Use of a membrane potential-sensitive probe to assess biological expression of the cystic fibrosis transmembrane conductance regulator.
AuthorsRenier M, Tamanini A, Nicolis E, Rolfini R, Imler JL, Pavirani A, Cabrini G
JournalHum Gene Ther
PubMed ID8590731
Cystic fibrosis is caused by defects in a chloride-transporting protein termed cystic fibrosis transmembrane conductance regulator (CFTR). This study presents an innovative procedure to evaluate expression of functional CFTR. The technique uses the potential-sensitive probe bis-(1,3-diethylthiobarbituric acid) trimethine oxonol or DiSBAC2(3), by single-cell fluorescence imaging. The DiSBAC2(3) method was first ... More
Expression of the voltage-gated sodium channel NaV1.5 in the macrophage late endosome regulates endosomal acidification.
AuthorsCarrithers MD, Dib-Hajj S, Carrithers LM, Tokmoulina G, Pypaert M, Jonas EA, Waxman SG,
JournalJ Immunol
PubMed ID17548620
'Voltage-gated sodium channels expressed on the plasma membrane activate rapidly in response to changes in membrane potential in cells with excitable membranes such as muscle and neurons. Macrophages also require rapid signaling mechanisms as the first line of defense against invasion by microorganisms. In this study, our goal was to ... More
Heat shock- and ethanol-induced ionic changes in C6 rat glioma cells determined by NMR and fluorescence spectroscopy.
AuthorsSkrandies S, Bremer B, Pilatus U, Mayer A, Neuhaus-Steinmetz U, Rensing L
JournalBrain Res
PubMed ID9037501
'The effects of two different stressors, heat shock (HS; 44 degrees C, 20 min) and ethanol (1.2 M, 60 min), on ion content and membrane potential were investigated in C6 rat glioma cells. Both treatments were previously shown to induce the HS response [26]. Intracellular pH (pH(i)), sodium ion concentration ... More
Membrane potential modulates release of tumor necrosis factor in lipopolysaccharide-stimulated mouse macrophages.
AuthorsHaslberger A, Romanin C, Koerber R
JournalMol Biol Cell
PubMed ID1498365
'Lipopolysaccharide (LPS)-mediated synthesis of macrophage gene products such as tumor necrosis factor (TNF) is controlled by different signaling pathways. We investigated intracellular free Ca2+ (Ca2+ic) and the membrane potential as early cellular responses to LPS and their role in the synthesis and release of TNF. In peritoneal macrophages and in ... More
Selective modulation by cGMP of the K+ channel activated by speract.
AuthorsCook SP, Babcock DF
JournalJ Biol Chem
PubMed ID7693667
'The egg peptide speract stimulates sperm guanylyl cyclase and presumably enhances fertilization, but the roles of cGMP in sperm responses are yet undetermined. Here we show that speract-induced accumulation of cGMP or cAMP is selectively enhanced by the phosphodiesterase inhibitors, 3-isobutyl-1-methylxanthine (IBMX) or papaverine, respectively. These inhibitors provided the unusual ... More
Discrimination between cystic fibrosis and CFTR-corrected epithelial cells by a membrane potential-sensitive probe.
AuthorsCoclet-Ninin J, Rochat T, Poitry S, Chanson M
JournalExp Lung Res
PubMed ID11936773
'Methods to detect functional cystic fibrosis transmembrane conductance regulator (CFTR) are needed for the assessment of new therapies in cystic fibrosis (CF). We have combined patch-clamp and fluorimetric techniques to investigate whether the fluorescent voltage-sensitive probe bis-(1,3-diethylthiobarbituic anid) trimethine oxonol (Di5BAC2(3)) discriminates between changes of membrane potential (Vm evoked by ... More
Extracellular nucleotides mediate Ca2+ fluxes in J774 macrophages by two distinct mechanisms.
AuthorsGreenberg S, Di Virgilio F, Steinberg TH, Silverstein SC
JournalJ Biol Chem
PubMed ID3392016
'We have studied the effects of extracellular nucleotides on the cytosolic free calcium concentration [( Ca2+]i) in J774 macrophages using quin2 and indo-1 as indicator dyes. Micromolar quantities of ATP induced a biphasic increase in [Ca2+]i: a rapid and transient increase (peak I) which was due to mobilization of Ca2+ ... More
Correlation between cytosolic free Ca2+ and insulin release in an insulin-secreting cell line.
AuthorsWollheim CB, Pozzan T
JournalJ Biol Chem
PubMed ID6365908
'Changes in the concentration of free cytosolic Ca2+ [( Ca2+]i), membrane potential, and immunoreactive insulin release were measured in suspensions of RINm5F cells. [Ca2+]i was monitored with the intracellularly trapped fluorescent Ca2+ indicator quin 2. Changes in membrane potential were assessed with the fluorescent probe bisoxonol. The effects of depolarizing ... More
Membrane potential changes after infection of monocytes by Toxoplasma gondii.
AuthorsBouchot A, Millot JM, Charpentier S, Bonhomme A, Villena I, Aubert D, Pinon JM
JournalInt J Parasitol
PubMed ID11429176
'Membrane potential changes in host cell plasma membrane were analyzed and the parasitophorous vacuole membrane (PVM) potential was characterized after infection by Toxoplasma gondii. Human monocytes infested by T. gondii were stained with two membrane potential sensitive dyes, DiOC(6)(3) carbocyanine and DiSBAC(2)(3) bis-oxonol, before fluorescence emission analysis by confocal laser ... More
Voltage-sensitive oxonol dyes are novel large-conductance Ca2+-activated K+ channel activators selective for beta1 and beta4 but not for beta2 subunits.
'The large-conductance Ca(2+)-activated K(+) (BK) channel is activated by both the increase of intracellular Ca(2+) concentration and membrane depolarization. The BK channel plays crucial roles as a key molecule in the negative feedback mechanism regulating membrane excitability and cellular Ca(2+) in various cell types. Here, we report that a widely ... More
Characterization of the activation of Na+/H+ exchange in lymphocytes by phorbol esters: change in cytoplasmic pH dependence of the antiport.
AuthorsGrinstein S, Cohen S, Goetz JD, Rothstein A, Gelfand EW
JournalProc Natl Acad Sci U S A
PubMed ID2983345
'Phorbol 12-myristate 13-acetate and other phorbol esters induce an intracellular alkalinization in rat thymic lymphocytes. An extracellular acidification can be recorded concomitantly. This transmembrane H+ (equivalent) flux is dependent on external Na+ and is amiloride sensitive. Phorbol esters also stimulate an amiloride-sensitive uptake of 22Na+, suggesting activation of Na+o/H+i exchange. ... More
Triggering of lymphocyte capping appears not to require changes in potential or ion fluxes across the plasma membrane.
'Capping induced by anti-Ig antibody on mouse spleen lymphocytes was found to proceed normally over a wide range of membrane potentials from approx. 0 to -65 mV, as estimated with fluorescent probes. The potential was manipulated by ionic substitution in the medium and/or application of gramicidin. Various agents which inhibit ... More
T cell activation is regulated by voltage-dependent and calcium-activated potassium channels.
