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https://www.readbyqxmd.com/read/28516252/chronic-eccentric-arm-cycling-improves-maximum-upper-body-strength-and-power
#1
Steven J Elmer, Dakota J Anderson, Travis R Wakeham, Matthew A Kilgas, John J Durocher, Stan L Lindstedt, Paul C LaStayo
INTRODUCTION: Eccentric leg cycling (cycle ergometry adapted to impose muscle lengthening contractions) offers an effective exercise for restoring lower-body muscular function, maintaining health, and improving performance in clinical and athletic populations. PURPOSE: We extended this model to the upper body and evaluated the effectiveness of a 7-week eccentric arm cycling (ECCarm) intervention to improve upper-body muscular function. We also explored whether ECCarm would alter arterial function...
May 17, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28510118/tampering-with-springs-phosphorylation-of-titin-affecting-the-mechanical-function-of-cardiomyocytes
#2
REVIEW
Nazha Hamdani, Melissa Herwig, Wolfgang A Linke
Reversible post-translational modifications of various cardiac proteins regulate the mechanical properties of the cardiomyocytes and thus modulate the contractile performance of the heart. The giant protein titin forms a continuous filament network in the sarcomeres of striated muscle cells, where it determines passive tension development and modulates active contraction. These mechanical properties of titin are altered through post-translational modifications, particularly phosphorylation. Titin contains hundreds of potential phosphorylation sites, the functional relevance of which is only beginning to emerge...
April 10, 2017: Biophysical Reviews
https://www.readbyqxmd.com/read/28508197/antinociceptive-effect-of-the-agonist-of-5-ht1a-receptors-buspirone-in-the-model-of-abdominal-pain-in-dogs
#3
O A Lyubashina, I I Busygina, S S Panteleev, A D Nozdrachev
We have demonstrated that activation of 5-HT1A receptors with buspirone promotes visceral analgesia in awake dogs. The administration of 0.035 mg/kg (i.m.) of the drug caused depression of viscero-motor (contraction of the abdominal muscles) and pressor (increase in the heart rate) responses to noxious distension of the large intestine. An increase in the dose to 0.07 and 0.14 mg/kg did not enhance the antinociceptive effect of buspirone but triggered basal tachycardia. The obtained results provide evidence of the inhibitory role of 5-HT1A receptors in modulating visceral pain sensitivity and the possibility of an exciting effect of their activation on the cardiovascular system...
March 2017: Doklady Biological Sciences: Proceedings of the Academy of Sciences of the USSR, Biological Sciences Sections
https://www.readbyqxmd.com/read/28481238/the-adenosinergic-system-as-a-therapeutic-target-in-the-vasculature-new-ligands-and-challenges
#4
REVIEW
Joana Beatriz Sousa, Carmen Diniz
Adenosine is an adenine base purine with actions as a modulator of neurotransmission, smooth muscle contraction, and immune response in several systems of the human body, including the cardiovascular system. In the vasculature, four P1-receptors or adenosine receptors-A₁, A2A, A2B and A₃-have been identified. Adenosine receptors are membrane G-protein receptors that trigger their actions through several signaling pathways and present differential affinity requirements. Adenosine is an endogenous ligand whose extracellular levels can reach concentrations high enough to activate the adenosine receptors...
May 6, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28474868/effects-of-drop-set-resistance-training-on-acute-stress-indicators-and-long-term-muscle-hypertrophy-and-strength
#5
Julius Fink, Brad J Schoenfeld, Naoki Kikuchi, Koichi Nakazato
BACKGROUND: We investigated the effects of 2 different resistance training (RT) protocols on muscle hypertrophy and strength. The first group (n = 8) performed a single drop set (DS) and the second group (n = 8) performed 3 sets of conventional RT (normal set, NS). METHODS: Eight young men in each group completed 6 weeks of RT. Muscle hypertrophy was assessed via magnetic resonance imaging (MRI) and strength via 12 RM tests before and after the 6 weeks. Acute stress markers such as muscle thickness (MT), blood lactate (BL), maximal voluntary contraction (MVC), heart rate (HR) and rating of perceived exertion (RPE) before and after one bout of RT...
