Cultured chick-embryo heart cells respond differently to ouabain as measured by the increase in their intracellular Na+ concentration.
AuthorsAhlemeyer B, Weintraut H, Schoner W
JournalBiochim Biophys Acta
PubMed ID1420320
Using digital imaging microscopy with the sodium-sensitive fluorescent indicator sodium-binding benzofuran isophtalate (SBFI), we examined the cytosolic free sodium ion concentration ([Na+]i) in single chick-embryo heart cells. The distribution of the [Na+]i was homogeneous within one cell, but we found a wide cell to cell variation in the range of ... More
The spread of Na+ spikes determines the pattern of dendritic Ca2+ entry into hippocampal neurons.
AuthorsJaffe DB, Johnston D, Lasser-Ross N, Lisman JE, Miyakawa H, Ross WN
JournalNature
PubMed ID1350327
'The dendrites of many types of neurons contain voltage-dependent Na+ and Ca2+ conductances that generate action potentials (see ref. 1 for review). The function of these spikes is not well understood, but the Ca2+ entry stimulated by spikes probably affects Ca(2+)-dependent processes in dendrites. These include synaptic plasticity, cytotoxicity and ... More
Synaptically activated increases in Ca2+ concentration in hippocampal CA1 pyramidal cells are primarily due to voltage-gated Ca2+ channels.
AuthorsMiyakawa H, Ross WN, Jaffe D, Callaway JC, Lasser-Ross N, Lisman JE, Johnston D
JournalNeuron
PubMed ID1361128
'Changes in intracellular Ca2+ concentration ([Ca2+]i) in the soma and dendrites of hippocampal CA1 pyramidal neurons were measured using intracellularly injected fura-2. A large component of the [Ca2+]i elevation caused by high frequency stimulation of the Schaffer collaterals was correlated with the Na+ spikes triggered by the excitatory postsynaptic potentials ... More
Fluorescence measurements of cytosolic free Na concentration, influx and efflux in gastric cells.
AuthorsNegulescu PA, Harootunian A, Tsien RY, Machen TE
JournalCell Regul
PubMed ID1712635
'Regulation of cytosolic free Na (Nai) was measured in isolated rabbit gastric glands with the use of a recently developed fluorescent indicator for sodium, SBFI. Intracellular loading of the indicator was achieved by incubation with an acetoxymethyl ester of the dye. Digital imaging of fluorescence was used to monitor Nai ... More
Reconstitution, identification, purification, and immunological characterization of the 110-kDa Na+/Ca2+ antiporter from beef heart mitochondria.
AuthorsLi W, Shariat-Madar Z, Powers M, Sun X, Lane RD, Garlid KD
JournalJ Biol Chem
PubMed ID1517231
'The mitochondrial Na+/Ca2+ antiporter plays a key role in the physiological regulation of intramitochondrial Ca2+, which in turn attunes mitochondrial enzymes to the changing demands of the cell for ATP. We have now purified the Na+/Ca2+ antiporter from beef heart mitochondria by assaying detergent-solubilized chromatography fractions for reconstitutive activity. Na+ ... More
A quantitative measurement of the dependence of short-term synaptic enhancement on presynaptic residual calcium.
AuthorsDelaney KR, Tank DW
JournalJ Neurosci
PubMed ID7931551
'We simultaneously measured presynaptic free calcium ion concentration ([Ca2+]i) and synaptic strength at the crayfish claw opener neuromuscular junction (nmj) under a variety of experimental conditions. Our experiments were designed both to test the hypothesis that elevated [Ca2+]i is necessary and sufficient for the induction of a form of synaptic ... More
Intracellular Na+ measurements in smooth muscle using SBFI--changes in [Na+], Ca2+ and force in normal and Na(+)-loaded ureter.
AuthorsLamont C, Burdyga TV, Wray S
JournalPflugers Arch
PubMed ID9446700
'Our understanding of the control and effects of intracellular [Na+] ([Na+]i) in intact smooth muscle is limited by the lack of data concerning [Na+]i. The initial aim of this work was therefore to investigate the suitability of using the Na+-sensitive fluorophore SBFI in intact smooth muscle. We find this to ... More
Intracellular Na+ measurements using sodium green tetraacetate with flow cytometry.
AuthorsAmorino GP, Fox MH
JournalCytometry
PubMed ID8582247
'Intracellular sodium concentration ([Na+]i) can be measured using SBFI with image analysis or spectrofluorometry. However, SBFI cannot be used with most flow cytometry systems, due to its requirement for dual excitation in the UV range. Recently a new sodium indicator, Sodium Green, was developed which can be used with flow ... More
Sodium imaging of climbing fiber innervation fields in developing mouse Purkinje cells.
