Although human pannexins (PanX) are homologous to gap junction molecules, their physiological function in vertebrates remains poorly understood. Our results demonstrate that overexpression of PanX1 results in the formation of Ca(2+)-permeable gap junction channels between adjacent cells, thus, allowing direct intercellular Ca(2+) diffusion and facilitating intercellular Ca(2+) wave propagation. More ... More
Spatially organised mitochondrial calcium uptake through a novel pathway in chick neurones.
AuthorsCoatesworth W, Bolsover S
JournalCell Calcium
PubMed ID16338004
'A brief depolarisation of chick sensory neurones evokes a calcium increase in mitochondria that peaks 1-2s after the depolarisation event and then decays over tens of seconds. Peripheral mitochondria take up more calcium than do central ones, even when the cytosolic calcium increase is spatially homogeneous. The calcium influx into ... More
Feedback inhibition of sodium/calcium exchange by mitochondrial calcium accumulation.
AuthorsOpuni K, Reeves JP
JournalJ Biol Chem
PubMed ID10801871
'Chinese hamster ovary cells expressing the bovine cardiac Na(+)/Ca(2+) exchanger were subjected to two periods of 5 and 3 min, respectively, during which the extracellular Na(+) concentration ([Na(+)](o)) was reduced to 20 mm; these intervals were separated by a 5-min recovery period at 140 mm Na(+)(o). The cytosolic Ca(2+) concentration ... More
Hydrolysis of Ca2+-sensitive fluorescent probes by perfused rat heart.
AuthorsScaduto RC, Grotyohann LW
JournalAm J Physiol Heart Circ Physiol
PubMed ID14561682
'Rat hearts were loaded with the fluorescent calcium indicators fura 2, indo 1, rhod 2, or fluo 3 to determine cytosolic calcium levels in the perfused rat heart. With fura 2, however, basal tissue fluorescence increased above anticipated levels, suggesting accumulation of intermediates of fura 2-AM deesterification. To examine this ... More
Nitric oxide-dependent mitochondrial biogenesis generates Ca2+ signaling profile of lupus T cells.
AuthorsNagy G, Barcza M, Gonchoroff N, Phillips PE, Perl A
JournalJ Immunol
PubMed ID15356113
'Abnormal T cell activation and cell death underlie the pathology of systemic lupus erythematosus. Although mitochondrial hyperpolarization (MHP) represents an early and reversible checkpoint of T cell activation and apoptosis, lupus T cells exhibit persistent MHP. NO has recently been recognized as a key signal of mitochondrial biogenesis and mediator ... More
Correlation of NADH and Ca2+ signals in mouse pancreatic acinar cells.
AuthorsVoronina S, Sukhomlin T, Johnson PR, Erdemli G, Petersen OH, Tepikin A
JournalJ Physiol
PubMed ID11850500
'Relationships between calcium signals and NADH responses were investigated in pancreatic acinar cells stimulated with calcium-releasing secretagogues. Cytosolic calcium signals were studied using Fura Red or calcium-sensitive Cl(-) current. Mitochondrial calcium was measured using Rhod-2. The highest levels of NADH autofluorescence were found around the secretory granule region. Stimulation of ... More
Pulsed laser imaging of rapid Ca2+ gradients in excitable cells.
AuthorsMonck JR, Robinson IM, Escobar AL, Vergara JL, Fernandez JM
JournalBiophys J
PubMed ID7948669
'Excitable cells are thought to respond to action potentials by forming short lived and highly localized Ca2+ gradients near sites of Ca2+ entry or near the site of Ca2+ release by intracellular stores. However, conventional imaging techniques lack the spatial and temporal resolution to capture these gradients. Here we demonstrate ... More
Calibration of the calcium dissociation constant of Rhod(2)in the perfused mouse heart using manganese quenching.
AuthorsDu C, MacGowan GA, Farkas DL, Koretsky AP
JournalCell Calcium
PubMed ID11243930
'Both theoretical and experimental results are presented for in vivo calibration of the dissociation constant K(Ca)(d)of the calcium-sensitive fluorescent dye Rhod(2)in the perfused mouse heart, using manganese quenching of fluorescence transients. An analytical model is derived, based on the biochemical equilibrium of manganese competition with calcium for Rhod(2)binding. Expressing the ... More
Purinergic receptors mediate two distinct glutamate release pathways in hippocampal astrocytes.
AuthorsFellin T, Pozzan T, Carmignoto G
JournalJ Biol Chem
PubMed ID16338906
'The purinergic P2X(7) receptor (P2X(7)R) can mediate glutamate release from cultured astrocytes. Using patch clamp recordings, we investigated whether P2X(7)Rs have the same action in hippocampal astrocytes in situ. We found that 2- and 3-O-(4-benzoylbenzoyl)ATP (BzATP), a potent, although unselective P2X(7)R agonist, triggers two different glutamate-mediated responses in CA1 pyramidal ... More
Identification of the erythropoietin receptor domain required for calcium channel activation.
AuthorsMiller BA, Barber DL, Bell LL, Beattie BK, Zhang MY, Neel BG, Yoakim M, Rothblum LI, Cheung JY
JournalJ Biol Chem
PubMed ID10400674
'Erythropoietin (Epo) activates a voltage-independent Ca2+ channel that is dependent on tyrosine phosphorylation. To identify the domain(s) of the Epo receptor (Epo-R) required for Epo-induced Ca2+ influx, Chinese hamster ovary (CHO) cells were transfected with wild-type or mutant Epo receptors subcloned into pTracer-cytomegalovirus vector. This vector contains an SV40 early ... More
Confocal microscopy to analyze cytosolic and nuclear calcium in cultured vascular cells.
AuthorsBurnier M, Centeno G, Burki E, Brunner HR
JournalAm J Physiol
PubMed ID8178959
'With the development of calcium-sensitive fluorescent dyes and videomicroscopic imaging, several investigators have located the changes in intracellular calcium in the cytoplasm, in the perinuclear region, and possibly in the nucleus. However, the presence of calcium in the nucleus is often difficult to ascertain because the fluorescence derived from the ... More
Pivotal role of mitochondrial calcium uptake in neural cell apoptosis and necrosis.
AuthorsKruman II, Mattson MP
JournalJ Neurochem
PubMed ID9930724
'Perturbed cellular calcium homeostasis has been implicated in both apoptosis and necrosis, but the role of altered mitochondrial calcium handling in the cell death process is unclear. The temporal ordering of changes in cytoplasmic ([Ca2+]C) and intramitochondrial ([Ca2+]M) calcium levels in relation to mitochondrial reactive oxygen species (ROS) accumulation and ... More
Dynamic origin of spatially discordant alternans in cardiac tissue.
AuthorsHayashi H, Shiferaw Y, Sato D, Nihei M, Lin SF, Chen PS, Garfinkel A, Weiss JN, Qu Z
JournalBiophys J
PubMed ID17071663
'Alternans, a condition in which there is a beat-to-beat alternation in the electromechanical response of a periodically stimulated cardiac cell, has been linked to the genesis of life-threatening ventricular arrhythmias. Optical mapping of membrane voltage (V(m)) and intracellular calcium (Ca(i)) on the surface of animal hearts reveals complex spatial patterns ... More
Metabolic consequences of functional complexes of mitochondria, myofibrils and sarcoplasmic reticulum in muscle cells.