April 26, 2017: Journal of Sports Medicine and Physical Fitness
https://www.readbyqxmd.com/read/28459744/electrical-stimulation-of-artificial-heart-muscle-a-look-into-the-electrophysiologic-and-genetic-implications
#6
Mohamed A Mohamed, Jose F Islas, Robert J Schwartz, Ravi K Birla
Development of tissue-engineered hearts for treatment of myocardial infarction or biologic pacemakers has been hindered by the production of mostly arrhythmic or in-synergistic constructs. Electrical stimulation (ES) of these constructs has been shown to produce tissues with greater twitch force and better adrenergic response. To further our understanding of the mechanisms underlying the effect of ES, we fabricated a bioreactor capable of delivering continuous or intermittent waveforms of various types to multiple constructs simultaneously...
May 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/28457965/calcium-dynamics-in-cardiac-excitatory-and-non-excitatory-cells-and-the-role-of-gap-junction
#7
Phonindra Nath Das, Parul Mehrotra, Aseem Mishra, Nandadulal Bairagi, Samrat Chatterjee
Calcium ions aid in the generation of action potential in myocytes and are responsible for the excitation-contraction coupling of heart. The heart muscle has specialized patches of cells, called excitatory cells (EC) such as the Sino-atrial node cells capable of auto-generation of action potential and cells which receive signals from the excitatory cells, called non-excitatory cells (NEC) such as cells of the ventricular and auricular walls. In order to understand cardiac calcium homeostasis, it is, therefore, important to study the calcium dynamics taking into account both types of cardiac cells...
April 27, 2017: Mathematical Biosciences
https://www.readbyqxmd.com/read/28448053/automated-contraction-analysis-of-human-engineered-heart-tissue-for-cardiac-drug-safety-screening
#8
Ingra Mannhardt, Umber Saleem, Anika Benzin, Thomas Schulze, Birgit Klampe, Thomas Eschenhagen, Arne Hansen
Cardiac tissue engineering describes techniques to constitute three dimensional force-generating engineered tissues. For the implementation of these procedures in basic research and preclinical drug development, it is important to develop protocols for automated generation and analysis under standardized conditions. Here, we present a technique to generate engineered heart tissue (EHT) from cardiomyocytes of different species (rat, mouse, human). The technique relies on the assembly of a fibrin-gel containing dissociated cardiomyocytes between elastic polydimethylsiloxane (PDMS) posts in a 24-well format...
April 15, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28444807/rkip-lessons-of-a-better-way-for-%C3%AE-adrenergic-receptor-activation-in-the-heart
#9
Kristina Lorenz, Marsha Rich Rosner, Theresa Brand, Joachim P Schmitt
Stimulation of β-adrenergic receptors (βAR) provides the most efficient physiological mechanism to enhance contraction and relaxation of the heart. Activation of βAR allows rapid enhancement of myocardial function in order to fuel the muscles for running and fighting in a fight-or-flight response. Likewise, βAR get activated during cardiovascular disease in an attempt to counteract the restrictions of cardiac output. However, long-term stimulation of βAR increases the likelihood of cardiac arrhythmias, adverse ventricular remodelling, decline of cardiac performance and premature death, thereby limiting the use of βAR agonists in the treatment of heart failure...
April 26, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28438764/neurogenic-hypertension-and-the-secret-of-respiration
#10
Benedito H Machado, Daniel B Zoccal, Davi J A Moraes
In spite of recent advances on the knowledgement of the neural control of cardiovascular function, the cause of sympathetic overactivity in neurogenic hypertension remains unknown. Studies from our laboratory point out that rats submitted to chronic intermittent hypoxia (CIH), an experimental model of neurogenic hypertension, present changes in the central respiratory network that impact the pattern of sympathetic discharge and the levels of arterial pressure. In addition to the fine coordination of respiratory muscle contraction and relaxation, essential for O2 and CO2 pulmonary exchanges, neurons of the respiratory network are precisely connected to the neurons controlling the sympathetic activity in the brainstem...