AuthorsRader RK, Kahn LE, Anderson GD, Martin CL, Chinn KS, Gregory SA
JournalJ Immunol
PubMed ID8568243
'Membrane potential (Vm) is tightly controlled in T cells through the regulated flux of ions across the plasma membrane. To investigate the functional role of voltage-dependent (Kv) and calcium-activated (KCa) potassium channels in T cell activation, we compared the effects of two K+ channel blockers, namely kaliotoxin (KTX) and charybdotoxin ... More
Mouse microglial cells express a plasma membrane pore gated by extracellular ATP.
AuthorsFerrari D, Villalba M, Chiozzi P, Falzoni S, Ricciardi-Castagnoli P, Di Virgilio F
JournalJ Immunol
PubMed ID8568257
'We have investigated responses to extracellular ATP (ATPe) in the microglial cell lines N9 and N13 and in freshly isolated mouse microglial cells. Upon stimulation with this nucleotide, N9 and N13 cells underwent an increase in the cytoplasmic free Ca2+ concentration ([Ca2+]i), a sustained depolarization of the plasma membrane, and ... More
Glucose-induced increase in cytoplasmic pH in pancreatic beta-cells is mediated by Na+/H+ exchange, an effect not dependent on protein kinase C.
AuthorsJuntti-Berggren L, Arkhammar P, Nilsson T, Rorsman P, Berggren PO
JournalJ Biol Chem
PubMed ID1660875
'Glucose-induced changes in cytoplasmic pH (pHi) were investigated using pancreatic beta-cells isolated from obese hyperglycemic mice. Glucose, at concentrations above 3-5 mM, depolarized the beta-cell and increased pHi, cytoplasmic free Ca2+ ([Ca2+]i), and insulin release. This increase in pHi was dependent on the presence of extracellular Na+ and was inhibited ... More
Multiple signaling pathways for Cl(-)-dependent depolarization of mesangial cells: role of Ca2+, PKC, and G proteins.
AuthorsKremer SG, Zeng W, Sridhara S, Skorecki KL
JournalAm J Physiol
PubMed ID1566880
'We have previously reported that vasopressin activates chloride channels, leading to depolarization of glomerular mesangial cells via both calcium-dependent and calcium-independent pathways (S.G. Kremer, W.V. Breuer, and K. L. Skorecki, J. Cell. Physiol. 138: 97-105, 1989). However, the calcium-independent pathways were not defined. Using fluorescent probes, we now demonstrate that ... More
Mitogen-induced changes in Ca2+ permeability are not mediated by voltage-gated K+ channels.
AuthorsGelfand EW, Cheung RK, Grinstein S
JournalJ Biol Chem
PubMed ID2427511
'Binding of mitogenic lectins to T lymphocytes results in elevated cytoplasmic Ca2+ concentrations ([Ca2+]i). This change in [Ca2+]i is thought to be essential for cellular proliferation. In addition, the lectins increase the conductance to K+ through voltage-sensitive channels. Based on the inhibitory effect of K+ channel blockers on lectin-induced mitogenesis, ... More
Chloride conductive pathways which support electrogenic H+ pumping by Leishmania major promastigotes.
AuthorsVieira L, Slotki I, Cabantchik ZI
JournalJ Biol Chem
PubMed ID7890641
'The proton extrusion mechanisms of Leishmania promastigotes were studied in terms of electrogenic movements of protons and anions (Cl- and HCO3-). Changes in membrane potential (Vm) and intracellular pH (pHi) were monitored fluorimetrically with the potential sensitive dye bis-oxonol and the pH-sensitive dye tetraacethoxymethyl 2',7'-bis-(carboxyethyl)-5,6-carboxyfluorescein, respectively. In nominal bicarbonate-free medium ... More
Development of resting membrane potentials of embryonic murine spinal cord cells evaluated by flow cytometric analysis.
AuthorsKrieger C, Puil E, Kim SU
JournalDev Neurosci
PubMed ID1647295
'The membrane electrical properties of embryonic murine spinal cord cells of embryonic day-10 (E10) to E14 were studied using a voltage-sensitive oxonol dye combined with fluorescence-activated cell sorting techniques. This period of development corresponds to the time when neurons differentiate from their neuroblast precursors. Bovine oligodendrocytes were also investigated in ... More
Sperm membrane potential: hyperpolarization during capacitation regulates zona pellucida-dependent acrosomal secretion.
AuthorsZeng Y, Clark EN, Florman HM
JournalDev Biol
PubMed ID7556936
'Membrane potential (VM) was investigated in mouse and bovine sperm populations. VM was determined from the fluorescence emission of the lipophilic anion, bis(1,3-diethylthiobarbituric acid)trimethine oxonol (DiSBAC2(3)), and from the lipophilic cation, 3,3''-dipropylthiodicarbocyanine iodide (DiSC3(5)). Fluorescent signals were corrected for contributions of mitochondrial potentials and apparent VM values were obtained by ... More
Interrelationship between cell pH and cell calcium in rat inner medullary collecting duct cells.
AuthorsSlotki I, Schwartz JH, Alexander EA
JournalAm J Physiol
PubMed ID8368272
'In this study we investigated the interrelationship between cell pH (pHi) and cell calcium (Cai) in cultured inner medullary collecting duct cells of the rat. Confluent monolayers were made quiescent by incubation for 24 h in Dulbecco''s modified Eagle''s medium supplemented with 0.1% serum before study. Changes in pHi and ... More
Human neutrophil stimulation by influenza virus: relationship of cytoplasmic pH changes to cell activation.
AuthorsHartshorn KL, Wright J, Collamer MA, White MR, Tauber AI
JournalAm J Physiol
PubMed ID2113768
'We have previously demonstrated that influenza A virus (IAV) stimulates the human neutrophil through phospholipase C activation. With the use of the fluorescent indicator 2'',7''-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF), cytoplasmic acidification and subsequent alkalinization are shown to accompany this activation. These responses are not inhibited by pertussis toxin (PT). The alkalinization is mediated ... More
Hydrodynamic hyperpolarization of endothelial cells.
AuthorsNakache M, Gaub HE
JournalProc Natl Acad Sci U S A
PubMed ID3162311
'The orientation and morphology of the endothelium lining the cardiovascular system may result from hemodynamic forces acting on the endothelial cells. To investigate the flow effects at the membrane level, we have examined the variations of the fluorescence intensity of two membrane-sensitive dyes, merocyanine 540 and bis(1,3-diethylthiobarbiturate)trimethineoxonol, (i) as a ... More
Activation by chemotactic peptide of a receptor-operated Ca2+ entry pathway in differentiated HL60 cells.