AuthorsAndrienko T, Kuznetsov AV, Kaambre T, Usson Y, Orosco A, Appaix F, Tiivel T, Sikk P, Vendelin M, Margreiter R, Saks VA
JournalJ Exp Biol
PubMed ID12756288
'Regulation of mitochondrial respiration both by endogenous and exogenous ADP in the cells in situ was studied in isolated and permeabilized cardiomyocytes, permeabilized cardiac fibers and ''ghost'' fibers (all with a diameter of 10-20 micro m) at different (0-3 micro moll(-1)) free Ca(2+) concentrations in the medium. In all these ... More
Phosphorylation of inositol 1,4,5-trisphosphate receptors by protein kinase B/Akt inhibits Ca2+ release and apoptosis.
AuthorsSzado T, Vanderheyden V, Parys JB, De Smedt H, Rietdorf K, Kotelevets L, Chastre E, Khan F, Landegren U, Söderberg O, Bootman MD, Roderick HL,
JournalProc Natl Acad Sci U S A
PubMed ID18250332
'Imbalance of signals that control cell survival and death results in pathologies, including cancer and neurodegeneration. Two pathways that are integral to setting the balance between cell survival and cell death are controlled by lipid-activated protein kinase B (PKB)/Akt and Ca(2+). PKB elicits its effects through the phosphorylation and inactivation ... More
Spatial Ca(2+) distribution in contracting skeletal and cardiac muscle cells.
AuthorsZoghbi ME, Bolaños P, Villalba-Galea C, Marcano A, Hernández E, Fill M, Escobar AL
JournalBiophys J
PubMed ID10620283
'The spatiotemporal distribution of intracellular Ca(2+) release in contracting skeletal and cardiac muscle cells was defined using a snapshot imaging technique. Calcium imaging was performed on intact skeletal and cardiac muscle cells during contractions induced by an action potential (AP). The sarcomere length of the skeletal and cardiac cells was ... More
Pseudoapoptosis induced by brief activation of ATP-gated P2X7 receptors.
AuthorsMackenzie AB, Young MT, Adinolfi E, Surprenant A
JournalJ Biol Chem
PubMed ID15994333
'P2X7 receptors are ATP-gated ion channels primarily expressed on antigen-presenting immune cells where they play a role in the acute inflammatory response. These ion channels couple not only to influx of cations, including calcium, but also to rapid alterations in cell morphology (membrane blebbing, phosphatidylserine exposure, microvesicle shedding). These features ... More
Origin of intracellular Ca2+ elevation induced by in vitro ischemia-like condition in hippocampal slices.
AuthorsMitani A, Yanase H, Sakai K, Wake Y, Kataoka K
JournalBrain Res
PubMed ID8431758
'Microfluorometry was used to investigate the origin of intracellular Ca2+ ([Ca2+]i) elevation in field CA1 of gerbil hippocampal slices perfused with a glucose-free physiological medium equilibrated with a 95% N2/5% CO2 gas mixture (standard in vitro ischemia-like condition). Large [Ca2+]i elevation was detected about 4 min after the beginning of ... More
Astrocyte-mediated control of cerebral blood flow.
AuthorsTakano T, Tian GF, Peng W, Lou N, Libionka W, Han X, Nedergaard M
JournalNat Neurosci
PubMed ID16388306
'Local increase in blood flow during neural activity forms the basis for functional brain imaging, but its mechanism remains poorly defined. Here we show that cortical astrocytes in vivo possess a powerful mechanism for rapid vasodilation. We imaged the activity of astrocytes labeled with the calcium (Ca(2+))-sensitive indicator rhod-2 in ... More
Reconstruction of firing rate changes across neuronal populations by temporally deconvolved Ca2+ imaging.
AuthorsYaksi E, Friedrich RW
JournalNat Methods
PubMed ID16628208
'Methods to record action potential (AP) firing in many individual neurons are essential to unravel the function of complex neuronal circuits in the brain. A promising approach is bolus loading of Ca(2+) indicators combined with multiphoton microscopy. Currently, however, this technique lacks cell-type specificity, has low temporal resolution and cannot ... More
Mitochondrial clearance of cytosolic Ca(2+) in stimulated lizard motor nerve terminals proceeds without progressive elevation of mitochondrial matrix [Ca(2+)].
AuthorsDavid G
JournalJ Neurosci
PubMed ID10460256
'This study used fluorescent indicator dyes to measure changes in cytosolic and mitochondrial [Ca(2+)] produced by physiological stimulation of lizard motor nerve terminals. During repetitive action potential discharge at 10-50 Hz, the increase in average cytosolic [Ca(2+)] reached plateau at levels that increased with increasing stimulus frequency. This stabilization of ... More
Differential Ca2+ and Sr2+ regulation of intracellular divalent cations release in ventricular myocytes.
AuthorsZoghbi ME, Copello JA, Villalba-Galea CA, Vélez P, Diaz Sylvester PL, Bolaños P, Marcano A, Fill M, Escobar AL
JournalCell Calcium
PubMed ID15193860
'The regulation of the Ca2+ -induced Ca2+ release (CICR) from intracellular stores is a critical step in the cardiac cycle. The inherent positive feedback of CICR should make it a self-regenerating process. It is accepted that CICR must be governed by some negative control, but its nature is still debated. ... More
Mitochondrial reactive oxygen species generation and calcium increase induced by visible light in astrocytes.
AuthorsJou MJ, Jou SB, Guo MJ, Wu HY, Peng TI
JournalAnn N Y Acad Sci
PubMed ID15126282
'Mitochondria contain photosensitive chromophores that can be activated or inhibited by light in the visible range. Rather than utilizing light energy, however, mitochondrial electron transport oxidation-reduction reaction and energy coupling could be stimulated or damaged by visible light. Our previous work demonstrated that reactive oxygen species (ROS) were generated in ... More
Dynamics of intracellular calcium and free radical production during ischemia in pyramidal neurons.
'Biochemical cascades initiated by oxidative stress and excitotoxic intracellular calcium rises are thought to converge on mitochondrial dysfunction. We investigated the contribution of mitochondrial dysfunction to free radical (FR) overproduction in rat CA1 pyramidal neurons of organotypic slices subjected to a hypoxic-hypoglycemic insult. Ischemia-induced FR generation was decreased by the ... More
Contribution of NMDA receptors to tetanus-induced increase in postsynaptic Ca2+ in visual cortex of young rats.
AuthorsTakahashi MP, Sugiyama M, Tsumoto T
JournalNeurosci Res
PubMed ID7901821
'Mechanisms underlying the Ca2+ increase during tetanic synaptic inputs in layer II/III of visual cortical slices of young rats were investigated with microfluorometry using a Ca2+ indicator, rhod-2, and simultaneous recordings of field potentials evoked by white matter stimulation. Application of an antagonist for N-methyl-D-aspartate (NMDA) receptors, 2-amino-5-phosphonovalerate, did not ... More
Extrusion of Ca2+ from mouse motor terminal mitochondria via a Na+-Ca2+ exchanger increases post-tetanic evoked release.
