NMR studies of the effect of hyperglycemia on intracellular cations in rat kidney.
AuthorsDowd TL, Gupta RK
JournalJ Biol Chem
PubMed ID8419377
'Alterations in intracellular cation concentrations in the kidney during hyperglycemia may play a role in a number of complications associated with diabetes mellitus such as renal hypertrophy and hypertension. In this study, we have investigated the effect of 25 mM glucose on intracellular pH and free Mg2+, free Ca2+, and ... More
Methylmercury-induced elevations in intrasynaptosomal zinc concentrations: an 19F-NMR study.
AuthorsDenny MF, Atchison WD
JournalJ Neurochem
PubMed ID8207443
'Methylmercury (MeHg) increases the concentration of intracellular Ca2+ ([Ca2+]i) and another endogenous polyvalent cation in both synaptosomes and NG108-15 cells. In synaptosomes, the elevation in [Ca2+]i was strictly dependent on extracellular Ca2+ (Ca2+e); similarly, in NG108-15 cells, a component of the elevations in [Ca2+]i was Ca2+e dependent. The MeHg-induced elevations ... More
19F nuclear magnetic resonance studies of free calcium in heart cells.
AuthorsGupta RK, Wittenberg BA
JournalBiophys J
PubMed ID8312491
'19F nuclear magnetic resonance is used in conjunction with 5,5''-difluoro-1,2-bis(o-aminophenoxy)ethane-N,N,N'',N''-tetraacetic acid (5FBapta), a fluorinated calcium chelator, to report steady-state intracellular free calcium levels ([Ca2+]i) in populations of resting, quiescent, isolated adult heart cells. 31P nuclear magnetic resonance shows that 5FBapta-loaded cells maintain normal intracellular high-energy phosphates, pH, and free Mg2+. ... More
19F-NMR study of the effect of lead on intracellular free calcium in human platelets.
AuthorsDowd TL, Gupta RK
JournalBiochim Biophys Acta
PubMed ID1904777
'Lead has been shown to affect calcium homeostasis. However, there is no prior evidence to indicate an effect of low concentrations of lead in the environment (approximately 1 microM) on the intracellular free Ca2+ concentration in any human tissue. We have investigated the effect of lead on the intracellular free ... More
Calcium regulates the association between mitochondria and a smooth subdomain of the endoplasmic reticulum.
AuthorsWang HJ, Guay G, Pogan L, Sauvé R, Nabi IR
JournalJ Cell Biol
PubMed ID10995452
'Association between the ER and mitochondria has long been observed, and the formation of close contacts between ER and mitochondria is necessary for the ER-mediated sequestration of cytosolic calcium by mitochondria. Autocrine motility factor receptor (AMF-R) is a marker for a smooth subdomain of the ER, shown here by confocal ... More
Digital imaging of free calcium changes and of spatial gradients in growing processes in single, mammalian central nervous system cells.
AuthorsConnor JA
JournalProc Natl Acad Sci U S A
PubMed ID3461482
'Intracellular free calcium levels have been measured in cultured central nervous system (CNS) cells by using the fluorescent indicator fura-2 and digital imaging techniques. Cells were plated from rat embryo diencephalon (embryonic day 17 or 18), with nearly all of the cells surviving dissociation having undergone final mitosis within the ... More
Cell-permeant Ca2+ chelators reduce early excitotoxic and ischemic neuronal injury in vitro and in vivo.
AuthorsTymianski M, Wallace MC, Spigelman I, Uno M, Carlen PL, Tator CH, Charlton MP
JournalNeuron
PubMed ID8102532
'We report the characterization of the first successful treatment of neuronal ischemic injury in vivo by cell-permeant Ca2+ chelators. The chelators attenuated glutamate-induced intracellular Ca2+ increases and neurotoxicity in neuronal explant cultures. When infused intravenously in rats, permeant fluorescent BAPTA analogs accumulated in neurons in several brain regions. BAPTA-AM, infused ... More
Factors determining the specificity of signal transduction by guanine nucleotide-binding protein-coupled receptors. III. Coupling of alpha 2-adrenergic receptor subtypes in a cell type-specific manner.
