Exercise training attenuates coronary smooth muscle phenotypic modulation and nuclear Ca2+ signaling.
AuthorsWamhoff BR, Bowles DK, Dietz NJ, Hu Q, Sturek M
JournalAm J Physiol Heart Circ Physiol
PubMed ID12388302
'Physical inactivity is an independent risk factor for coronary heart disease, yet the mechanism(s) of exercise-related cardioprotection remains unknown. We tested the hypothesis that coronary smooth muscle after exercise training would have decreased mitogen-induced phenotypic modulation and enhanced regulation of nuclear Ca(2+). Yucatan swine were endurance exercise trained (EX) on ... More
Ratiometric measurement of endothelial depolarization in arterioles with a potential-sensitive dye.
AuthorsBeach JM, McGahren ED, Xia J, Duling BR
JournalAm J Physiol
PubMed ID8764277
'A fluorescence ratio technique based on the voltage-sensitive dye 1-(3-sulfonatopropyl)-8-[beta-[2-di-n-butylamino)-6-naphythyl++ +]vinyl] pyridinium betaine (di-8-ANEPPS)has been developed for recording membrane potential changes during vascular responses of arterioles. Perfusion of hamster cheek pouch arterioles with the dye labeled the endothelial cell layer. voltage responses from the endothelium of intact arterioles were determined ... More
Spatially non-uniform Ca2+ signals induced by the reduction of transverse tubules in citrate-loaded guinea-pig ventricular myocytes in culture.
AuthorsLipp P, Hüser J, Pott L, Niggli E
JournalJ Physiol
PubMed ID9003546
'1. Ratiometric confocal microscopy and the whole-cell patch clamp technique were used to simultaneously record intracellular Ca2+ transients and membrane currents from guinea-pig ventricular myocytes. Intracellular dialysis with the low-affinity Ca2+ buffer citrate enabled us to record and analyse Ca2+ transients caused by Ca2+ influx alone and by additional Ca2+ ... More
The effect of asymmetric surface potentials on the intramembrane electric field measured with voltage-sensitive dyes.
AuthorsXu C, Loew LM
JournalBiophys J
PubMed ID12668484
'Ratiometric imaging of styryl potentiometric dyes can be used to measure the potential gradient inside the membrane (intramembrane potential), which is the sum of contributions from transmembrane potential, dipole potential, and the difference in the surface potentials at both sides of the membrane. Here changes in intramembrane potential of the ... More
Dye screening and signal-to-noise ratio for retrogradely transported voltage-sensitive dyes.
'Using a novel method for retrogradely labeling specific neuronal populations, we tested different styryl dyes in attempt to find dyes whose staining would be specific, rapid, and lead to large activity dependent signals. The dyes were injected into the ventral roots of the isolated chick spinal cord from embryos at ... More
Optical recording system based on a fiber optic image conduit: assessment of microscopic activation patterns in cardiac tissue.
AuthorsRohr S, Kucera JP
JournalBiophys J
PubMed ID9675208
'Optical recording of transmembrane voltage changes with the use of potentiometric dyes has opened the possibility of determining spatial patterns of electrical activity in excitable tissues. To follow such activation patterns on the cellular/subcellular level in heart cell cultures, a recording system was developed that features both high spatial resolution ... More
Near infrared two-photon excitation cross-sections of voltage-sensitive dyes.
AuthorsFisher JA, Salzberg BM, Yodh AG
JournalJ Neurosci Methods
PubMed ID16129493
'Microscopy based on voltage-sensitive dyes has proven effective for revealing spatio-temporal patterns of neuronal activity in vivo and in vitro. Two-photon microscopy using voltage-sensitive dyes offers the possibility of wide-field visualization of membrane potential on sub-cellular length scales, hundreds of microns below the tissue surface. Very little information is available, ... More
Depolarization of cell membrane is associated with an increase in ciliary beat frequency (CBF).
AuthorsMao H, Wong LB
JournalBiochem Biophys Res Commun
PubMed ID7488025
'We hypothesize that activation of muscarinic cholinergic receptors depolarizes the cell membrane of the mammalian ciliated cells which in turn causes an increase of CBF. To test this hypothesis, a di-8-ANEPPS fluorescence photon counting and nonstationary heterodyne laser light scattering system was developed to measure cell membrane potential (psi) and ... More
Fluorescence emission spectral shift measurements of membrane potential in single cells.
AuthorsKao WY, Davis CE, Kim YI, Beach JM
JournalBiophys J
PubMed ID11463657
'Previous measurements of transmembrane potential using the electrochromic probe di-8-ANEPPS have used the excitation spectral shift response by alternating excitation between two wavelengths centered at voltage-sensitive portions of the excitation spectrum and recording at a single wavelength near the peak of the emission spectrum. Recently, the emission spectral shift associated ... More
Optical detection of membrane dipole potential: avoidance of fluidity and dye-induced effects.
AuthorsClarke RJ, Kane DJ
JournalBiochim Biophys Acta
PubMed ID9042345
'Fluorescent styrylpyridinium dyes have recently been suggested as probes of the membrane dipole potential and of the kinetics of electrogenic ion pumps. It is necessary, however, to be able to confidently attribute observed fluorescence changes to electrical effects alone and avoid interference from changes in membrane fluidity. Furthermore, the effect ... More
Propagation of action potentials in the dendrites of neurons from rat spinal cord slice cultures.
AuthorsLarkum ME, Rioult MG, Lüscher HR
JournalJ Neurophysiol
PubMed ID8822549
'1. We examined the propagation of action potentials in the dendrites of ventrally located presumed motoneurons of organotypic rat spinal cord cultures. Simultaneous patch electrode recordings were made from the dendrites and somata of individual cells. In other experiments we visualized the membrane voltage over all the proximal dendrites simultaneously ... More
Novel naphthylstyryl-pyridium potentiometric dyes offer advantages for neural network analysis.