AuthorsGarcía-Chacón LE, Nguyen KT, David G, Barrett EF
JournalJ Physiol
PubMed ID16613870
'Mitochondria sequester much of the Ca2+ that enters motor nerve terminals during repetitive stimulation at frequencies exceeding 10-20 Hz. We studied the post-stimulation extrusion of Ca2+ from mitochondria by measuring changes in matrix [Ca2+] with fluorescent indicators loaded into motor terminal mitochondria in the mouse levator auris longus muscle. Trains ... More
Heterogeneity of mitochondrial matrix free ca2+: resolution of Ca2+ dynamics in individual mitochondria in situ.
AuthorsMonteith GR, Blaustein MP
JournalAm J Physiol
PubMed ID10329969
'The role of mitochondria in Ca2+ homeostasis is controversial. We employed the Ca2+-sensitive dye rhod 2 with novel, high temporal and spatial resolution imaging to evaluate changes in the matrix free Ca2+ concentration of individual mitochondria ([Ca2+]m) in agonist-stimulated, primary cultured aortic myocytes. Stimulation with 10 microM serotonin (5-HT) evoked ... More
Fluorescent indicators for cytosolic calcium based on rhodamine and fluorescein chromophores.
AuthorsMinta A, Kao JP, Tsien RY
JournalJ Biol Chem
PubMed ID2498308
'A new group of fluorescent indicators with visible excitation and emission wavelengths has been synthesized for measurements of cytosolic free Ca2+. The five compounds, "rhod-1," "rhod-2," "fluo-1," "fluo-2," and "fluo-3" (Figs. 2 and 3), combine the 8-coordinate tetracarboxylate chelating site of 1,2-bis(2-amino-phenoxyethane-N,N,N'',N''-tetraacetic acid with a xanthene chromophore to give a ... More
Role of Ca2+/K+ ion exchange in intracellular storage and release of Ca2+.
AuthorsNguyen T, Chin WC, Verdugo P
JournalNature
PubMed ID9804425
'Although fluctuations in cytosolic Ca2+ concentration have a crucial role in relaying intracellular messages in the cell, the dynamics of Ca2+ storage in and release from intracellular sequestering compartments remains poorly understood. The rapid release of stored Ca2+ requires large concentration gradients that had been thought to result from low-affinity ... More
A fast signal-induced activation of Poly(ADP-ribose) polymerase: a novel downstream target of phospholipase c.
AuthorsHomburg S, Visochek L, Moran N, Dantzer F, Priel E, Asculai E, Schwartz D, Rotter V, Dekel N, Cohen-Armon M
JournalJ Cell Biol
PubMed ID10908573
'We present the first evidence for a fast activation of the nuclear protein poly(ADP-ribose) polymerase (PARP) by signals evoked in the cell membrane, constituting a novel mode of signaling to the cell nucleus. PARP, an abundant, highly conserved, chromatin-bound protein found only in eukaryotes, exclusively catalyzes polyADP-ribosylation of DNA-binding proteins, ... More
Examining intracellular organelle function using fluorescent probes: from animalcules to quantum dots.
AuthorsZorov DB, Kobrinsky E, Juhaszova M, Sollott SJ
JournalCirc Res
PubMed ID15297386
'Fluorescence microscopy imaging has become one of the most useful techniques to assess the activity of individual cells, subcellular trafficking of signals to and between organelles, and to appreciate how organelle function is regulated. The past 2 decades have seen a tremendous advance in the rational design and development in ... More
Localization of the site of Ca2+ release at the level of a single sarcomere in skeletal muscle fibres.
'The development of mechanical force in skeletal muscle fibres is brought about by rapid increases in the intracellular calcium concentration (Ca2+ transients) which can be detected by optical methods. Local stimulation experiments and ultrastructural evidence suggest that, at a microscopic level, these Ca2+ transients are generated by the release of ... More
Ca2+ blinks: rapid nanoscopic store calcium signaling.
AuthorsBrochet DX, Yang D, Di Maio A, Lederer WJ, Franzini-Armstrong C, Cheng H
JournalProc Natl Acad Sci U S A
PubMed ID15710901
'Luminal Ca(2+) in the endoplasmic and sarcoplasmic reticulum (ER/SR) plays an important role in regulating vital biological processes, including store-operated capacitative Ca(2+) entry, Ca(2+)-induced Ca(2+) release, and ER/SR stress-mediated cell death. We report rapid and substantial decreases in luminal [Ca(2+)], called "Ca(2+) blinks," within nanometer-sized stores (the junctional cisternae of ... More
Role of mitochondria in calcium regulation of spontaneously contracting cardiac muscle cells.
AuthorsBowser DN, Minamikawa T, Nagley P, Williams DA
JournalBiophys J
PubMed ID9746542
'Mitochondrial involvement in the regulation of cytosolic calcium concentration ([Ca2+]i) in cardiac myocytes has been largely discounted by many authors. However, recent evidence, including the results of this study, has forced a reappraisal of this role. [Ca2+]i and Ca2+ in the mitochondria ([Ca2+]m) were measured in this study with specific ... More
Mitochondrial Ca(2+) uptake depends on the spatial and temporal profile of cytosolic Ca(2+) signals.
AuthorsCollins TJ, Lipp P, Berridge MJ, Bootman MD
JournalJ Biol Chem
PubMed ID11333261
'Using confocal imaging of Rhod-2-loaded HeLa cells, we examined the ability of mitochondria to sequester Ca(2+) signals arising from different sources. Mitochondrial Ca(2+) (Ca(2+)mit) uptake was stimulated by inositol 1,4,5-trisphosphate (InsP(3))-evoked Ca(2+) release, capacitative Ca(2+) entry, and Ca(2+) leaking from the endoplasmic reticulum. For each Ca(2+) source, the relationship between ... More
Mitochondria exert a negative feedback on the propagation of intracellular Ca2+ waves in rat cortical astrocytes.
AuthorsBoitier E, Rea R, Duchen MR
JournalJ Cell Biol
PubMed ID10330407
'We have used digital fluorescence imaging techniques to explore the interplay between mitochondrial Ca2+ uptake and physiological Ca2+ signaling in rat cortical astrocytes. A rise in cytosolic Ca2+ ([Ca2+]cyt), resulting from mobilization of ER Ca2+ stores was followed by a rise in mitochondrial Ca2+ ([Ca2+]m, monitored using rhod-2). Whereas [Ca2+]cyt ... More
'Our understanding of the underlying mechanisms of Ca2+ signaling as well as our appreciation for its ubiquitous role in cellular processes has been rapidly advanced, in large part, due to the development of fluorescent Ca2+ indicators. In this chapter, we discuss some of the most common chemical Ca2+ indicators that ... More
Agonist-evoked mitochondrial Ca2+ signals in mouse pancreatic acinar cells.