April 24, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28435092/-terpinen-4-ol-changes-intracellular-ca-2-handling-and-induces-pacing-disturbance-in-rat-hearts
#11
Antonio Nei Santana Gondim, Aline Lara, Artur Santos-Miranda, Danilo Roman-Campos, Sandra Lauton-Santos, José Evaldo Rodrigues Menezes-Filho, Carla Maria Lins de Vasconcelos, Eduardo Antonio Conde-Garcia, Silvia Guatimosim, Jader S Cruz
(-)-Terpinen-4-ol is a naturally occurring plant monoterpene and has been shown to have a plethora of biological activities. The objective of this study was to investigate the effects of (-)-terpinen-4-ol on the rat heart, a key player in the control and maintenance of arterial blood pressure. The effects of (-)-terpinen-4-ol on the rat heart were investigated using isolated left atrium isometric force measurements, in vivo electrocardiogram (ECG) recordings, patch clamp technique, and confocal microscopy. It was observed that (-)-terpinen-4-ol reduced contraction force in an isolated left atrium at millimolar concentrations...
April 20, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28432557/proteomic-analysis-of-mitochondrial-proteins-in-the-guinea-pig-heart-following-long-term-normobaric-hyperoxia
#12
Lucia Lichardusova, Zuzana Tatarkova, Andrea Calkovska, Daniela Mokra, Ivan Engler, Peter Racay, Jan Lehotsky, Peter Kaplan
Normobaric hyperoxia is applied for the treatment of a wide variety of diseases and clinical conditions related to ischemia or hypoxia, but it can increase the risk of tissue damage and its efficiency is controversial. In the present study, we analyzed cardiac mitochondrial proteome derived from guinea pigs after 60 h exposure to 100% molecular oxygen (NBO) or O2 enriched with oxygen cation (NBO+). Two-dimensional gel electrophoresis followed by MALDI-TOF/TOF mass spectrometry identified twenty-two different proteins (among them ten nonmitochondrial) that were overexpressed in NBO and/or NBO+ group...
April 21, 2017: Molecular and Cellular Biochemistry
https://www.readbyqxmd.com/read/28431977/transcriptome-comparison-reveals-insights-into-muscle-response-to-hypoxia-in-blunt-snout-bream-megalobrama-amblycephala
#13
Bo-Xiang Chen, Shao-Kui Yi, Wei-Feng Wang, Yan He, Yan Huang, Ze-Xia Gao, Hong Liu, Wei-Min Wang, Huan-Ling Wang
The economic and biological significance of blunt snout bream (Megalobrama amblycephala) makes this species important to explore the underlying molecular mechanism of hypoxia response. In the present study, we compared the transcriptional responses to serious hypoxia in skeletal muscle among hypoxia tolerant (MT), sensitive (MS) and control (without hypoxia treatment, MC) M. amblycephala obtained according to the time difference of losing balance after hypoxia treatment. A total of 88,200,889 clean reads were generated and assembled into 44,493 unigenes...
April 18, 2017: Gene
https://www.readbyqxmd.com/read/28428008/force-development-and-intracellular-ca-2-in-intact-cardiac-muscles-from-gravin-mutant-mice
#14
Zhitao Li, Sonal Singh, Santosh V Suryavanshi, Wengang Ding, Xiaoxu Shen, Cori S Wijaya, Wei Dong Gao, Bradley K McConnell
Gravin (AKAP12) is an A-kinase-anchoring-protein that scaffolds protein kinase A (PKA), β2-adrenergic receptor (β2-AR), protein phosphatase 2B and protein kinase C. Gravin facilitates β2-AR-dependent signal transduction through PKA to modulate cardiac excitation-contraction coupling and its removal positively affects cardiac contraction. Trabeculae from the right ventricles of gravin mutant (gravin-t/t) mice were employed for force determination. Simultaneously, corresponding intracellular Ca(2+) transient ([Ca(2+)]i) were measured...
April 17, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28427997/distinct-sequences-and-post-translational-modifications-in-cardiac-atrial-and-ventricular-myosin-light-chains-revealed-by-top-down-mass-spectrometry
#15
Zachery R Gregorich, Wenxuan Cai, Ziqing Lin, Albert J Chen, Ying Peng, Takushi Kohmoto, Ying Ge
Myosin is the principal component of the thick filaments that, through interactions with the actin thin filaments, mediates force production during muscle contraction. Myosin is a hexamer, consisting of two heavy chains, each associated with an essential (ELC) and a regulatory (RLC) light chain, which bind the lever-arm of the heavy chain and play important modulatory roles in striated muscle contraction. Nevertheless, a comprehensive assessment of the sequences of the ELC and RLC isoforms, as well as their post-translational modifications, in the heart remains lacking...