AuthorsDuzic E, Lanier SM
JournalJ Biol Chem
PubMed ID1358886
'A number of diverse signaling pathways can be activated by G-protein coupled receptors. However, the factors involved in selection of a particular transduction pathway by a single receptor are not well understood. We are attempting to address this issue utilizing the alpha 2-adrenergic receptor (alpha 2-AR) subfamily as a representative ... More
Measurement of intracellular Ca2+ in young and old human erythrocytes using 19F-NMR spectroscopy.
AuthorsAiken NR, Satterlee JD, Galey WR
JournalBiochim Biophys Acta
PubMed ID1504100
'Elevated cell calcium has been implicated in functional changes with human erythrocyte aging. However, until recently it has been difficult to measure free ionic intracellular calcium in red cells. We have made use of a fluorinated calcium chelator probe (5,5''-difluoroBAPTA) and fluorine nuclear magnetic resonance (19F-NMR) techniques to measure changes ... More
Lead increases free Ca2+ concentration in cultured osteoblastic bone cells: simultaneous detection of intracellular free Pb2+ by 19F NMR.
AuthorsSchanne FA, Dowd TL, Gupta RK, Rosen JF
JournalProc Natl Acad Sci U S A
PubMed ID2500664
Lead (Pb) has been shown to perturb Ca-mediated cellular processes. However, to date, a direct effect of Pb on intracellular free Ca2+ concentration ([Ca2+]i) has not been demonstrated. 19F NMR in combination with 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (5F-BAPTA) was used to simultaneously measure [Ca2+]i and intracellular free Pb2+ concentration ([Pb2+]i) in the ... More
Intracellular calcium measurements by 19F NMR of fluorine-labeled chelators.
Symmetrically substituted difluoro derivatives of 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (nFBAPTA) show large 19F NMR chemical shifts on chelating divalent cations. The complexes of Ca2+ with 4FBAPTA and 5FBAPTA show fast and slow exchange behavior, respectively, and the chemical shift or the areas of the resonances from the free and complexed forms can ... More
19F NMR magnetization transfer between 5-FBAPTA and its complexes. An alternative means for measuring free Ca2+ concentration, and detection of complexes with protein in erythrocytes.
AuthorsGilboa H, Chapman BE, Kuchel PW
JournalNMR Biomed
PubMed ID7718434
The 19F NMR Ca(2+)-indicator molecule 5,5'-difluoro-1,2-bis(o- aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (5-FBAPTA) was used in a procedure that enhances its range of applications to measuring free Ca2+ concentrations in buffer solutions and human erythrocytes. Even if the signal from the Ca-5-FBAPTA complex was not visible, the concentration of the complex could be calculated ... More
Nuclear magnetic resonance measurement of cytosolic free calcium levels in human red blood cells.
AuthorsMurphy E, Levy L, Berkowitz LR, Orringer EP, Gabel SA, London RE
JournalAm J Physiol
PubMed ID3094375
Red blood cells were loaded with 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (FBAPTA) by incubation with 50 microM of the acetoxymethyl ester (FBAPTA-AM), and cytosolic free Ca2+ was monitored with 19F-nuclear magnetic resonance (NMR). Loading with 50 microM FBAPTA-AM, which results in a final FBAPTA level of approximately 0.5 mM, caused only a 25-30% ... More
Extracellular Mg2+ inhibits both histamine-stimulated Ca(2+)-signaling and exocytosis in human tracheal secretory gland cells.
AuthorsSebille S, Pereira M, Millot JM, Jacquot J, Delabroise AM, Arnaud M, Manfait M
JournalBiochem Biophys Res Commun
PubMed ID9600077
The effects of extracellular Mg2+ concentration have been investigated on the histamine-stimulated exocytotic process of human tracheal secretory gland (HTG) cells. The exocytosis of secretory granules (SG) was observed concomitantly with dynamic changes of intracellular Ca2+ ([Ca2+]i) and Mg2+ concentrations ([Mg2+]i). The rate of SG exocytosis was appraised by the ... More
Use of 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (5FBAPTA) in the measurement of free intracellular calcium in the brain by 19F-nuclear magnetic resonance spectroscopy.
