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Wangde Dai, Elissa Cheung, Rick J Alleman, Justin B Perry, Mitchell E Allen, David A Brown, Robert A Kloner
PURPOSE: Dysfunctional mitochondria are considered to be the major source of intracellular reactive oxygen species and play a central role in the pathophysiology of myocardial ischemia/reperfusion. This study sought to determine effects of mitochondria-targeted cytoprotective peptide SBT-20 on myocardial infarct size in two different models of ischemia/reperfusion. METHODS: For in vivo studies, anesthetized Sprague Dawley rats were subjected to 30 min of coronary artery occlusion followed by 3 h of reperfusion...
October 17, 2016: Cardiovascular Drugs and Therapy
Ryan M Broxterman, Phillip F Skiba, Jesse C Craig, Samuel L Wilcox, Carl J Ade, Thomas J Barstow
The sustainable duration of severe intensity exercise is well-predicted by critical power (CP) and the curvature constant (W'). The development of the W'BAL model allows for the pattern of W' expenditure and reconstitution to be characterized and this model has been applied to intermittent exercise protocols. The purpose of this investigation was to assess the influence of relaxation phase duration and exercise intensity on W' reconstitution during dynamic constant power severe intensity exercise. Six men (24...
October 2016: Physiological Reports
Julie Larsen, Peter Bushnell, John Steffensen, Morten Pedersen, Klaus Qvortrup, Richard Brill
We assessed the functional properties in atrial and ventricular myocardium (using isolated cardiac strips) of smooth dogfish (Mustelus canis), clearnose skate (Raja eglanteria), and sandbar shark (Carcharhinus plumbeus) by blocking Ca(2+) release from the sarcoplasmic reticulum (SR) with ryanodine and thapsigargin and measuring the resultant changes in contraction-relaxation parameters and the force-frequency relationship at 20 °C and 30 °C. We also examined ultrastructural differences with electron microscopy...
September 29, 2016: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Jia Li, Ruping Wang, Dale D Tang
BACKGROUND: The intermediate filament protein vimentin undergoes reversible phosphorylation and dephosphorylation at Ser-56, which plays an important role in regulating the contraction-relaxation cycles of smooth muscle. The protein phosphatases that mediate vimentin dephosphorylation in smooth muscle have not been previously investigated. METHODS: The associations of protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A) with vimentin in mouse tracheal rings was evaluated by co-immunoprecipitation...
2016: Respiratory Research
Marie C Valenza, Irene Torres-Sánchez, Irene Cabrera-Martos, Gerald Valenza-Demet, Marcelo Cano-Cappellacci
Valenza, MC, Torres-Sánchez, I, Cabrera-Martos, I, Valenza-Demet, G, and Cano-Cappellacci, M. Acute effects of contract-relax stretching vs. TENS in young subjects with anterior knee pain: A randomized controlled trial. J Strength Cond Res 30(8): 2271-2278, 2016-The aim of this study was to examine the immediate effects on pressure point tenderness, range of motion (ROM), and vertical jump (VJ) of contract-relax stretching vs. transcutaneous electrical nerve stimulation (TENS) therapy in individuals with anterior knee pain (AKP)...
August 2016: Journal of Strength and Conditioning Research
Pável Vázquez, Aldo Tirado-Cortés, Rocío Álvarez, Michel Ronjat, Araceli Amaya, Alicia Ortega
The mechanism underlying fatigue in skeletal muscle (SM) related to the redox-potential hypothesis, ranges from a direct effect of oxygen reactive species, to a number of other free radical intermediates targeting specific amino acids in the Ca(2+)-regulatory proteins of the sarcoplasmic reticulum (SR). In the present study, we investigate the selective oxidation/reduction of the protein motif Cys-(Xn=2-6)-Cys, known as a vicinal thiol group (VTG), present in the SR Ca(2+)-ATPase (SERCA) and in the Ca(2+)-channel ryanodine receptor (RyR) which are modified during muscle fatigue in SM...
October 2016: Cell Calcium
Zarife Nigâr Özdemir Kumral, Meltem Kolgazi, Savaş Üstünova, Özgür Kasımay Çakır, Özge Dağdeviren Çevik, Göksel Şener, Berrak Ç Yeğen
Although endogenous estrogen is known to offer cardiac and vascular protection, the involvement of estrogen receptors in mediating the protective effect of estrogen on hypertension-induced cardiovascular and renal injury is not fully explained. We aimed to investigate the effects of estrogen receptor (ER) agonists on oxidative injury, cardiovascular and renal functions of rats with renovascular hypertension (RVH). Female Sprague-Dawley rats were randomly divided as control and RVH groups, and RVH groups had either ovariectomy (OVX) or sham-OVX...
2016: Clinical and Experimental Hypertension: CHE
Shane M Hammer, Jesse C Craig, Ryan M Broxterman, Thomas J Barstow
No abstract text is available yet for this article.