April 17, 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/28423017/auxotonic-to-isometric-contraction-transitioning-in-a-beating-heart-causes-myosin-step-size-to-down-shift
#16
Thomas P Burghardt, Xiaojing Sun, Yihua Wang, Katalin Ajtai
Myosin motors in cardiac ventriculum convert ATP free energy to the work of moving blood volume under pressure. The actin bound motor cyclically rotates its lever-arm/light-chain complex linking motor generated torque to the myosin filament backbone and translating actin against resisting force. Previous research showed that the unloaded in vitro motor is described with high precision by single molecule mechanical characteristics including unitary step-sizes of approximately 3, 5, and 8 nm and their relative step-frequencies of approximately 13, 50, and 37%...
2017: PloS One
https://www.readbyqxmd.com/read/28419739/cardiac-troponin-t-and-fast-skeletal-muscle-denervation-in-ageing
#17
Zherong Xu, Xin Feng, Juan Dong, Zhong-Min Wang, Jingyun Lee, Cristina Furdui, Daniel Clark Files, Kristen M Beavers, Stephen Kritchevsky, Carolanne Milligan, Jian-Ping Jin, Osvaldo Delbono, Tan Zhang
BACKGROUND: Ageing skeletal muscle undergoes chronic denervation, and the neuromuscular junction (NMJ), the key structure that connects motor neuron nerves with muscle cells, shows increased defects with ageing. Previous studies in various species have shown that with ageing, type II fast-twitch skeletal muscle fibres show more atrophy and NMJ deterioration than type I slow-twitch fibres. However, how this process is regulated is largely unknown. A better understanding of the mechanisms regulating skeletal muscle fibre-type specific denervation at the NMJ could be critical to identifying novel treatments for sarcopenia...
April 16, 2017: Journal of Cachexia, Sarcopenia and Muscle
https://www.readbyqxmd.com/read/28413031/matrix-metalloproteinases-in-remodeling-of-lower-extremity-veins-and-chronic-venous-disease
#18
Yunfei Chen, Wei Peng, Joseph D Raffetto, Raouf A Khalil
The veins of the lower extremity are equipped with efficient wall, contractile vascular smooth muscle (VSM), and competent valves in order to withstand the high venous hydrostatic pressure in the lower limb and allow unidirectional movement of deoxygenated blood toward the heart. The vein wall structure and function are in part regulated by matrix metalloproteinases (MMPs). MMPs are zinc-dependent endopeptidases that are secreted as inactive pro-MMPs by different cells in the venous wall including fibroblasts, VSM, and leukocytes...
2017: Progress in Molecular Biology and Translational Science
https://www.readbyqxmd.com/read/28410968/increase-in-serum-noradrenaline-concentration-by-short-dives-with-bradycardia-in-indo-pacific-bottlenose-dolphin-tursiops-aduncus
#19
Miwa Suzuki, Mika Tomoshige, Miki Ito, Sotaro Koga, Makio Yanagisawa, Takashi Bungo, Yuya Makiguchi
In cetaceans, diving behavior immediately induces a change in blood circulation to favor flow to the brain and heart; this is achieved by intense vasoconstriction of the blood vessels that serve other organs. This blood circulation response is allied to a decrease in heart rate in order to optimize oxygen usage during diving. Vasoconstrictors are present in all mammals and stimulate the contraction of the smooth muscle in the walls of blood vessels. The most important of these vasoconstrictors are the hormones adrenaline (A), noradrenaline (NA), and angiotensin II (ANG II)...
April 11, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28381456/muscle-mechanoreflex-activation-via-passive-calf-stretch-causes-renal-vasoconstriction-in-healthy-humans
#20
Rachel C Drew, Cheryl A Blaha, Michael D Herr, Ruda Cui, Lawrence I Sinoway
Reflex renal vasoconstriction occurs during exercise, and renal vasoconstriction in response to upper-limb muscle mechanoreflex activation has been documented. However, the renal vasoconstrictor response to muscle mechanoreflex activation originating from lower limbs, with and without local metabolite accumulation, has not been assessed. Eleven healthy young subjects (26 ± 1y; 5 men) underwent two trials involving 3-min passive calf muscle stretch (mechanoreflex) during 7.5-min lower-limb circulatory occlusion (CO)...
April 5, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
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