AuthorsBadar-Goffer RS, Ben-Yoseph O, Dolin SJ, Morris PG, Smith GA, Bachelard HS
JournalJ Neurochem
PubMed ID2117051
We have applied the 19F-nuclear magnetic resonance (NMR) calcium indicator 1,2-bis(2-amino-5-fluoro-phenoxy)ethane-N,N,N',N'-tetraacetic acid (5FBAPTA) to the measurement of the free intracellular calcium concentration [( Ca2+]i) in superfused brain slices. A mean +/- SD control value of 380 +/- 71 nM (n = 18) was obtained at 37 degrees C using 2.4 ... More
Increased intracellular Ca2+: a critical link in the pathophysiology of sepsis?
AuthorsSong SK, Karl IE, Ackerman JJ, Hotchkiss RS
JournalProc Natl Acad Sci U S A
PubMed ID8483913
Severe bloodstream-borne infection--i.e., sepsis--and the resulting multiorgan failure are now the most common cause of death in many intensive care units. One of the most fundamentally important and controversial issues concerning the pathophysiology of sepsis is the role of intracellular free calcium concentration ([Ca2+]i) in this disorder. Because of the ... More
Intracellular free calcium concentration measured with 19F NMR spectroscopy in intact ferret hearts.
AuthorsMarban E, Kitakaze M, Kusuoka H, Porterfield JK, Yue DT, Chacko VP
JournalProc Natl Acad Sci U S A
PubMed ID3112778
Changes in the intracellular free Ca2+ concentration, [Ca2+]i, mediate excitation-contraction coupling in the heart and contribute to cellular injury during ischemia and reperfusion. To study these processes directly, we measured [Ca2+]i in perfused ferret (Mustela putorius furo) hearts using 19F NMR spectroscopy to detect the 5,5'-difluoro derivative of the Ca2+ ... More
Mechanism of ischemic contracture in ferret hearts: relative roles of [Ca2+]i elevation and ATP depletion.
AuthorsKoretsune Y, Marban E
JournalAm J Physiol
PubMed ID2301617
When coronary perfusion is interrupted, the diastolic force generated by the myocardium first falls but eventually increases. The delayed rise in force, ischemic contracture, has been attributed either to ATP depletion or to elevation of the intracellular free calcium concentration ([Ca2+]i). To distinguish between these possibilities, we measured [Ca2+]i and ... More
Isolated cardiomyocytes in conjunction with NMR spectroscopy techniques to study metabolism and ion flux.
AuthorsOsbakken M, Ivanics T, Zhang D, Mitra R, Blum H
JournalJ Biol Chem
PubMed ID1639780
To distinguish cellular from vascular responses to physiological and pathophysiological stimuli, we developed methods to perform NMR spectroscopy on isolated ventricular cardiomyocytes. Isolated adult rat cardiomyocytes, placed in agarose beads and superfused with phosphate-free buffer (Media 199 (GIBCO 400-1100) gassed with 95% O2, 5% CO2), were used to evaluate a ... More
A peroxidative model of human erythrocyte intracellular Ca2+ changes with in vivo cell aging: measurement by 19F-NMR spectroscopy.
AuthorsAiken NR, Galey WR, Satterlee JD
JournalBiochim Biophys Acta
PubMed ID7827135
Numerous changes occur with human erythrocyte aging in vivo, including an increase in free ionic intracellular calcium concentration ([Ca2+]i) (N.R. Aiken et al. (1992) Biochim. Biophys. Acta 1136, 155-160). An attractive hypothesis of cell aging suggests that oxidative stress is responsible for many age-related changes. To determine whether oxidative stress ... More
Synthesis and characterization of 19F NMR chelators for measurement of cytosolic free Ca.
AuthorsLevy LA, Murphy E, London RE
JournalAm J Physiol
PubMed ID3105327
Fluorine 19 nuclear magnetic resonance (NMR) studies of intracellular fluorinated calcium chelators provide a useful strategy for the determination of cytosolic free calcium levels in cells and perfused organs. However, the fluorinated chelator with the highest affinity for calcium ions which has been described to date. 1,2-bis-(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (5FBAPTA), exhibits ... More
A novel mechanism for coupling of m4 muscarinic acetylcholine receptors to calmodulin-sensitive adenylyl cyclases: crossover from G protein-coupled inhibition to stimulation.
Muscarinic m4 acetylcholine receptors are normally coupled through Gi to inhibition of adenylyl cyclases. In the olfactory bulb and some cultured cells, however, m4 receptors can couple to stimulation of adenylyl cyclase activity. In this study, m4 receptors and specific isozymes of adenylyl cyclases were coexpressed in HEK-293 cells to ... More
Measurement of cytosolic free calcium in perfused rat heart using TF-BAPTA.