AuthorsScelfo B, Strata P, Knöpfel T
JournalJ Neurophysiol
PubMed ID12612029
'Maturation of specific neuronal connections in the mature nervous system includes elimination of redundant synapses formed earlier during development. In the cerebellum of adult animals, each Purkinje cell (PC) is innervated by a single climbing fiber (CF). In early postnatal development each PC is innervated by multiple CFs and elimination ... More
Excitotoxic degeneration is initiated at non-random sites in cultured rat cerebellar neurons.
AuthorsBindokas VP, Miller RJ
JournalJ Neurosci
PubMed ID7472456
'Prolonged stimulation of cultured cerebellar neurons by kainic acid (KA) leads to death of neurons first evident from the swelling of soma and neurites. Stimulation is accompanied by increases in [Ca2+]i and [Na+]i as monitored using digital imaging microfluorimetry. "Blebs" tended to form on neurites with the highest increases in ... More
Elevation of intracellular Na+ induced by hyperpolarization at the dendrites of pyramidal neurones of mouse hippocampus.
AuthorsTsubokawa H, Miura M, Kano M
JournalJ Physiol
PubMed ID10226155
'1. Whole-cell recordings were made from CA1 pyramidal cells in mouse hippocampal slices with patch pipettes containing the sodium indicator dye SBFI (sodium binding benzofuran isophthalate). Using a high-speed imaging system, we investigated changes in intracellular sodium concentration, [Na+]i, in response to hyperpolarizing pulses applied to the soma. 2. In ... More
Proton-sodium stoichiometry of NhaA, an electrogenic antiporter from Escherichia coli.
AuthorsTaglicht D, Padan E, Schuldiner S
JournalJ Biol Chem
PubMed ID8383669
'The H+:Na+ exchange stoichiometry of NhaA, a sodium-proton antiporter coded by the nhaA gene of Escherichia coli, has been determined using purified NhaA protein reconstituted into sodium-loaded proteoliposomes. One approach involved measuring, in parallel experiments, the Na+ efflux and H+ influx from such proteoliposomes and calculating the stoichiometry from the ... More
Phospholipid subclass-specific alterations in the kinetics of ion transport across biologic membranes.
AuthorsChen X, Gross RW
JournalBiochemistry
PubMed ID7947788
'Although the predominance of plasmalogens in electrically-active membranes (e.g., sarcolemma) is well-known, identification of the molecular mechanisms through which the vinyl ether linkage facilitates electrophysiologic function has remained elusive. Herein we demonstrate that the kinetics of both carrier-mediated (i.e., valinomycin) and passive ion transport are substantially different in membranes comprised ... More
Measurement of intracellular Na+ concentration by a Na+-sensitive fluorescent dye, sodium-binding benzofuran isophthalate, in porcine adrenal chromaffin cells--usage of palytoxin as a Na+ ionophore.
AuthorsIto S, Ohta T, Kadota H, Kitamura N, Nakazato Y
JournalJ Neurosci Methods
PubMed ID9262139
'Palytoxin was found to equilibrate sodium ions (Na+) across the cell membrane much faster than dose gramicidin, which has been frequently used to calibrate the intracellular Na+ concentration ([Na+]in), in cells treated with a Na+-sensitive fluorescent dye, sodium-binding benzofuran isophthalate (SBFI). Palytoxin was capable of equilibrating Na+ in cells treated ... More
Imaging voltage and synaptically activated sodium transients in cerebellar Purkinje cells.
AuthorsLasser-Ross N, Ross WN
JournalProc Biol Sci
PubMed ID1348119
'Transient changes in sodium concentration in response to electrical activity were detected in Purkinje cells by using the fluorescent indicator SBFI (Minta & Tsien (J. biol. Chem. 264, 19,449 (1989)). Fast sodium action potentials caused large increases in internal sodium concentration, [Na]i, in the soma and axon, and were generally ... More
Optical methods to measure membrane transport processes.
AuthorsVerkman AS
JournalJ Membr Biol
PubMed ID8606370
Quantification of intracellular free sodium ions by using a new fluorescent indicator, sodium-binding benzofuran isophthalate in guinea pig myocytes.
