Normal fertilization occurs with eggs lacking the integrin alpha6beta1 and is CD9-dependent.
AuthorsMiller BJ, Georges-Labouesse E, Primakoff P, Myles DG
JournalJ Cell Biol
PubMed ID10851025
'Previous results, based on inhibition of fertilization by an anti-alpha6 integrin mAb (GoH3), suggest that the alpha6beta1 integrin on mouse eggs functions as the receptor for sperm (Almeida, E.A., A.P. Huovila, A.E. Sutherland, L.E. Stephens, P.G. Calarco, L. M. Shaw, A.M. Mercurio, A. Sonnenberg, P. Primakoff, D.G. Myles, and J.M. ... More
Acetylcholine-induced calcium signaling and contraction of airway smooth muscle cells in lung slices.
AuthorsBergner A, Sanderson MJ
JournalJ Gen Physiol
PubMed ID11815668
'The Ca(2+) signaling and contractility of airway smooth muscle cells (SMCs) were investigated with confocal microscopy in murine lung slices (approximately 75-microm thick) that maintained the in situ organization of the airways and the contractility of the SMCs for at least 5 d. 10--500 nM acetylcholine (ACH) induced a contraction ... More
Intracellular astrocyte calcium waves in situ increase the frequency of spontaneous AMPA receptor currents in CA1 pyramidal neurons.
AuthorsFiacco TA, McCarthy KD
JournalJ Neurosci
PubMed ID14736858
'Spontaneous neurotransmitter release and activation of group I metabotropic glutamate receptors (mGluRs) each play a role in the plasticity of neuronal synapses. Astrocytes may contribute to short- and long-term synaptic changes by signaling to neurons via these processes. Spontaneous whole-cell AMPA receptor (AMPAR) currents were recorded in CA1 pyramidal cells ... More
The sources and sequestration of Ca(2+) contributing to neuroeffector Ca(2+) transients in the mouse vas deferens.
AuthorsBrain KL, Cuprian AM, Williams DJ, Cunnane TC
JournalJ Physiol
PubMed ID14500773
'The detection of focal Ca(2+) transients (called neuroeffector Ca(2+) transients, or NCTs) in smooth muscle of the mouse isolated vas deferens has been used to detect the packeted release of ATP from nerve terminal varicosities acting at postjunctional P2X receptors. The present study investigates the sources and sequestration of Ca(2+) ... More
Control of IP(3)-mediated Ca2+ puffs in Xenopus laevis oocytes by the Ca2+-binding protein parvalbumin.
AuthorsJohn LM, Mosquera-Caro M, Camacho P, Lechleiter JD
JournalJ Physiol
PubMed ID11507154
'1. Elementary events of Ca2+ release (Ca2+ puffs) can be elicited from discrete clusters of inositol 1,4,5 trisphosphate receptors (IP(3)Rs) at low concentrations of IP(3). Ca(2+) puffs have rarely been observed unless elicited by either hormone treatment or introduction of IP(3) into the cell. However, cells appear to have sufficient ... More
Mapping the sensitivity of T cells with an optical trap: polarity and minimal number of receptors for Ca(2+) signaling.
AuthorsWei X, Tromberg BJ, Cahalan MD
JournalProc Natl Acad Sci U S A
PubMed ID10411899
'Contact with antigen-presenting cells (APCs) initiates an activation cascade within T lymphocytes, including a rise in cytosolic calcium, lymphokine production, and cell division. Although T cell-APC physical contact is required for an immune response, little is known about the patterns of cellular interactions and their relation to activation. Calcium imaging ... More
pH-dependent regulation of lysosomal calcium in macrophages.
AuthorsChristensen KA, Myers JT, Swanson JA
JournalJ Cell Sci
PubMed ID11861766
'Calcium measurements in acidic vacuolar compartments of living cells are few, primarily because calibration of fluorescent probes for calcium requires knowledge of pH and the pH-dependence of the probe calcium-binding affinities. Here we report pH-corrected measurements of free calcium concentrations in lysosomes of mouse macrophages, using both ratiometric and time-resolved ... More
Fast scanning and efficient photodetection in a simple two-photon microscope.
AuthorsTan YP, Llano I, Hopt A, Würriehausen F, Neher E
JournalJ Neurosci Methods
PubMed ID10595710
'Two-photon laser scan microscopy carries many advantages for work on brain slices and bulk tissue. However, it has very low signal levels compared to conventional fluorescence microscopy. This is disadvantageous in fast imaging applications when photon shot noise is limiting. Working on brain slices with excitation powers of 8-10 mW ... More
AII amacrine cells express L-type calcium channels at their output synapses.
AuthorsHabermann CJ, O'Brien BJ, Wässle H, Protti DA
JournalJ Neurosci
PubMed ID12890785
'AII amacrine cells play a critical role in the high-fidelity signal transmission pathways involved with nighttime vision. The temporal properties of the light responses strongly depend on the transfer function at different synaptic stages and consequently on presynaptic calcium influx. AII light responses are complex waveforms generated by graded input, ... More
Two-photon laser-scanning microscopy: tests of objective lenses and Ca2+ probes.