AuthorsGonzález A, Schulz I, Schmid A
JournalJ Biol Chem
PubMed ID10995756
'In the present study we have investigated cytosolic and mitochondrial Ca(2+) signals in isolated mouse pancreatic acinar cells double-loaded with the fluorescent probes fluo-3 and rhod-2. Stimulation of pancreatic acinar cells with 500 nm acetylcholine caused release of Ca(2+) from intracellular stores and produced cytosolic Ca(2+) signals in form of ... More
Cyclophilin D-dependent mitochondrial permeability transition regulates some necrotic but not apoptotic cell death.
AuthorsNakagawa T, Shimizu S, Watanabe T, Yamaguchi O, Otsu K, Yamagata H, Inohara H, Kubo T, Tsujimoto Y
JournalNature
PubMed ID15800626
'Mitochondria play an important role in energy production, Ca2+ homeostasis and cell death. In recent years, the role of the mitochondria in apoptotic and necrotic cell death has attracted much attention. In apoptosis and necrosis, the mitochondrial permeability transition (mPT), which leads to disruption of the mitochondrial membranes and mitochondrial ... More
Quantification of calcium signal transmission from sarco-endoplasmic reticulum to the mitochondria.
AuthorsPacher P, Csordás P, Schneider T, Hajnóczky G
JournalJ Physiol
PubMed ID11118489
'Recent studies have shown that ryanodine and IP3 receptor (RyR/IP3R)-mediated cytosolic Ca2+ signals propagate to the mitochondria, initiating chains of events vital in the regulation of different cellular functions. However, the fraction of released Ca2+ utilized by the mitochondria during these processes has not been quantified. To measure the amount ... More
Histamine induces oscillations of mitochondrial free Ca2+ concentration in single cultured rat brain astrocytes.
AuthorsJou MJ, Peng TI, Sheu SS
JournalJ Physiol
PubMed ID8961176
'1. The free Ca2+ concentration of mitochondria ([Ca2+]m) in cultured rat brain astrocytes was measured with a fluorescent Ca2+ indicator, rhod-2, and laser confocal microscopy. 2. Confocal images revealed a rhod-2 distribution that matched mitochondrial localization. 3. Using a Ca2+ ionophore, ionomycin, to clamp the [Ca2+]m from 0 to 100 ... More
Laminar difference in tetanus-induced increase of intracellular Ca2+ in visual cortex of young rats.
AuthorsTakahashi MP, Sugiyama M, Tsumoto T
JournalNeurosci Res
PubMed ID8233125
'Changes in intracellular Ca2+ evoked by electrical stimulation of the white matter were observed by means of microfluorometry with a Ca2+ indicator, rhod-2, in slice preparations of the visual cortex obtained from young rats. Tetanic stimulation at 5 Hz for 1 min induced a marked fluorescence increase, while single-shock stimulation ... More
Termination of cardiac Ca2+ sparks: role of intra-SR [Ca2+], release flux, and intra-SR Ca2+ diffusion.
AuthorsZima AV, Picht E, Bers DM, Blatter LA,
JournalCirc Res
PubMed ID18787194
'Ca(2+) release from cardiac sarcoplasmic reticulum (SR) via ryanodine receptors (RyRs) is regulated by dyadic cleft [Ca(2+)] and intra-SR free [Ca(2+)] ([Ca(2+)](SR)). Robust SR Ca(2+) release termination is important for stable excitation-contraction coupling, and partial [Ca(2+)](SR) depletion may contribute to release termination. Here, we investigated the regulation of SR Ca(2+) ... More
Imaging in vivo: watching the brain in action.
AuthorsKerr JN, Denk W,
JournalNat Rev Neurosci
PubMed ID18270513
'The appeal of in vivo cellular imaging to any neuroscientist is not hard to understand: it is almost impossible to isolate individual neurons while keeping them and their complex interactions with surrounding tissue intact. These interactions lead to the complex network dynamics that underlie neural computation which, in turn, forms ... More
Monitoring simultaneous subcellular events in vitro by means of coherent multiprobe fluorescence.
AuthorsPlymale DR, Haskins JR, de la Iglesia FA
JournalNat Med
PubMed ID10086396
Confocal Ca2+ imaging of organelles, cells, tissues, and organs.
AuthorsWilliams DA, Bowser DN, Petrou S
JournalMethods Enzymol
PubMed ID10506988
Practical aspects of measuring [Ca2+] with fluorescent indicators.
AuthorsKao JP
JournalMethods Cell Biol
PubMed ID8201975
Suicidal membrane repair regulates phosphatidylserine externalization during apoptosis.
One of the hallmarks of apoptosis is the redistribution of phosphatidylserine (PS) from the inner-to-outer plasma membrane (PM) leaflet, where it functions as a ligand for phagocyte recognition and the suppression of inflammatory responses. The mechanism by which apoptotic cells externalize PS has been assumed to involve ... More
Acidic fibroblast growth factor delays in vitro ischemia-induced intracellular calcium elevation in gerbil hippocampal slices: a sign of neuroprotection.
AuthorsMitani A, Oomura Y, Yanase H, Kataoka K
JournalNeurochem Int
PubMed ID1284622
Using microfluorometry, effects of acidic fibroblast growth factor (aFGF) on the in vitro ischemia-induced intracellular calcium elevation were investigated in gerbil hippocampal slices at 35 degrees C. When slices were superfused with hypoxic and glucose-free medium, the mean latency of the in vitro ischemia-induced calcium elevation was 209 +/- 51 ... More
The facilitating and suppressing effects of delta 9-tetrahydrocannabinol on the rise in intrasynaptosomal Ca2+ concentration in rats.
AuthorsOkada M, Urae A, Mine K, Shoyama Y, Iwasaki K, Fujiwara M
JournalNeurosci Lett
PubMed ID1328966
The effects of delta 9-tetrahydrocannabinol (delta 9-THC) on the rise in intracellular Ca2+ concentrations ([Ca2+]i) after stimulation with 15 mM or 29 mM K+ in rat whole brain synaptosomes were examined. A fluorescent chelating agent, Rhod-2, was employed to monitor any alterations of K(+)-evoked [Ca2+]i. Pretreatment with 10(-10) M delta ... More
Assessing mitochondrial potential, calcium, and redox state in isolated mammalian cells using confocal microscopy.
AuthorsDavidson SM, Yellon D, Duchen MR,
JournalMethods Mol Biol
PubMed ID18314743
Mitochondria play a vital role in the regulation of intracellular calcium dynamics. Fluorescent dyes can be used to provide a direct measurement of the redox state, mitochondrial membrane potential, and mitochondrial calcium content. The simplicity of this approach lends itself to high-throughput assays and time-resolved analyses; however, care must be ... More
Selective loading of Rhod 2 into mitochondria shows mitochondrial Ca2+ transients during the contractile cycle in adult rabbit cardiac myocytes.
