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vasodilation and exercise

Luciana G Madeira, Renata Lf Passos, Juliana F de Souza, Nilton A Rezende, Luiz O C Rodrigues
Objective: Neurofibromatosis type 1 (NF1) causes neural and cutaneous disorders and reduced exercise capacity. Exercise/heat exposure increasing internal temperature must be compensated by eccrine sweat function and warmed skin vasodilation. We suspected NF1 could adversely affect eccrine sweat function and/or vascular thermoregulatory responses (VTR). Methods: The eccrine sweat function and VTR of 25 NF1 volunteers (14 males, 11 females; 16-57 years old) were compared with 23 non-NF1 controls matched by sex, age, height and weight (CG)...
October 2016: Arquivos de Neuro-psiquiatria
Arturo Figueroa, Alexei Wong, Salvador J Jaime, Joaquin U Gonzales
PURPOSE OF REVIEW: L-Citrulline, either synthetic or in watermelon, may improve vascular function through increased L-arginine bioavailability and nitric oxide synthesis. This article analyses potential vascular benefits of L-citrulline and watermelon supplementation at rest and during exercise. RECENT FINDINGS: There is clear evidence that acute L-citrulline ingestion increases plasma L-arginine, the substrate for endothelial nitric oxide synthesis. However, the subsequent acute improvement in nitric oxide production and mediated vasodilation is inconsistent, which likely explains the inability of acute L-citrulline or watermelon to improve exercise tolerance...
October 5, 2016: Current Opinion in Clinical Nutrition and Metabolic Care
Naoto Fujii, Sheila M Dervis, Ronald J Sigal, Glen P Kenny
Both cyclooxygenase (COX) and nitric oxide synthase (NOS) contribute to sweating, whereas NOS alone contributes to cutaneous vasodilation during exercise in the heat. Here, we evaluated if type 1 diabetes mellitus (T1DM) modulates these responses. Adults with (n=11, 25±5 years) and without (n=12, 24±4 years) T1DM performed two bouts of 30-min cycling at a fixed rate of heat production of 400W in the heat (35°C); each followed by a 20- and 40-min recovery period respectively. Sweat rate and cutaneous vascular conductance (CVC) were measured at four intradermal microdialysis sites treated with either 1) lactated Ringer (vehicle control site), 2) 10mM ketorolac (non-selective COX inhibitor), 3) 10mM N(G)-nitro-L-arginine methyl ester (non-selective NOS inhibitor), or 4) a combination of both inhibitors...
October 12, 2016: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Srdjan Aleksandric, Ana Djordjevic-Dikic, Branko Beleslin, Biljana Parapid, Gordana Teofilovski-Parapid, Jelena Stepanovic, Dragan Simic, Ivana Nedeljkovic, Milan Petrovic, Milan Dobric, Miloje Tomasevic, Marko Banovic, Milan Nedeljkovic, Miodrag Ostojic
BACKGROUND: To consider hemodynamic assessment of myocardial bridging (MB) adequate, it is believed that inotropic stimulation with dobutamine should be estimated because its dynamic nature depends on the degree of extravascular coronary compression. This study evaluated comparative assessment of hemodynamic relevance of MB using coronary flow velocity reserve (CFVR) measurements by transthoracic Doppler echocardiography (TTDE) with vasodilatative and inotropic challenges. METHODS: This prospective study included forty-four patients with angiographic evidence of isolated MB of the left anterior descending coronary artery (LAD) and systolic compression of ≥50% diameter stenosis...
September 28, 2016: International Journal of Cardiology
Waseem Hindieh, Arnon Adler, Adaya Weissler-Snir, Dana Fourey, Sarah Harris, Harry Rakowski
Hypertrophic cardiomyopathy is a common genetic disorder with a prevalence of 1:500 in the general population. Amongst a varied spectrum of clinical presentations, the most feared complication of this cardiac disorder is sudden cardiac death. Although only a minority of patients with hypertrophic cardiomyopathy who suffer sudden cardiac death or resuscitated cardiac arrest do so during exercise, strenuous physical activity is regarded as an important trigger for these tragic outcomes. Furthermore, during exercise, patients with hypertrophic cardiomyopathy may develop augmentation of left ventricular outflow tract obstruction, myocardial ischemia, diastolic dysfunction and/or inappropriate vasodilation in non-exercising vascular beds...
September 20, 2016: Journal of Science and Medicine in Sport
Daniel R Machin, Heather L Clifton, Ryan S Garten, Jayson R Gifford, Russell S Richardson, D Walter Wray, Tracy M Frech, Anthony John Donato
Systemic sclerosis (SSc) is a rare, auto-immune disease characterized by debilitating fibrosis and vascular dysfunction, however, little is known about the circulatory response to exercise in this population. Therefore, we examined the peripheral hemodynamic and vasodilatory responses to handgrip exercise in 10 patients with SSc (61 ± 4 yr) and 15 age-matched healthy controls (56 ± 5 yr). Brachial artery diameter, blood flow, and mean arterial pressure (MAP), were determined at rest and during progressive static-intermittent handgrip exercise...
