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https://www.readbyqxmd.com/read/28091727/intrinsic-cardiac-ganglia-and-acetylcholine-are-important-in-the-mechanism-of-ischaemic-preconditioning
#1
J M J Pickard, N Burke, S M Davidson, D M Yellon
This study aimed to investigate the role of the intrinsic cardiac nervous system in the mechanism of classical myocardial ischaemic preconditioning (IPC). Isolated perfused rat hearts were subjected to 35-min regional ischaemia and 60-min reperfusion. IPC was induced as three cycles of 5-min global ischaemia-reperfusion, and provided significant reduction in infarct size (IS/AAR = 14 ± 2% vs control IS/AAR = 48 ± 3%, p < 0.05). Treatment with the ganglionic antagonist, hexamethonium (50 μM), blocked IPC protection (IS/AAR = 37 ± 7%, p < 0...
March 2017: Basic Research in Cardiology
https://www.readbyqxmd.com/read/28087819/electrophysiologic-effects-of-the-ik1-inhibitor-pa-6-are-modulated-by-extracellular-potassium-in-isolated-guinea-pig-hearts
#2
Gregory S Hoeker, Mark A Skarsfeldt, Thomas Jespersen, Steven Poelzing
The pentamidine analog PA-6 was developed as a specific inward rectifier potassium current (IK1) antagonist, because established inhibitors either lack specificity or have side effects that prohibit their use in vivo. We previously demonstrated that BaCl2, an established IK1 inhibitor, could prolong action potential duration (APD) and increase cardiac conduction velocity (CV). However, few studies have addressed whether targeted IK1 inhibition similarly affects ventricular electrophysiology. The aim of this study was to determine the effects of PA-6 on cardiac repolarization and conduction in Langendorff-perfused guinea pig hearts...
January 2017: Physiological Reports
https://www.readbyqxmd.com/read/28087358/vascular-calcification-abrogates-the-nicorandil-mediated-cardio-protection-in-ischemia-reperfusion-injury-of-rat-heart
#3
Sriram Ravindran, Jeyashri Murali, Sunil Kumar Amirthalingam, Senthilkumar Gopalakrishnan, Gino A Kurian
The present study was aimed to determine the efficacy of nicorandil in treating cardiac reperfusion injury with an underlying co-morbidity of vascular calcification (VC). Adenine diet was used to induce VC in Wistar rat and the heart was isolated to induce global ischemia reperfusion (IR) by Langendorff method, with and without the nicorandil (7.5mg/kg) pre-treatment and compared with those fed on normal diet. The adenine-treated rats displayed abnormal ECG changes and altered mitochondrial integrity compared to a normal rat heart...
January 10, 2017: Vascular Pharmacology
https://www.readbyqxmd.com/read/28081514/role-of-mirna-1-in-regulating-connexin-43-in-ischemia-reperfusion-heart-injury-a-rat-model
#4
Bo Bian, Xue-Fang Yu, Guo-Qin Wang, Tian-Ming Teng
MiRNA-1 may participate in regulating ischemia-reperfusion injury (IRI) by affecting the expression and distribution of connexin 43 (Cx43). The aim of this study is to investigate miR-1 expression and its potential role in regulating Cx43 during ischemic postconditioning (IPOST) in a rat model. Fifty-five Wistar male rats were randomly divided into five groups: N, IR, IPOST, agomir-1, and antagomir-1 group. The hearts were perfused with the Langendorff system. The reperfusion arrhythmia (RA) and myocardial infarct size were observed and recorded...
January 3, 2017: Cardiovascular Pathology: the Official Journal of the Society for Cardiovascular Pathology
https://www.readbyqxmd.com/read/28079401/hemo2life-as-a-protective-additive-to-celsior-solution-for-static-storage-of-donor-hearts-prior-to-transplantation
#5
Elaine S Teh, Franck Zal, Valérie Polard, Philippe Menasché, David J Chambers
BACKGROUND: Prior to heart transplantation, static storage of donor hearts is currently limited to 4-5 h, despite profound hypothermia (4-8 °C). Because heart transplantation is an emergency procedure, improved protection to extend safe storage duration would be advantageous. We investigated whether the naturally respiratory pigment HEMO2life(®), which is effective at hypothermia for the passive release of oxygen via oxygen gradient, could improve long-term preservation. METHODS: Isolated Langendorff-perfused rat hearts (n = 12/group) were equilibrated (20 min) and function (left ventricular developed pressure: LVDP) measured by intraventricular balloon before arrest with cold (7...