AuthorsSatoh H, Hayashi H, Noda N, Terada H, Kobayashi A, Yamashita Y, Kawai T, Hirano M, Yamazaki N
JournalBiochem Biophys Res Commun
PubMed ID2018505
Isolated guinea pig myocytes were loaded with the Na(+)-sensitive fluorescent probe, sodium-binding benzofuran isophthalate (SBFI). The 340/380 nm fluorescence ratios were measured with fluorescence microscopy. The distribution of intracellular Na+ concentration ([Na+]i) was homogenous, and the mean resting [Na+]i was 8.4 +/- 0.5 mM. There was a significant relationship (r ... More
Dendritic excitability in CNS neurons: insights from dynamic calcium and sodium imaging in single cells.
AuthorsRoss WN, Miyakawa H, Lev-Ram V, Lasser-Ross N, Lisman J, Jaffe D, Johnston D
JournalJpn J Physiol
PubMed ID8271520
We measured changes in [Ca2+]i and [Na+]i in the dendrites of cerebellar Purkinje cells and hippocampal pyramidal cells using high speed imaging of the fluorescence changes of intracellularly injected fura-2 and SBFI. These transients were detected in synchrony with intracellular recordings of membrane potential. In this way rapid calcium or ... More
Video enhanced imaging of the fluorescent Na+ probe SBFI indicates that colonic crypts absorb fluid by generating a hypertonic interstitial fluid.
AuthorsNaftalin RJ, Pedley KC
JournalFEBS Lett
PubMed ID2298298
Extracellular accumulation of Na+ detected by video-enhanced microscopic imaging of the impermeant fluorescent probe SBFI confirms the view that colonic crypts produce a hypertonic ascorbate ca 1000 mOsm.kg-1, thereby generating a large osmotic pressure across the crypt wall. This creates a high fluid tension within the crypt lumen, sufficient to ... More
Loading of cells and a possible upper limit of load response with respect to strain energy density.
AuthorsMcDonald F, Yettram AL
JournalJ Biomed Mater Res
PubMed ID8600148
A model has been established to examine the effects of mechanically loading bone on the ionic distribution in osteocytes. The ionic concentrations are determined from the fluorescence of specific ionic indicators SPFI, PBFI, and SPQ. A deformation was induced in the calvariae of neonatal rats which were used as the ... More
Anoxia induces an increase in intracellular sodium in rat central neurons in vitro.
AuthorsFriedman JE, Haddad GG
JournalBrain Res
PubMed ID7874519
Following our previous observations that anoxia induces a drop in extracellular Na+ in the brain slice and that removal of extracellular Na+ prevents the anoxia-induced morphological changes in dissociated hippocampal neurons, we hypothesized that intracellular Na+ increases during anoxia in isolated neurons. Using the fluorophore Sodium Green in freshly dissociated ... More
Synaptically induced sodium signals in hippocampal astrocytes in situ.
AuthorsLanger J, Rose CR,
JournalJ Physiol
PubMed ID19858225
Astrocytes are in close contact to excitatory synapses and express transporters which mediate the sodium-dependent uptake of glutamate. In cultured astrocytes, selective activation of glutamate transport results in sodium elevations which stimulate Na(+)/K(+)-ATPase and glucose uptake, indicating that synaptic release of glutamate might couple excitatory neuronal activity to glial sodium ... More
Somatic spikes regulate dendritic signaling in small neurons in the absence of backpropagating action potentials.
AuthorsMyoga MH, Beierlein M, Regehr WG,
JournalJ Neurosci
PubMed ID19535592
Somatic spiking is known to regulate dendritic signaling and associative synaptic plasticity in many types of large neurons, but it is unclear whether somatic action potentials play similar roles in small neurons. Here we ask whether somatic action potentials can also influence dendritic signaling in an electrically compact neuron, the ... More
Potential misevaluation of the ground-state dissociation constant from fluorimetric titrations: application to the ion indicators SBFI, PBFI, and fura-2.
AuthorsKowalczyk A, Boens N, Meuwis K, Ameloot M
JournalAnal Biochem
PubMed ID9025965
A test based on time-resolved fluorescence experiments is proposed to assess the interference of an excited-state reaction with the fluorimetric determination of the ground-state dissociation constant Kd of ion [symbol: see text] fluorescent indicator complexes. If an inflection point occurs in the plot of the fluorescence signal vs -log [ion] ... More
Sodium Green as a potential probe for intracellular sodium imaging based on fluorescence lifetime.
AuthorsSzmacinski H, Lakowicz JR
JournalAnal Biochem
PubMed ID9245429
We characterized the use of the fluorescent probe Sodium Green for measurements of intracellular free sodium using frequency-domain, phase-modulation fluorometry. The intensity decays were found to be strongly Na+ dependent, with mean lifetime increasing from 1.13 ns in the absence of Na+ to 2.39 ns in the presence of 140 ... More
Fluorescent indicators for cytosolic sodium.