AuthorsTrollinger DR, Cascio WE, Lemasters JJ
JournalBiochem Biophys Res Commun
PubMed ID9245725
A strategy of cold loading of the Ca2+-indicating fluorophore Rhod 2-AM followed by warm incubation was developed to selectively label mitochondria of adult rabbit cardiac myocytes. After electrical stimulation, mitochondrial Rhod 2 fluorescence observed by confocal microscopy increased and then rapidly decayed to baseline. In regions between mitochondria, the fluorescent ... More
Fluorescent molecular sensors and multi-photon microscopy in brain studies.
AuthorsBakalova R
JournalBrain Res Bull
PubMed ID17499649
To clarify the brain phenomena, to prove directly the major biochemical pathways in cerebral tissue, and to discover the crucial steps in brain pathology, it is necessary to develop a high speed deep-tissue imaging techniques with high spatial and temporal resolution, and ultra-fast and highly selective molecular sensors, giving a ... More
Mitochondrial permeability transition: a common pathway to necrosis and apoptosis.
AuthorsKim JS, He L, Lemasters JJ
JournalBiochem Biophys Res Commun
PubMed ID12729580
Opening of high conductance permeability transition pores in mitochondria initiates onset of the mitochondrial permeability transition (MPT). The MPT is a causative event, leading to necrosis and apoptosis in hepatocytes after oxidative stress, Ca(2+) toxicity, and ischemia/reperfusion. CsA blocks opening of permeability transition pores and protects cell death after these ... More
T cell activation requires mitochondrial translocation to the immunological synapse.
AuthorsQuintana A, Schwindling C, Wenning AS, Becherer U, Rettig J, Schwarz EC, Hoth M,
JournalProc Natl Acad Sci U S A
PubMed ID17726106
T helper (Th) cell activation is required for the adaptive immune response. Formation of the immunological synapse (IS) between Th cells and antigen-presenting cells is essential for Th cell activation. IS formation induces the polarization and redistribution of many signaling molecules; however, very little is known about organelle redistribution during ... More
Purine receptor mediated actin cytoskeleton remodeling of human fibroblasts.
AuthorsGoldman N, Chandler-Militello D, Langevin HM, Nedergaard M, Takano T,
JournalCell Calcium
PubMed ID23462235
Earlier studies have shown that activation of adenosine A1 receptors on peripheral pain fibers contributes to acupuncture-induced suppression of painful input. In addition to adenosine, acupuncture triggers the release of other purines, including ATP and ADP that may bind to purine receptors on nearby fibroblasts. We here show that purine ... More
Genetically encoded pH-indicators reveal activity-dependent cytosolic acidification of Drosophila motor nerve termini in vivo.
AuthorsRossano AJ, Chouhan AK, Macleod GT,
JournalJ Physiol
PubMed ID23401611
All biochemical processes, including those underlying synaptic function and plasticity, are pH sensitive. Cytosolic pH (pH(cyto)) shifts are known to accompany nerve activity in situ, but technological limitations have prevented characterization of such shifts in vivo. Genetically encoded pH-indicators (GEpHIs) allow for tissue-specific in vivo measurement of pH. We expressed ... More
GTPase of the immune-associated nucleotide-binding protein 5 (GIMAP5) regulates calcium influx in T-lymphocytes by promoting mitochondrial calcium accumulation.
Mature T-lymphocytes undergo spontaneous apoptosis in the biobreeding diabetes-prone strain of rats due to the loss of the functional GIMAP5 (GTPase of the immune-associated nucleotide-binding protein 5) protein. The mechanisms underlying the pro-survival function of GIMAP5 in T-cells have not yet been elucidated. We have previously shown that GIMAP5 deficiency in ... More
In vitro electrophysiological mapping of stem cells.
AuthorsWeinberg S, Lipke EA, Tung L,
JournalMethods Mol Biol
PubMed ID20680822
The use of stem cells for cardiac regeneration is a revolutionary, emerging research area. For proper function as replacement tissue, stem cell-derived cardiomyocytes (SC-CMs) must electrically couple with the host cardiac tissue. Electrophysiological mapping techniques, including microelectrode array (MEA) and optical mapping, have been developed to study cardiomyocytes and cardiac ... More
Spatially discordant alternans in cardiomyocyte monolayers.
Authorsde Diego C, Pai RK, Dave AS, Lynch A, Thu M, Chen F, Xie LH, Weiss JN, Valderrábano M,
JournalAm J Physiol Heart Circ Physiol
PubMed ID18223190
Repolarization alternans is a harbinger of sudden cardiac death, particularly when it becomes spatially discordant. Alternans, a beat-to-beat alternation in the action potential duration (APD) and intracellular Ca (Cai), can arise from either tissue heterogeneities or dynamic factors. Distinguishing between these mechanisms in normal cardiac tissue is difficult because of ... More
'Pressure-flow'-triggered intracellular Ca2+ transients in rat cardiac myocytes: possible mechanisms and role of mitochondria.
AuthorsBelmonte S, Morad M,
JournalJ Physiol
PubMed ID18187469
Cardiac myocytes, in the intact heart, are exposed to shear/fluid forces during each cardiac cycle. Here we describe a novel Ca(2+) signalling pathway, generated by 'pressurized flows' (PFs) of solutions, resulting in the activation of slowly developing ( approximately 300 ms) Ca(2+) transients lasting approximately 1700 ms at room temperature. ... More
Caspase-cleaved tau expression induces mitochondrial dysfunction in immortalized cortical neurons: implications for the pathogenesis of Alzheimer disease.
AuthorsQuintanilla RA, Matthews-Roberson TA, Dolan PJ, Johnson GV,
JournalJ Biol Chem
PubMed ID19389700
In Alzheimer disease (AD) mitochondrial abnormalities occur early in the pathogenic process and likely play a significant role in disease progression. Tau is a microtubule-associated protein that is abnormally processed in AD, and a connection between tau pathology and mitochondrial impairment has been proposed. However, few studies have examined the ... More
Rosiglitazone treatment prevents mitochondrial dysfunction in mutant huntingtin-expressing cells: possible role of peroxisome proliferator-activated receptor-gamma (PPARgamma) in the pathogenesis of Huntington disease.
AuthorsQuintanilla RA, Jin YN, Fuenzalida K, Bronfman M, Johnson GV,
JournalJ Biol Chem
PubMed ID18640979
Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a member of the PPAR family of transcription factors. Synthetic PPARgamma agonists are used as oral anti-hyperglycemic drugs for the treatment of non-insulin-dependent diabetes. However, emerging evidence indicates that PPARgamma activators can also prevent or attenuate neurodegeneration. Given these previous findings, the focus of this ... More
Transaldolase deficiency influences the pentose phosphate pathway, mitochondrial homoeostasis and apoptosis signal processing.
AuthorsQian Y, Banerjee S, Grossman CE, Amidon W, Nagy G, Barcza M, Niland B, Karp DR, Middleton FA, Banki K, Perl A,
JournalBiochem J
PubMed ID18498245
TAL (transaldolase) was originally described in the yeast as an enzyme of the PPP (pentose phosphate pathway). However, certain organisms and mammalian tissues lack TAL, and the overall reason for its existence is unclear. Recently, deletion of Ser(171) (TALDeltaS171) was found in five patients causing inactivation, proteasome-mediated degradation and complete ... More
A transient rise in intracellular Ca2+ is a precursor reaction to the zona pellucida-induced acrosome reaction in mouse sperm and is blocked by the induced acrosome reaction inhibitor 3-quinuclidinyl benzilate.
