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Calcium wave

Andreas Reichenbach, Andreas Bringmann
Müller glia, the principal macroglia of the retina, express diverse subtypes of adenosine and metabotropic purinergic (P2Y) receptors. Müller cells of several species, including man, also express ionotropic P2X7 receptors. ATP is liberated from Müller cells after activation of metabotropic glutamate receptors and during osmotic and mechanical induction of membrane stretch; adenosine is released through equilibrative nucleoside transporters. Müller cell-derived purines modulate the neuronal activity and have autocrine effects, for example, induction of glial calcium waves and regulation of the cellular volume...
October 2016: Journal of Ocular Pharmacology and Therapeutics
Yi-Bang Cheng, Li-Hua Li, Qian-Hui Guo, Chang-Sheng Sheng, Qi-Fang Huang, Fei-Ka Li, Dong-Yan Zhang, Ji-Guang Wang, Yan Li
OBJECTIVE: Disorders of mineral metabolism predicted incidence of cardiovascular events in various clinical settings, possibly because that arterial stiffness mediate this pathway in part. We investigated the interrelationship between mineral metabolism factors and carotid-femoral PWV, and compared the effect sizes of blood pressure (BP) and mineral factors with carotid-femoral PWV in untreated Chinese. DESIGN AND METHOD: Consecutive untreated outpatients referred for ambulatory BP monitoring were recruited...
September 2016: Journal of Hypertension
Yohannes Shiferaw
Spontaneous calcium (Ca) waves in cardiac myocytes are known to underlie a wide range of cardiac arrhythmias. However, it is not understood which physiological parameters determine the onset of waves. In this study, we explore the relationship between Ca signaling between ion channels and the nucleation of Ca waves. In particular, we apply a master equation approach to analyze the stochastic interaction between neighboring clusters of ryanodine receptor (RyR) channels. Using this analysis, we show that signaling between clusters can be described as a barrier hopping process with exponential sensitivity to system parameters...
September 2016: Physical Review. E
Julliane Vasconcelos Joviano-Santos, Artur Santos-Miranda, Humberto Cavalcante Joca, Jader Santos Cruz, Anderson José Ferreira
Angiotensin (Ang)-(1-7) has been proved to have cardio-protective effects. However, the effects of this peptide on in vivo cardiac arrhythmias and details regarding its mechanisms of action are still undetermined. The aim of this study was to investigate the protective effects of Ang-(1-7) against cardiac arrhythmias, its in vivo effects and cellular mechanisms of action. In vivo electrocardiography analysis upon inducement of arrhythmias using a combination of halothane and epinephrine were performed. To analyze the effects of Ang-(1-7) on cells, freshly ventricular cardiomyocytes were isolated...
October 12, 2016: Experimental Physiology
Hang Yao, Priti Azad, Huiwen W Zhao, Juan Wang, Orit Poulsen, Beatriz C Freitas, Alysson R Muotri, Gabriel G Haddad
The sodium bicarbonate co-transporter (NBC) is the major bicarbonate-dependent acid-base transporter in mammalian astrocytes and has been implicated in ischemic brain injury. A malfunction of astrocytes could have great impact on the outcome of stroke due to their participation in the formation of blood-brain barrier, synaptic transmission, and electrolyte balance in the human brain. Nevertheless, the role of NBC in the ischemic astrocyte death has not been well understood. In this work, we obtained skin biopsies from healthy human subjects and had their fibroblasts grown in culture and reprogrammed into human-induced pluripotent stem cells (hiPSCs)...
October 4, 2016: Neuroscience
Jaime Eugenín León, María José Olivares, Sebastián Beltrán-Castillo
Astrocytes perform various homeostatic functions in the nervous system beyond that of a supportive or metabolic role for neurons. A growing body of evidence indicates that astrocytes are crucial for central respiratory chemoreception. This review presents a classical overview of respiratory central chemoreception and the new evidence for astrocytes as brainstem sensors in the respiratory response to hypercapnia. We review properties of astrocytes for chemosensory function and for modulation of the respiratory network...
2016: Advances in Experimental Medicine and Biology
Silke Agte, Thomas Pannicke, Elke Ulbricht, Andreas Reichenbach, Andreas Bringmann
Tractional forces or mechanical stimulation are known to induce calcium responses in retinal glial cells. The aim of the study was to determine the characteristics of calcium responses in Müller glial cells of the avascular guinea pig retina induced by focal mechanical stimulation. Freshly isolated retinal wholemounts were loaded with Mitotracker Deep Red (to fill Müller cells) and the calcium-sensitive dye Fluo-4/AM. The inner retinal surface was mechanically stimulated with a micropipette tip for 10 ms...
