shoemaker
To study how changes in baroreceptor afferent activity affect patterns of sympathetic neural activation, we manipulated arterial blood pressure using intravenous nitroprusside (NTP) and phenylephrine (PE) and measured action potential (AP) patterns with wavelet-based methodology. We hypothesized: 1) Baroreflex unloading (NTP) would increase firing of low-threshold axons and recruitment of latent axons, and 2) Baroreflex loading (PE) would decrease firing of low-threshold axons. Heart rate (HR, ECG), arterial blood pressure (BP, brachial catheter), and muscle sympathetic nerve activity (MSNA, microneurography of the peroneal nerve) were measured at baseline and during steady-state systemic, intravenous NTP (0...
February 28, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29472865/intracranial-pressure-is-a-determinant-of-sympathetic-activity
#12
Eric A Schmidt, Fabien Despas, Anne Pavy-Le Traon, Zofia Czosnyka, John D Pickard, Kamal Rahmouni, Atul Pathak, Jean M Senard
Intracranial pressure (ICP) is the pressure within the cranium . ICP rise compresses brain vessels and reduces cerebral blood delivery. Massive ICP rise leads to cerebral ischemia, but it is also known to produce hypertension, bradycardia and respiratory irregularities due to a sympatho-adrenal mechanism termed Cushing response. One still unresolved question is whether the Cushing response is a non-synaptic acute brainstem ischemic mechanism or part of a larger physiological reflex for arterial blood pressure control and homeostasis regulation...
2018: Frontiers in Physiology
https://www.readbyqxmd.com/read/29465712/ambulatory-arterial-stiffness-index-as-a-predictor-of-blood-pressure-response-to-renal-denervation
#13
Yusuke Sata, Dagmara Hering, Geoffrey A Head, Antony S Walton, Karlheinz Peter, Petra Marusic, Jaqueline Duval, Rebecca Lee, Louise J Hammond, Elisabeth A Lambert, Gavin W Lambert, Murray D Esler, Markus P Schlaich
BACKGROUND: Renal denervation (RDN) can reduce blood pressure (BP) in patients with resistant hypertension, but less so in patients with isolated systolic hypertension. A possible explanation is that patients with stiffer arteries may have lesser neural contribution to their hypertension. METHOD: We hypothesized that arterial stiffness predicts the response to RDN. From ambulatory BP monitoring (ABPM), ambulatory arterial stiffness index (AASI) was calculated as 1 - the regression slope of DBP versus SBP...
February 20, 2018: Journal of Hypertension
https://www.readbyqxmd.com/read/29465328/mechano-and-thermosensitivity-of-injured-muscle-afferents-20-to-80-days-after-nerve-injury
#14
Jan Tode, Irina Kirillova-Woytke, Vanessa H Rausch, Ralf Baron, Wilfrid Jänig
Chronic injury of limb nerves leading to neuropathic pain affects deep somatic nerves. Here the functional properties of injured afferent fibers in the lateral gastrocnemius-soleus nerve were investigated 20 days and 80 days after suturing the central stump of this muscle nerve to the distal stump of the sural nerve in anesthetized rats. Neurophysiological recordings were made from afferent axons identified in either the sciatic nerve (87 A-, 63 C-fibers) or the dorsal root L4/L5 (52 A-, 26 C-fibers) by electrical stimulation of the injured nerve...
February 21, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29462837/reduced-arterial-vasodilatation-in-response-to-hypoxia-impairs-cerebral-and-peripheral-oxygen-delivery-in-hypertensive-men
#15
Igor A Fernandes, Marcos P Rocha, Monique O Campos, João D Mattos, Daniel E Mansur, Helena N M Rocha, Paulo A C Terra, Vinícius P Garcia, Natália G Rocha, Niels H Secher, Antonio C L Nóbrega
KEY POINTS: Hypoxaemia evokes a repertoire of homeostatic adjustments that maintain oxygen supply to organs and tissues including the brain and skeletal muscles. Because hypertensive patients have impaired endothelial-dependent vasodilatation and an increased sympathetic response to arterial oxygen desaturation, we investigated whether hypertension impairs isocapnic hypoxia-induced cerebral and skeletal muscle hyperaemia to an extent that limits oxygen supply. In middle-aged hypertensive men, vertebral and femoral artery blood flow do not increase in response to isocapnic hypoxia, limiting brain and peripheral hyperaemia and oxygen supply...
