Ion selectivities of the Ca(2+) sensors for exocytosis in rat phaeochromocytoma cells.
AuthorsKishimoto T, Liu TT, Ninomiya Y, Takagi H, Yoshioka T, Ellis-Davies GC, Miyashita Y, Kasai H
JournalJ Physiol
PubMed ID11410622
'1. The ion selectivities of the Ca(2+) sensors for the two components of exocytosis in rat phaeochromocytoma (PC12) cells were examined by measurement of membrane capacitance and amperometry. The cytosolic concentrations of metal ions were increased by photolysis of caged-Ca(2+) compounds and measured with low-affinity indicators benzothiazole coumarin (BTC) or ... More
The binding of calcium to the B-repeat segment of SdrD, a cell surface protein of Staphylococcus aureus.
AuthorsJosefsson E, O'Connell D, Foster TJ, Durussel I, Cox JA
JournalJ Biol Chem
PubMed ID9813018
'In the Sdr family of Staphylococcus aureus cell surface proteins, three recently cloned members (Josefsson, E., McCrea, K., Ni Eidhin, D., O''Connell, D., Cox, J. A., Hook, M., and Foster, T. (1998) Microbiology, in press) display variable numbers of B-repeats, i.e. segments of 110-113 residues that probably make up one ... More
Photolysis-induced suppression of inhibition in rat hippocampal CA1 pyramidal neurons.
AuthorsWang J, Zucker RS
JournalJ Physiol
PubMed ID11410632
'1. Whole cell patch clamp recording, Ca(2+) measurement with ratiometric fluorescent dyes and photolysis of caged Ca(2+) were combined to investigate the depolarization- and photolysis-induced suppression of inhibition (DSI and PSI) in rat hippocampal CA1 pyramidal cells. 2. A 5-s depolarization from -70 mV to 0 mV or a 6-s ... More
'Cytosolic calcium ([Ca2+]i) is an important mediator of neuronal signal transduction, participating in diverse biochemical reactions that elicit changes in synaptic efficacy, metabolic rate, and gene transcription. Excessive [Ca2+]i also has been implicated as a cause of acute neuronal injury, although measurement of [Ca2+]i in living neurons by fluorescent calcium ... More
Ionic selectivity of low-affinity ratiometric calcium indicators: mag-Fura-2, Fura-2FF and BTC.
AuthorsHyrc KL, Bownik JM, Goldberg MP
JournalCell Calcium
PubMed ID10756974
'Accurate measurement of elevated intracellular calcium levels requires indicators with low calcium affinity and high selectivity. We examined fluorescence spectral properties and ionic specificity of three low-affinity, ratiometric indicators structurally related to Fura-2: mag-Fura-2 (furaptra), Fura-2FF, and BTC. The indicators differed in respect to their excitation wavelengths, affinity for Ca2+ ... More
Ca2+-dependent exocytotic pathways in Chinese hamster ovary fibroblasts revealed by a caged-Ca2+ compound.
AuthorsNinomiya Y, Kishimoto T, Miyashita Y, Kasai H
JournalJ Biol Chem
PubMed ID8663485
'Ca2+-dependent exocytosis and endocytosis of Chinese hamster ovary (CHO) fibroblasts were investigated using capacitance measurement and rapid photolysis of a caged-Ca2+ compound, dimethoxynitrophenamine tetrasodium salt. CHO cells exhibited large and fast increases in membrane capacitance (1.9 +/- 1 picofarads, or 13 +/- 7% of total membrane area, mean +/- S.D., ... More
Poisson-distributed active fusion complexes underlie the control of the rate and extent of exocytosis by calcium.
AuthorsVogel SS, Blank PS, Zimmerberg J
JournalJ Cell Biol
PubMed ID8707819
'We have investigated the consequences of having multiple fusion complexes on exocytotic granules, and have identified a new principle for interpreting the calcium dependence of calcium-triggered exocytosis. Strikingly different physiological responses to calcium are expected when active fusion complexes are distributed between granules in a deterministic or probabilistic manner. We ... More
Detection of cardiovascular calcified deposits via tetracarboxylate ion dye (BTC) probing and laser-induced fluorescence spectroscopy.
AuthorsPapazoglou TG, Iatridou H, Foukaraki E, Katerinopoulos HE
JournalJ Photochem Photobiol B
PubMed ID7699525
In order to develop a reliable, laser-induced, fluorescence-guided, angioplasty system, fluorescence spectra were recorded during exposure of normal and atherosclerotic cadaveric aortic tissue to argon ion laser irradiation. A characteristic increase in the fluorescence signal in the 520-560 nm spectral region for atheromatous tissue was observed after treatment of the ... More
The development of a new family of intracellular calcium probes.
AuthorsIatridou H, Foukaraki E, Kuhn MA, Marcus EM, Haugland RP, Katerinopoulos HE
JournalCell Calcium
PubMed ID8149419
Four new potential fluorescent probes for Ca2+ using the coumarin moiety as a fluorophore have been synthesized and their spectral properties and binding affinities for Ca2+ determined. The most promising derivative for intracellular use, BTC, exhibits an excitation wavelength shift from 462 nm to 401 nm on binding Ca2+, with ... More
Multiple exocytotic pathways in pancreatic beta cells.