AuthorsStorey BT, Hourani CL, Kim JB
JournalMol Reprod Dev
PubMed ID1515148
The acrosome reaction induced by the zona pellucida in mouse sperm has been shown to proceed in two stages experimentally distinguishable by the fluorescent probe chlortetracycline. Entry into the first stage of sperm bound to isolated, structurally intact zonae pellucidae is blocked by the compound 3-quinuclidinyl benzilate. In this study, ... More
The anti-apoptotic protein Mcl-1 inhibits mitochondrial Ca2+ signals.
AuthorsMinagawa N, Kruglov EA, Dranoff JA, Robert ME, Gores GJ, Nathanson MH
JournalJ Biol Chem
PubMed ID16027162
Apoptosis contributes to the regulation of cell growth and regeneration and to the development of neoplasia. Mcl-1 is an anti-apoptotic protein that is particularly important for the development of hematological and biliary malignancies, but the mechanism of action of Mcl-1 is unknown. A number of pro- and anti-apoptotic proteins exhibit ... More
BAX and BAK regulation of endoplasmic reticulum Ca2+: a control point for apoptosis.
BAX and BAK are "multidomain" proapoptotic proteins that initiate mitochondrial dysfunction but also localize to the endoplasmic reticulum (ER). Mouse embryonic fibroblasts deficient for BAX and BAK (DKO cells) were found to have a reduced resting concentration of calcium in the ER ([Ca2+]er) that results in decreased uptake of Ca2+ ... More
Mitochondrial calcium response in human transformed lymphoblastoid cells.
AuthorsKato T, Ishiwata M, Nagai T
JournalLife Sci
PubMed ID12052442
Human lymphoblastoid cell line (LCL) transformed by Epstein-Barr Virus (EBV) is a unique cellular model for the study of human diseases. Although pathophysiological significance of mitochondrial calcium regulation is drawing attention, it is not known whether or not mitochondria in LCLs play a role in intracellular calcium signaling. In this ... More
Mitochondrial subpopulations and heterogeneity revealed by confocal imaging: possible physiological role?
AuthorsKuznetsov AV, Troppmair J, Sucher R, Hermann M, Saks V, Margreiter R
JournalBiochim Biophys Acta
PubMed ID16712778
Heterogeneity of mitochondria has been reported for a number of various cell types. Distinct mitochondrial subpopulations may be present in the cell and may be differently involved in physiological and pathological processes. However, the origin and physiological roles of mitochondrial heterogeneity are still unknown. In mice skeletal muscle, a much ... More
Rapid report: a novel technique for quantitative measurement of free Ca2+ concentration in rat heart mitochondria.
AuthorsSheu SS, Sharma VK
JournalJ Physiol
PubMed ID10381602
1. The free mitochondrial Ca2+ concentration ([Ca2+]m) in rat heart mitochondria was measured quantitatively by loading the mitochondria with fura-2 and then injecting them into Xenopus laevis oocytes. 2. When oocytes were incubated with a physiological solution, the free cytosolic Ca2+ concentration ([Ca2+]c) in the oocytes was 82 +/- 11 ... More
Optical imaging of the heart.
AuthorsEfimov IR, Nikolski VP, Salama G
JournalCirc Res
PubMed ID15242982
Optical techniques have revolutionized the investigation of cardiac cellular physiology and advanced our understanding of basic mechanisms of electrical activity, calcium homeostasis, and metabolism. Although optical methods are widely accepted and have been at the forefront of scientific discoveries, they have been primarily applied at cellular and subcellular levels and ... More
Decoding of cytosolic calcium oscillations in the mitochondria.
AuthorsHajnóczky G, Robb-Gaspers LD, Seitz MB, Thomas AP
JournalCell
PubMed ID7634331
Frequency-modulated oscillations of cytosolic Ca2+ ([Ca2+]c) are believed to be important in signal transduction, but it has been difficult to correlate [Ca2+]c oscillations directly with the activity of Ca(2+)-regulated targets. We have studied the control of Ca(2+)-sensitive mitochondrial dehydrogenases (CSMDHs) by monitoring mitochondrial Ca2+ ([Ca2+]m) and the redox state of ... More
Mitochondrial calcium transients in adult rabbit cardiac myocytes: inhibition by ruthenium red and artifacts caused by lysosomal loading of Ca(2+)-indicating fluorophores.
AuthorsTrollinger DR, Cascio WE, Lemasters JJ
JournalBiophys J
PubMed ID10866936
A cold/warm loading protocol was used to ester-load Rhod 2 into mitochondria and other organelles and Fluo 3 into the cytosol of adult rabbit cardiac myocytes for confocal fluorescence imaging. Transient increases in both cytosolic Fluo 3 and mitochondrial Rhod 2 fluorescence occurred after electrical stimulation. Ruthenium red, a blocker ... More
Opening of mitochondrial K(ATP) channels attenuates the ouabain-induced calcium overload in mitochondria.
AuthorsIshida H, Hirota Y, Genka C, Nakazawa H, Nakaya H, Sato T
JournalCirc Res
PubMed ID11701611
We tested whether opening of mitochondrial ATP-sensitive K(+) (mitoK(ATP)) channels depolarizes mitochondrial membrane potential (DeltaPsi(m)) and thereby prevents the mitochondrial Ca(2+) overload. With the use of a Nipkow disk confocal system, the mitochondrial Ca(2+) concentration ([Ca(2+)](m)) and DeltaPsi(m) in rat ventricular myocytes were measured by loading cells with Rhod-2 and ... More
Cyclic GMP modulates depletion-activated Ca2+ entry in pancreatic acinar cells.
AuthorsBahnson TD, Pandol SJ, Dionne VE
JournalJ Biol Chem
PubMed ID8098704
In the pancreatic acinar cell, hormonal stimulation causes a rise in the intracellular free Ca2+ concentration by activating the inositol 1,4,5-trisphosphate-mediated release of Ca2+ from intracellular stores (Berridge, M. J., and Irvine, R. F. (1989) Nature 341, 197-205). The released Ca2+ is, for the most part, extruded from the cell, ... More
Calcium transients in astrocyte endfeet cause cerebrovascular constrictions.
AuthorsMulligan SJ, MacVicar BA
JournalNature
PubMed ID15356633
Cerebral blood flow (CBF) is coupled to neuronal activity and is imaged in vivo to map brain activation. CBF is also modified by afferent projection fibres that release vasoactive neurotransmitters in the perivascular region, principally on the astrocyte endfeet that outline cerebral blood vessels. However, the role of astrocytes in ... More
Inositol 1,4,5-trisphosphate directs Ca(2+) flow between mitochondria and the Endoplasmic/Sarcoplasmic reticulum: a role in regulating cardiac autonomic Ca(2+) spiking.