AuthorsMontero M, Garcia-Sancho J, Alvarez J
JournalJ Biol Chem
PubMed ID7961926
'N-Formyl-methionyl-leucyl-phenylalanine (fMLP) is able to accelerate Ca2+ entry into differentiated HL60 cells by a rather indirect mechanism consisting of the opening of a plasma membrane pathway activated by the emptying of the intracellular Ca2+ stores caused by the agonist. This Ca2+ pathway can also be fully activated by Ca2+ store ... More
Cytoplasmic [Ca2+] and intracellular pH in lymphocytes. Role of membrane potential and volume-activated Na+/H+ exchange.
AuthorsGrinstein S, Cohen S
JournalJ Gen Physiol
PubMed ID3559512
'The effect of elevating cytoplasmic Ca2+ [( Ca2+]i) on the intracellular pH (pHi) of thymic lymphocytes was investigated. In Na+-containing media, treatment of the cells with ionomycin, a divalent cation ionophore, induced a moderate cytoplasmic alkalinization. In the presence of amiloride or in Na+-free media, an acidification was observed. This ... More
Dicarbocyanine fluorescent probes of membrane potential block lymphocyte capping, deplete cellular ATP and inhibit respiration of isolated mitochondria.
AuthorsMontecucco C, Pozzan T, Rink T
JournalBiochim Biophys Acta
PubMed ID87222
'3,3''-Dipropylthiodicarbocyanine iodide, a widely used fluorescent probe of membrane potential, was found to inhibit anti-Ig antibody, induced capping of mouse lymphocytes. The dye also lowered the cell ATP content. Experiments with isolated mitochondria revealed that the probe had a potent inhibitory action at site I of the respiratory chain. This ... More
Cyclic AMP-induced depolarization measured by bis-oxonol fluorescence in bovine adrenal medullary chromaffin cells.
AuthorsMinami N, Morita K, Suemitsu T, Miyasako T, Dohi T
JournalJ Neural Transm Gen Sect
PubMed ID7888150
'Effects of cyclic AMP on membrane potentials were examined by measuring the changes of bis-oxonol fluorescence in bovine adrenal medullary chromaffin cells. 8-Bromo cyclic AMP (8Br-cAMP) or forskolin caused a gradual and long lasting increase of the fluorescence intensity. The effects of 8br-cAMP was blocked by cyclic AMP-dependent protein kinase ... More
Depolarization of rat basophilic leukemia cells inhibits calcium uptake and exocytosis.
AuthorsMohr FC, Fewtrell C
JournalJ Cell Biol
PubMed ID2950123
'We have investigated the unusual observation that depolarization of rat basophilic leukemia cells in high potassium not only fails to induce secretion, but also inhibits the secretion induced when receptors for IgE are aggregated by antigen. Antigen-stimulated 45Ca uptake and the rise in cytoplasmic free ionized calcium measured with the ... More
Plasma membrane potential modulates chemotactic peptide-stimulated cytosolic free Ca2+ changes in human neutrophils.
AuthorsDi Virgilio F, Lew PD, Andersson T, Pozzan T
JournalJ Biol Chem
PubMed ID2435712
'The relationship between fMet-Leu-Phe-induced changes in the cytosolic free Ca2+ concentration [( Ca2+]i), plasma membrane potential depolarization, and metabolic responses was studied in human neutrophils. Receptor-activated depolarization occurred both at high and resting [Ca2+]i, but was inhibited at very low [Ca2+]i. Phorbol 12-myristate 13-acetate-induced plasma membrane depolarization, on the contrary, ... More
Free cytoplasmic Ca2+ and neurotransmitter release: studies on PC12 cells and synaptosomes exposed to alpha-latrotoxin.
AuthorsMeldolesi J, Huttner WB, Tsien RY, Pozzan T
JournalProc Natl Acad Sci U S A
PubMed ID6141561
'The relationship between the free cytoplasmic Ca2+ concentration, [Ca2+]i, and neurotransmitter release was investigated in guinea pig brain synaptosomes and the neurosecretory cell line PC12. Release was induced by alpha-latrotoxin, which acts in both Ca2+ -containing and Ca2+ -free incubation media, or by the classical depolarizing agents high K+ and ... More
The relative contributions of extracellular and intracellular calcium to secretion from tumor mast cells. Multiple effects of the proton ionophore carbonyl cyanide m-chlorophenylhydrazone.
AuthorsMohr FC, Fewtrell C
JournalJ Biol Chem
PubMed ID2440869
'The proton ionophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) inhibited antigen-stimulated secretion and calcium influx in rat basophilic leukemia cells. In a glucose-free solution the inhibitory effects of CCCP were due to a decrease in the intracellular ATP concentration; however, when glucose was present there was no decrease in ATP. Instead, we ... More
Calcium entry-dependent oscillations of cytoplasmic calcium concentration in cultured endothelial cell monolayers.
AuthorsLaskey RE, Adams DJ, Cannell M, van Breemen C
JournalProc Natl Acad Sci U S A
PubMed ID1542661
'Bovine endothelial cell monolayers grown to confluence and stimulated with bradykinin responded with periodic fluctuations in intracellular Ca2+ concentration ([Ca2+]i) when exposed to K(+)-free Hepes-buffered saline. The fluctuations in [Ca2+]i measured with fura-2 were synchronized among the population of cells observed and were sensitive to extracellular Ca2+ concentration ([Ca2+]o). Thapsigargin, ... 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
A new method of monitoring membrane potential in rat hippocampal slices using cyanine voltage-sensitive dyes.
AuthorsDasheiff RM
JournalJ Neurosci Methods
PubMed ID4010331
'A novel application of voltage-sensitive dyes is described. Hippocampal slices in vitro accumulated voltage-sensitive cyanine dyes under conditions presumed to cause depolarization and hyperpolarization. Increasing extracellular potassium caused a depression of dye uptake that correlated linearly with the membrane potential calculated from the Goldman equation. Veratrine depressed dye uptake, and ... More
Modulation of Ca2+ influx dependent on store depletion by intracellular adenine-guanine nucleotide levels.
AuthorsGamberucci A, Innocenti B, Fulceri R, Bànhegyi G, Giunti R, Pozzan T, Benedetti A
JournalJ Biol Chem
PubMed ID8089128
'The effects of a number of metabolic inhibitors on the influx of Ca2+ activated by stimulation of receptors coupled to inositol 1,4,5-trisphosphate generation or by depletion of intracellular Ca2+ stores with thapsigargin were investigated in four different cell types: Ehrlich ascites tumor cells, Jurkat and HeLa cell lines, and rat ... More
Lysine N(epsilon)-trimethylation, a tool for improving the selectivity of antimicrobial peptides.
AuthorsFernández-Reyes M, Díaz D, de la Torre BG, Cabrales-Rico A, Vallès-Miret M, Jiménez-Barbero J, Andreu D, Rivas L,
JournalJ Med Chem
PubMed ID20617807
'The effects of lysine N(epsilon)-trimethylation at selected positions of the antimicrobial cecropin A-melittin hybrid peptide KWKLFKKIGAVLKVL-amide have been studied. All five monotrimethylated, four bis-trimethylated plus the per-trimethylated analogues have been synthesized and tested for antimicrobial activity on Leishmania parasites and on Gram-positive and -negative bacteria, as well as for hemolysis ... More
Galanin inhibits glucose-stimulated insulin release by a mechanism involving hyperpolarization and lowering of cytoplasmic free Ca2+ concentration.
