Ca2+ fluorescence imaging with pico- and femtosecond two-photon excitation: signal and photodamage.
AuthorsKoester HJ, Baur D, Uhl R, Hell SW
JournalBiophys J
PubMed ID10512842
'The signal and limitations of calcium florescence imaging using nonresonant multiphoton absorption of near-infrared femto- and picosecond laser pulses were examined. The fluorescence changes of various Ca(2+)-indicators induced by transient increases of the intradendritic calcium concentration were evaluated by evoking physiological activity in neocortical neurons in rat brain slices. Photodamage ... More
Light dependence of calcium and membrane potential measured in blowfly photoreceptors in vivo.
AuthorsOberwinkler J, Stavenga DG
JournalJ Gen Physiol
PubMed ID9689022
'Light adaptation in insect photoreceptors is caused by an increase in the cytosolic Ca2+ concentration. To better understand this process, we measured the cytosolic Ca2+ concentration in vivo as a function of adapting light intensity in the white-eyed blowfly mutant chalky. We developed a technique to measure the cytosolic Ca2+ ... More
Modulation of [Ca2+]i signaling dynamics and metabolism by perinuclear mitochondria in mouse parotid acinar cells.
AuthorsBruce JI, Giovannucci DR, Blinder G, Shuttleworth TJ, Yule DI
JournalJ Biol Chem
PubMed ID14699167
'Parotid acinar cells exhibit rapid cytosolic calcium signals ([Ca2+]i) that initiate in the apical region but rapidly become global in nature. These characteristic [Ca2+]i signals are important for effective fluid secretion, which critically depends on a synchronized activation of spatially separated ion fluxes. Apically restricted [Ca2+]i signals were never observed ... More
A novel role for MNTB neuron dendrites in regulating action potential amplitude and cell excitability during repetitive firing.
AuthorsLeão RN, Leão RM, da Costa LF, Rock Levinson S, Walmsley B,
JournalEur J Neurosci
PubMed ID18598256
'Principal cells of the medial nucleus of the trapezoid body (MNTB) are simple round neurons that receive a large excitatory synapse (the calyx of Held) and many small inhibitory synapses on the soma. Strangely, these neurons also possess one or two short tufted dendrites, whose function is unknown. Here we ... More
Extracellular Ca2+ depletion contributes to fast activity-dependent modulation of synaptic transmission in the brain.
AuthorsRusakov DA, Fine A
JournalNeuron
PubMed ID12546823
'Synaptic activation is associated with rapid changes in intracellular Ca(2+), while the extracellular Ca(2+) level is generally assumed to be constant. Here, using a novel optical method to measure changes in extracellular Ca(2+) at high spatial and temporal resolution, we find that brief trains of synaptic transmission in hippocampal area ... More
A role for phosphorylation of inositol 1,4,5-trisphosphate receptors in defining calcium signals induced by Peptide agonists in pancreatic acinar cells.
AuthorsStraub SV, Giovannucci DR, Bruce JI, Yule DI
JournalJ Biol Chem
PubMed ID12065595
'Stimulation of pancreatic acinar cells with acetylcholine (ACh) and cholecystokinin (CCK) results in an elevation of cytosolic calcium ([Ca(2+)](c)) through activation of inositol 1,4,5-trisphosphate receptors (InsP(3)R). The global temporal pattern of the [Ca(2+)](c) changes produced by ACh or CCK stimulation differs significantly. The hypothesis was tested that CCK stimulation results ... More
Photo-physical properties of Ca2+-indicator dyes suitable for two-photon fluorescence-lifetime recordings.
AuthorsWilms CD, Eilers J,
JournalJ Microsc
PubMed ID17371443
We analyzed the suitability of various Ca2+-indicator dyes for quantitative two-photon fluorescence-lifetime imaging. Although fura-2, fluo-3, BTC and calcein did not show useful Ca2+-dependent lifetime changes, calcium orange, calcium green-1, oregon green-2 and -5N, as well as magnesium green allowed to quantify the Ca2+-free and Ca2+-bound dye fractions by a ... More
Amphetamine selectively blocks inhibitory glutamate transmission in dopamine neurons.
AuthorsPaladini CA, Fiorillo CD, Morikawa H, Williams JT
JournalNat Neurosci
PubMed ID11224544
Amphetamine is a highly addictive psychostimulant that promotes the release of the catecholamines dopamine and norepinephrine. Amphetamine-induced release of dopamine in the midbrain inhibits the activity of dopamine neurons through activation of D2 dopamine autoreceptors. Here we show that amphetamine may also excite dopamine neurons through modulation of glutamate neurotransmission. ... More
Synaptic calcium transients in single spines indicate that NMDA receptors are not saturated.