AuthorsMurphy E, Steenbergen C, Levy LA, Gabel S, London RE
JournalAm J Physiol
PubMed ID8203497
The feasibility and usefulness of loading 1,2-bis(2-amino-5,6-difluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (TF-BAPTA), a new high-dissociation constant (KD) (65 microM) Ca2+ indicator, into perfused rat heart is demonstrated. TF-BAPTA-loaded perfused rat heart showed less than a 10% reduction in left ventricular developed pressure. In addition, loading perfused rat heart with TF-BAPTA had no effect ... More
NMR studies of intracellular free calcium, free magnesium and sodium in the guinea pig reticulocyte and mature red cell.
AuthorsJelicks LA, Weaver J, Pollack S, Gupta RK
JournalBiochim Biophys Acta
PubMed ID2474326
During the maturation process reticulocytes lose their intracellular organelles and undergo changes in membrane lipid composition and ion transport properties. While several reports indicate differences in the levels of magnesium, sodium and calcium in reticulocytes and erythrocytes, controversy remains concerning the actual magnitude and direction of ionic alterations during reticulocyte ... More
Multinuclear NMR studies of intracellular cations in the prehypertensive rat kidney.
AuthorsDowd TL, Gupta RK
JournalBiochim Biophys Acta
PubMed ID8155743
We previously reported a significant derangement of intracellular free calcium ion concentration in the isolated perfused kidney of adult spontaneously hypertensive rat (SHR) (J. Biol. Chem. 267, 3637-3643, 1992). In order to investigate whether an abnormality in intracellular free calcium or another ion precedes the development of elevated blood pressure ... More
Properties of neuroprotective cell-permeant Ca2+ chelators: effects on [Ca2+]i and glutamate neurotoxicity in vitro.
AuthorsTymianski M, Charlton MP, Carlen PL, Tator CH
JournalJ Neurophysiol
PubMed ID7823112
1. Cell-permeant Ca2+ chelators such as 1,2-bis-(2-amino-phenoxy)ethane- N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM) protect neurons against excitotoxic and ischemic neuronal injury in vitro and in vivo. Here we provide the first steps toward characterizing the mechanisms by which these agents produce their neuroprotective effects. 2. Cultured mouse spinal neurons were simultaneously ... More
NMR measurement of cytosolic free calcium, free magnesium, and intracellular sodium in the aorta of the normal and spontaneously hypertensive rat.
AuthorsJelicks LA, Gupta RK
JournalJ Biol Chem
PubMed ID2295635
We have utilized multinuclear NMR spectroscopy to examine the relationship between cytosolic free Ca2+ ([Ca2+]in), free Mg2+ ([Mg2+]in) and intracellular Na+ ([Na+]in) levels of the intact thoracic aorta and primary hypertension using the Wistar-Kyoto and Sprague-Dawley rats as controls and the spontaneously hypertensive rat as a model for genetic hypertension. ... More
Thapsigargin-induced calcium influx in the absence of detectable tyrosine phosphorylation in human platelets.
AuthorsVostal JG, Shafer B
JournalJ Biol Chem
PubMed ID8702645
Tyrosine phosphorylation is a potential mechanism for mediating store-operated calcium (SOC) influx in platelets and other nonexcitable cells. Thapsigargin induces calcium-dependent tyrosine phosphorylation and SOC influx in platelets. We prevented thapsigargin-induced tyrosine phosphorylation by buffering cytosolic calcium rise with the calcium chelator 1, 2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetomethoxyester (BAPTA-AM). Calcium influx, induced by ... More
Multinuclear NMR studies of intracellular cations in perfused hypertensive rat kidney.
AuthorsDowd TL, Gupta RK
JournalJ Biol Chem
PubMed ID1740416
We have investigated hypertension-associated alterations in intracellular cations in the kidney by measuring intracellular pH, free Mg2+, free Ca2+, and Na+ concentrations in perfused normotensive and hypertensive rat (8-14 weeks old) kidneys using 31P, 19F, and double quantum-filtered (DQ) 23Na NMR. The effects of both anoxia and ischemia on the ... More