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muscle sympathetic nerve activity

Katsuya Nagai, Yoshiko Misonou, Yosiyuki Fujisaki, Risa Fuyuki, Yuko Horii
We previously obtained evidence suggesting that physical exercise increases the release of L-carnosine (CAR) from muscles and that CAR affects autonomic neurotransmission and physiological phenomena in rats. It has also been reported that exercise elicits an increase in activity of the sympathetic nerve innervating the skeletal muscle. Therefore, in this study, we investigated the effect of CAR application, onto the surface of the right femoral muscle, on activity of the sympathetic nerve innervating the left femoral muscle, in urethane-anesthetized rats...
June 20, 2018: Amino Acids
Guido Grassi, Anna Pisano, Davide Bolignano, Gino Seravalle, Graziella D'Arrigo, Fosca Quarti-Trevano, Francesca Mallamaci, Carmine Zoccali, Giuseppe Mancia
Muscle sympathetic nerve activity (MSNA) has shown that sympathetic activation may occur in essential hypertension (EHT). However, the small sample size of the studies, the heterogeneity of the patients examined, and the presence of confounders represented major weaknesses not allowing to draw definite conclusions. Among the 432 studies identified providing information in EHT on MSNA, 63 were eligible (1216 patients) and meta-analyzed grouping them on the basis of clinically relevant questions: (1) Is MSNA increased in hypertension of mild/moderate-to-severe degree? (2) Does sympathetic activation occur in borderline, white-coat, and masked EHT? (3) Is MSNA related to clinic and ambulatory blood pressure and target organ damage? (4) Are heart rate and venous plasma norepinephrine valuable surrogate markers of MSNA in clinical practice? The results show that MSNA was significantly greater (1...
June 18, 2018: Hypertension
Tim W Ford, Peter A Kirkwood
There are hardly any published data on the characteristics of muscle nerve sympathetic discharges occurring in parallel with the somatic motoneurone discharges in the same nerves. Here, we take advantage of the naturally occurring respiratory activity in recordings of efferent discharges from branches of the intercostal and abdominal nerves in anesthetized cats to make this comparison. The occurrence of efferent spikes with amplitudes below that for alpha motoneurones were analyzed for cardiac modulation, using cross-correlation between the times of the R-wave of the ECG and the efferent spikes...
June 2018: Physiological Reports
Aida Luiza Ribeiro Turquetto, Marcelo Rodrigues Dos Santos, Ana Luiza Carrari Sayegh, Francis Ribeiro de Souza, Daniela Regina Agostinho, Patrícia Alves de Oliveira, Yarla Alves Dos Santos, Gabriela Liberato, Maria Angélica Binotto, Maria Concepcion Garcia Otaduy, Carlos Eduardo Negrão, Luiz Fernando Canêo, Fabio Biscegli Jatene, Marcelo Biscegli Jatene
BACKGROUND: Changes in circulatory physiology are common in Fontan patients due to suboptimal cardiac output, which may reduce the peripheral blood flow and impair the skeletal muscle. The objective of this study was to investigate the forearm blood flow (FBF), cross-sectional area (CSA) of the thigh and functional capacity in asymptomatic clinically stable patients undergoing Fontan surgery. METHODS: Thirty Fontan patients and 27 healthy subjects underwent venous occlusion plethysmography, magnetic resonance imaging of the thigh musculature and maximal cardiopulmonary exercise testing...
May 25, 2018: International Journal of Cardiology
Moisés M Picón, Iván M Chulvi, Juan-Manuel T Cortell, Juan Tortosa, Yasser Alkhadar, José Sanchís, Gilberto Laurentino
Different types of exercise might produce reductions in blood pressure (BP). One physiological mechanism that could explain the lowering adaptation effect on BP after an exercise program is an improved in baroreflex control of muscle sympathetic nerve activity. Consequently, exploring the different methods of training and their post-exercise hypotension (PEH) becomes of interest for healthcare providers. Recently, it has been suggested that blood flow restriction training (BFR) can generate PEH. The aim of this study was to determine the acute response on cardiovascular variables after low intensity resistance training with BFR in normotensive subjects...