AuthorsObaid AL, Loew LM, Wuskell JP, Salzberg BM
JournalJ Neurosci Methods
PubMed ID15003384
'The submucous plexus of the guinea pig intestine is a quasi-two-dimensional mammalian neural network that is particularly amenable to study using multiple site optical recording of transmembrane voltage (MSORTV) [Biol. Bull. 183 (1992) 344; J. Neurosci. 19 (1999) 3073]. For several years the potentiometric dye of choice for monitoring the ... More
High-resolution nonlinear optical imaging of live cells by second harmonic generation.
AuthorsCampagnola PJ, Wei MD, Lewis A, Loew LM
JournalBiophys J
PubMed ID10585956
'By adapting a laser scanning microscope with a titanium sapphire femtosecond pulsed laser and transmission optics, we are able to produce live cell images based on the nonlinear optical phenomenon of second harmonic generation (SHG). Second harmonic imaging (SHIM) is an ideal method for probing membranes of living cells because ... More
Nonuniform responses of transmembrane potential during electric field stimulation of single cardiac cells.
AuthorsCheng DK, Tung L, Sobie EA
JournalAm J Physiol
PubMed ID10409215
'The response of cellular transmembrane potentials (V(m)) to applied electric fields is a critical factor during electrical pacing, cardioversion, and defibrillation, yet the coupling relationship of the cellular response to field intensity and polarity is not well documented. Isolated guinea pig ventricular myocytes were stained with a voltage-sensitive fluorescent dye, ... More
Multiple site optical recording of transmembrane voltage (MSORTV) in patterned growth heart cell cultures: assessing electrical behavior, with microsecond resolution, on a cellular and subcellular scale.
AuthorsRohr S, Salzberg BM
JournalBiophys J
PubMed ID7811945
'We have applied multiple site optical recording of transmembrane voltage (MSORTV) to patterned growth cultures of heart cells to analyze the effect of geometry per se on impulse propagation in excitable tissue, with cellular and subcellular resolution. Extensive dye screening led to the choice of di-8-ANEPPS as the most suitable ... More
Supercharging accelerates T-tubule membrane potential changes in voltage clamped frog skeletal muscle fibers.
AuthorsKim AM, Vergara JL
JournalBiophys J
PubMed ID9746552
'In voltage-clamp studies of single frog skeletal muscle fibers stained with the potentiometric indicator 1-(3-sulfonatopropyl)-4-[beta[2-(di-n-octylamino)-6-naphthyl] vinyl]pyridinium betaine (di-8 ANEPPS), fluorescence transients were recorded in response to both supercharging and step command pulses. Several illumination paradigms were utilized to study global and localized regions of the transverse tubule system (T-system). The ... More
Characterization of the calcium release domains during excitation-contraction coupling in skeletal muscle fibres.
AuthorsDiFranco M, Novo D, Vergara JL
JournalPflugers Arch
PubMed ID11907817
'The spatiotemporal properties of the Ca2+ release process in skeletal muscle fibres were determined using a confocal spot detection system. The low-affinity, fluorescent Ca2+ indicator Oregon Green 488 BAPTA-5N (OGB-5N) was used to record localized, action potential-induced fluorescence signals from consecutive locations separated by 200 nm within a single sarcomere. ... More
Reduced synchrony of Ca2+ release with loss of T-tubules-a comparison to Ca2+ release in human failing cardiomyocytes.
'OBJECTIVES: During cardiac excitation-contraction coupling, Ca2+ release from the sarcoplasmic reticulum (SR) occurs at the junctional complex with the T-tubules, containing the L-type Ca2+ channels. A partial loss of T-tubules has been described in myocytes from failing canine and human hearts. We examined how graded reduction of T-tubule density would ... More
High-speed, random-access fluorescence microscopy: I. High-resolution optical recording with voltage-sensitive dyes and ion indicators.
AuthorsBullen A, Patel SS, Saggau P
JournalBiophys J
PubMed ID9199810
'The design and implementation of a high-speed, random-access, laser-scanning fluorescence microscope configured to record fast physiological signals from small neuronal structures with high spatiotemporal resolution is presented. The laser-scanning capability of this nonimaging microscope is provided by two orthogonal acousto-optic deflectors under computer control. Each scanning point can be randomly ... More
Fluorescent probes for living cells.
AuthorsJohnson I
JournalHistochem J
PubMed ID10188922
'The functional characteristics of fluorescent probes used for imaging and measuring dynamic processes in living cells are reviewed. Initial consideration is given to general design requirements for delivery, targeting, detectability and fluorescence readout, and current technologies for attaining them. Discussion then proceeds to the more application-specific properties of intracellular ion ... More
Sustained activity of calcium release-activated calcium channels requires translocation of mitochondria to the plasma membrane.
AuthorsQuintana A, Schwarz EC, Schwindling C, Lipp P, Kaestner L, Hoth M
JournalJ Biol Chem
PubMed ID17056596
'A rise of the intracellular Ca(2+) concentration has multiple signaling functions. Sustained Ca(2+) influx across plasma membrane through calcium release-activated calcium (CRAC) channels is required for T-cell development in the thymus, gene transcription, and proliferation and differentiation of naïve T-cells into armed effectors cells. Intracellular Ca(2+) signals are shaped by ... More
Free and bound intracellular calmodulin measurements in cardiac myocytes.
AuthorsWu X, Bers DM
JournalCell Calcium
PubMed ID16999996
'Calmodulin (CaM) is a ubiquitous Ca2+ binding protein and Ca2+-CaM activates many cellular targets and functions. While much of CaM is thought to be protein bound, quantitative data in cardiac myocytes is lacking regarding CaM location, [CaM]free and CaM redistribution during changes in [Ca2+]i. Here, we demonstrated that in adult ... More
Dipole potential and head-group spacing are determinants for the membrane partitioning of pregnanolone.