May 2016: Medicine and Science in Sports and Exercise
Qiang Jia, Shanfeng Ma, Xiaofen Liu, Sai Li, Yuanyuan Wang, Qin Gao, Rui Yang
OBJECTIVE: To investigate the effects of hydrogen sulfide (H2S) on contraction capacity of diaphragm in type 1 diabetic rats.
 METHODS: Thirty-two male SD rats were randomly divided into a normal group (NC), a diabetic group (DM), a NaHS treatment group (DM+NaHS) and a NaHS group (NaHS) (n=8). Intraperitoneal injection of streptozotocin was utilized to establish diabetic rat model. After the modeling, the rats in the DM+NaHS and the NaHS groups were intraperitoneally injected with 28 μmol/kg NaHS solution...
May 2016: Zhong Nan da Xue Xue Bao. Yi Xue Ban, Journal of Central South University. Medical Sciences
Minttu Mattila, Juha Koskenvuo, Mirva Söderström, Kim Eerola, Mikko Savontaus
BACKGROUND: Doxorubicin is an effective anticancer drug. The major limitation to its use is the induction of dose-dependent cardiomyopathy. No specific treatment exists for doxorubicin-induced cardiomyopathy and treatments used for other forms of heart failure have only limited beneficial effects. The contraction-relaxation cycle of the heart is controlled by cytosolic calcium concentrations, which, in turn, are critically regulated by the activity of the sarcoplasmic reticulum Ca(2) (+) ATPase (SERCA2a) pump...
July 2016: Journal of Gene Medicine
Andrea Cuíñas, Verónica García-Morales, Dolores Viña, José Gil-Longo, Manuel Campos-Toimil
AIMS: We investigated the implication of PKA and Epac proteins in the endothelium-independent vasorelaxant effects of cyclic AMP (cAMP). MAIN METHODS: Cytosolic Ca(2+) concentration ([Ca(2+)]c) was measured by fura-2 imaging in rat aortic smooth muscle cells (RASMC). Contraction-relaxation experiments were performed in rat aortic rings deprived of endothelium. KEY FINDINGS: In extracellular Ca(2+)-free solution, cAMP-elevating agents induced an increase in [Ca(2+)]c in RASMC that was reproduced by PKA and Epac activation and reduced after depletion of intracellular Ca(2+) reservoirs...
June 15, 2016: Life Sciences
Jonathan Melka, Mario Rienzo, Alain Bizé, Mathieu Jozwiak, Lucien Sambin, Luc Hittinger, Jin Bo Su, Alain Berdeaux, Bijan Ghaleh
Chronic hypertension is associated with left ventricular (LV) hypertrophy and LV diastolic dysfunction with impaired isovolumic relaxation and abnormal LV filling. Increased heart rate (HR) worsens these alterations. We investigated whether the I f channel blocker ivabradine exerts beneficial effects on LV filling dynamic. In this setting, we also evaluated the relationship between LV filling and isovolumic contraction as a consequence of contraction-relaxation coupling. Therefore, hypertension was induced by a continuous infusion of angiotensin II during 28 days in 10 chronically instrumented pigs...
May 2016: Basic Research in Cardiology
Tiankai Li, Heng-Jie Cheng, Nobuyuki Ohte, Hiroshi Hasegawa, Atsushi Morimoto, David M Herrington, William C Little, Weimin Li, Che Ping Cheng
In heart failure (HF), the impaired left ventricular (LV) arterial coupling and diastolic dysfunction present at rest are exacerbated during exercise. C-type natriuretic peptide (CNP) is elevated in HF; however, its functional effects are unclear. We tested the hypotheses that CNP with vasodilating, natriuretic, and positive inotropic and lusitropic actions may prevent this abnormal exercise response after HF. We determined the effects of CNP (2 μg/kg plus 0.4 μg/kg per minute, i.v., 20 minutes) on plasma levels of cGMP before and after HF and assessed LV dynamics during exercise in 10 chronically instrumented dogs with pacing-induced HF...
June 2016: Journal of Pharmacology and Experimental Therapeutics
Motonao Tanaka, Tsuguya Sakamoto, Shigeo Sugawara, Yoshiaki Katahira, Kaoru Hasegawa, Hiroyuki Nakajima, Takafumi Kurokawa, Hiroshi Kanai, Hideyuki Hasegawa
BACKGROUND: Although the deformability of the left ventricular (LV) wall appears to be important in maintaining effective cardiac performance, this has not been debated by anyone, probably owing to the difficulties of the investigation. OBJECTIVES: This study applies a new technology to demonstrate how the LV wall deforms so as to adjust for optimum cardiac performance. SUBJECTS AND METHODS: Ten healthy volunteers were the subjects. Using echo-dynamography, an analysis at the "microscopic" (muscle fiber) level was done by measuring the myocardial axial strain rate (aSR), while the "macroscopic" (muscle layer) level contraction-relaxation/extension (C-R/E) properties of the LV wall were analyzed using high frame rate 2D echocardiography...