AuthorsJaconi M, Bony C, Richards SM, Terzic A, Arnaudeau S, Vassort G, Pucéat M
JournalMol Biol Cell
PubMed ID10793156
The signaling role of the Ca(2+) releaser inositol 1,4, 5-trisphosphate (IP(3)) has been associated with diverse cell functions. Yet, the physiological significance of IP(3) in tissues that feature a ryanodine-sensitive sarcoplasmic reticulum has remained elusive. IP(3) generated by photolysis of caged IP(3) or by purinergic activation of phospholipase Cgamma slowed ... More
Prostaglandin F2alpha potentiates the calcium dependent activation of mitochondrial metabolism in luteal cells.
AuthorsPitter JG, Szanda G, Duchen MR, Spät A
JournalCell Calcium
PubMed ID15541462
Cytoplasmic Ca2+ signals are transferred to the mitochondria and activate the Krebs cycle. We have compared the efficiency of this process for two Ca2+ mobilising agonists, PGF2alpha and ATP (acting at metabotropic P2 receptors) in rat luteal cells. [Ca2+]c, [Ca2+]m and mitochondrial NAD(P)H were monitored by means of microspectrofluorimetry and ... More
Identification of a ryanodine receptor in rat heart mitochondria.
AuthorsBeutner G, Sharma VK, Giovannucci DR, Yule DI, Sheu SS
JournalJ Biol Chem
PubMed ID11297554
Recent studies have shown that, in a wide variety of cells, mitochondria respond dynamically to physiological changes in cytosolic Ca(2+) concentrations ([Ca(2+)](c)). Mitochondrial Ca(2+) uptake occurs via a ruthenium red-sensitive calcium uniporter and a rapid mode of Ca(2+) uptake. Surprisingly, the molecular identity of these Ca(2+) transport proteins is still ... More
Spatial heterogeneity of calcium transient alternans during the early phase of myocardial ischemia in the blood-perfused rabbit heart.
AuthorsQian YW, Clusin WT, Lin SF, Han J, Sung RJ
JournalCirculation
PubMed ID11673350
BACKGROUND: Optical mapping of cytosolic calcium transients in intact mammalian hearts is now possible using long-wavelength [Ca(2+)](i) indicators. We propose that beat-to-beat [Ca(2+)](i) transient alternans during ischemia may lead to spatial and temporal heterogeneity of calcium-activated membrane currents. METHODS AND RESULTS: To test this hypothesis, isolated rabbit hearts were loaded ... More
Contributions of mitochondria to animal physiology: from homeostatic sensor to calcium signalling and cell death.
AuthorsDuchen MR
JournalJ Physiol
PubMed ID10066918
Over recent years, it has become clear that mitochondria play a central role in many key aspects of animal physiology and pathophysiology. Their central and ubiquitous task is clearly the production of ATP. Nevertheless, they also play subtle roles in glucose homeostasis, acting as the sensor for substrate supply in ... More
Mitochondria are morphologically and functionally heterogeneous within cells.
AuthorsCollins TJ, Berridge MJ, Lipp P, Bootman MD
JournalEMBO J
PubMed ID11927546
We investigated whether mitochondria represent morphologically continuous and functionally homogenous entities within single intact cells. Physical continuity of mitochondria was determined by three-dimensional reconstruction of fluorescence from mitochondrially targeted DsRed1 or calcein. The mitochondria of HeLa, PAEC, COS-7, HUVEC, hepatocytes, cortical astrocytes and neuronal cells all displayed heterogeneous distributions and ... More
Simultaneous measurements of mitochondrial NADH and Ca(2+) during increased work in intact rat heart trabeculae.
AuthorsBrandes R, Bers DM
JournalBiophys J
PubMed ID12124250
The main goal of this study is to investigate the role of mitochondrial [Ca(2+)], [Ca(2+)](m), in the possible up-regulation of the NADH production rate during increased workload. Such up-regulation is necessary to support increased flux through the electron transport chain and increased ATP synthesis rates. Intact cardiac trabeculae were loaded ... More
Release of Ca2+ from the sarcoplasmic reticulum increases mitochondrial [Ca2+] in rat pulmonary artery smooth muscle cells.
AuthorsDrummond RM, Tuft RA
JournalJ Physiol
PubMed ID10066929
1. The Ca2+-sensitive fluorescent indicator rhod-2 was used to measure mitochondrial [Ca2+] ([Ca2+]m) in single smooth muscle cells from the rat pulmonary artery, while simultaneously monitoring cytosolic [Ca2+] ([Ca2+]i) with fura-2. 2. Application of caffeine produced an increase in [Ca2+]i and also increased [Ca2+]m. The increase in [Ca2+]m occurred after ... More
AMPA/kainate receptor-triggered Zn2+ entry into cortical neurons induces mitochondrial Zn2+ uptake and persistent mitochondrial dysfunction.
AuthorsSensi SL, Yin HZ, Weiss JH
JournalEur J Neurosci
PubMed ID11029652
Rapid Zn2+ influx through Ca2+-permeable AMPA/kainate (Ca-A/K) channels triggers reactive oxygen species (ROS) generation and is potently neurotoxic. The first aim of this study was to determine whether these effects might result from direct mitochondrial Zn2+ uptake. Adapting the mitochondrially sequestered divalent cation sensitive probe, rhod-2, to visualize mitochondrial Zn2+, ... More
Chronic exposure to paclitaxel diminishes phosphoinositide signaling by calpain-mediated neuronal calcium sensor-1 degradation.
AuthorsBoehmerle W, Zhang K, Sivula M, Heidrich FM, Lee Y, Jordt SE, Ehrlich BE
JournalProc Natl Acad Sci U S A
PubMed ID17581879
Paclitaxel (Taxol) is a well established chemotherapeutic agent for the treatment of solid tumors, but it is limited in its usefulness by the frequent induction of peripheral neuropathy. We found that prolonged exposure of a neuroblastoma cell line and primary rat dorsal root ganglia with therapeutic concentrations of Taxol leads ... More
Stimulation-induced mitochondrial [Ca2+] elevations in mouse motor terminals: comparison of wild-type with SOD1-G93A.
AuthorsVila L, Barrett EF, Barrett JN
JournalJ Physiol
PubMed ID12717010
Changes in mitochondrial matrix [Ca2+] evoked by trains of action potentials were studied in levator auris longus motor terminals using Ca2+-sensitive fluorescent indicator dyes (rhod-2, rhod-5F). During a 2500 impulse 50 Hz train, mitochondrial [Ca2+] in most wild-type terminals increased within 5-10 s to a plateau level that was sustained ... More
Mitochondria shape hormonally induced cytoplasmic calcium oscillations and modulate exocytosis.
AuthorsKaftan EJ, Xu T, Abercrombie RF, Hille B
JournalJ Biol Chem
PubMed ID10835418
Pituitary gonadotropes transduce hormonal input into cytoplasmic calcium ([Ca(2+)](cyt)) oscillations that drive rhythmic exocytosis of gonadotropins. Using Calcium Green-1 and rhod-2 as optical measures of cytoplasmic and mitochondrial free Ca(2+), we show that mitochondria sequester Ca(2+) and tune the frequency of [Ca(2+)](cyt) oscillations in rat gonadotropes. Mitochondria accumulated Ca(2+) rapidly ... More
Kinetics of calcium channel opening by inositol 1,4,5-trisphosphate.