AuthorsAhrén B, Arkhammar P, Berggren PO, Nilsson T
JournalBiochem Biophys Res Commun
PubMed ID2430570
'The intrapancreatic neuropeptide galanin has been demonstrated to lower plasma insulin levels in vivo. The effects of this peptide on insulin secretion, cytoplasmic free Ca2+ concentration and membrane potential have now been studied in vitro. Glucose-stimulated insulin secretion was inhibited by galanin under these conditions, indicating a direct effect of ... More
Calcium-activated potassium channels in lymphocytes.
AuthorsRink TJ, Deutsch C
JournalCell Calcium
PubMed ID6323008
Ion transport, membrane potential, and cytoplasmic pH in lymphocytes: changes during activation.
AuthorsGrinstein S, Dixon SJ
JournalPhysiol Rev
PubMed ID2648419
Confocal microscopy of potentiometric fluorescent dyes.
AuthorsLoew LM
JournalMethods Cell Biol
PubMed ID8246781
Optical methods to measure membrane transport processes.
AuthorsVerkman AS
JournalJ Membr Biol
PubMed ID8606370
Optical measurement of membrane potential in cells, organelles, and vesicles.
AuthorsFreedman JC, Novak TS
JournalMethods Enzymol
PubMed ID2747524
Cell membrane potential analysis.
AuthorsShapiro HM
JournalMethods Cell Biol
PubMed ID7532258
Signal processing in slit-scan flow cytometry of cell conjugates.
AuthorsBakker Schut TC, Florians A, Radosevic K, de Grooth BG, Greve J
JournalCytometry
PubMed ID8513700
The design and implementation of a real-time signal processing system for slit-scan flow cytometry is described. The system is used to measure the separate scatter and fluorescence peak heights of 2 adherent cells. Preliminary measurements of changes in the membrane potential induced by interactions between natural killer (NK) cells and ... More
Cytotoxic action of triphenyltin on mouse thymocytes: a flow-cytometric study using fluorescent dyes for membrane potential and intracellular Ca2+.
AuthorsOyama Y, Chikahisa L, Tomiyoshi F, Hayashi H
JournalJpn J Pharmacol
PubMed ID1813667
Effects of triphenyltin on mouse thymocytes were examined using fluorescent dyes to monitor membrane potential and intracellular Ca2+. Triphenyltin at 3 x 10(-7) M to 1 x 10(-6) M hyperpolarized thymocytes and depolarized them at 3 x 10(-6) M or more, associated with increasing intracellular Ca2+. Hyperpolarization was suppressed by ... More
Optical imaging of neuronal populations during decision-making.
AuthorsBriggman KL, Abarbanel HD, Kristan WB
JournalScience
PubMed ID15705844
We investigated decision-making in the leech nervous system by stimulating identical sensory inputs that sometimes elicit crawling and other times swimming. Neuronal populations were monitored with voltage-sensitive dyes after each stimulus. By quantifying the discrimination time of each neuron, we found single neurons that discriminate before the two behaviors are ... More
Insulin stimulation of glucose uptake and the transmembrane potential of muscle cells in culture.
AuthorsKlip A, Ramlal T, Walker D
JournalFEBS Lett
PubMed ID3527748
The membrane potential of L6 muscle cells was measured with the fluorescent dye bis-oxonol. Hyperpolarizations of up to 15 mV were caused by gramicidin (in N-methyl-D-glucamine+ medium), or by monensin or ionomycin. Depolarization was achieved with gramicidin (in Na+ medium), or with K+. Insulin did not change the resting membrane ... More
Identification of neural circuits by imaging coherent electrical activity with FRET-based dyes.
AuthorsCacciatore TW, Brodfuehrer PD, Gonzalez JE, Jiang T, Adams SR, Tsien RY, Kristan WB, Kleinfeld D
JournalNeuron
PubMed ID10433258
We show that neurons that underlie rhythmic patterns of electrical output may be identified by optical imaging and frequency-domain analysis. Our contrast agent is a two-component dye system in which changes in membrane potential modulate the relative emission between a pair of fluorophores. We demonstrate our methods with the circuit ... More
Method to improve the sensitivity of flow cytometric membrane potential measurements in mouse spinal cord cells.
AuthorsSeamer LC, Mandler RN
JournalCytometry
PubMed ID1633734
We have developed a technique to improve the sensitivity of relative membrane potential measurements in mouse spinal cord cells using the fluorescent, anionic, voltage sensitive dye, DiBa-C4(3) (Oxonol) and flow cytometry. In order to attribute cellular fluorescence primarily to membrane potential, signal variability due to cell size and shape was ... More
Tumor promoter phorbol myristate acetate inhibits Ca2+ influx through voltage-gated Ca2+ channels in two secretory cell lines, PC12 and RINm5F.
Protein kinase C is known to be involved both in initiation and termination of cellular responses due to phosphoinositide breakdown. Here we report that in PC12 cells (a line of neurosecretory cells derived from a rat pheochromocytoma), pretreatment with nanomolar concentrations of phorbol myristate acetate, PMA, which is believed to ... More
Comparative study of membrane potential-sensitive fluorescent probes and their use in ion channel screening assays.
AuthorsWolff C, Fuks B, Chatelain P,
JournalJ Biomol Screen
PubMed ID14567780
In this study, the authors compared and evaluated 4 membrane potential probes in the same cellular assay: the oxonol dye DiBAC(4)(3), the FLIPR membrane potential (FMP) dye (Molecular Devices), and 2 novel fluorescence resonance energy transfer (FRET) dye systems from PanVera [CC2-DMPE/DiSBAC(2)(3)] and Axiom [DiSBAC(1)(3)/DiSBAC(1)(5)]. The kinetic parameters of each ... More
Effect of ion composition on the changes in membrane potential induced with several stimuli in rat mast cells.
AuthorsCabado AG, Vieytes MR, Botana LM
JournalJ Cell Physiol
PubMed ID7508944
We studied, in different ionic conditions, the effect of various agents on the membrane potential of rat peritoneal mast cells using the fluorescent probe bisoxonol. Ouabain and ionophore A23187 lead to a fast depolarization of the plasma membrane of mast cells, while compound 48/80 and thapsigargin induced membrane hyperpolarization, which ... More
GABAA receptor-mediated increase of cytosolic Ca2+ in isolated bovine adrenal chromaffin cells.
AuthorsKitayama S, Morita K, Dohi T, Tsujimoto A
JournalBiochim Biophys Acta
PubMed ID2166586
We have studied the effects of GABA on cytosolic free Ca2+ concentration ([Ca2+]i) as a means of investigating the role of GABA in adrenal catecholamine (CA) secretion. It was demonstrated that GABA caused an elevation of [Ca2+]i via the GABAA receptor in a concentration-dependent manner, which was well correlated with ... More
ZP3-dependent activation of sperm cation channels regulates acrosomal secretion during mammalian fertilization.