'The membrane interactions of pregnanolone, an intravenous general anesthetic steroid, were characterized using fluorescence spectroscopy and monolayer technique. di-8-ANEPPS [4-[2-[6-(dioctylamino)-2-naphthalenyl]ethenyl]-1-(3-sulfopropyl)-pyridinium], a membrane dipole potential (Psi)-sensitive probe, revealed pregnanolone to decrease Psi similarly as reported previously for other anesthetics. The decrement in Psi was approximately 16 and 10 mV in dipalmitoylphosphatidylcholine ... More
Zymogen granule exocytosis is characterized by long fusion pore openings and preservation of vesicle lipid identity.
AuthorsThorn P, Fogarty KE, Parker I
JournalProc Natl Acad Sci U S A
PubMed ID15090649
'The dynamics of the fusion pore that forms between a secretory vesicle and the plasma membrane are important in the regulation of both exocytosis and endocytosis. Here, we describe characteristics of fusion during zymogen granule exocytosis in exocrine pancreatic acinar cells. By using fluorescence recovery after photobleaching techniques, we show ... More
Synthesis, spectra, delivery and potentiometric responses of new styryl dyes with extended spectral ranges.
'Styryl dyes have been among the most widely used probes for mapping membrane potential changes in excitable cells. However, their utility has been somewhat limited because their excitation wavelengths have been restricted to the 450-550 nm range. Longer wavelength probes can minimize interference from endogenous chromophores and, because of decreased ... More
Fluorescence-imaged microdeformation of the outer hair cell lateral wall.
AuthorsOghalai JS, Patel AA, Nakagawa T, Brownell WE
JournalJ Neurosci
PubMed ID9412485
'Outer hair cell (OHC) electromotility appears to be central to mammalian hearing and originates within its lateral wall. The OHC lateral wall is a unique trilaminate structure consisting of the plasma membrane (PM), the cortical lattice (CL), and the subsurface cisternae (SSC). We selectively labeled and imaged the lateral wall ... More
Effects of the membrane dipole potential on the interaction of saquinavir with phospholipid membranes and plasma membrane receptors of Caco-2 cells.
AuthorsAsawakarn T, Cladera J, O'Shea P
JournalJ Biol Chem
PubMed ID11500495
'The combined use of the membrane surface potential fluorescent sensor fluorescein phosphatidylethanolamine (FPE) and the membrane dipole potential fluorescent sensor di-8-ANEPPS to characterize the interaction of molecules with model and cellular membranes and to asses the influence of the dipole potential on the interaction is reported. The study of the ... More
Changes of intrinsic membrane potentials induced by flip-flop of long-chain fatty acids.
AuthorsPohl EE, Peterson U, Sun J, Pohl P
JournalBiochemistry
PubMed ID10677234
'The passive transbilayer movement-flip-flop-was investigated on planar bilayer lipid membranes (BLMs), containing myristic, stearic, or linoleic long-chain fatty acids (FA). In response to a transbilayer pH gradient, a difference in the surface charges between inner and outer leaflets appeared. Because the BLM was formed from FA and neutral lipid, a ... More
Gating charge displacement in voltage-gated ion channels involves limited transmembrane movement.
AuthorsChanda B, Asamoah OK, Blunck R, Roux B, Bezanilla F
JournalNature
PubMed ID16094369
'Voltage-gated ion channels are responsible for generating electrical impulses in nerves and other excitable cells. The fourth transmembrane helix (S4) in voltage-gated channels is the primary voltage-sensing unit that mediates the response to a changing membrane electric field. The molecular mechanism of voltage sensing, particularly with respect to the magnitude ... More
Involvement of the calcium inward current in cardiac impulse propagation: induction of unidirectional conduction block by nifedipine and reversal by Bay K 8644.
AuthorsRohr S, Kucera JP
JournalBiophys J
PubMed ID9017201
'In general, the fast sodium inward current (INa) is regarded as the main inward current ensuring fast and safe excitation of the normally polarized working myocardium. However, under conditions of locally delayed excitation in the millisecond range, the slow inward current (ICa) might additionally contribute to the success of impulse ... More
Validation of formamide as a detubulation agent in isolated rat cardiac cells.
AuthorsBrette F, Komukai K, Orchard CH
JournalAm J Physiol Heart Circ Physiol
PubMed ID12234828
'Kawai M, Hussain M, and Orchard CH. Am J Heart Circ Physiol 277: H603-H609, 1999 developed a technique to detubulate rat ventricular myocytes using formamide and showed that detubulation results in a decrease in cell capacitance, Ca(2+) current density, and Ca(2+) transient amplitude. We have investigated the mechanism of this ... More
Excitation of fluorescent dyes inactivates the outer hair cell integral membrane motor protein prestin and betrays its lateral mobility.
AuthorsSantos-Sacchi J, Zhao HB
JournalPflugers Arch
PubMed ID12783229
'The outer hair cell motor protein, prestin, which resides exclusively in the cell''s lateral membrane, underlies the mammal''s exquisite sense of hearing. Here we show that photoexposure of the commonly used dyes Lucifer yellow, 6-carboxy-fluorescein, and 4-(2-[6-(dioctylamino)-2-naphthalenyl]ethenyl)-1-(3-sulfopropyl)-pyridinium (di-8-ANEPPS), that are in contact with the cell''s lateral membrane can photo-inactivate the ... More
Distinct electric potentials in soma and neurite membranes.
AuthorsBedlack RS, Wei MD, Fox SH, Gross E, Loew LM
JournalNeuron
PubMed ID7946355
'Structurally similar voltage-dependent ion channels may behave differently in different locations along the surface of a neuron. A possible reason could be that channels experience nonuniform electrical potentials along the plasmalemma. Here, we map the electrical potentials along the membrane of differentiated N1E-115 neuroblastoma cells with a potential-sensitive dye. We ... More
Ultrasensitive two-color fluorescence probes for dipole potential in phospholipid membranes.