AuthorsTakahashi N, Kadowaki T, Yazaki Y, Miyashita Y, Kasai H
JournalJ Cell Biol
PubMed ID9214381
Ca2+-dependent exocytotic pathways in mouse pancreatic beta cells were investigated using both capacitance measurement and amperometric detection of vesicular contents. Serotonin was preloaded into large dense-core vesicles for the amperometry. Exocytosis was induced by rapid elevation of cytosolic Ca2+ concentrations using caged-Ca2+ compounds. Capacitance measurement revealed two major components of ... More
Dynamic behavior of rod photoreceptor disks.
AuthorsChen C, Jiang Y, Koutalos Y
JournalBiophys J
PubMed ID12202366
Eukaryotic cells use membrane organelles, like the endoplasmic reticulum or the Golgi, to carry out different functions. Vertebrate rod photoreceptors use hundreds of membrane sacs (the disks) for the detection of light. We have used fluorescent tracers and single cell imaging to study the properties of rod photoreceptor disks. Labeling ... More
Properties of tri- and tetracarboxylate Ca2+ indicators in frog skeletal muscle fibers.
AuthorsZhao M, Hollingworth S, Baylor SM
JournalBiophys J
PubMed ID8789107
Recently a number of lower-affinity fluorescent Ca2+ indicators have become available with principal absorbance bands at visible wavelengths. This article evaluates these indicators, as well as two shorter wavelength indicators, mag-fura-5 and mag-indo-1, for their suitability as rapid Ca2+ indicators in frog skeletal muscle fibers. With three lower-affinity tricarboxylate indicators ... More
Neuronal free calcium measurement using BTC/AM, a low affinity calcium indicator.
AuthorsHyrc KL, Bownik JM, Goldberg MP
JournalCell Calcium
PubMed ID9883271
BTC is a low affinity calcium indicator (Kd approximately 7-26 microM) featuring many desirable properties for cellular calcium imaging, including long excitation wavelengths (400/485 nm), low sensitivity to Mg2+, and accuracy of ratiometric measurement [Iatridou H., Foukaraki E., Kuhn M.A., Marcus E.M., Haugland R.P., Katerinopoulos H.E. The development of a ... More
Presynaptic target of Ca2+ action on neuropeptide and acetylcholine release in Aplysia californica.
1. When buccal neuron B2 of Aplysia californica is co-cultured with sensory neurons (SNs), slow peptidergic synapses are formed. When B2 is co-cultured with neurons B3 or B6, fast cholinergic synapses are formed. 2. Patch pipettes were used to voltage clamp pre- and postsynaptic neurons and to load the caged ... More
Fast exocytosis with few Ca(2+) channels in insulin-secreting mouse pancreatic B cells.
AuthorsBarg S, Ma X, Eliasson L, Galvanovskis J, Göpel SO, Obermüller S, Platzer J, Renström E, Trus M, Atlas D, Striessnig J, Rorsman P
JournalBiophys J
PubMed ID11720994
The association of L-type Ca(2+) channels to the secretory granules and its functional significance to secretion was investigated in mouse pancreatic B cells. Nonstationary fluctuation analysis showed that the B cell is equipped with <500 alpha1(C) L-type Ca(2+) channels, corresponding to a Ca(2+) channel density of 0.9 channels per microm(2). ... More
Calcium transients in cerebellar granule cell presynaptic terminals.
AuthorsRegehr WG, Atluri PP
JournalBiophys J
PubMed ID7612860
Calcium ions act presynaptically to modulate synaptic strength and to trigger neurotransmitter release. Here we detect stimulus-evoked changes in residual free calcium ([Ca2+]i) in rat cerebellar granule cell presynaptic terminals. Granule cell axons, known as parallel fibers, and their associated boutons, were labeled with several calcium indicators. When parallel fibers ... More
Two components of exocytosis and endocytosis in phaeochromocytoma cells studied using caged Ca2+ compounds.
AuthorsKasai H, Takagi H, Ninomiya Y, Kishimoto T, Ito K, Yoshida A, Yoshioka T, Miyashita Y
JournalJ Physiol
PubMed ID8814606
1. Changes in membrane capacitance evoked by the rapid photolysis of a caged Ca2+ compound, DM-nitrophen or nitrophenyl-EGTA, were investigated in undifferentiated PC12 cells. They were interpreted as representing exocytosis and endocytosis. 2. The Ca2+ jumps evoked two components of exocytosis. Slow exocytosis was selectively evoked with small increases in ... More
Cyclosporin A inhibits inositol 1,4,5-trisphosphate-dependent Ca2+ signals by enhancing Ca2+ uptake into the endoplasmic reticulum and mitochondria.
AuthorsSmaili SS, Stellato KA, Burnett P, Thomas AP, Gaspers LD
JournalJ Biol Chem
PubMed ID11323421
Cytosolic Ca(2+) ([Ca(2+)](i)) oscillations may be generated by the inositol 1,4,5-trisphosphate receptor (IP(3)R) driven through cycles of activation/inactivation by local Ca(2+) feedback. Consequently, modulation of the local Ca(2+) gradients influences IP(3)R excitability as well as the duration and amplitude of the [Ca(2+)](i) oscillations. In the present work, we demonstrate that ... More