AuthorsArnoult C, Zeng Y, Florman HM
JournalJ Cell Biol
PubMed ID8707844
The sperm acrosome reaction is a Ca(2+)-dependent secretory event required for fertilization. Adhesion to the egg's zona pellucida promotes Ca2+ influx through voltage-sensitive channels, thereby initiating secretion. We used potentiometric fluorescent probes to determine the role of sperm membrane potential in regulating Ca2+ entry. ZP3, the glycoprotein agonist of the ... More
Intracellular calcium homeostasis in a human neuroblastoma cell line: modulation by depolarization, cholinergic receptors, and alpha-latrotoxin.
AuthorsSher E, Gotti C, Pandiella A, Madeddu L, Clementi F
JournalJ Neurochem
PubMed ID2453611
Intracellular calcium homeostasis and its modulation by different agents was studied in control and differentiated IMR32 human neuroblastoma cells by using the Ca2+-sensitive fluorescent dye quin2. The results obtained demonstrate the existence in IMR32 cells of (a) voltage-dependent, verapamil sensitive, Ca2+ channels, which are expressed before differentiation; (b) muscarinic receptors ... More
Depolarization of osteoclast plasma membrane potential by 17beta-estradiol.
AuthorsBrubaker KD, Gay CV
JournalJ Bone Miner Res
PubMed ID10571686
The effect of estrogen on plasma membrane potential of isolated avian osteoclasts was examined through the use of a fluorescent potential-sensitive dye, bis-(1,3-dibutylbarbiturate) trimethine oxonol, also known as bis-oxonol. A decrease in potential was observed within seconds of addition of 17beta-estradiol. Ouabain, a specific Na+K+-ATPase inhibitor, and BaCl2, an inhibitor ... More
Plasma membrane hyperpolarization and [Ca2+]i increase induced by fibroblast growth factor in NIH-3T3 fibroblasts: resemblance to early signals generated by platelet-derived growth factor.
AuthorsPandiella A, Magni M, Meldolesi J
JournalBiochem Biophys Res Commun
PubMed ID2783138
The effects of different substances on [Ca2+]i and membrane potential (measured by fura-2 and bis-oxonol fluorescence techniques, respectively) were studied in wild-type and NIH-3T3 fibroblasts transfected with the cDNA encoding the human epidermal growth factor receptor. Application of partially purified PDGF or FGF induced, after a lag (0.5-1 min), a ... More
The A1 agonist CCPA reduced bisoxonol-monitored membrane potential depolarization elicited by high K+ in cerebrocortical nerve endings.
AuthorsAmoroso S, Iannotti E, Saggese ML, Di Renzo G, Annunziato L
JournalBiochim Biophys Acta
PubMed ID7548146
In this study the effect of the A1 agonist 2-chloro-N6-cyclopentyladenosine (CCPA) on bis(1,3-diethylthiobarbituric acid)trimethine oxonol (bisoxonol)-monitored membrane potential in cerebrocortical nerve endings was evaluated. CCPA (30, 100 and 300 microM) caused a dose-dependent decrease of high K(+)- and veratridine-induced membrane depolarization. This decrease was counteracted by the A1-specific antagonist 1,3-dipropyl-8-cyclopentylxanthine ... More
Evidence for a phorbol ester-insensitive phosphorylation step in capacitative calcium entry in rat thymic lymphocytes.
AuthorsMarriott I, Mason MJ
JournalJ Biol Chem
PubMed ID8900152
Experiments were undertaken to investigate the regulation of capacitative Ca2+ entry by phorbol ester-sensitive protein kinase C and serine/threonine protein phosphatase activity. The thapsigargin-activated Ca2+ entry pathway was probed in control cells and cells treated with phosphatase type 1/2A inhibitors, okadaic acid and calyculin A, or with the phorbol ester, ... More
Correlation between plasma membrane potential and second messenger generation in the promyelocytic cell line HL-60.
AuthorsPittet D, Di Virgilio F, Pozzan T, Monod A, Lew DP
JournalJ Biol Chem
PubMed ID1696945
The effects of plasma membrane depolarization on cytosolic free calcium ([Ca2+]i) and inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) generation were investigated in the human promyelocytic cell line HL-60 differentiated with either dimethyl sulfoxide or retinoic acid into neutrophil-like cells. Increases in [Ca2+]i and accumulation of Ins(1,4,5)P3 were triggered by two chemoattractants fMet-Leu-Phe and ... More
12-O-tetradecanoylphorbol 13-acetate and forskolin modify muscarinic receptor-linked Ca2+ mobilization in SH-SY5Y neuroblastoma cells through different mechanisms.
AuthorsAkerman KE, Heikkilä JE
JournalJ Neurochem
PubMed ID2299348
The phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA), which causes differentiation of SH-SY5Y neuroblastoma cells, reduces carbachol binding and carbachol-stimulated Ca2+ mobilization in these cells. The decrease in responsiveness to carbachol is due partially to a reduction in the amount of Ca2+ released by the cells and partially to a decrease in ... More
Characterization of the purinergic P2 receptors in PC12 cells. Evidence for a novel subtype.
AuthorsKim WK, Rabin RA
JournalJ Biol Chem
PubMed ID8119998
The properties of the purinergic receptors in the PC12 cells were studied. The rank order of potency to increase [Ca2+]i was: adenosine 5'-O-(1-thiotriphosphate) > ATP > adenosine 5'-O-(3-thiotriphosphate) >>> 3'-O-(4-benzoyl-benzoyl)ATP. ADP, AMP, GTP, UTP, alpha, beta- and beta,gamma-methylene adenosine 5'-triphosphates, 5'-adenylylimido-diphosphate, and adenosine analogues were ineffective. Although tetrabasic ATP4- was ... More
Toxin pharmacology of the ATP-induced hyperpolarization in Madin-Darby canine kidney cells.
AuthorsTauc M, Gastineau M, Poujeol P
JournalBiochim Biophys Acta
PubMed ID1373656
The effects of Leiurus quinquestriatus hebraeus (LQH) venom, mamba venom, Buthus tamulus (BT) venom, purified apamin and synthetic charybdotoxin on the membrane hyperpolarization induced by extracellular ATP were examined in Madin-Darby canine kidney cells. For this we used a membrane potential probe (bisoxonol) to determine the potential variations. The relation ... More
Flow cytometric detection of membrane potential changes in murine lymphocytes induced by concanavalin A.
AuthorsTatham PE, Delves PJ
JournalBiochem J
PubMed ID6540562
The effect of the mitogenic lectin concanavalin A on the membrane potential of murine lymphocytes was investigated by observing the fluorescence of cells stained with carbocyanine and oxonol dyes. We describe a rapid and reliable method for detecting lectin-induced membrane potential changes in individual cells by flow cytometric analysis of ... More
FRET-based voltage probes for confocal imaging: membrane potential oscillations throughout pancreatic islets.