AuthorsKlymchenko AS, Duportail G, Mély Y, Demchenko AP
JournalProc Natl Acad Sci U S A
PubMed ID12972636
'The principle of electrochromic modulation of excited-state intramolecular proton-transfer reaction was applied for the design of fluorescence probes with high two-color sensitivity to dipole potential, Psid, in phospholipid bilayers. We report on the effect of Psid variation on excitation and fluorescence spectra of two new 3-hydroxyflavone probes, which possess opposite ... More
Apoptotic cells initiate endothelial cell sprouting via electrostatic signaling.
AuthorsWeihua Z, Tsan R, Schroit AJ, Fidler IJ
JournalCancer Res
PubMed ID16357162
'Angiogenesis, the development of new blood vessels from preexisting vessels, is crucial to tissue growth, repair, and maintenance. This process begins with the formation of endothelial cell sprouts followed by the proliferation and migration of neighboring endothelial cells along the preformed extensions. The initiating event and mechanism of sprouting is ... More
Use of confocal microscopy to investigate cell structure and function.
AuthorsBkaily G, Jacques D, Pothier P
JournalMethods Enzymol
PubMed ID10506971
The use of confocal microscopy in the investigation of cell structure and function in the heart, vascular endothelium and smooth muscle cells.
AuthorsBkaily G, Pothier P, D'Orléans-Juste P, Simaan M, Jacques D, Jaalouk D, Belzile F, Hassan G, Boutin C, Haddad G, Neugebauer W
JournalMol Cell Biochem
PubMed ID9278244
In recent years, fluorescence microscopy imaging has become an important tool for studying cell structure and function. This non invasive technique permits characterization, localisation and qualitative quantification of free ions, messengers, pH, voltage and a pleiad of other molecules constituting living cells. In this paper, we present results using various ... More
Cholesterol-enriched lipid domains can be visualized by di-4-ANEPPDHQ with linear and nonlinear optics.
AuthorsJin L, Millard AC, Wuskell JP, Clark HA, Loew LM
JournalBiophys J
PubMed ID15879475
We present a membrane-staining dye, di-4-ANEPPDHQ, which differentiates liquid-ordered phases from liquid-disordered phases coexisting in model membranes under both linear and nonlinear microscopies. The dye's fluorescence emission spectrum is blue-shifted 60 nm in liquid-ordered phases compared with liquid-disordered phases, and shows strong second harmonic generation in the liquid-disordered phase compared ... More
Voltage- and tension-dependent lipid mobility in the outer hair cell plasma membrane.
AuthorsOghalai JS, Zhao HB, Kutz JW, Brownell WE
JournalScience
PubMed ID10650000
The mechanism responsible for electromotility of outer hair cells in the ear is unknown but is thought to reside within the plasma membrane. Lipid lateral diffusion in the outer hair cell plasma membrane is a sigmoidal function of transmembrane potential and bathing media osmolality. Cell depolarization or hyposmotic challenge shorten ... More
Fluorescence correlation spectroscopy in small cytosolic compartments depends critically on the diffusion model used.
AuthorsGennerich A, Schild D
JournalBiophys J
PubMed ID11106632
Fluorescence correlation spectroscopy (FCS) is a powerful technique for measuring low concentrations of fluorescent molecules and their diffusion constants. In the standard case, fluorescence fluctuations are measured in an open detection volume defined by the confocal optics. However, if FCS measurements are carried out in cellular processes that confine the ... More
Recordings from human myenteric neurons using voltage-sensitive dyes.
AuthorsVignali S, Peter N, Ceyhan G, Demir IE, Zeller F, Senseman D, Michel K, Schemann M,
JournalJ Neurosci Methods
PubMed ID20691728
Voltage-sensitive dye (VSD) imaging became a powerful tool to detect neural activity in the enteric nervous system, including its routine use in submucous neurons in freshly dissected human tissue. However, VSD imaging of human myenteric neurons remained a challenge because of limited visibility of the ganglia and dye accessibility. We ... More
Localized membrane depolarizations and localized calcium influx during electric field-guided neurite growth.
AuthorsBedlack RS, Wei M, Loew LM
JournalNeuron
PubMed ID1524823
Our study explores the mechanisms behind neurite galvanotropism. Using phase, differential interference contrast and ratiometric fluorescence microscopy, we reveal four responses of N1E-115 mouse neuroblastoma cells to 0.1-1.0 mV/microns uniform DC electric fields: cathode-directed neurite initiation and elongation, cathode-biased growth cone filopodial protrusions, transient cathode-localized calcium increases, and persistent cathode-localized ... More
Retardation of cation channel deactivation by mitochondrial dysfunction in adrenal medullary cells.
AuthorsInoue M, Fujishiro N, Imanaga I
JournalAm J Physiol Cell Physiol
PubMed ID10644508
The mechanism for cyanide (CN) activation of a nonselective cation (NS) channel coupled with a muscarinic receptor in a guinea pig chromaffin cell was studied with the perforated-patch method. Bath application of a protein kinase inhibitor resulted in a dose-dependent inhibition of muscarine-induced current (I(M)) but had no apparent effect ... More
Measuring the induced membrane voltage with Di-8-ANEPPS.
AuthorsPucihar G, Kotnik T, Miklavcic D,
JournalJ Vis Exp
PubMed ID19927116
Placement of a cell into an external electric field causes a local charge redistribution inside and outside of the cell in the vicinity of the cell membrane, resulting in a voltage across the membrane. This voltage, termed the induced membrane voltage (also induced transmembrane voltage, or induced transmembrane potential difference) ... More
Three fluorescent protein voltage sensors exhibit low plasma membrane expression in mammalian cells.