March 21, 2016: Journal of Cardiology
Z N O Kumral, G Sener, S Ozgur, M Koc, S Suleymanoglu, C Hurdag, B C Yegen
The importance of physical activity in the management of renovascular diseases is well-known, but lacks evidence of underlying mechanisms. The purpose of the study was to elucidate the protective/therapeutic effects of regular exercise on experimental renovascular hypertension (RVH)-induced oxidative stress and cardiac dysfunction. Wistar albino rats underwent a RVH surgery (2K1C, Goldblatt). Three weeks later half of the rats started swimming exercise for 9 weeks (n = 15), while the sedentary RVH group (n = 15) had no exercise during that period...
February 2016: Journal of Physiology and Pharmacology: An Official Journal of the Polish Physiological Society
Matthias Goßmann, Ralf Frotscher, Peter Linder, Stephan Neumann, Robin Bayer, Matthias Epple, Manfred Staat, Ayşegül Temiz Artmann, Gerhard M Artmann
BACKGROUND/AIMS: Common systems for the quantification of cellular contraction rely on animal-based models, complex experimental setups or indirect approaches. The herein presented CellDrum technology for testing mechanical tension of cellular monolayers and thin tissue constructs has the potential to scale-up mechanical testing towards medium-throughput analyses. Using hiPS-Cardiac Myocytes (hiPS-CMs) it represents a new perspective of drug testing and brings us closer to personalized drug medication...
2016: Cellular Physiology and Biochemistry
Shi Tai, Xin-Qun Hu, Dao-Quan Peng, Sheng-Hua Zhou, Xi-Long Zheng
Autophagy, which is an evolutionarily conserved mechanism and links to several cellular pathways, impacts vascular smooth muscle cells (VSMCs) survival and function. Activation of autophagy by intercellular and/or extracellular stimuli has protective effects on VSMCs against cell death, while on the contrary, overloading autophagy has been recognized as a deleterious process by excessive self-digestion. Alterations in autophagy has been documented in VSMC in response to various stimuli, resulting in modulation of VSMC functions, including proliferation, migration, matrix secretion, contraction/relaxation, and differentiation...
May 15, 2016: International Journal of Cardiology
Yoshihiko Kobayashi, Yuki Yamamoto, Soichi Kageyama, Hiroki Hirayama, Koji Kimura, Kiyoshi Okuda
Nitric oxide (NO) is a regulator of sperm motility, oocyte/embryo survival, and waves of contraction/relaxation in mammalian oviducts. As follicles control oviductal functions by two routes at least, (1) a systemic way via blood vessels before ovulation, (2) a direct way by entering of follicular fluid through fimbria at ovulation, we hypothesized that NO synthesis in the bovine oviduct is regulated by follicular steroids and prostaglandins (PGs). Quantification of mRNA expressions in the ampullary tissues showed that inducible NO synthase (NOS2) mRNA expression was highest on the day of ovulation (day 0)...
June 2016: Reproduction: the Official Journal of the Society for the Study of Fertility
Hongfei Li, Ji-Hong Chen, Zixian Yang, Min Huang, Yuanjie Yu, Shiyun Tan, Hesheng Luo, Jan D Huizinga
BACKGROUND/AIMS: Neurotensin is a gut-brain peptide with both inhibitory and excitatory actions on the colonic musculature; our objective was to understand the implications of this for motor patterns occurring in the intact colon of the rat. METHODS: The effects of neurotensin with concentrations ranging from 0.1-100 nM were studied in the intact rat colon in vitro, by investigating spatio-temporal maps created from video recordings of colonic motility before and after neurotensin...
July 30, 2016: Journal of Neurogastroenterology and Motility
Benjamin R Nelson, Catherine A Makarewich, Douglas M Anderson, Benjamin R Winders, Constantine D Troupes, Fenfen Wu, Austin L Reese, John R McAnally, Xiongwen Chen, Ege T Kavalali, Stephen C Cannon, Steven R Houser, Rhonda Bassel-Duby, Eric N Olson
Muscle contraction depends on release of Ca(2+) from the sarcoplasmic reticulum (SR) and reuptake by the Ca(2+)adenosine triphosphatase SERCA. We discovered a putative muscle-specific long noncoding RNA that encodes a peptide of 34 amino acids and that we named dwarf open reading frame (DWORF). DWORF localizes to the SR membrane, where it enhances SERCA activity by displacing the SERCA inhibitors, phospholamban, sarcolipin, and myoregulin. In mice, overexpression of DWORF in cardiomyocytes increases peak Ca(2+) transient amplitude and SR Ca(2+) load while reducing the time constant of cytosolic Ca(2+) decay during each cycle of contraction-relaxation...
January 15, 2016: Science
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