AuthorsKuznetsov A, Bindokas VP, Marks JD, Philipson LH
JournalAm J Physiol Cell Physiol
PubMed ID15758044
Insulin secretion is dependent on coordinated pancreatic islet physiology. In the present study, we found a way to overcome the limitations of cellular electrophysiology to optically determine cell membrane potential (V(m)) throughout an islet by using a fast voltage optical dye pair. Using laser scanning confocal microscopy (LSCM), we observed ... More
Confocal ratiometric voltage imaging of cultured human keratinocytes reveals layer-specific responses to ATP.
Recent evidence suggests that changes in membrane potential influence the proliferation and differentiation of keratinocytes. To further elucidate the role of changes in membrane potential for their biological fate, the electrical behavior of keratinocytes needs to be studied under complex conditions such as multilayered cultures. However, electrophysiological recordings from cells ... More
Intracellular pH and the stimulus-secretion coupling in insulin-producing RINm5F cells.
AuthorsJuntti-Berggren L, Rorsman P, Siffert W, Berggren PO
JournalBiochem J
PubMed ID1417791
The regulation of intracellular pH (pHi) and its role in the insulin-secretory process were evaluated, by using the clonal insulin-secreting cell line RINm5F. Glyceraldehyde, lactate and dihydroxyacetone decreased pHi, but only the first two released insulin. In the presence of extracellular Na+ the cells counteracted the acidification. Blocking the Na+/H+ ... More
Determination of the viability of Trichomonas vaginalis using flow cytometry.
AuthorsHumphreys MJ, Allman R, Lloyd D
JournalCytometry
PubMed ID8026224
In clinical laboratories, viability of Trichomonas vaginalis is determined by using light microscopy (differential count of motile to nonmotile organisms). Alternative methods are proposed that utilise flow cytometry. Under an epifluorescence microscope, live organisms fluorescence intensely green with fluorescein diacetate (FDA), whereas dead cells fluoresce orange with propidium iodide (PI). ... More
Improved indicators of cell membrane potential that use fluorescence resonance energy transfer.
AuthorsGonzález JE, Tsien RY
JournalChem Biol
PubMed ID9195864
BACKGROUND: Fluorescence detection of cell membrane potentials is an important technique in neurobiology, cell physiology and pharmaceutical screening, but traditional one-fluorophore indicators either respond too slowly or have limited sensitivity. Recently, we introduced two-component sensors based on the transfer of fluorescence resonance energy from fluorescent lectins bound on one side ... More
Spreading of human endothelial cells on fibronectin or vitronectin triggers elevation of intracellular free calcium.
AuthorsSchwartz MA
JournalJ Cell Biol
PubMed ID7679387
Intracellular calcium ([Ca2+]i) was measured in FURA 2-loaded endothelial cells plated on fibronectin or vitronectin. Average values for [Ca2+]i increased to approximately twofold above basal levels by approximately 1 h after plating, and then declined. The increase in [Ca2+]i required extracellular calcium. Substituting potassium for sodium in the medium reduced ... More
IgE receptor-mediated depolarization of rat basophilic leukemia cells measured with the fluorescent probe bis-oxonol.
AuthorsMohr FC, Fewtrell C
JournalJ Immunol
PubMed ID2949017
Receptor-mediated changes in plasma membrane potential were recorded in rat basophilic leukemia (RBL) cells with the potential-sensitive fluorescent indicator bis-oxonol. Depolarization of the mitochondria with metabolic inhibitors was not detected by bis-oxonol, suggesting that only potential changes across the plasma membrane were being measured. The resting membrane potential of RBL ... More
Voltage-dependent increase in ionized cytoplasmic calcium in the L6H9 muscle cell line detected with quin2.
AuthorsKlip A, Mack E, Ramlal T, Walker D
JournalArch Biochem Biophys
PubMed ID2423034
The concentration of free Ca2+ ions in the cytoplasm ([Ca2+]i) is a key parameter in the function of muscle cells. This study describes the effect of membrane depolarization on [Ca2+]i in differentiating cells of the L6H9 line of rat skeletal muscle. [Ca2+]i was assessed using the fluorescent indicator quin2. In ... More
Inhibition of H2 histamine receptor-mediated cation channel opening by protein kinase C in human promyelocytic cells.
AuthorsSuh BC, Lee H, Jun DJ, Chun JS, Lee JH, Kim KT
JournalJ Immunol
PubMed ID11466390
Histamine, through H(2) receptors, triggers a prominent rise in intracellular free Ca(2+) concentration ([Ca(2+)](i)) in addition to an elevation of cAMP level in HL-60 promyelocytes. Here we show that the histamine-induced [Ca(2+)](i) rise was due to influx of Ca(2+) from the extracellular space, probably through nonselective cation channels, as incubation ... More
Transport system ASC for neutral amino acids. An electroneutral sodium/amino acid cotransport sensitive to the membrane potential.
AuthorsBussolati O, Laris PC, Rotoli BM, Dall'Asta V, Gazzola GC
JournalJ Biol Chem
PubMed ID1569087
The influx of L-threonine through system ASC does not influence the membrane potential in cultured human fibroblasts although comparable fluxes of amino acids through another Na(+)-dependent agency, system A, effectively depolarize the cells. The membrane potential, however, stimulates the influx of amino acids through system ASC with a maximal effect ... More
Lymphocyte membrane potential and Ca2+-sensitive potassium channels described by oxonol dye fluorescence measurements.
AuthorsWilson HA, Chused TM
JournalJ Cell Physiol
PubMed ID2413058
A method is described for quantitative measurement of lymphocyte transmembrane electrical potential difference (psi) by flow cytometric recording of the oxonol dye fluorescence of single cells. Both the simultaneous collection and analysis of multiple optical parameters and the use of a negatively charged oxonol probe allowed more accurate measurement of ... More
Effect of the sulfhydryl reagent thimerosal on cytosolic free Ca2+ and membrane potential of thymocytes.
The sulfhydryl reagent thimerosal at concentrations 5-100 microM has been found to induce a variety of changes in ion transport in rat thymocytes. In particular, [Ca2+]i increases about 10-fold from the basal level. The [Ca2+]i response to thimerosal displays a two-stage time course, with the main [Ca2+]i rise during the ... More
Membrane potential changes visualized in complete growth media through confocal laser scanning microscopy of bis-oxonol-loaded cells.
AuthorsDall'Asta V, Gatti R, Orlandini G, Rossi PA, Rotoli BM, Sala R, Bussolati O, Gazzola GC
JournalExp Cell Res
PubMed ID9087166
Confocal laser scanning microscopy (CLSM) was employed to visualize and measure membrane potential changes in several types of cultured adherent cells, such as human fibroblasts, mouse mammary tumor C127 cells, and human saphenous vein endothelial cells, preloaded with the anionic dye bis-1, 3,-diethylthiobarbituratetrimethineoxonol (bis-oxonol). The fluorescence of cell-associated bis-oxonol was ... More
Stimulation of transient elevations in cytosolic Ca2+ is related to inhibition of Pi transport in OK cells.
