Disease relevance of Furaptra

• By fluorescence spectroscopy with furaptra-loaded cells, the free intracellular Mg2+ concentration within the intact neuroblastoma cells was found to increase from 0 [1].
• The intracellular magnesium and calcium concentrations in cultured dorsal root ganglion neurons were measured using a fluorescent Mg2+ indicator, Mag-Fura-2 and a Ca2+ indicator, Fura-2, respectively [2].
• Fluorescence measurements of free [Mg2+] by use of mag-fura 2 in Salmonella enterica [3].
• To test the hypothesis that abnormal platelet Ca2+ handling in essential hypertension results from cellular Mg2+ deficiency, cytosolic free Mg2+ concentration ([Mg2+]i) and Ca2+ metabolism were studied in mag-fura 2 and fura 2-loaded platelets from 30 essential hypertensive patients and 30 sex- and age-matched normotensive controls [4].

High impact information on Furaptra

• METHODS: We evaluated the effects of DCA on Ca2+ signaling in BHK-21 fibroblasts using fura-2 and mag-fura-2 to measure cytoplasmic and intraluminal internal stores [Ca2+], respectively [5].
• Making use of the fluorescent dye mag-fura 2 to measure free Mg(2+) concentrations continuously, we describe here a high capacity, rapid Mg(2+) influx system in isolated yeast mitochondria, driven by the mitochondrial membrane potential Deltapsi and inhibited by cobalt(III)hexaammine [6].
• Ca homeostasis in thapsigargin-sensitive internal Ca stores of single permeabilized BHK-21 fibroblasts was examined using digital image processing of compartmentalized mag-fura-2 (a low-affinity Ca indicator) [7].
• Free [Ca] within organelles of permeabilized BHK-21 cells was measured using ratio imaging of compartmentalized mag-fura-2 [8].
• In experiments using cells loaded with mag-fura-2 to report endoplasmic reticulum Ca(2+), Msp reduced Ca(2+) efflux from endoplasmic reticulum stores when ATP was used as an agonist [9].

Biological context of Furaptra

• In fibers containing less than 0.5 mM furaptra and stimulated by a single action potential, the calibrated peak value of delta[Ca2+] averaged 5.1 (+/- 0.3, SEM) microM [10].
• These binding kinetics do not explain the difference in the size of the [Ca2+]i transients reported by fura-2 and furaptra [11].
• The continuation of exocytosis was correlated with a persistent increase in [Ca2+]i in the synaptic terminal, as indicated by the activation of a Ca2+-dependent conductance and measurements of [Ca2+]i using the fluorescent indicator furaptra [12].
• As detected with Mag-Fura-2, a brief 50ms light flash activated rapid Ca(2+) depletion of SER, followed by an effective refilling within 1min of dark adaptation after the light flash [13].
• Furaptra is present at high concentrations (up to 500 microM) in the matrix when introduced by hydrolysis of the acetoxymethyl ester [14].

Anatomical context of Furaptra

• To investigate the mechanism responsible for this quantal release phenomenon, [Ca2+] changes inside intracellular stores in isolated single smooth muscle cells were monitored with mag-fura 2 [15].
• Free Ca2+ was measured in intracellular stores of individual mouse pancreatic beta-cells using dual-wavelength microfluorometry and the low-affinity Ca2+ indicator furaptra [16].
• Controlled permeabilization of the plasma membrane with 4 micromol/l digitonin revealed that 22% of the furaptra was trapped in intracellular nonnuclear compartments [16].
• Porcine aortic endothelial cells were extensively coupled, as assessed by gap junctional transfer of Lucifer yellow and the fluorescent calcium indicators fluo-3 and furaptra, but were not permeable to rhodamine B isothiocyanate-dextran 10S [17].
• Myoplasmic calcium transients in intact frog skeletal muscle fibers monitored with the fluorescent indicator furaptra [10].

Associations of Furaptra with other chemical compounds

• Effects of extracellular magnesium ions ([Mg2+]o) on intracellular free Mg2+ ([Mg2+]i) and its subcellular distribution in single fission yeast cells, Schizosaccharomyces pombe, were studied with digital-imaging microscopy and an Mg2+ fluorescent probe (mag-fura-2) [18].
• 1. The concentration of free Mg2+ ([Mg2+]m) within the matrix of isolated rat heart mitochondria was measured after loading of the mitochondria with the fluorescent Mg2+ indicators mag-indo-1 and mag-fura-2 [19].
• Apparent free cytoplasmic concentrations of Mg2+ ([Mg2+]i) and Na+ ([Na+]i) were estimated in rat ventricular myocytes using fluorescent indicators, furaptra (mag-fura-2) for Mg2+ and sodium-binding benzofuran isophthalate for Na+, at 25 degrees C in Ca2+-free conditions [20].
• 1. The potentiation by Ca2+ of inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release was studied by measuring luminal Ca2+ concentrations of the Ca2+ stores using a fluorescent Ca2+ indicator, furaptra, in permeabilized smooth muscle cells [21].
• Simultaneous Ca2+ measurements in the cytosol and intracellular stores (IS) of rat hepatocytes were performed using two Ca(2+)-sensitive probes (Fluo-3 and Mag-fura-2), and combined whole-cell patch clamp and fluorescence microscopy [22].

Gene context of Furaptra

• Ionic selectivity of low-affinity ratiometric calcium indicators: mag-Fura-2, Fura-2FF and BTC [23].
• The peak calcium transient studied with mag-fura-2 (400 microM) was 6.3 +/- 0.4 microM and 4.2 +/- 0.3 microM for young and old muscle fibers, respectively [24].
• In cells loaded with the Mg(2+)-sensitive fluorescent indicator, Mag-fura-2, intracellular Mg2+ concentration ([Mg2+]i) increased after exposure to EGF after a 5-min lag; a similar lag was routinely observed before the stimulation of 28Mg2+ uptake by EGF [25].
• Because the total Mg content and cell volume remained constant during this time, the difference between the amount of Mg2+ liberated (2.7 mM) and the 0.9 mM increase in cytosolic Mg2+ activity measured fluorometrically with mag-fura-2 indicates a sizable Mg2+ buffering [26].

Analytical, diagnostic and therapeutic context of Furaptra

• Fluorometry with the dye, mag-fura-2, was used to characterize intracellular Mg2+ concentration ([Mg2+]i) in single cTAL cells [27].
• The regulation of the intracellular free Mg2+ concentration ([Mg2+]i) was monitored in rat sublingual mucous acini using dual wavelength microfluorometry of the Mg(2+)-sensitive dye mag-fura-2 [28].
• Recordings using the low-affinity dye mag-fura-2 and a Cs+-based intracellular solution revealed a similar pattern of hot spots in response to depolarisation, ruling out measurement artefacts or possible effects of inhomogeneous dye distribution in the generation of hot spots [29].
• Extracellular perfusion of muscle fibers with high Mg2+ concentration solution or low Na+ concentration solution did not cause any detectable changes in the [Mg2+]-related furaptra fluorescence within 4 min [30].
• 3. In the current study we used the low-affinity Ca2+ indicator mag-fura-2 to reexamine the spatiotemporal distribution pattern of Ca2+ after axotomy and to map the free intracellular Mg2+ concentration gradients [31].

References