October 5, 2016: Glia
Felix Hohendanner, Jaime DeSantiago, Frank R Heinzel, Lothar A Blatter
We tested the hypothesis that in atrial myocytes from a rabbit left ventricular heart failure (HF) model, spatial inhomogeneity and temporal dyssynchrony of Ca removal during excitation-contraction coupling together with increased Na/Ca exchange (NCX) activity generates a substrate for proarrhythmic Ca release. Ca removal occurs via Ca reuptake into the sarcoplasmic reticulum and extrusion via NCX exclusively in the cell periphery since rabbit atrial myocytes lack transverse tubules. Ca removal kinetics were assessed by the time constant τ of decay of local peripheral subsarcolemmal (SS) and central (CT) action potential (AP) induced Ca transients (CaTs) recorded in confocal line scan mode (using Fluo-4)...
September 30, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Niels Niethard, Masashi Hasegawa, Takahide Itokazu, Carlos N Oyanedel, Jan Born, Takashi R Sato
Sleep is characterized by unique patterns of cortical activity alternating between the stages of slow-wave sleep (SWS) and rapid-eye movement (REM) sleep. How these patterns relate to the balanced activity of excitatory pyramidal cells and inhibitory interneurons in cortical circuits is unknown. We investigated cortical network activity during wakefulness, SWS, and REM sleep globally and locally using in vivo calcium imaging in mice. Wide-field imaging revealed a reduction in pyramidal cell activity during SWS compared with wakefulness and, unexpectedly, a further profound reduction in activity during REM sleep...
September 20, 2016: Current Biology: CB
Yan-Yan Jin, Meng-Zao He, Zhen-Yong Wu, Ke Huang, Ying Shen, Li Liang, Jian-Hua Mao
OBJECTIVE: To investigate the role of intrauterine malnourishment in the development and function of pancreatic islet β-cells. METHODS: Whole-cell patch clamping was used to record voltage-gated calcium channel (VGCC)-mediated currents. Insulin secretion was detected by measuring capacitance using a sequence of sine wave stimuli. VGCC currents and insulin secretion were measured in the small for gestational age (SGA) group treated with human recombinant growth hormone (hGH)...
September 29, 2016: Growth Factors
Yuan-Ling Lee, Wen-Hsi Wang, Feng-Huie Lin, Chun-Pin Lin
BACKGROUND/PURPOSE: Calcium silicate (CS)-based biomaterials, such as mineral trioxide aggregate (MTA), have become the most popular and convincing material used in restorative endodontic treatments. However, the commercially available CS-based biomaterials all contain different minor additives, which may affect their hydration behaviors and material properties. The purpose of this study was to evaluate the hydration behavior of CS-based biomaterials with/without minor additives. METHODS: A novel CS-based biomaterial with a simplified composition, without mineral oxides as minor additives, was produced...
September 20, 2016: Journal of the Formosan Medical Association, Taiwan Yi Zhi
Eleonora Grespan, Sebastian Martewicz, Elena Serena, Vincent Le Houérou, Jürgen Rühe, Nicola Elvassore
The mechanical activity of cardiomyocytes is the result of a process called excitation contraction coupling (ECC). A membrane depolarization wave induces a transient cytosolic calcium concentration increase that triggers activation calcium-sensitive contractile proteins leading to cell contraction and force generation. An experimental setup capable of acquiring simultaneously all ECC features would have an enormous impact on cardiac drug development and disease study. In this work, we develop a micro-engineered elastomeric substrate with tailor-made surface chemistry to measure simultaneously the uni-axial contraction force and the calcium transients generated by single human cardiomyocytes in vitro...
September 19, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Yi-Bang Cheng, Li-Hua Li, Qian-Hui Guo, Chang-Sheng Sheng, Qi-Fang Huang, Fei-Ka Li, Dong-Yan Zhang, Ji-Guang Wang, Yan Li
OBJECTIVE: Disorders of mineral metabolism predicted incidence of cardiovascular events in various clinical settings, possibly because that arterial stiffness mediate this pathway in part. We investigated the interrelationship between mineral metabolism factors and carotid-femoral PWV, and compared the effect sizes of blood pressure (BP) and mineral factors with carotid-femoral PWV in untreated Chinese. DESIGN AND METHOD: Consecutive untreated outpatients referred for ambulatory BP monitoring were recruited...