February 20, 2018: Journal of Physiology
https://www.readbyqxmd.com/read/29412776/50-years-of-microneurography-learning-the-language-of-the-peripheral-sympathetic-nervous-system-in-humans
#16
J Kevin Shoemaker, Mark B Badrov, Stephen A Klassen, Paul J Fadel
As a primary component of homeostasis, the sympathetic nervous system enables rapid adjustments to stress through its ability to communicate messages among organs and cause targeted and graded end organ responses. Key in this communication model is the pattern of neural signals emanating from the central to peripheral components of the sympathetic nervous system. But what is the communication strategy employed in peripheral sympathetic nerve activity (SNA)? Can we develop and interpret the system of coding in SNA that improves our understanding of the neural control of the circulation? In 1968, Hagbarth and Vallbo reported the first use of microneurographic methods to record sympathetic discharges in peripheral nerves of conscious humans, allowing quantification of SNA at rest and sympathetic responsiveness to physiological stressors in health and disease...
February 7, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29411383/vasoconstrictor-stimulus-determines-the-functional-contribution-of-myoendothelial-feedback-to-mesenteric-arterial-tone
#17
R Wei, S E Lunn, R Tam, S L Gust, B Classen, P M Kerr, F Plane
Constriction of isolated resistance arteries in response to α1 -adrenoceptor agonists is limited by reciprocal engagement of inhibitory endothelial mechanisms via myoendothelial feedback. In the current model of feedback, agonist stimulation of smooth muscle cells results in localized InsP3 -dependent Ca2+ transients that activate endothelial IKCa channels. The subsequent hyperpolarization of the endothelial membrane potential then feeds back to the smooth muscle to limit further reductions in vessel diameter...
February 7, 2018: Journal of Physiology
https://www.readbyqxmd.com/read/29405505/sympathetic-vasomotor-activity-during-dynamic-exercise-with-resistive-breathing-sex-differences-and-the-nerve-to-show-it
#18
Ken D O'Halloran
Respiratory muscle metaboreflexes exert substantial influence over cardiorespiratory and autonomic control, exemplified during heavy dynamic exercise in health, and in obstructive airways disease even at rest. This article is protected by copyright. All rights reserved.
February 5, 2018: Experimental Physiology
https://www.readbyqxmd.com/read/29395374/effects-of-weight-changes-in-the-autonomic-nervous-system-a-systematic-review-and-meta-analysis
#19
João Costa, André Moreira, Pedro Moreira, Luís Delgado, Diana Silva
BACKGROUND: Obesity has been linked to autonomic dysfunction, which is thought to be one of the main contributors for hypertension, cardiac remodelling and death. Exercise and diet-based weight loss are the mainstay therapy for obesity, but there is a paucity of data regarding the effect of weight changes in autonomic nervous system (ANS) activity. OBJECTIVE: To describe the impact of weight changes in autonomic nervous system. METHODS: A systematic literature search of four biomedical databases was performed evaluating effects of weight changes, thorough diet and/or exercise-based interventions, in the following ANS outcomes: heart rate variability, namely low frequency (LF)/high frequency (HF) ratio (LF/HF ratio), normalized units of LF (LFnu) and HF (HFnu), muscle sympathetic nerve activity (MSNA), noradrenaline spillover rate (NA-SR), standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (RMSSD), baroreflex sensitivity and pupillometry...
January 9, 2018: Clinical Nutrition: Official Journal of the European Society of Parenteral and Enteral Nutrition
https://www.readbyqxmd.com/read/29388357/airway-obstruction-produces-widespread-sympathoexcitation-role-of-hypoxia-carotid-chemoreceptors-and-nts-neurotransmission
#20
Caroline B Ferreira, Sergio L Cravo, Sean D Stocker
Obstructive sleep apnea (OSA) is the most common respiratory disturbance of sleep and is closely associated to cardiovascular diseases. In humans, apnea increases respiratory effort and elevates muscle sympathetic nerve activity (SNA), but the primary stimulus for the SNA activation has not been identified. We recently developed a model of apnea in rodents using acute airway obstruction. In this study, we employed this model to test whether the elevation in SNA was mediated by hypoxia, carotid chemoreceptors, or neurotransmission in the nucleus tractus solitarius (NTS)...
February 2018: Physiological Reports
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