2018: International Journal of Exercise Science
Marcelo R Dos Santos, Ana L C Sayegh, Rafael Armani, Valéria Costa-Hong, Francis R de Souza, Edgar Toschi-Dias, Luiz A Bortolotto, Mauricio Yonamine, Carlos E Negrão, Maria-Janieire N N Alves
OBJECTIVES: Misuse of anabolic androgenic steroids in athletes is a strategy used to enhance strength and skeletal muscle hypertrophy. However, its abuse leads to an imbalance in muscle sympathetic nerve activity, increased vascular resistance, and increased blood pressure. However, the mechanisms underlying these alterations are still unknown. Therefore, we tested whether anabolic androgenic steroids could impair resting baroreflex sensitivity and cardiac sympathovagal control. In addition, we evaluate pulse wave velocity to ascertain the arterial stiffness of large vessels...
May 21, 2018: Clinics
Young-Sil Yoon, Wen-Wei Tsai, Sam Van de Velde, Zhijiang Chen, Kuo-Fen Lee, Donald A Morgan, Kamal Rahmouni, Shigenobu Matsumura, Ezra Wiater, Youngsup Song, Marc Montminy
In response to cold exposure, placental mammals maintain body temperature by increasing sympathetic nerve activity in brown adipose tissue (BAT). Triggering of β-adrenergic receptors on brown adipocytes stimulates thermogenesis via induction of the cAMP/PKA pathway. Although cAMP response element-binding protein (CREB) and its coactivators-the cAMP-regulated transcriptional coactivators (CRTCs)-mediate transcriptional effects of cAMP in most tissues, other transcription factors such as ATF2 appear critical for induction of thermogenic genes by cAMP in BAT...
May 21, 2018: Proceedings of the National Academy of Sciences of the United States of America
Barbara J Morgan, Mihaela Teodorescu, David F Pegelow, Emily R Jackson, Devin L Schneider, David T Plante, James P Gapinski, Scott J Hetzel, John M Dopp
Chemoreflex sensitization produced by chronic intermittent hypoxia (CIH) in rats is attenuated by angiotensin II type 1 receptor (AT1 R) blockade. AT1 R blockade and xanthine oxidase inhibition both ameliorate CIH-induced endothelial dysfunction. We hypothesized treatment with losartan and allopurinol would reduce chemoreflex sensitivity and improve hypoxic vasodilation in patients with obstructive sleep apnoea (OSA). Eighty-six hypertensive patients with apnoea-hypopnoea index ≥25 events/hr and no other cardiovascular, pulmonary, renal, or metabolic disease were randomly assigned to receive allopurinol, losartan, or placebo for 6 weeks...
May 11, 2018: Experimental Physiology
Lauro C Vianna, Igor A Fernandes, Thales C Barbosa, André L Teixeira, Antonio Claudio Lucas da Nóbrega
The exercise pressor reflex (EPR) is comprised from group III and IV skeletal muscle afferents and is one of the principal mediators of the cardiovascular response to exercise. In animals, capsaicin-based analgesic balm (CAP) attenuates the pressor response to muscle contraction, indicating the transient receptor potential vanilloid 1 (TRPv1) receptor (localized on the group IV afferent neuron) as an important mediator of the EPR. However, whether these findings can be extrapolated to humans remain unknown...
April 26, 2018: Journal of Applied Physiology
Sophie Kobuch, Luke A Henderson, Vaughan G Macefield, R Brown
Pain elicited by intramuscular infusion of hypertonic saline solution causes muscle sympathetic nerve activity (MSNA) to increase in some subjects, yet decrease in others. Although the direction of the response is not predictable based on baseline physiological and psychological parameters, we know that it results from sustained functional changes in specific brain regions that are responsible for the behavioral and cardiovascular responses to psychological stressors, as well as those involved in attention...
April 25, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
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
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
Nisha Charkoudian
No abstract text is available yet for this article.
April 18, 2018: Journal of Neurophysiology
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
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
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
Seth W Holwerda, Marshall T Holland, Chandan G Reddy, Gary L Pierce
NEW FINDINGS: What is the central question of this research? Does acute spinal cord stimulation increase vascular conductance and decrease muscle sympathetic nerve activity in the lower limbs of humans? What is the main finding and its importance? Acute spinal cord stimulation led to a rapid rise in femoral vascular conductance, and peroneal muscle sympathetic nerve activity demonstrated a delayed reduction that was not associated with the initial increase in femoral vascular conductance...
June 2018: Experimental Physiology
Keith Morrison, Franck Haag, Roland Ernst, Marc Iglarz, Martine Clozel
Selexipag [2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}- N -(methylsulfonyl)acetamide] is a selective nonprostanoid 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 nonselective agonists at prostanoid receptors and can also activate contractile prostaglandin E receptor 3 (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...
June 2018: Journal of Pharmacology and Experimental Therapeutics
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
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
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