Isoproterenol increases the fraction of spark-dependent RyR-mediated leak in ventricular myocytes.


:Recent research suggests that the diastolic ryanodine-receptor-mediated release of Ca(2+) (J(leak)) from the sarcoplasmic reticulum of ventricular myocytes occurs in spark and nonspark forms. Further information about the role(s) of these release manifestations is scarce, however. This study addresses whether the fraction of spark-mediated J(leak) increases due to β-adrenergic stimulation. Confocal microscopy was used to simultaneously image Ca(2+) sparks and quantify J(leak) in intact rabbit myocytes, either in the absence or in the presence of 125 nM isoproterenol. It was found that isoproterenol treatment shifts the spark-frequency-J(leak) relationship toward an increased sensitivity to a [Ca(2+)] trigger. In agreement, a small but significant increase in spark width was found for cells with matched baseline [Ca(2+)] and total SR [Ca(2+)]. The reconstruction of release fluxes, when applied to the average sparks from those selected cells, yielded a wider release source in the isoproterenol event, indicating the recruitment of peripheral ryanodine receptors. Overall, the results presented here indicate that β-adrenergic stimulation increases the spark-dependent fraction of J(leak). Working together, the increased Ca(2+) sensitivity and the greater spark width found during isoproterenol treatment may increase the probability of Ca(2+) wave generation.


Biophys J


Biophysical journal


Santiago DJ,Ríos E,Shannon TR




Has Abstract


2013-03-05 00:00:00














  • Molecular dynamics simulations of the ligand-binding domain of the ionotropic glutamate receptor GluR2.

    abstract::Ionotropic glutamate receptors are essential for fast synaptic nerve transmission. Recent x-ray structures for the ligand-binding (S1S2) region of the GluR2 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-sensitive receptor have suggested how differences in protein/ligand interactions may determine wh...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Arinaminpathy Y,Sansom MS,Biggin PC

    更新日期:2002-02-01 00:00:00

  • The rotating Fourier's ring. An alternative model for cell kinetic studies.

    abstract::A simple method of simulating cell kinetics experiments, suitable for use on small generally available computers and capable of any degree of accuracy without increase of store required, is described. No assumption is necessary as to cycle-time distribution; the computer program, after being adjusted to generate perce...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Eaves G

    更新日期:1972-11-01 00:00:00

  • Microscopic mechanism for experimentally observed anomalous elasticity of DNA in two dimensions.

    abstract::By exploring a recent model in which DNA bending elasticity, described by the wormlike chain model, is coupled to basepair denaturation, we demonstrate that small denaturation bubbles lead to anomalies in the flexibility of DNA at the nanometric scale, when confined in two dimensions (2D), as reported in atomic-force ...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Destainville N,Manghi M,Palmeri J

    更新日期:2009-06-03 00:00:00

  • A molecular dynamics study of the ligand release path in yeast cytosine deaminase.

    abstract::Yeast cytosine deaminase, a zinc metalloenzyme, catalyzes the deamination of cytosine to uracil. Experimental and computational evidence indicates that the rate-limiting step is product release, instead of the chemical reaction step. In this work, we use molecular dynamics to suggest ligand exit paths. Simulation at 3...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Yao L,Yan H,Cukier RI

    更新日期:2007-04-01 00:00:00

  • Effects of redox and sulfhydryl reagents on the bioelectric properties of the giant axon of the squid.

    abstract::The effects of internally and externally applied sulfhydryl reagents on the bioelectric properties of the giant axon of the squid Loligo pealeii and Dosidicus gigas were studied. Cysteine-HCl (400 mM, pH 7.3) was used to remove axoplasm from the perfusion channel. Oxidizing agents (1 to 60 mM) tended to increase the d...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Huneeus-Cox F,Fernandez HL,Smith BH

    更新日期:1966-09-01 00:00:00

  • Electron paramagnetic resonance characterization of tyrosine radical, M+, in site-directed mutants of photosystem II(t).

    abstract::Photosystem II contains two well-characterized tyrosine radicals, D(.) and Z(.). Z is an electron carrier between the primary chlorophyll donor and the manganese catalytic site and is essential for enzymatic function. On the other hand, D forms a stable radical with no known role in oxygen evolution. D(.) and Z(.) giv...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Ma C,Barry BA