AuthorsBaker BJ, Lee H, Pieribone VA, Cohen LB, Isacoff EY, Knopfel T, Kosmidis EK
JournalJ Neurosci Methods
PubMed ID17126911
Three first-generation fluorescent protein voltage sensitive probes (FP-voltage sensors) were characterized in mammalian cells. Flare, a Kv1.4 variant of FlaSh [Siegel MS, Isacoff EY. Neuron 1997;19(October (4)):735-41], SPARC [Ataka K, Pieribone VA. Biophys J 2002;82(January (1 Pt 1)):509-16], and VSFP-1 [Sakai R, Repunte-Canonigo V, Raj CD, Knopfel T. Eur J ... More
Membrane electric properties by combined patch clamp and fluorescence ratio imaging in single neurons.
AuthorsZhang J, Davidson RM, Wei MD, Loew LM
JournalBiophys J
PubMed ID9449308
An experimental method has been established to measure the electric properties of a cell membrane by combination of patch clamp and dual-wavelength ratio imaging of a fluorescent potentiometric dye, 1-(3-sulfonatopropyl)-4-[beta[2-(di-n-octylamino)-6-naphthyl]vinyl ]pyridinium betaine (di-8-ANEPPS). Pairs of fluorescence images from the dye-stained membrane of neuroblastoma N1E-115 cells excited at two wavelengths were ... More
Inhibition of sea urchin fertilization by jaspisin, a specific inhibitor of matrix metalloendoproteinase.
AuthorsKato KH, Takemoto K, Kato E, Miyazaki K, Kobayashi H, Ikegami S
JournalDev Growth Differ
PubMed ID9572364
Jaspisin, originally isolated from a marine sponge as an inhibitor of the hatching of the sea urchin (Hemicentrotus pulcherrimus) embryo, causes inhibition of sea urchin fertilization. Electron microscopic examination revealed that the acrosome reaction was induced in jaspisin-treated sperm when they were incubated with an intact egg. The acrosome-reacted sperm ... More
Decomposition of field-induced transmembrane potential responses of single cardiac cells.
AuthorsSharma V, Lu SN, Tung L
JournalIEEE Trans Biomed Eng
PubMed ID12214875
In this study, we used a multi-site optical mapping system to record field-induced responses of single cells isolated from guinea pig hearts. The cells were stained with voltage sensitive dye di-8-ANEPPS and stimulated with two uniform field (S1-S2) pulses along their longitudinal axes. The first pulse (S1 = 5 ms, ... More
A high-resolution, confocal laser-scanning microscope and flash photolysis system for physiological studies.
AuthorsParker I, Callamaras N, Wier WG
JournalCell Calcium
PubMed ID9223680
We describe the construction of a high-resolution confocal laser-scanning microscope, and illustrate its use for studying elementary Ca2+ signalling events in cells. An avalanche photodiode module and simple optical path provide a high efficiency system for detection of fluorescence signals, allowing use of a small confocal aperture giving near diffraction-limited ... More
Membrane tether formation from outer hair cells with optical tweezers.
AuthorsLi Z, Anvari B, Takashima M, Brecht P, Torres JH, Brownell WE
JournalBiophys J
PubMed ID11867454
Optical tweezers were used to characterize the mechanical properties of the outer hair cell (OHC) plasma membrane by pulling tethers with 4.5-microm polystyrene beads. Tether formation force and tether force were measured in static and dynamic conditions. A greater force was required for tether formations from OHC lateral wall (499 ... More
Influence of molecular dipoles on human skin permeability: Use of 6-ketocholestanol to enhance the transdermal delivery of bacitracin.
AuthorsCladera J, O'Shea P, Hadgraft J, Valenta C
JournalJ Pharm Sci
PubMed ID12712421
In the present work, we report the possibility of modifying the electrostatic properties of the skin by treating human epidermis with compounds whose structures possess a large molecular dipole moment. Data are presented showing that such a modification can be used to enhance dermal drug delivery. Inclusion of such compounds ... More
A K+-selective cGMP-gated ion channel controls chemosensation of sperm.
AuthorsStrünker T, Weyand I, Bönigk W, Van Q, Loogen A, Brown JE, Kashikar N, Hagen V, Krause E, Kaupp UB
JournalNat Cell Biol
PubMed ID16964244
Eggs attract sperm by chemical factors, a process called chemotaxis. Sperm from marine invertebrates use cGMP signalling to transduce incident chemoattractants into changes in the Ca2+ concentration in the flagellum, which control the swimming behaviour during chemotaxis. The signalling pathway downstream of the synthesis of cGMP by a guanylyl cyclase ... More
Optical detection of neuromodulatory effects of conditioned taste aversion in the pond snail Lymnaea stagnalis.
AuthorsKojima S, Hosono T, Fujito Y, Ito E
JournalJ Neurobiol
PubMed ID11598919
Multiple site optical recording was used to analyze the neural activity changes caused by conditioned taste aversion (CTA) training in the pond snail Lymnaea stagnalis. In response to electrical stimulation of the median lip nerve, which transmits chemosensory signals of appetitive taste to the central nervous system, we optically detected ... More
Confocal microscopic detection of potential-sensitive dyes used to reveal loss of voltage control during patch-clamp experiments.
AuthorsHüser J, Lipp P, Niggli E
JournalPflugers Arch
PubMed ID9019723
We used a fast, fluorescent, potential-sensitive indicator (Di-8-ANEPPS) in combination with laser-scanning confocal microscopy in the line-scan mode (temporal resolution 500 Hz) to independently determine the transmembrane potential in voltage-clamped cells. While a linear relation between command voltage and Di-8-ANEPPS fluorescence was found in unexcitable Sf9 cells, pronounced nonlinearities were ... More
Influence of anions and cations on the dipole potential of phosphatidylcholine vesicles: a basis for the Hofmeister effect.