AuthorsMainen ZF, Malinow R, Svoboda K
JournalNature
PubMed ID10335844
At excitatory synapses in the central nervous system, the number of glutamate molecules released from a vesicle is much larger than the number of postsynaptic receptors. But does release of a single vesicle normally saturate these receptors? Answering this question is critical to understanding how the amplitude and variability of ... More
Cooperative Ca2+ removal from presynaptic terminals of the spiny lobster neuromuscular junction.
AuthorsOhnuma K, Kazawa T, Ogawa S, Suzuki N, Miwa A, Kijima H
JournalBiophys J
PubMed ID10096881
Stimulation-induced changes in presynaptic free calcium concentration ([Ca2+]i) were examined by fluorescent imaging at the spiny lobster excitor motor nerve terminals. The Ca2+ removal process in the terminal was analyzed based on a single compartment model, under the assumption that the Ca2+ removal rate from the terminal cytoplasm is proportional ... More
Nontranscriptional modulation of intracellular Ca2+ signaling by ligand stimulated thyroid hormone receptor.
AuthorsSaelim N, John LM, Wu J, Park JS, Bai Y, Camacho P, Lechleiter JD
JournalJ Cell Biol
PubMed ID15569710
Thyroid hormone 3,5,3'-tri-iodothyronine (T3) binds and activates thyroid hormone receptors (TRs). Here, we present evidence for a nontranscriptional regulation of Ca2+ signaling by T3-bound TRs. Treatment of Xenopus thyroid hormone receptor beta subtype A1 (xTRbetaA1) expressing oocytes with T3 for 10 min increased inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ wave periodicity. Coexpression ... More
Localized detection of action potential-induced presynaptic calcium transients at a Xenopus neuromuscular junction.
AuthorsDiGregorio DA, Vergara JL
JournalJ Physiol
PubMed ID9457637
1. Action potential (AP)-induced fluorescence transients were measured, using Ca2+ indicators and a spot-detection method, at single nerve terminals of a cultured Xenopus neuromuscular junction preparation with simultaneous measurement of neurotransmitter release. 2. Transients obtained using the low affinity Ca2+ indicator Oregon Green 488 BAPTA-5N (OGB-5N) exhibited rapid rising (t1/2 ... More
Ca2+ and Mg2+ binding properties of GCAP-1. Evidence that Mg2+-bound form is the physiological activator of photoreceptor guanylyl cyclase.
AuthorsPeshenko IV, Dizhoor AM
JournalJ Biol Chem
PubMed ID16793776
Guanylyl cyclase-activating protein 1 (GCAP-1) is an EF-hand protein that activates retinal guanylyl cyclase (RetGC) in photoreceptors at low free Ca2+ in the light and inhibits it in the dark when Ca2+ concentrations rise. We present the first direct evidence that Mg2+-bound form of GCAP-1, not its cation-free form, is ... More
Exocytosis and endocytosis of small vesicles in PC12 cells studied with TEPIQ (two-photon extracellular polar-tracer imaging-based quantification) analysis.
AuthorsLiu TT, Kishimoto T, Hatakeyama H, Nemoto T, Takahashi N, Kasai H
JournalJ Physiol
PubMed ID16150796
We investigated exocytosis of PC12 cells using two-photon excitation imaging and extracellular polar tracers (TEP imaging) in the lateral membranes not facing the glass-cover slip. Upon photolysis of a caged Ca2+ compound, TEP imaging with FM1-43 (a polar membrane tracer) detected massive exocytosis of vesicles with a time constant of ... More
Calcium imaging in live rat optic nerve myelinated axons in vitro using confocal laser microscopy.
AuthorsRen Y, Ridsdale A, Coderre E, Stys PK
JournalJ Neurosci Methods
PubMed ID11040413
Intracellular Ca(2+) plays a major role in the physiological responses of excitable cells, and excessive accumulation of internal Ca(2+) is a key determinant of cell injury and death. Many studies have been carried out on the internal Ca(2+) dynamics in neurons. In constrast, there is virtually no such information for ... More
Targeted phosphorylation of inositol 1,4,5-trisphosphate receptors selectively inhibits localized Ca2+ release and shapes oscillatory Ca2+ signals.
AuthorsGiovannucci DR, Groblewski GE, Sneyd J, Yule DI
JournalJ Biol Chem
PubMed ID10887192
The current study provides biochemical and functional evidence that the targeting of protein kinase A (PKA) to sites of localized Ca(2+) release confers rapid, specific phosphoregulation of Ca(2+) signaling in pancreatic acinar cells. Regulatory control of Ca(2+) release by PKA-dependent phosphorylation of inositol 1,4, 5-trisphosphate (InsP(3)) receptors was investigated by ... More