AuthorsMeyer T, Wensel T, Stryer L
JournalBiochemistry
PubMed ID1691015
The subsecond mobilization of intracellular Ca2+ by IP3 was measured with rapid mixing techniques to determine how cells achieve rapid rises in cytosolic [Ca2+] during receptor-triggered calcium spiking. In permeabilized rat basophilic leukemia cells at 11 degrees C, more than 80% of the 0.7 fmol of Ca2+/cell sequestered by the ... More
Confocal microscopy reveals coordinated calcium fluctuations and oscillations in synaptic boutons.
AuthorsMelamed N, Helm PJ, Rahamimoff R
JournalJ Neurosci
PubMed ID8426230
Calcium ions are one of the main factors regulating quantal transmitter release and thus synaptic transmission in the nervous system. Using confocal microscopy, fluorescent imaging with the calcium indicator Rhod-2, and time series analysis, we show that the levels of calcium ions inside single synaptic boutons of the lizard neuromuscular ... More
Pulsed laser imaging of Ca(2+) influx in a neuroendocrine terminal.
AuthorsFisher TE, Fernandez JM
JournalJ Neurosci
PubMed ID10460251
The surge of Ca(2+) that triggers vesicle fusion is shaped by the distribution of Ca(2+) channels and the physical relationship between those channels and the exocytotic apparatus. Although channels and the release apparatus are thought to be tightly associated at fast synapses, the arrangement at neuroendocrine cells is less clear. ... More
Inactivation of EF-hands makes GCAP-2 (p24) a constitutive activator of photoreceptor guanylyl cyclase by preventing a Ca2+-induced "activator-to-inhibitor" transition.
AuthorsDizhoor AM, Hurley JB
JournalJ Biol Chem
PubMed ID8702620
Guanylyl cyclase activator proteins GCAP-1 and GCAP-2 (Dizhoor et al. , 1995, Gorczyca et al., 1995) are members of a recently identified subclass of EF-hand type Ca2+-binding proteins that respond to Ca2+ differently than any other known members of the EF-hand superfamily. GCAPs acquire an activating conformation only in their ... More
Evidence that mitochondria buffer physiological Ca2+ loads in lizard motor nerve terminals.
AuthorsDavid G, Barrett JN, Barrett EF
JournalJ Physiol
PubMed ID9547381
1. Changes in cytosolic and mitochondrial [Ca2+] produced by brief trains of action potentials were measured in motor nerve terminals using a rapidly scanning confocal microscope. Cytosolic [Ca2+] was measured using ionophoretically injected Oregon Green BAPTA 5N (OG-5N). Mitochondrial [Ca2+] was measured using rhod-2, bath loaded as dihydrorhod-2. 2. In ... More
Changes in mitochondrial activity evoked by cholecystokinin in isolated mouse pancreatic acinar cells.
AuthorsGonzález A, Granados MP, Salido GM, Pariente JA
JournalCell Signal
PubMed ID14499347
In the present study, we have employed confocal laser scanning microscopy to investigate the effect that stimulation of mouse pancreatic acinar cells with the secretagogue cholecystokinin (CCK) has on mitochondrial activity. We have monitored changes in cytosolic as well as mitochondrial Ca2+ concentrations, mitochondrial membrane potential and FAD autofluorescence by ... More
Contribution of increased mitochondrial free Ca2+ to the mitochondrial permeability transition induced by tert-butylhydroperoxide in rat hepatocytes.
AuthorsByrne AM, Lemasters JJ, Nieminen AL
JournalHepatology
PubMed ID10216138
Previously, we showed that the oxidant chemical, tert-butylhydroperoxide (t-BuOOH), induces a mitochondrial permeability transition (MPT) in intact hepatocytes, causing lethal cell injury. Here, we investigated the role of mitochondrial free Ca2+ in t-BuOOH cytotoxicity to 1-day-cultured rat hepatocytes using confocal microscopy of autofluorescence and parameter-indicating fluorophores. t-BuOOH (100 micromol/L) caused ... More
Sublethal oxidant stress induces a reversible increase in intracellular calcium dependent on NAD(P)H oxidation in rat alveolar macrophages.
AuthorsLivingston FR, Lui EM, Loeb GA, Forman HJ
JournalArch Biochem Biophys
PubMed ID1444455
A concentration-dependent elevation of intracellular calcium ([Ca2+]i) and oxidation of NAD(P)H occurred in alveolar macrophages during exposure to sublethal tert-butylhydroperoxide concentrations (tBOOH) (< or = 100 microM in 1 ml with 1 x 10(6) cells). Oxidation of NAD(P)H preceded a rise in [Ca2+]i. The elevation of [Ca2+]i was reversible at ... More
Mechanism of cyclosporin-induced inhibition of intracellular collagen degradation.
AuthorsArora PD, Silvestri L, Ganss B, Sodek J, McCulloch CA
JournalJ Biol Chem
PubMed ID11278659
The immunosuppressant cyclosporin A (CsA) markedly inhibits collagen degradation by an intracellular phagocytic pathway in fibroblasts, an effect that can lead to massive gingival overgrowth. We used a collagen bead model of collagen phagocytosis to determine whether CsA inhibits internalization by blocking efflux of calcium from endoplasmic reticulum (ER) and ... More
Mitochondria suppress local feedback activation of inositol 1,4, 5-trisphosphate receptors by Ca2+.
AuthorsHajnóczky G, Hager R, Thomas AP
JournalJ Biol Chem
PubMed ID10318833
The concerted action of inositol 1,4,5-trisphosphate (IP3) and Ca2+ on the IP3 receptor Ca2+ release channel (IP3R) is a fundamental step in the generation of cytosolic Ca2+ oscillations and waves, which underlie Ca2+ signaling in many cells. Mitochondria appear in close association with regions of endoplasmic reticulum (ER) enriched in ... More
Changes in intracellular Ca2+ and energy levels during in vitro ischemia in the gerbil hippocampal slice.
AuthorsMitani A, Takeyasu S, Yanase H, Nakamura Y, Kataoka K
JournalJ Neurochem
PubMed ID8294926
The time course of the decline in energy levels during an in vitro ischemia-like condition was compared with changes in intracellular Ca2+ concentration ([Ca2+]i) in subregions of the gerbil hippocampal slice [CA1, CA3, and the inner and outer portions of the dentate gyrus (DG)]. Hippocampal transverse slices were loaded with ... More
Early development of functional spatial maps in the zebrafish olfactory bulb.
AuthorsLi J, Mack JA, Souren M, Yaksi E, Higashijima S, Mione M, Fetcho JR, Friedrich RW
JournalJ Neurosci
PubMed ID15958745
In the adult olfactory bulb (OB), particular chemical classes of odorants preferentially activate glomeruli within loosely defined regions, resulting in a coarse and fractured "chemotopic" map. In zebrafish, amino acids and bile acids predominantly stimulate glomeruli in the lateral and medial OB, respectively. We studied the development of these spatial ... More