    更新日期:1996-10-01 00:00:00

  • A GTPase chimera illustrates an uncoupled nucleotide affinity and release rate, providing insight into the activation mechanism.

    abstract::The release of GDP from GTPases signals the initiation of a GTPase cycle, where the association of GTP triggers conformational changes promoting binding of downstream effector molecules. Studies have implicated the nucleotide-binding G5 loop to be involved in the GDP release mechanism. For example, biophysical studies...

    journal_title:Biophysical journal

    pub_type: 信件


    authors: Guilfoyle AP,Deshpande CN,Font Sadurni J,Ash MR,Tourle S,Schenk G,Maher MJ,Jormakka M

    更新日期:2014-12-16 00:00:00

  • Patch-Clamp Study of Hepatitis C p7 Channels Reveals Genotype-Specific Sensitivity to Inhibitors.

    abstract::Hepatitis C is a major worldwide disease and health hazard, affecting ∼3% of the world population. The p7 protein of hepatitis C virus (HCV) is an intracellular ion channel and pH regulator that is involved in the viral replication cycle. It is targeted by various classical ion channel blockers. Here, we generated p7 ...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Breitinger U,Farag NS,Ali NKM,Breitinger HA

    更新日期:2016-06-07 00:00:00

  • On translocation through a membrane channel via an internal binding site: kinetics and voltage dependence.

    abstract::Here we present a model for maltodextrin translocation through maltoporin channels. In a first step, our theoretical analysis does consider the case of a single binding site for a given substrate in a structurally unaffected channel with a possibly different entrance barrier on either side. It is shown how by means of...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Schwarz G,Danelon C,Winterhalter M

    更新日期:2003-05-01 00:00:00

  • Mechanistic Insights into the Modulation of Voltage-Gated Ion Channels by Inhalational Anesthetics.

    abstract::General anesthesia is a relatively safe medical procedure, which for nearly 170 years has allowed life saving surgical interventions in animals and people. However, the molecular mechanism of general anesthesia continues to be a matter of importance and debate. A favored hypothesis proposes that general anesthesia res...

    journal_title:Biophysical journal

    pub_type: 杂志文章,评审


    authors: Covarrubias M,Barber AF,Carnevale V,Treptow W,Eckenhoff RG

    更新日期:2015-11-17 00:00:00

  • Why pancreatic islets burst but single beta cells do not. The heterogeneity hypothesis.

    abstract::Previous mathematical modeling of beta cell electrical activity has involved single cells or, recently, clusters of identical cells. Here we model clusters of heterogeneous cells that differ in size, channel density, and other parameters. We use gap-junctional electrical coupling, with conductances determined by an ex...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Smolen P,Rinzel J,Sherman A

    更新日期:1993-06-01 00:00:00

  • Single-molecule measurement of the stiffness of the rigor myosin head.

    abstract::The force-extension curve of single myosin subfragment-1 molecules, interacting in the rigor state with an actin filament, has been investigated at low [ATP] by applying a slow triangle-wave movement to the optical traps holding a bead-actin-bead dumbbell. In combination with a measurement of the overall stiffness of ...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Lewalle A,Steffen W,Stevenson O,Ouyang Z,Sleep J

    更新日期:2008-03-15 00:00:00

  • A method for determining transmembrane helix association and orientation in detergent micelles using small angle x-ray scattering.

    abstract::Solution small angle x-ray scattering can be used to study the association of transmembrane proteins solubilized in detergent micelles. We have used the alpha-helical transmembrane domain of the human erythrocyte glycophorin A (GpA) fused to the carboxyl terminus of monomeric staphylococcal nuclease (SN/GpA) as a mode...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Bu Z,Engelman DM

    更新日期:1999-08-01 00:00:00

  • Effect of protein kinase A-induced phosphorylation on the gating mechanism of the brain Na+ channel: model fitting to whole-cell current traces.

    abstract::The activity of the voltage-gated Na+ channel is subjected to modulation through covalent modifications. It has been previously shown that brain Na+ currents are reduced following the activation of the protein kinase A (PKA) pathway, but the effect of the phosphorylation on the gating mechanism of the channel has not ...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: d'Alcantara P,Schiffmann SN,Swillens S