AuthorsMinta A, Tsien RY
JournalJ Biol Chem
PubMed ID2808435
Fluorescent indicators sensitive to cytosolic concentrations of free Na+ have been synthesized and characterized. They consist of a crown ether, 1,7-diaza-4,10,13-trioxacyclopentadecane, linked via its nitrogens to fluorophores bearing additional liganding centers. In the currently preferred dye, SBFI (short for sodium-binding benzofuran isophthalate), the fluorophores are benzofurans linked to isophthalate groups. ... More
Hyperpolarization induces a rise in intracellular sodium concentration in dopamine cells of the substantia nigra pars compacta.
AuthorsKnöpfel T, Guatteo E, Bernardi G, Mercuri NB
JournalEur J Neurosci
PubMed ID9751162
We investigated the effect of changes in membrane-voltage on intracellular sodium concentration ([Na+]i) of dopamine-sensitive neurons of the substantia nigra pars compacta in a slice preparation of rat mesencephalon. Whole-cell patch-clamp techniques were combined with microfluorometric measurements of [Na+]i using the Na+-sensitive probe, sodium-binding benzofuran isophthalate (SBFI). Hyperpolarization of spontaneously ... More
Neurotrophin-evoked rapid excitation through TrkB receptors.
AuthorsKafitz KW, Rose CR, Thoenen H, Konnerth A
JournalNature
PubMed ID10553907
Neurotrophins are a family of structurally related proteins that regulate the survival, differentiation and maintenance of function of different populations of peripheral and central neurons. They are also essential for modulating activity-dependent neuronal plasticity. Here we show that neurotrophins elicit action potentials in central neurons. Even at low concentrations, brain-derived ... More
NMDA receptor-mediated Na+ signals in spines and dendrites.
AuthorsRose CR, Konnerth A
JournalJ Neurosci
PubMed ID11404406
Spines and dendrites of central neurons represent an important site of synaptic signaling and integration. Here we identify a new, synaptically mediated spine signal with unique properties. Using two-photon Na(+) imaging, we show that suprathreshold synaptic stimulation leads to transient increases in Na(+) concentration in postsynaptic spines and their adjacent ... More
Transmembrane gradients of free Na+ in isolated heart mitochondria estimated using a fluorescent probe.
AuthorsJung DW, Apel LM, Brierley GP
JournalAm J Physiol
PubMed ID1566810
The concentration of free Na+ in the matrix of isolated pig heart mitochondria has been monitored using the fluorescent probe sodium-binding benzofuran isophthalate (SBFI) developed by Minta and Tsien (J. Biol. Chem. 264: 19449-19457, 1989). SBFI was sequestered in the matrix by hydrolysis of the permeant acetoxymethyl ester. The sequestered ... More
Fluorescence lifetime microscopy of the sodium indicator sodium-binding benzofuran isophthalate in HeLa cells.
AuthorsDespa S, Steels P, Ameloot M
JournalAnal Biochem
PubMed ID10790305
The behavior of the sodium indicator sodium-binding benzofuran isophthalate (SBFI) is investigated in HeLa cells by time-resolved fluorescence microscopy. The fluorescence relaxation of SBFI in HeLa cells can be described by a triexponential for intracellular sodium concentration ([Na(+)](i)) between 0 and 90 mM. Changes in [Na(+)](i) affect neither the fluorescence ... More
Two-photon Na+ imaging in spines and fine dendrites of central neurons.
AuthorsRose CR, Kovalchuk Y, Eilers J, Konnerth A
JournalPflugers Arch
PubMed ID10651018
Dendritic spines are assumed to be the smallest units of neuronal integration. Because of their miniature size, however, many of their functional properties are still unclear. New insights in spine physiology have been provided by two-photon laser-scanning microscopy which allows fluorescence imaging with high spatial resolution and minimal photodamage. For ... More
Na/K pump current and [Na](i) in rabbit ventricular myocytes: local [Na](i) depletion and Na buffering.
AuthorsDespa S, Bers DM
JournalBiophys J
PubMed ID12770918
Na/K pump current (I(pump)) and intracellular Na concentration ([Na](i)) were measured simultaneously in voltage-clamped rabbit ventricular myocytes, under conditions where [Na](i) is controlled mainly by membrane transport. Upon abrupt pump reactivation (after 10-12 min blockade), I(pump) decays in two phases. Initially, I(pump) declines with little [Na](i) change, whereas the second ... More
Heat-induced changes in intracellular sodium and membrane potential: lack of a role in cell killing and thermotolerance.