January 12, 2017: Artificial Cells, Nanomedicine, and Biotechnology
https://www.readbyqxmd.com/read/28071786/functional-and-cardioprotective-effects-of-simultaneous-and-individual-activation-of-protein-kinase-a-and-epac
#6
Igor Khaliulin, Mark Bond, Andrew F James, Zara Dyar, Raheleh Amini, Jason L Johnson, M-Saadeh Suleiman
BACKGROUND AND PURPOSE: Myocardial cAMP elevation confers cardioprotection against ischaemia/reperfusion (I/R) injury. cAMP activates two independent signalling pathways, PKA and Epac. This study investigated the cardiac effects of activating PKA and/or Epac and their involvement in cardioprotection against I/R. EXPERIMENTAL APPROACH: Hearts extracted from male rats were used either for determination of PKA and PKC activation or perfused in the Langendorff mode for either cardiomyocytes isolation or used to monitor functional activity at basal levels and after 30 min global ischaemia and 2 h reperfusion...
January 10, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28063261/isolated-heart-models-for-studying-cardiac-electrophysiology-a-historical-perspective-and-recent-advances
#7
Jie Ming Yeo, Vivian Tse, Judy Kung, Hiu Yu Lin, Yee Ting Lee, Joseph Kwan, Bryan P Yan, Gary Tse
Experimental models used in cardiovascular research range from cellular to whole heart preparations. Isolated whole hearts show higher levels of structural and functional integration than lower level models such as tissues or cellular fragments. Cardiovascular diseases are multi-factorial problems that are dependent on highly organized structures rather than on molecular or cellular components alone. This article first provides a general introduction on the animal models of cardiovascular diseases. It is followed by a detailed overview and a historical perspective of the different isolated heart systems with a particular focus on the Langendorff perfusion method for the study of cardiac arrhythmias...
January 7, 2017: Journal of Basic and Clinical Physiology and Pharmacology
https://www.readbyqxmd.com/read/28060289/high-resolution-optical-mapping-of-the-mouse-sino-atrial-node
#8
Di Lang, Alexey V Glukhov
Sino-atrial node (SAN) dysfunctions and associated complications constitute important causes of morbidity in patients with cardiac diseases. The development of novel pharmacological therapies to cure these patients relies on the thorough understanding of both normal physiology and pathophysiology of the SAN. Among the studies of cardiac pacemaking, the mouse SAN is widely used due to its feasibility for modifications in the expression of different genes that encode SAN ion channels or calcium handling proteins...
December 2, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28057852/endothelin-1-and-et-receptors-impair-left-ventricular-function-by-mediated-coronary-arteries-dysfunction-in-chronic-intermittent-hypoxia-rats
#9
Jin-Wei Wang, Ai-Ying Li, Qiu-Hong Guo, Ya-Jing Guo, James W Weiss, En-Sheng Ji
Obstructive sleep apnea (OSA) results in cardiac dysfunction and vascular endothelium injury. Chronic intermittent hypoxia (CIH), the main characteristic of OSAS, is considered to be mainly responsible for cardiovascular system impairment. This study is aimed to evaluate the role of endothelin-1(ET-1) system in coronary injury and cardiac dysfunction in CIH rats. In our study, Sprague-Dawley rats were exposed to CIH (FiO2 9% for 1.5 min, repeated every 3 min for 8 h/d, 7 days/week for 3 weeks). After 3 weeks, the left ventricular developed pressure (LVDP) and coronary resistance (CR) were measured with the langendorff mode in isolated hearts...
January 2017: Physiological Reports
https://www.readbyqxmd.com/read/28040057/the-effects-of-mebudipine-on-myocardial-arrhythmia-induced-by-ischemia-reperfusion-injury-in-isolated-rat-heart
#10
R Ghiasi, M Mohammadi, M Majidinia, B Yousefi, A Ghiasi, R Badalzadeh
Reperfusion of the heart after an ischemic insult may lead to potentially lethal arrhythmias and cardimyocyte cell death via apoptosis and necrosis. In addition, previous studies showed that calcium channel blockers may have a protective role in the myocardium against arrhythmia and irreversible tissue injury. Therefore, this study was aimed to investigate the effects of mebudipine on myocardial arrhythmias and tissue injury induced by ischemia/reperfusion injury in isolated rat hearts. Male Wistar rats (250‑300g) were randomly divided to Sham group (without ischemia), control group (ischemia without drug), drug group (ischemia with mebudipine 0...