AuthorsClarke RJ, Lüpfert C
JournalBiophys J
PubMed ID10233076
Anions and cations have long been recognized to be capable of modifying the functioning of various membrane-related physiological processes. Here, a fluorescent ratio method using the styrylpyridinium dyes, RH421 and di-8-ANEPPS, was applied to determine the effect of a range of anions and cations on the intramembrane dipole potential of ... More
Activation of phospholipase C increases intramembrane electric fields in N1E-115 neuroblastoma cells.
AuthorsXu C, Loew LM
JournalBiophys J
PubMed ID12770917
We imaged the intramembrane potential (a combination of transmembrane, surface, and dipole potential) on N1E-115 neuroblastoma cells with a voltage-sensitive dye. After activation of the B(2) bradykinin receptor, the electric field sensed by the dye increased by an amount equivalent to a depolarization of 83 mV. The increase in intramembrane ... More
High-speed, random-access fluorescence microscopy: II. Fast quantitative measurements with voltage-sensitive dyes.
AuthorsBullen A, Saggau P
JournalBiophys J
PubMed ID10096922
An improved method for making fast quantitative determinations of membrane potential with voltage-sensitive dyes is presented. This method incorporates a high-speed, random-access, laser-scanning scheme (Bullen et al., 1997. Biophys. J. 73:477-491) with simultaneous detection at two emission wavelengths. The basis of this ratiometric approach is the voltage-dependent shift in the ... More
Functional cardiac cell constructs on cellulose-based scaffolding.
AuthorsEntcheva E, Bien H, Yin L, Chung CY, Farrell M, Kostov Y
JournalBiomaterials
PubMed ID15147821
Cellulose and its derivatives have been successfully employed as biomaterials in various applications, including dialysis membranes, diffusion-limiting membranes in biosensors, in vitro hollow fibers perfusion systems, surfaces for cell expansion, etc. In this study, we tested the potential of cellulose acetate (CA) and regenerated cellulose (RC) scaffolds for growing functional ... More
An immediate endothelial cell signaling response to lung ischemia.
AuthorsSong C, Al-Mehdi AB, Fisher AB
JournalAm J Physiol Lung Cell Mol Physiol
PubMed ID11557603
Abrupt cessation of lung perfusion induces a rapid endothelial response that is not associated with anoxia but reflects loss of normal shear stress. This response includes membrane depolarization, H(2)O(2) generation, and increased intracellular Ca(2+). We evaluated these parameters immediately upon nonhypoxic ischemia using fluorescence videomicroscopy to image in situ endothelial ... More
Effect of lipid structure on the dipole potential of phosphatidylcholine bilayers.
AuthorsClarke RJ
JournalBiochim Biophys Acta
PubMed ID9271269
A fluorescent ratio method utilizing styrylpyridinium dyes has recently been suggested for the measurement of the membrane dipole potential. Up to now only qualititative measurements have been possible. Here the fluorescence excitation ratio of the dye di-8-ANEPPS has been measured in lipid vesicles composed of a range of saturated and ... More
Fluorescence imaging of electrical activity in cardiac cells using an all-solid-state system.
AuthorsEntcheva E, Kostov Y, Tchernev E, Tung L
JournalIEEE Trans Biomed Eng
PubMed ID14765706
Tracking spatial and temporal determinants of cardiac arrhythmogenesis at the cellular level presents challenges to the optical mapping techniques employed. In this paper, we describe a compact system combining two nontraditional low-cost solutions for excitation light sources and emission filters in fluorescence measurements of transmembrane potentials, Vm, or intracellular calcium, ... More
Properties of the demarcation membrane system in living rat megakaryocytes.
The demarcation membrane system (DMS) is the precursor of platelet cell membranes yet little is known of its properties in living megakaryocytes. Using confocal microscopy, we now demonstrate that demarcation membranes in freshly isolated rat marrow megakaryocytes are rapidly stained by styryl membrane indicators such as di-8-ANEPPS and FM 2-10, ... More
Measurement of membrane potential and [Ca2+]i in cell ensembles: application to the study of glutamate taste in mice.
AuthorsHayashi Y, Zviman MM, Brand JG, Teeter JH, Restrepo D
JournalBiophys J
PubMed ID8842242
We have studied the spectral properties of the voltage-sensitive dye, 1-(3-sulfonatopropyl)-4-[beta [2-(di-n-octylamino)-6-naphtyl]vinyl] pyridinium betaine (di-8-ANEPPS), and the Ca(2+)-sensitive dye, fura-2, in azolectin liposomes and in isolated taste buds from mouse. We find that the fluorescence excitation spectra of di-8-ANEPPS and fura-2 are largely nonoverlapping, allowing alternate ratio measurements of membrane ... More
Formation of planar and spiral Ca2+ waves in isolated cardiac myocytes.
AuthorsIshida H, Genka C, Hirota Y, Nakazawa H, Barry WH
JournalBiophys J
PubMed ID10512831
A novel Nipkow-type confocal microscope was applied to image spontaneously propagating Ca2+ waves in isolated rat ventricular myocytes by means of fluo-3. The sarcolemma was imaged with di-8-ANEPPS and the nucleus with SYTO 11. Full frame images in different vertical sections were obtained at video frame rate by means of ... More
Effect of cholesterol on the interaction of the HIV GP41 fusion peptide with model membranes. Importance of the membrane dipole potential.
AuthorsBuzón V, Cladera J
JournalBiochemistry
PubMed ID17176099
Fusion of viral and cell membranes is a key event in the process by which the human immunodeficiency virus (HIV) enters the target cell. Membrane fusion is facilitated by the interaction of the viral gp41 fusion peptide with the cell membrane. Using synthetic peptides and model membrane systems, it has ... More
Capillaries demonstrate changes in membrane potential in response to pharmacological stimuli.