    更新日期:1999-07-01 00:00:00

  • The stiffness of the flagella of impaled bull sperm.

    abstract::The elastic rigidity (stiffness) of impaled motionless bull sperm flagella has been determined by a manipulatory technique which permitted direct analytical treatment of the experimental system. The effects of external ATP and ADP were measured. It was found that ATP acts as a plasticizing agent, while ADP does not. T...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Lindemann CB,Rudd WG,Rikmenspoel R

    更新日期:1973-05-01 00:00:00

  • Orientation and dynamics of synthetic transbilayer polypeptides containing GpATM dimerization motifs.

    abstract::Deuterium NMR spectroscopy was used to study how the positioning of a dimerization motif within a transbilayer polypeptide influences its orientation and dynamics in bilayers. Three polypeptide variants comprising glycophorin A transmembrane (GpATM) dimerization motifs incorporated into lysine-terminated poly-leucine-...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: McDonald MC,Booth V,Morrow MR

    更新日期:2011-02-02 00:00:00

  • TI-205 nuclear magnetic resonance determination of the thermodynamic parameters for the binding of monovalent cations to gramicidins A and C.

    abstract::Thermodynamic parameters for the binding of the monovalent cations, Li+, Na+, K+, Rb+, Cs+, NH4+, TI+, and Ag+, to gramicidin A and for the binding of TI+ to gramicidin C, incorporated into lysophosphatidylcholine, have been determined using a combination of TI-205 nuclear magnetic resonance spectroscopy and competiti...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Hinton JF,Fernandez JQ,Shungu DC,Whaley WL,Koeppe RE 2nd,Millett FS

    更新日期:1988-09-01 00:00:00

  • Excess dNTPs Trigger Oscillatory Surface Flow in the Early Drosophila Embryo.

    abstract::During the first 2 hours of Drosophila development, precisely orchestrated nuclear cleavages, cytoskeletal rearrangements, and directed membrane growth lead to the formation of an epithelial sheet around the yolk. The newly formed epithelium remains relatively quiescent during the next hour as it is patterned by mater...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Dutta S,Djabrayan NJ,Smits CM,Rowley CW,Shvartsman SY

    更新日期:2020-05-19 00:00:00

  • Structural and functional similarities between the nucleotide-binding domains of CFTR and GTP-binding proteins.

    abstract::The opening and closing of the CFTR Cl- channel are regulated by ATP hydrolysis at its two nucleotide binding domains (NBDs). However, the mechanism and functional significance of ATP hydrolysis are unknown. Sequence similarity between the NBDs of CFTR and GTP-binding proteins suggested the NBDs might have a structure...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Carson MR,Welsh MJ

    更新日期:1995-12-01 00:00:00

  • Fourier transform infrared evidence for early deprotonation of Asp(85) at alkaline pH in the photocycle of bacteriorhodopsin mutants containing E194Q.

    abstract::The role of the extracellular Glu side chains of bacteriorhodopsin in the proton transport mechanism has been studied using the single mutants E9Q, E74Q, E194Q, and E204Q; the triple mutant E9Q/E194Q/E204Q; and the quadruple mutant E9Q/E74Q/E194Q/E204Q. Steady-state difference and deconvoluted Fourier transform infrar...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Lazarova T,Sanz C,Querol E,Padrós E

    更新日期:2000-04-01 00:00:00

  • Aggregation of melted DNA by divalent metal ion-mediated cross-linking.

    abstract::In an accompanying paper we reported the use of differential scanning calorimetry and optical densitometry to characterize the melting and aggregation of 160 bp fragments of calf thymus DNA during heating in the presence of divalent metal cations. Aggregation is observed as thermal denaturation begins and becomes more...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Duguid JG,Bloomfield VA

    更新日期:1995-12-01 00:00:00

  • Base of pore loop is important for rectification, activation, permeation, and block of Kir3.1/Kir3.4.

    abstract::The Kir3.1/Kir3.4 channel is an inward rectifier, agonist-activated K(+) channel. The location of the binding site within the channel pore that coordinates polyamines (and is thus responsible for inward rectification) and the location of the gate that opens the channel in response to agonist activation is unclear. In ...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Makary SM,Claydon TW,Dibb KM,Boyett MR