November 30, 2016: Cellular and Molecular Biology
https://www.readbyqxmd.com/read/28035008/regulator-of-g-protein-signaling-6-protects-the-heart-from-ischemic-injury
#11
Boyd R Rorabaugh, Bandana Chakravarti, Nathaniel W Mabe, Sarah L Seeley, Albert D Bui, Jianqi Yang, Stephanie W Watts, Richard R Neubig, Rory A Fisher
Gαi-coupled receptors play important roles in protecting the heart from ischemic injury. Regulator of G protein signaling (RGS) proteins suppress Gαi signaling by accelerating the GTPase activity of Gαi subunits. However, the roles of individual RGS proteins in modulating ischemic injury are unknown. In the present study, we investigated the impact of RGS6 deletion on myocardial sensitivity to ischemic injury. Hearts from RGS6 knockout (RGS6-/-) and wildtype (RGS6+/+) mice were subjected to 30 min ischemia and 2 hr reperfusion on a Langendorff heart apparatus...
December 29, 2016: Journal of Pharmacology and Experimental Therapeutics
https://www.readbyqxmd.com/read/28017639/selective-coupling-of-the-s1p3-receptor-subtype-to-s1p-mediated-rhoa-activation-and-cardioprotection
#12
Bryan S Yung, Cameron S Brand, Sunny Y Xiang, Charles B B Gray, Christopher K Means, Hugh Rosen, Jerold Chun, Nicole H Purcell, Joan Heller Brown, Shigeki Miyamoto
Sphingosine-1-phosphate (S1P), a bioactive lysophospholipid, is generated and released at sites of tissue injury in the heart and can act on S1P1, S1P2, and S1P3 receptor subtypes to affect cardiovascular responses. We established that S1P causes little phosphoinositide hydrolysis and does not induce hypertrophy indicating that it does not cause receptor coupling to Gq. We previously demonstrated that S1P confers cardioprotection against ischemia/reperfusion by activating RhoA and its downstream effector PKD...
December 23, 2016: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/28011835/comparing-maximum-rate-and-sustainability-of-pacing-by-mechanical-vs-electrical-stimulation-in-the-langendorff-perfused-rabbit-heart
#13
T Alexander Quinn, Peter Kohl
AIMS: Mechanical stimulation (MS) represents a readily available, non-invasive means of pacing the asystolic or bradycardic heart in patients, but benefits of MS at higher heart rates are unclear. Our aim was to assess the maximum rate and sustainability of excitation by MS vs. electrical stimulation (ES) in the isolated heart under normal physiological conditions. METHODS AND RESULTS: Trains of local MS or ES at rates exceeding intrinsic sinus rhythm (overdrive pacing; lowest pacing rates 2...
December 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28011703/optogenetic-termination-of-ventricular-arrhythmias-in-the-whole-heart-towards-biological-cardiac-rhythm-management
#14
Emile C A Nyns, Annemarie Kip, Cindy I Bart, Jaap J Plomp, Katja Zeppenfeld, Martin J Schalij, Antoine A F de Vries, Daniël A Pijnappels
AIMS: Current treatments of ventricular arrhythmias rely on modulation of cardiac electrical function through drugs, ablation or electroshocks, which are all non-biological and rather unspecific, irreversible or traumatizing interventions. Optogenetics, however, is a novel, biological technique allowing electrical modulation in a specific, reversible and trauma-free manner using light-gated ion channels. The aim of our study was to investigate optogenetic termination of ventricular arrhythmias in the whole heart...
December 23, 2016: European Heart Journal
https://www.readbyqxmd.com/read/28006943/cardioprotection-induced-by-remote-ischemic-preconditioning-preserves-the-mitochondrial-respiratory-function-in-acute-diabetic-myocardium
#15
I Kancirová, M Jašová, M Muráriková, Z Sumbalová, O Uličná, T Ravingerová, I Waczulíková, A Ziegelhöffer, M Ferko
A 2×2 factorial design was used to evaluate possible preservation of mitochondrial functions in two cardioprotective experimental models, remote ischemic preconditioning and streptozotocin-induced diabetes mellitus, and their interaction during ischemia/reperfusion injury (I/R) of the heart. Male Wistar rats were randomly allocated into four groups: control (C), streptozotocin-induced diabetic (DM), preconditioned (RPC) and preconditioned streptozotocin-induced diabetic (DM+RPC). RPC was conducted by 3 cycles of 5-min hind-limb ischemia and 5-min reperfusion...