AuthorsMiyauchi A, Dobre V, Rickmeyer M, Cole J, Forte L, Hruska KA
JournalAm J Physiol
PubMed ID2396674
Stimulation of changes in cytosolic free calcium by parathyroid hormone was determined in three opossum kidney (OK) cell types, OK wild-type, OKP clone, and OKH clone. All three types of OK cells express parathyroid hormone (PTH)-sensitive adenylate cyclase and adenosine 3',5'-cyclic monophosphate (cAMP) production. However, only the OK wild-type and ... More
Vacuolar-type H+-ATPase regulates cytoplasmic pH in Toxoplasma gondii tachyzoites.
AuthorsMoreno SN, Zhong L, Lu HG, Souza WD, Benchimol M
JournalBiochem J
PubMed ID9480901
Cytoplasmic pH (pHi) regulation was studied in Toxoplasma gondii tachyzoites by using the fluorescent dye 2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein. Their mean baseline pHi (7.07+/-0.06; n=5) was not significantly affected in the absence of extracellular Na+, K+ or HCO3(-) but was significantly decreased in a dose-dependent manner by low concentrations of N, N'-dicyclohexylcarbodi-imide (DCCD), ... More
Activation of K+ and Cl- channels by Ca2+ and cyclic AMP in dissociated kidney epithelial (MDCK) cells.
AuthorsBreuer WV, Mack E, Rothstein A
JournalPflugers Arch
PubMed ID2456518
In dissociated MDCK cells, activators of the cyclic AMP system cause depolarization detectable by changes in fluorescence of the membrane potential sensitive dye bisoxonol. Addition of forskolin (60 microM), vasopressin (2 microM), 8-bromo-cyclic AMP (0.5 mM) or 1-epinephrine (10 microM) depolarized the cells substantially in low Cl- (5 mM) but ... More
Influence of Ca2+ on the plasma membrane potential and electrogenic uptake of glycine by myeloma cells. Involvement of a Ca2+-activated K+ channel.
AuthorsPershadsingh HA, Stubbs EB, Noteboom WD, Vorbeck ML, Martin AP
JournalBiochim Biophys Acta
PubMed ID2416348
The involvement of Ca2+-activated K+ channels in the regulation of the plasma membrane potential and electrogenic uptake of glycine in SP 2/0-AG14 lymphocytes was investigated using the potentiometric indicator 3,3'-diethylthiodicarbocyanine iodide. The resting membrane potential was estimated to be -57 +/- 6 mV (n = 4), a value similar to ... More
Hepoxilin A3 induces changes in cytosolic calcium, intracellular pH and membrane potential in human neutrophils.
AuthorsDho S, Grinstein S, Corey EJ, Su WG, Pace-Asciak CR
JournalBiochem J
PubMed ID2106877
The effects of hepoxilin A3 (HxA3), a 12-lipoxygenase metabolite of arachidonic acid, on cytosolic calcium ([Ca2+]i), intracellular pH (pHi), transmembrane potential and right-angle light scattering in human neutrophils were investigated. A rapid, transient elevation of [Ca2+]i was observed with HxA3 which was dependent on the concentration used. The effect of ... More
The relationship between mitogen-induced membrane potential changes and intracellular free calcium in human T-lymphocytes.
AuthorsTatham PE, O'Flynn K, Linch DC
JournalBiochim Biophys Acta
PubMed ID3485446
We have investigated the effects of mitogenic lectins on human T-lymphocytes, isolated from peripheral blood, and cells from the T-cell clone, HPB-ALL, using the fluorescent dyes, bis-thiobarbiturate tri-methineoxonol (bisoxonol) and quin2 to sense changes in membrane potential and intracellular free [Ca2+], respectively. The resting potential of both cell types is ... More
Activation of Ca2+-dependent K+ channels in human B lymphocytes by anti-immunoglobulin.
AuthorsMacDougall SL, Grinstein S, Gelfand EW
JournalJ Clin Invest
PubMed ID2448342
Many mammalian cell types exhibit Ca2+-dependent K+ channels, and activation of these channels by increasing intracellular calcium generally leads to a hyperpolarization of the plasma membrane. Their presence in B lymphocytes is as yet uncertain. Crosslinking Ig on the surface of B lymphocytes is known to increase the level of ... More
Inhibition of glucose-stimulated insulin release by alpha 2-adrenoceptor activation is parallelled by both a repolarization and a reduction in cytoplasmic free Ca2+ concentration.
AuthorsNilsson T, Arkhammar P, Rorsman P, Berggren PO
JournalJ Biol Chem
PubMed ID2892833
Effects of the alpha 2-adrenergic agonist clonidine on insulin release, membrane potential, and cytoplasmic free Ca2+ concentration ([Ca2+]i) were investigated using pancreatic beta-cells isolated from obese hyperglycemic mice. Addition of 2 microM clonidine promptly inhibited glucose-stimulated insulin release, an effect accompanied by a lowering in both membrane potential and [Ca2+]i. ... More
Flow cytometric analysis of altered mononuclear cell transmembrane potential induced by cyclosporin.
AuthorsTanner MK, Wellhausen SR, Klein JB
JournalCytometry
PubMed ID8432204
Immunosuppression by the fungal metabolite cyclosporin A (CsA) is characterized by functional inhibition, rather than destruction of cells. Because activation of immune cells involves intracellular signalling events associated with modulations of cell transmembrane potential (TMP), we tested the ability of cyclosporin A (CsA) to modulate immune mononuclear cell TMP in ... More
Dissociation of the pore-forming and phospholipase D activities stimulated via P2z purinergic receptors in BAC1.2F5 macrophages. Product inhibition of phospholipase D enzyme activity.
Authorsel-Moatassim C, Dubyak GR
JournalJ Biol Chem
PubMed ID7687997
We have previously reported that the occupancy of P2z purinergic receptors in BAC1.2F5 macrophages stimulates both the formation of nonselective membrane pores/channels and a novel phospholipase D (PLD) activity. In the present study, the relationship between these two P2z receptor-mediated responses was investigated. In [3H]oleic acid-labeled macrophages, isoosmotic replacement of ... More
Neutrophil hyperpolarization in response to a chemotactic peptide.
AuthorsLazzari KG, Proto P, Simons ER
JournalJ Biol Chem
PubMed ID2162827
The chemotactic peptide formylmethionyl-leucyl-phenylalanine (fMLP), at concentrations below 10(-9) M, elicits a sustained increase in the human neutrophil's membrane potential within 10 s of its addition. This hyperpolarization, detected with the fluorescent cationic potentiometric probes, 3,3'-dipentyloxacarbocyanine (diO-C5-(3)), and 1,1'-dipropyl-3,3,3',3'-tetramethylindocarbocyanine iodide (diI-C3-(3)), and with the anionic probe bis-(1,3-diethylthiobarbituric)trimethine oxonol (bis-oxonol), is ... More
The use of the potential-sensitive fluorescent probe bisoxonol in mast cells.