September 2016: Journal of Hypertension
Adonis Z Wu, Dongzhu Xu, Na Yang, Shien-Fong Lin, Peng-Sheng Chen, Steven E Cala, Zhenhui Chen
AIMS: Phospholamban (PLB) regulates the cardiac Ca(2+)-ATPase (SERCA2a) in sarcoplasmic reticulum (SR). However, the localization of PLB at subcellular sites outside the SR and possible contributions to Ca(2+) cycling remain unknown. We examined the intracellular distribution of PLB and tested whether a pool of PLB exists in the nuclear envelope (NE) that might regulate perinuclear/nuclear Ca(2+) (nCa(2+)) handling in cardiomyocytes (CMs). METHODS AND RESULTS: Using confocal immunofluorescence microscopy and immunoblot analyses of CMs and CM nuclei, we discovered that PLB was highly concentrated in NE...
September 15, 2016: Journal of Molecular and Cellular Cardiology
Ali Pourmand, Rahul Nadendla, Maryann Mazer-Amirshahi, Francis O'Connell
In the United States, urolithiasis affects approximately 1 in 11 people, and there is evidence that the prevalence is increasing. A relatively recent treatment strategy for urolithiasis involves using medical expulsive therapy (MET) to increase the likelihood of spontaneous passage of ureteral stones. The 2 leading drug classes for MET are alpha-1-andrenergic receptor blockers and calcium channel blockers. Tamsulosin, an alpha-1-adrenocepter blocking agent, is thought to induce spontaneous stone passage by relaxing ureteral smooth muscle tone...
September 8, 2016: American Journal of Emergency Medicine
Arnaud Malvache, Susanne Reichinnek, Vincent Villette, Caroline Haimerl, Rosa Cossart
The chained activation of neuronal assemblies is thought to support major cognitive processes, including memory. In the hippocampus, this is observed during population bursts often associated with sharp-wave ripples, in the form of an ordered reactivation of neurons. However, the organization and lifetime of these assemblies remain unknown. We used calcium imaging to map patterns of synchronous neuronal activation in the CA1 region of awake mice during runs on a treadmill. The patterns were composed of the recurring activation of anatomically intermingled, but functionally orthogonal, assemblies...
September 16, 2016: Science
Yuan Chen, Hong Qi, Xiang Li, Meichun Cai, Xingqiang Chen, Wen Liu, Jianwei Shuai
As local signals, calcium puffs arise from the concerted opening of a few nearby inositol 1,4,5-trisphospate receptor channels to release Ca^{2+} ions from the endoplasmic reticulum. Although Ca^{2+} puffs have been well studied, little is known about the modulation of cytosolic basal Ca^{2+} concentration ([Ca^{2+}]_{Basal}) on puff dynamics. In this paper we consider a puff model to study how the statistical properties of puffs are modulated by [Ca^{2+}]_{Basal}. The puff frequency and lifetime trivially increase with the increasing [Ca^{2+}]_{Basal}, but an unexpected result is that the puff amplitude and the maximum open-channel number of the puff show decreasing relationship with the increasing [Ca^{2+}]_{Basal}...
August 2016: Physical Review. E
Christopher J Derrick, Anna H York-Andersen, Timothy T Weil
Egg activation is a universal process that includes a series of events to allow the fertilized egg to complete meiosis and initiate embryonic development. One aspect of egg activation, conserved across all organisms examined, is a change in the intracellular concentration of calcium (Ca(2+)) often termed a 'Ca(2+) wave'. While the speed and number of oscillations of the Ca(2+) wave varies between species, the change in intracellular Ca(2+) is key in bringing about essential events for embryonic development...
2016: Journal of Visualized Experiments: JoVE
Alessandro Capitanini, Luca Rosso, Laura Giannecchini, Ophelia Meniconi, Adamasco Cupisti
A 47-year old, Caucasian man underwent extracorporeal shock wave lithotripsy (ESWL) of a 14mm calcium stone in the right renal pelvis, without urinary tract obstruction or sepsis. 24 hours after ESWL septic shock occurred and the patient was admitted to the Intensive Care Unit (ICU). Escherichia coli emerged from the blood and urine culture. The patient developed acute renal failure and it was necessary to start a continuous renal replacement therapy (CRRT). Infection was successfully treated, patient recovered renal function and an improvement of general condition occurred...
September 1, 2016: International Braz J Urol: Official Journal of the Brazilian Society of Urology
Keisuke Sakurai, Frans Vinberg, Tian Wang, Jeannie Chen, Vladimir J Kefalov
Calcium ions (Ca(2+)) modulate the phototransduction cascade of vertebrate cone photoreceptors to tune gain, inactivation, and light adaptation. In darkness, the continuous current entering the cone outer segment through cGMP-gated (CNG) channels is carried in part by Ca(2+), which is then extruded back to the extracellular space. The mechanism of Ca(2+) extrusion from mammalian cones is not understood. The dominant view has been that the cone-specific isoform of the Na(+)/Ca(2+), K(+) exchanger, NCKX2, is responsible for removing Ca(2+) from their outer segments...
2016: Scientific Reports
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