December 22, 2016: Physiological Research
https://www.readbyqxmd.com/read/27979911/atrioventricular-node-dysfunction-and-ion-channel-transcriptome-in-pulmonary-hypertension
#16
Ian P Temple, Sunil Jit R J Logantha, Mais Absi, Yu Zhang, Eleftheria Pervolaraki, Joseph Yanni, Andrew Atkinson, Maria Petkova, Gillian M Quigley, Simon Castro, Mark Drinkhill, Heiko Schneider, Oliver Monfredi, Elizabeth Cartwright, Min Zi, Tomoko T Yamanushi, Vaikom S Mahadevan, Alison M Gurney, Ed White, Henggui Zhang, George Hart, Mark R Boyett, Halina Dobrzynski
BACKGROUND: Heart block is associated with pulmonary hypertension, and the aim of the study was to test the hypothesis that the heart block is the result of a change in the ion channel transcriptome of the atrioventricular (AV) node. METHODS AND RESULTS: The most commonly used animal model of pulmonary hypertension, the monocrotaline-injected rat, was used. The functional consequences of monocrotaline injection were determined by echocardiography, ECG recording, and electrophysiological experiments on the Langendorff-perfused heart and isolated AV node...
December 2016: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/27979472/regulation-of-myocardial-stromal-cell-derived-factor-1%C3%AE-cxcl12-by-tumor-necrosis-factor-signaling
#17
Meijing Wang, Lina Wang, Chunyan Huang, I-Wen Wang, Mark W Turrentine
BACKGROUND: Global myocardial ischemia-reperfusion (I/R) occurs during cardiac operations. This I/R injury leads to increased production of tumor necrosis factor α (TNF) instantly and upregulated expression of stromal cell-derived factor 1 α (SDF-1). On the basis of the published data from our laboratory and other groups, locally produced TNF contributes to cardiac dysfunction mainly via binding to its receptor (tumor necrosis factor receptor 1 [TNFR1]), whereas ischemia-induced myocardial SDF-1 mediates cardioprotection...
January 2017: Journal of Surgical Research
https://www.readbyqxmd.com/read/27978950/gene-therapy-with-angiotensin-1-9-preserves-left-ventricular-systolic-function-after-myocardial-infarction
#18
Caroline Fattah, Katrin Nather, Charlotte S McCarroll, Maria P Hortigon-Vinagre, Victor Zamora, Monica Flores-Munoz, Lisa McArthur, Lorena Zentilin, Mauro Giacca, Rhian M Touyz, Godfrey L Smith, Christopher M Loughrey, Stuart A Nicklin
BACKGROUND: Angiotensin-(1-9) [Ang-(1-9)] is a novel peptide of the counter-regulatory axis of the renin-angiotensin-aldosterone system previously demonstrated to have therapeutic potential in hypertensive cardiomyopathy when administered via osmotic mini-pump. Here, we investigate whether gene transfer of Ang-(1-9) is cardioprotective in a murine model of myocardial infarction (MI). OBJECTIVES: The authors evaluated effects of Ang-(1-9) gene therapy on myocardial structural and functional remodeling post-infarction...
December 20, 2016: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/27959577/hyperosmotic-environment-blunts-effectivity-of-ischemic-preconditioning-against-ischemia-reperfusion-injury-and-improves-ischemic-tolerance-in-non-preconditioned-isolated-rat-hearts
#19
M Zálešák, P BlaŽíček, D Pancza, I Gablovský, V Štrbák, T Ravingerová
Several studies have shown that diabetes mellitus modulates heart resistance to ischemia and abrogates effectivity of cardioprotective interventions, such as ischemic preconditioning (IP). The aim of this study was to evaluate whether the effect of hyperglycemic conditions on the severity of ischemia-reperfusion (I/R) injury in preconditioned and non-preconditioned hearts (controls, C) is related to changes in osmotic activity of glucose. Experiments were performed in isolated rat hearts perfused according to Langendorff exposed to 30-min coronary occlusion/120-min reperfusion...
December 13, 2016: Physiological Research
https://www.readbyqxmd.com/read/27936050/gene-targeted-mice-with-the-human-troponin-t-r141w-mutation-develop-dilated-cardiomyopathy-with-calcium-desensitization
#20
Mohun Ramratnam, Guy Salama, Ravi K Sharma, David Wen Rui Wang, Stephen H Smith, Sanjay K Banerjee, Xueyin N Huang, Lindsey M Gifford, Michele L Pruce, Bethann E Gabris, Samir Saba, Sanjeev G Shroff, Ferhaan Ahmad
Most studies of the mechanisms leading to hereditary dilated cardiomyopathy (DCM) have been performed in reconstituted in vitro systems. Genetically engineered murine models offer the opportunity to dissect these mechanisms in vivo. We generated a gene-targeted knock-in murine model of the autosomal dominant Arg141Trp (R141W) mutation in Tnnt2, which was first described in a human family with DCM. Mice heterozygous for the mutation (Tnnt2R141W/+) recapitulated the human phenotype, developing left ventricular dilation and reduced contractility...
2016: PloS One
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