AuthorsMcGahren ED, Beach JM, Duling BR
JournalAm J Physiol
PubMed ID9458852
It has been proposed that capillaries can detect changes in tissue metabolites and generate signals that are communicated upstream to resistance vessels. The mechanism for this communication may involve changes in capillary endothelial cell membrane potentials which are then conducted to upstream arterioles. We have tested the capacity of capillary ... More
Role of endothelial intermediate conductance KCa channels in cerebral EDHF-mediated dilations.
AuthorsMarrelli SP, Eckmann MS, Hunte MS
JournalAm J Physiol Heart Circ Physiol
PubMed ID12805022
The present study evaluated the role of endothelial intermediate conductance calcium-sensitive potassium channels (IKCa) in the mechanism of endothelium-derived hyperpolarizing factor (EDHF)-mediated dilations in pressurized cerebral arteries. Male rat middle cerebral arteries (MCA) were mounted in an isolated vessel chamber, pressurized (85 mmHg), and luminally perfused (100 microl/min). Artery diameter ... More
Fast voltage gating of Ca2+ release in frog skeletal muscle revealed by supercharging pulses.
AuthorsKim AM, Vergara JL
JournalJ Physiol
PubMed ID9706027
1. In single frog skeletal muscle fibres, we utilized supercharging voltage clamp command pulses to boost the rate of depolarization in the transverse tubular system (T-system) such that 95 % of steady-state potential is achieved in < 2 ms (as indicated by fluorescent potentiometric dye signals detected from a global ... More
Functional coupling of calcineurin and protein kinase A in mouse ventricular myocytes.
AuthorsSantana LF, Chase EG, Votaw VS, Nelson MT, Greven R
JournalJ Physiol
PubMed ID12356880
We examined the role of the Ca(2+)-regulated protein phosphatase calcineurin in controlling Ca(2+) signalling in mouse ventricular myocytes. Membrane currents and voltage were measured in single myocytes using the patch-clamp technique. Cytoplasmic Ca(2+) concentration ([Ca(2+)](i)) was measured in cells loaded with the fluorescent Ca(2+) indicators fluo-4 or fura-2 using a ... More
Fetal and postnatal development of Ca2+ transients and Ca2+ sparks in rat cardiomyocytes.
AuthorsSeki S, Nagashima M, Yamada Y, Tsutsuura M, Kobayashi T, Namiki A, Tohse N
JournalCardiovasc Res
PubMed ID12798426
OBJECTIVE: The aim of this study was to characterize the spatio-temporal dynamics of [Ca(2+)](i) in rat heart in the fetal and neonatal periods. METHODS: Using confocal scanning laser microscopy and the Ca(2+) indicator fluo-3, we investigated Ca(2+) transients and Ca(2+) sparks in single ventricular myocytes freshly isolated from rat fetuses ... More
Calcium release domains in mammalian skeletal muscle studied with two-photon imaging and spot detection techniques.
AuthorsGómez J, Neco P, DiFranco M, Vergara JL
JournalJ Gen Physiol
PubMed ID16735751
The spatiotemporal characteristics of the Ca(2+) release process in mouse skeletal muscle were investigated in enzymatically dissociated fibers from flexor digitorum brevis (FDB) muscles, using a custom-made two-photon microscope with laser scanning imaging (TPLSM) and spot detection capabilities. A two-microelectrode configuration was used to electrically stimulate the muscle fibers, to ... More
Location of the initiation site of calcium transients and sparks in rabbit heart Purkinje cells.
1.The distribution and localization of Ca2+ transients and Ca2+ sparks in isolated adult rabbit Purkinje cells were examined using confocal microscopy and the Ca2+ indicator fluo-3. 2.When cells were field stimulated in 2.0 mM Ca2+ buffer, a transverse confocal line scan (500 Hz) showed that the fluorescence intensity was greatest ... More
Contribution of ryanodine receptor type 3 to Ca(2+) sparks in embryonic mouse skeletal muscle.
AuthorsConklin MW, Barone V, Sorrentino V, Coronado R
JournalBiophys J
PubMed ID10465751
The kinetic behavior of Ca(2+) sparks in knockout mice lacking a specific ryanodine receptor (RyR) isoform should provide molecular information on function and assembly of clusters of RyRs. We examined resting Ca(2+) sparks in RyR type 3-null intercostal myotubes from embryonic day 18 (E18) mice and compared them to Ca(2+) ... More
Ion channel clustering enhances weak electric field detection by neutrophils: apparent roles of SKF96365-sensitive cation channels and myeloperoxidase trafficking in cellular responses.
AuthorsKindzelskii AL, Petty HR
JournalEur Biophys J
PubMed ID16044273
We have tested Galvanovskis and Sandblom's prediction that ion channel clustering enhances weak electric field detection by cells as well as how the elicited signals couple to metabolic alterations. Electric field application was timed to coincide with certain known intracellular chemical oscillators (phase-matched conditions). Polarized, but not spherical, neutrophils labeled ... More
A glucose-activated electron transfer system in the plasma membrane stimulates the H(+)-ATPase in Penicillium cyclopium.
AuthorsPönitz J, Roos W
JournalJ Bacteriol
PubMed ID8071221
Hyphal cells of three fungal species of the genus Penicillium reduced the nonpermeable, external electron acceptor hexabromoiridate IV (HBI IV). In Penicillium cyclopium, the rate of HBI IV reduction by hyphal cells was drastically increased by the addition of beta-glucose. The stimulation showed high specificity for this sugar and did ... More
Dual-wavelength ratiometric fluorescence measurement of the membrane dipole potential.