September 30, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Bradley Witbrodt, Abhinav Goyal, Anita A Kelkar, Sharmila Dorbala, Benjamin J W Chow, Marcelo F Di Carli, Brent A Williams, Michael E Merhige, Daniel S Berman, Guido Germano, Robert S Beanlands, James K Min, Punitha Arasaratnam, Masoud Sadreddini, Marjolein Lidwine van Velthuijsen, Leslee J Shaw
BACKGROUND: A drop in blood pressure (BP) or blunted BP response is an established high-risk marker during exercise myocardial perfusion imaging (MPI); however, data are sparse regarding the prognostic value of BP response in patients undergoing vasodilator stress rubidium-82 (Rb-82) Positron Emission Tomography (PET) MPI. METHODS AND RESULTS: From the PET Prognosis Multicenter Registry, a cohort of 3413 patients underwent vasodilator stress Rb-82 PET MPI with dipyridamole or adenosine...
September 22, 2016: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
David John Webb
Treatment-resistant hypertension (TRH) is defined as the failure to achieve an office BP target of <140/90 mmHg (<130/80 mmHg in patients with chronic kidney disease (CKD) or diabetes) in patients with hypertension (HT), despite adherence to at least 3 antihypertensive medications at optimal tolerated doses, ideally including a diuretic (Calhoun et al., Circulation 2008). TRH identifies patients with hard-to-treat HT, who might benefit from specialist investigation and treatment. Although some studies put the prevalence of TRH as >10%, these levels may be inflated by white-coat hypertension and poor adherence...
September 2016: Journal of Hypertension
Shawn B Bender, Vincent J de Beer, Darla L Tharp, Douglas K Bowles, M Harold Laughlin, Daphne Merkus, Dirk J Duncker
Accelerated development of coronary atherosclerosis is a defining characteristic of familial hypercholesterolemia (FH). However, the recent data highlight a significant cardiovascular risk prior to the development of critical coronary stenosis. We, therefore, examined the hypothesis that FH produces coronary microvascular dysfunction and impairs coronary vascular control at rest and during exercise in a swine model of FH. Coronary vascular responses to drug infusions and exercise were examined in chronically instrumented control and FH swine...
November 2016: Basic Research in Cardiology
Claudia M Meirelles, Cristiane Matsuura
BACKGROUND: L-arginine is a semi-essential amino acid involved in nitric oxide production. As nitric oxide is an important vasodilator, L-arginine supplementation would increase blood perfusion and, subsequently, muscle performance during exercises. The aim of this study was to determine the acute effect of L-arginine supplementation on strength performance and nitric oxide levels in healthy trained individuals. METHODS: In a doubleblind, placebo-controlled, cross-over study, 12 men were randomly assigned to L-arginine or placebo supplementation...
September 13, 2016: Journal of Sports Medicine and Physical Fitness
Bruno-Pierre Dubé, Piergiuseppe Agostoni, Pierantonio Laveneziana
Exertional dyspnoea is among the dominant symptoms in patients with chronic heart failure and progresses relentlessly as the disease advances, leading to reduced ability to function and engage in activities of daily living. Effective management of this disabling symptom awaits a better understanding of its underlying physiology.Cardiovascular factors are believed to play a major role in dyspnoea in heart failure patients. However, despite pharmacological interventions, such as vasodilators or inotropes that improve central haemodynamics, patients with heart failure still complain of exertional dyspnoea...
September 2016: European Respiratory Review: An Official Journal of the European Respiratory Society
Steven A Romero, Jennifer L McCord, Matthew R Ely, Dylan C Sieck, Tahisha M Buck, Meredith J Luttrell, David A MacLean, John R Halliwill
In humans, acute aerobic exercise elicits a sustained post-exercise vasodilation within previously active skeletal muscle. This response is dependent on activation of histamine H1 and H2 receptors, but the source of intramuscular histamine remains unclear. We tested the hypothesis that interstitial histamine in skeletal muscle would be increased with exercise and would be dependent on de novo formation via the inducible enzyme histidine decarboxylase and/or mast cell degranulation. Subjects performed 1 h of unilateral dynamic knee-extension exercise or sham (seated rest)...
August 25, 2016: Journal of Applied Physiology
Denise M Arrick, Chun Li, William G Mayhan
OBJECTIVE: Our goals were to determine the influence of sex on reactivity of cerebral arterioles and whether moderate exercise training (MExT) could influence sex-related differences in reactivity of cerebral arterioles. MATERIALS AND METHODS: Responses of cerebral arterioles were measured in Sedentary (Sed) and MExT adult male and female Sprague-Dawley rats to eNOS-dependent (ADP); nNOS-dependent (NMDA) and NOS-independent (nitroglycerin) agonists before and following L-NMMA...