AuthorsAmorino GP, Fox MH
JournalRadiat Res
PubMed ID8752306
Hyperthermia induces transient changes in intracellular free sodium levels and membrane potential. The possible role of these changes in cell killing by hyperthermia and thermotolerance has been evaluated using Chinese hamster ovary IS1 and HeLa cells. Intracellular sodium was measured with Sodium Green and SBFI, while membrane potential was measured ... More
Effects of salinity on cytosolic Na+ and K+ in root hairs of Arabidopsis thaliana: in vivo measurements using the fluorescent dyes SBFI and PBFI.
AuthorsHalperin SJ, Lynch JP
JournalJ Exp Bot
PubMed ID12925666
Toxicity from sodium accumulation is an important aspect of salinity stress that has been well studied at the organ and tissue level. However, the effects of salinity on sodium accumulation in the cytosol, where much of the sodium toxicity is thought to occur, are poorly understood due to the difficulty ... More
Interplay between sodium and calcium dynamics in granule cell presynaptic terminals.
AuthorsRegehr WG
JournalBiophys J
PubMed ID9370441
Fluorescent indicators were used to detect stimulus-evoked changes in presynaptic levels of intracellular sodium (Na(i)) and calcium (Ca(i)) in granule cell parallel fibers in brain slices from rat cerebellum. Ca(i) increased during stimulation, and three exponentials were needed to approximate its return to prestimulus levels. Ca(i) decayed to approximately 10% ... More
Mechanisms of glutamate-stimulated Mg2+ influx and subsequent Mg2+ efflux in rat forebrain neurones in culture.
AuthorsStout AK, Li-Smerin Y, Johnson JW, Reynolds IJ
JournalJ Physiol
PubMed ID8734978
1. Mag-fura-2 fluorescence microscopy and whole-cell patch-clamp recordings were used to measure glutamate-induced changes in the intracellular free Mg2+ concentration ([Mg2+]i) and Mg2+ currents, respectively, in cultured forebrain neurones from fetal rats in the absence of extracellular Na+ (Nao+) and Ca2+ (Cao2+). 2. Increasing the extracellular Mg2+ concentration ([Mg2+]o) from ... More
Spatiotemporal gradients of intra-axonal [Na+] after transection and resealing in lizard peripheral myelinated axons.
AuthorsDavid G, Barrett JN, Barrett EF
JournalJ Physiol
PubMed ID9032679
1. Post-transection changes in intracellular Na+ ([Na+]i) were measured in lizard peripheral axons ionophoretically injected with the Na(+)-sensitive ratiometric dye, sodium-binding benzofuran isophthalate (SBFI). 2. Following axonal transection in physiological saline [Na+]i increased to more than 100 mM in a region that quickly extended hundreds of micrometers from the transection ... More
Fluorescence ratio imaging of cytosolic free Na+ in individual fibroblasts and lymphocytes.
AuthorsHarootunian AT, Kao JP, Eckert BK, Tsien RY
JournalJ Biol Chem
PubMed ID2478559
New fluorescent Na+ indicators, SBFI (short for sodium-binding benzofuran isophthalate) and SBFP (short for sodium-binding benzofuran phthalate) (Minta, A., and Tsien, R. Y. (1989) J. Biol. Chem. 264, 19449-19457), were tested in Jurkat tumor lymphocytes and in REF52 rat embryo fibroblasts. Both dyes could be introduced by direct microinjection. However, ... More
Characterization of oscillations in cytosolic free Ca2+ concentration and measurement of cytosolic Na+ concentration changes evoked by angiotensin II and vasopressin in individual rat aortic smooth muscle cells. Use of microfluorometry and digital imaging.
Dual wavelength microfluorometry was used to characterize the changes in cytosolic free Ca2+ concentration [( Ca2+]i) in individual cultured rat aortic vascular smooth muscle cells (VSMC). Angiotensin II (ANG II) at 10(-8) M induced a transient rise in [Ca2+]i from 43 +/- 2 to 245 +/- 23 nM, lasting for ... More
Effect of ATP-induced permeabilization on loading of the Na+ probe SBFI into endothelial cells.
AuthorsCutaia M, Davis R, Parks N, Rounds S
JournalJ Appl Physiol
PubMed ID8828703
The fluoroprobe sodiumbinding benzofuran isophthalate (SBFI) is used to measure intracellular cytosolic sodium concentration ([Na]i). A problem with the use of this probe is the difficulty in loading it into cells. ATP reversibly increases membrane permeability of some cells via activation of receptors of the tetrabasic form of ATP (ATP4-). ... More
Monitoring intracellular nanomolar calcium using fluorescence lifetime imaging.