AuthorsGross E, Bedlack RS, Loew LM
JournalBiophys J
PubMed ID7918989
The electrostatic potentials associated with cell membranes include the transmembrane potential (delta psi), the surface potential (psi s), and the dipole potential (psi D). psi D, which originates from oriented dipoles at the surface of the membrane, rises steeply just within the membrane to approximately 300 mV. Here we show ... More
Role of the transverse-axial tubule system in generating calcium sparks and calcium transients in rat atrial myocytes.
AuthorsKirk MM, Izu LT, Chen-Izu Y, McCulle SL, Wier WG, Balke CW, Shorofsky SR
JournalJ Physiol
PubMed ID12562899
Cardiac atrial cells lack a regular system of transverse tubules like that in cardiac ventricular cells. Nevertheless, many atrial cells do possess an irregular internal transverse-axial tubular system (TATS). To investigate the possible role of the TATS in excitation-contraction coupling in atrial myocytes, we visualized the TATS (labelled with the ... More
Optical imaging and functional characterization of the transverse tubular system of mammalian muscle fibers using the potentiometric indicator di-8-ANEPPS.
AuthorsDiFranco M, Capote J, Vergara JL
JournalJ Membr Biol
PubMed ID16645743
Potentiometric dyes are useful tools for studying membrane potential changes from compartments inaccessible to direct electrical recordings. In the past, we have combined electrophysiological and optical techniques to investigate, by using absorbance and fluorescence potentiometric dyes, the electrical properties of the transverse tubular system in amphibian skeletal muscle fibers. In ... More
Intramembrane molecular dipoles affect the membrane insertion and folding of a model amphiphilic peptide.
AuthorsCladera J, O'Shea P
JournalBiophys J
PubMed ID9591669
The relationship between the dipole potential and the interaction of the mitochondrial amphipathic signal sequence known as p25 with model membranes has been studied using 1-(3-sulfonatopropyl)-4-[beta[2-(di-n-octyl-amino)-6-naphthyl]viny l] pyridinium betaine (di-8-ANEPPS) as a fluorescent probe. The dipole potential of phosphatidylcholine membranes was modified by incorporating into the bilayer the sterols phloretin ... More
Endothelial cell signaling during conducted vasomotor responses.
AuthorsDora KA, Xia J, Duling BR
JournalAm J Physiol Heart Circ Physiol
PubMed ID12793976
ACh and KCl stimulate vasomotor responses that spread rapidly and bidirectionally along arteriole walls, most likely via spread of electric current or Ca2+ through gap junctions. We examined these possibilities with isolated, cannulated, and perfused hamster cheek pouch arterioles (50- to 80-microm resting diameter). After intraluminal loading of 2 microM ... More
Characterization of the sequence of interactions of the fusion domain of the simian immunodeficiency virus with membranes. Role of the membrane dipole potential.
AuthorsCladera J, Martin I, Ruysschaert JM, O'Shea P
JournalJ Biol Chem
PubMed ID10514478
The simian immunodeficiency virus fusion peptide constitutes a 12-residue N-terminal segment of the gp32 protein that is involved in the fusion between the viral and cellular membranes, facilitating the penetration of the virus in the host cell. Simian immunodeficiency virus fusion peptide is a hydrophobic peptide that in Me(2)SO forms ... More
Calcium gradients during excitation-contraction coupling in cat atrial myocytes.
AuthorsHüser J, Lipsius SL, Blatter LA
JournalJ Physiol
PubMed ID8865063
1. Confocal microscopy in combination with the calcium-sensitive fluorescent probe fluo-3 was used to study spatial aspects of intracellular Ca2+ signals during excitation-contraction coupling in isolated atrial myocytes from cat heart. 2. Imaging of [Ca2+]i transients evoked by electrical stimulation revealed that Ca2+ release started at the periphery and subsequently ... More
Comparison of Ca(2+) sparks produced independently by two ryanodine receptor isoforms (type 1 or type 3).
AuthorsConklin MW, Ahern CA, Vallejo P, Sorrentino V, Takeshima H, Coronado R
JournalBiophys J
PubMed ID10733959
The molecular determinants of a Ca(2+) spark, those events that determine the sudden opening and closing of a small number of ryanodine receptor (RyR) channels limiting Ca(2+) release to a few milliseconds, are unknown. As a first step we investigated which of two RyR isoforms present in mammalian embryonic skeletal ... More
Microtubules orchestrate local translation to enable cardiac growth.
Authors
JournalNat Commun
PubMed ID33707436
Statin-boosted cellular uptake and endosomal escape of penetratin due to reduced membrane dipole potential.
Authors
JournalBr J Pharmacol
PubMed ID33908640
Nexilin Is Necessary for Maintaining the Transverse-Axial Tubular System in Adult Cardiomyocytes.
Authors
JournalCirc Heart Fail
PubMed ID32635769
Optical estimation of absolute membrane potential using fluorescence lifetime imaging.
Authors
JournalElife
PubMed ID31545164
Layer-by-Layer Assembly of Supported Lipid Bilayer Poly-L-Lysine Multilayers.
Authors
JournalBiomacromolecules
PubMed ID26642374
Genetic Background and Kinetics Define Wound Bed Extracellular Vesicles in a Mouse Model of Cutaneous Injury.
Authors
JournalInt J Mol Sci
PubMed ID33805585
Ca2+ release via InsP3Rs enhances RyR recruitment during Ca2+ transients by increasing dyadic [Ca2+] in cardiomyocytes.
Authors
JournalJ Cell Sci
PubMed ID34125209
Alternative splicing regulates vesicular trafficking genes in cardiomyocytes during postnatal heart development.
Authors
JournalNat Commun
PubMed ID24752171
Activation of TRPV4 Induces Exocytosis and Ferroptosis in Human Melanoma Cells.
Authors
JournalInt J Mol Sci
PubMed ID35456964
Single-cell analysis of murine fibroblasts identifies neonatal to adult switching that regulates cardiomyocyte maturation.