AuthorsBronner C, Landry Y
JournalBiochim Biophys Acta
PubMed ID1764450
The regulation of the plasma membrane potential of rat peritoneal mast cells at the resting state and during activation was investigated using bisoxonol as a potential-sensitive fluorescent dye. Fluorescence microphotography showed that this negatively charged probe was not only present in the plasma membrane, but was also distributed in the ... More
Generation of inositol phosphates, cytosolic Ca2+, and ionic fluxes in PC12 cells treated with bradykinin.
AuthorsFasolato C, Pandiella A, Meldolesi J, Pozzan T
JournalJ Biol Chem
PubMed ID3141420
Accumulation of inositol phosphates (Ins-Ps, revealed by high performance liquid chromatography), changes of the cytosolic free Ca2+ [( Ca2+]i, revealed by fura-2), membrane potential and ionic currents (revealed by bis-oxonol and patch clamping) were investigated in PC12 cells treated with bradykinin (BK). The phenomena observed were (a) due to the ... More
Dopamine inhibits cytosolic Ca2+ increases in rat lactotroph cells. Evidence of a dual mechanism of action.
AuthorsMalgaroli A, Vallar L, Elahi FR, Pozzan T, Spada A, Meldolesi J
JournalJ Biol Chem
PubMed ID2443499
Single rat lactotroph cells were studied after loading with the cytosolic free Ca2+ concentration ([Ca2+]i) indicator fura-2 either 1 or 3 days after cell dispersion. Under unstimulated conditions, two groups of lactotrophs were observed, the first (predominant at day 1) with large [Ca2+]i fluctuations (peaks up to 300 nM) probably ... More
Stimulus-response coupling in insulin-secreting HIT cells. Effects of secretagogues on cytosolic Ca2+, diacylglycerol, and protein kinase C activity.
AuthorsRegazzi R, Li GD, Deshusses J, Wollheim CB
JournalJ Biol Chem
PubMed ID2203766
The hamster islet B cell line HIT retains the ability to secret insulin in response to glucose and several receptor agonists. We used HIT cells to study the initial signaling events in glucose or receptor agonist-stimulated insulin secretion. Glucose stimulated insulin release from HIT cells in a dose-dependent manner with ... More
Characterization of the cyclic AMP-independent actions of somatostatin in GH cells. I. An increase in potassium conductance is responsible for both the hyperpolarization and the decrease in intracellular free calcium produced by somatostatin.
AuthorsKoch BD, Blalock JB, Schonbrunn A
JournalJ Biol Chem
PubMed ID2891695
The neuropeptide somatostatin causes membrane hyperpolarization and reduces the intracellular free calcium ion concentration ([Ca2+]i) in GH pituitary cells. In this study, we have used the fluorescent dyes bisoxonol (bis,-(1,3-diethylthiobarbiturate)-trimethineoxonol) and quin2 to elucidate the mechanisms by which these ionic effects are triggered. Addition of 100 nM somatostatin to GH4C1 ... More
The delta F508 mutation decreases the stability of cystic fibrosis transmembrane conductance regulator in the plasma membrane. Determination of functional half-lives on transfected cells.
AuthorsLukacs GL, Chang XB, Bear C, Kartner N, Mohamed A, Riordan JR, Grinstein S
JournalJ Biol Chem
PubMed ID7691813
Deletion of the phenylalanine at position 508 of the cystic fibrosis transmembrane conductance regulator (CFTR) is the most prevalent mutation in cystic fibrosis (CF). This mutation (delta F508CFTR) leads to a reduced cAMP-sensitive Cl- conductance in epithelial cells. While the mutant protein can function as a Cl- channel, it seems ... More
Lower electrical membrane potential and altered pHi homeostasis in multidrug-resistant (MDR) cells: further characterization of a series of MDR cell lines expressing different levels of P-glycoprotein.
AuthorsRoepe PD, Wei LY, Cruz J, Carlson D
JournalBiochemistry
PubMed ID8105888
Recently [Roepe, P.D. (1992) Biochemistry 31, 12555-12564], increased steady-state levels of chemotherapeutic drug efflux from multidrug-resistant (MDR) myeloma cells were correlated with intracellular alkalinization. To better understand elevated pHi in MDR cells, Na(+)- and Cl-dependent recovery of pHi upon intracellular acid or alkaline shock has been examined for this same ... More
Cellular responses to Pyrularia thionin are mediated by Ca2+ influx and phospholipase A2 activation and are inhibited by thionin tyrosine iodination.
AuthorsEvans J, Wang YD, Shaw KP, Vernon LP
JournalProc Natl Acad Sci U S A
PubMed ID2503825
Pyrularia thionin, isolated from nuts of Pyrularia pubera, is a strongly basic peptide of 47 amino acids. The amino acid sequence and configuration of its four disulfide bonds place this plant peptide, known to be hemolytic, cytotoxic, and neurotoxic, among the thionins. We report and compare several cellular responses mediated ... More
Lymphocyte membrane potential assessed with fluorescent probes.
AuthorsRink TJ, Montecucco C, Hesketh TR, Tsien RY
JournalBiochim Biophys Acta
PubMed ID6153065
The membrane potential of mouse spleen lymphocytes has been assessed with two fluorescent probes. 3,3'-Dipropylthiadicarbocyanine (diS-C3-(5)) was used for most of the experiments. Solutions with high K+ concentrations depolarised the cells. Valinomycin, an inophore which adds a highly K+-selective permeability membranes, slightly hyperpolarised cells in standard (6 mM K+) solution, ... More
Galanin can inhibit insulin release by a mechanism other than membrane hyperpolarization or inhibition of adenylate cyclase.
AuthorsSharp GW, Le Marchand-Brustel Y, Yada T, Russo LL, Bliss CR, Cormont M, Monge L, Van Obberghen E
JournalJ Biol Chem
PubMed ID2468668
Studies on the mode of action of galanin to inhibit insulin release in RINm5F cells have shown that basal and glyceraldehyde-stimulated release were both inhibited. Galanin was inhibitory at concentrations in the low nanomolar range. Binding studies with 125I-labeled galanin indicated that the RINm5F cells exhibit a single set of ... More
Effect of increases in cytosolic Ca2+ on inner medullary collecting duct cell pH.
AuthorsSlotki IN, Schwartz JH, Alexander EA
JournalAm J Physiol
PubMed ID2764121
Changes in cytosolic calcium concentration (Cai2+) have been implicated in the regulation of intracellular pH (pHi) in several cell types. In the present study we investigated the mechanism by which an increase in Cai2+ stimulates H+ secretion and a rise in pHi in cultured rat inner medullary collecting duct (IMCD) ... More
Slow fluorescent indicators of membrane potential: a survey of different approaches to probe response analysis.
AuthorsPlásek J, Sigler K
JournalJ Photochem Photobiol B
PubMed ID8691353
Basic tenets related to the use of three main classes of potentiometric redistribution fluorescent dyes (carbocyanines, oxonols, and rhodamines) are discussed in detail. They include the structure/function relationship, formation of nonfluorescent (H-type) and fluorescent (J-type) dimers and higher aggregates, probe partitioning between membranes and medium and binding to membranes and ... More