August 26, 2016: Microcirculation: the Official Journal of the Microcirculatory Society, Inc
Christopher M Hearon, Brett S Kirby, Gary J Luckasen, Dennis G Larson, Frank A Dinenno
KEY POINTS: 'Functional sympatholysis' describes the ability of contracting skeletal muscle to attenuate sympathetic vasoconstriction, and is critical to ensure proper blood flow and oxygen delivery to metabolically active skeletal muscle. The signalling mechanism responsible for sympatholysis in healthy humans is unknown. Evidence from animal models has identified endothelium-derived hyperpolarization (EDH) as a potential mechanism capable of attenuating sympathetic vasoconstriction...
August 26, 2016: Journal of Physiology
Michael Nyberg, Jon Egelund, Camilla M Mandrup, Mads B Nielsen, Alexander S Mogensen, Bente Stallknecht, Jens Bangsbo, Ylva Hellsten
The postmenopausal phase is associated with an accelerated rate of rise in the prevalence of vascular dysfunction and hypertension; however, the mechanisms underlying these adverse vascular changes and whether exercise training can reverse the decline in vascular function remains unclear. We examined the function of the vascular prostanoid system in matched pre- and postmenopausal women before and after 12 weeks of exercise training. Twenty premenopausal and 16 early postmenopausal (3.1±0.5 [mean±SE] years after final menstrual period) women only separated by 4 (50±0 versus 54±1) years of age were included...
October 2016: Hypertension
Romeo B Batacan, Mitch J Duncan, Vincent J Dalbo, Kylie J Connolly, Andrew S Fenning
Physical activity has the potential to reduce cardiometabolic risk factors but evaluation of different intensities of physical activity and the mechanisms behind their health effects still need to be fully established. This study examined the effects of sedentary behaviour, light-intensity training, and high-intensity interval training on biometric indices, glucose and lipid metabolism, inflammatory and oxidative stress markers, and vascular and cardiac function in adult rats. Rats (12 weeks old) were randomly assigned to 1 of 4 groups: control (CTL; no exercise), sedentary (SED; no exercise and housed in small cages to reduce activity), light-intensity trained (LIT; four 30-min exercise bouts/day at 8 m/min separated by 2-h rest period, 5 days/week), and high-intensity interval trained (HIIT, four 2...
September 2016: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
Matthew Lumley, Rupert Williams, Kaleab N Asrress, Satpal Arri, Natalia Briceno, Howard Ellis, Ronak Rajani, Maria Siebes, Jan J Piek, Brian Clapp, Simon R Redwood, Michael S Marber, John B Chambers, Divaka Perera
BACKGROUND: Severe aortic stenosis (AS) can manifest as exertional angina even in the presence of unobstructed coronary arteries. OBJECTIVES: The authors describe coronary physiological changes during exercise and hyperemia in the healthy heart and in patients with severe AS. METHODS: Simultaneous intracoronary pressure and flow velocity recordings were made in unobstructed coronary arteries of 22 patients with severe AS (mean effective orifice area 0...
August 16, 2016: Journal of the American College of Cardiology
Juefei Wu, David Barton, Feng Xie, Edward O'Leary, John Steuter, Gregory Pavlides, Thomas R Porter
BACKGROUND: Real-time myocardial contrast echocardiography (RTMCE) directly measures capillary flow (CBF), which in turn is a major regulator of coronary flow and resistance during demand or hyperemic stress. Although fractional flow reserve (FFR) was developed to assess the physiological relevance of an epicardial stenosis, it assumes maximal microvascular vasodilation and minimal resistance during vasodilator stress. Therefore, we sought to determine the relationship between CBF assessed with RTMCE during stress echocardiography and FFR in intermediate coronary lesions...
August 2016: Circulation. Cardiovascular Imaging
Jean Ruf, Franck Paganelli, Laurent Bonello, Nathalie Kipson, Giovanna Mottola, Julien Fromonot, Jocelyne Condo, Alain Boussuges, Laurie Bruzzese, François Kerbaul, Yves Jammes, Vlad Gariboldi, Frédéric Franceschi, Emmanuel Fenouillet, Régis Guieu
During exercise, cardiac oxygen-consumption increases and the resulting low oxygen level in myocardium triggers coronary vasodilation. This response to hypoxia is controlled notably by the vasodilator adenosine and its A2A receptor (A2AR). According to the "spare receptor" pharmacological model, a strong A2AR-mediated response can occur in the context of a large number of receptors remaining unoccupied, activation of only a weak fraction of A2AR (evaluated using KD) resulting in maximal cAMP production (evaluated using EC50), and hence in maximal coronary vasodilation...
July 19, 2016: Molecular Medicine
John R A Shepherd, Michael J Joyner, Frank A Dinenno, Timothy B Curry, Sushant M Ranadive
In humans, intra-arterial ATP infusion in limbs mimics many features of exercise hyperemia. However, it remains unknown whether ATP can evoke the prolonged vasodilation seen during exercise. Therefore, we addressed two questions during a continuous 3-h brachial artery infusion of ATP [20 μg·100 ml forearm volume (FAV)(-1)·min(-1)]: 1) would skeletal muscle blood flow remain robust or wane over time (tachyphylaxis); and 2) would the hyperemic response to moderate-intensity exercise performed during the ATP administration be blunted compared with that during control (saline) infusion...
September 1, 2016: Journal of Applied Physiology
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