    更新日期:2006-06-01 00:00:00

  • Myosin regulatory light chain phosphorylation and strain modulate adenosine diphosphate release from smooth muscle Myosin.

    abstract::The effects of myosin regulatory light chain (RLC) phosphorylation and strain on adenosine diphosphate (ADP) release from cross-bridges in phasic (rabbit bladder (Rbl)) and tonic (femoral artery (Rfa)) smooth muscle were determined by monitoring fluorescence transients of the novel ADP analog, 3'-deac-eda-ADP (deac-ed...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Khromov AS,Webb MR,Ferenczi MA,Trentham DR,Somlyo AP,Somlyo AV

    更新日期:2004-04-01 00:00:00

  • Benjamin Franklin, Philadelphia's favorite son, was a membrane biophysicist.

    abstract::Benjamin Franklin, mostly known for his participation in writing The Declaration of Independence and work on electricity, was also one of the first scientists to seek to understand the properties of oil monolayers on water surfaces. During one of his many voyages across the Atlantic Ocean, Franklin observed that oil h...

    journal_title:Biophysical journal

    pub_type: 传,历史文章,杂志文章


    authors: Wang DN,Stieglitz H,Marden J,Tamm LK

    更新日期:2013-01-22 00:00:00

  • Spectroscopic and molecular modeling studies of caffeine complexes with DNA intercalators.

    abstract::Recent studies have demonstrated that caffeine can act as an antimutagen and inhibit the cytoxic and/or cytostatic effects of some DNA intercalating agents. It has been suggested that this inhibitory effect may be due to complexation of the DNA intercalator with caffeine. In this study we employ optical absorption, fl...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Larsen RW,Jasuja R,Hetzler RK,Muraoka PT,Andrada VG,Jameson DM

    更新日期:1996-01-01 00:00:00

  • The solution structure of the four-way DNA junction at low-salt conditions: a fluorescence resonance energy transfer analysis.

    abstract::The four-way DNA (Holliday) junction is an important postulated intermediate in the process of genetic recombination. Earlier studies have suggested that the junction exists in two alternative conformations, depending upon the salt concentration present. At high salt concentrations the junction folds into a stacked X ...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Clegg RM,Murchie AI,Lilley DM

    更新日期:1994-01-01 00:00:00

  • A method for anchoring round shaped cells for atomic force microscope imaging.

    abstract::More and more researchers are interested in imaging living (Henderson, 1994) or fixed cells in their natural environment using the atomic force microscope (AFM). However, the AFM tip interacts strongly with the sample, and its z range freedom is limited to a few micrometers. This means that the cells to be imaged have...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Kasas S,Ikai A

    更新日期:1995-05-01 00:00:00

  • Specific binding of chloride ions to lipid vesicles and implications at molecular scale.

    abstract::Biological membranes composed of lipids and proteins are in contact with electrolytes like aqueous NaCl solutions. Based on molecular dynamics studies it is widely believed that Na(+) ions specifically bind to 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membranes, whereas Cl(-) ions stay in solution. Here,...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Knecht V,Klasczyk B

    更新日期:2013-02-19 00:00:00

  • Covalent immobilization of native biomolecules onto Au(111) via N-hydroxysuccinimide ester functionalized self-assembled monolayers for scanning probe microscopy.

    abstract::We have worked out a procedure for covalent binding of native biomacromolecules on flat gold surfaces for scanning probe microscopy in aqueous buffer solutions and for other nanotechnological applications, such as the direct measurement of interaction forces between immobilized macromolecules, of their elastomechanica...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Wagner P,Hegner M,Kernen P,Zaugg F,Semenza G

    更新日期:1996-05-01 00:00:00

  • The enthalpy of acyl chain packing and the apparent water-accessible apolar surface area of phospholipids.

    abstract::The energetics of phospholipid aggregation depend on the apparent water-accessible apolar surface area (ASAap), ordering effects of the chains, and headgroup interactions. We quantify the enthalpy and entropy of these interactions separately. For that purpose, the thermodynamics of micelle formation of lysophosphatidy...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Heerklotz H,Epand RM

    更新日期:2001-01-01 00:00:00