AuthorsKuba K, Nakayama S
JournalNeurosci Res
PubMed ID9875569
'The characteristics of objective lenses and Ca2+-sensitive probes were examined for imaging with a two-photon laser-scanning microscope (TP-LSM). The brightness of the images of beads taken by different objectives greatly varied and depended predominantly on their numerical aperture (NA) and less on transmittance and chirping effects. Lateral and axial resolutions, ... More
Stimulation-evoked increases in cytosolic [Ca(2+)] in mouse motor nerve terminals are limited by mitochondrial uptake and are temperature-dependent.
AuthorsDavid G, Barrett EF
JournalJ Neurosci
PubMed ID11007886
'Increases in cytosolic [Ca(2+)] evoked by trains of action potentials (20-100 Hz) were recorded from mouse and lizard motor nerve terminals filled with a low-affinity fluorescent indicator, Oregon Green BAPTA 5N. In mouse terminals at near-physiological temperatures (30-38 degrees C), trains of action potentials at 25-100 Hz elicited increases in ... More
G alpha minigenes expressing C-terminal peptides serve as specific inhibitors of thrombin-mediated endothelial activation.
AuthorsGilchrist A, Vanhauwe JF, Li A, Thomas TO, Voyno-Yasenetskaya T, Hamm HE
JournalJ Biol Chem
PubMed ID11274183
'The C termini of G protein alpha subunits are critical for binding to their cognate receptors, and peptides corresponding to the C terminus can serve as competitive inhibitors of G protein-coupled receptor-G protein interactions. This interface is quite specific as a single amino acid difference annuls the ability of a ... More
Nuclear calcium signaling evoked by cholinergic stimulation in hippocampal CA1 pyramidal neurons.
AuthorsPower JM, Sah P
JournalJ Neurosci
PubMed ID11978822
'The cholinergic system is thought to play an important role in hippocampal-dependent learning and memory. However, the mechanism of action of the cholinergic system in these actions in not well understood. Here we examined the effect of muscarinic receptor stimulation in hippocampal CA1 pyramidal neurons using whole-cell recordings in acute ... More
Calbindin in cerebellar Purkinje cells is a critical determinant of the precision of motor coordination.
AuthorsBarski JJ, Hartmann J, Rose CR, Hoebeek F, Mörl K, Noll-Hussong M, De Zeeuw CI, Konnerth A, Meyer M
JournalJ Neurosci
PubMed ID12716955
'Long-term depression (LTD) of Purkinje cell-parallel fiber synaptic transmission is a critical determinant of normal cerebellar function. Impairment of LTD through, for example, disruption of the metabotropic glutamate receptor-IP3-calcium signaling cascade in mutant mice results in severe deficits of both synaptic transmission and cerebellar motor control. Here, we demonstrate that ... More
Integrin alpha IIb beta 3-dependent calcium signals regulate platelet-fibrinogen interactions under flow. Involvement of phospholipase C gamma 2.
AuthorsGoncalves I, Hughan SC, Schoenwaelder SM, Yap CL, Yuan Y, Jackson SP
JournalJ Biol Chem
PubMed ID12832405
'Platelet adhesion to fibrinogen is important for platelet aggregation and thrombus growth. In this study we have examined the mechanisms regulating platelet adhesion on immobilized fibrinogen under static and shear conditions. We demonstrate that integrin alpha IIb beta 3 engagement of immobilized fibrinogen is sufficient to induce an oscillatory calcium ... 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
Properties of the vertebrate skeletal muscle tubular system as a sealed compartment.
AuthorsLaunikonis BS, Stephenson DG
JournalCell Biol Int
PubMed ID12421583
'Confocal imaging of impermeant fluorescent dyes trapped in the tubular (t-) system of skeletal muscle fibres of rat and cane toad was used to examine changes in the morphology of the t-system upon mechanical skinning, the time course of dye loss from the sealed t-system in mechanically skinned fibres and ... More
In vivo imaging of seizure activity in a novel developmental seizure model.
AuthorsHewapathirane DS, Dunfield D, Yen W, Chen S, Haas K,
JournalExp Neurol
PubMed ID18402939
'The immature brain is exceptionally susceptible to seizures. However, it remains unclear whether seizures occurring during development affect critical processes underlying neural circuit formation, leading to long-term functional consequences. Here we characterize a novel in vivo model system of developmental seizures based on the transparent albino Xenopus laevis tadpole, which ... More
Depression of transmitter release at synapses in the rat superior cervical ganglion: the role of transmitter depletion.
AuthorsLin YQ, Graham K, Bennett MR
JournalAuton Neurosci
PubMed ID11474542
'The characteristics of depression of the excitatory postsynaptic potential (EPSP) during a short train of impulses to the rat superior cervical ganglion (SCG) have been ascertained with the object of determining the relative contributions of transmitter depletion and autoreceptors to depression. Successive EPSPs in a short train were depressed after ... More
Cytosolic phosphorylation of calnexin controls intracellular Ca(2+) oscillations via an interaction with SERCA2b.
AuthorsRoderick HL, Lechleiter JD, Camacho P
JournalJ Cell Biol
PubMed ID10851021
'Calreticulin (CRT) and calnexin (CLNX) are lectin chaperones that participate in protein folding in the endoplasmic reticulum (ER). CRT is a soluble ER lumenal protein, whereas CLNX is a transmembrane protein with a cytosolic domain that contains two consensus motifs for protein kinase (PK) C/proline- directed kinase (PDK) phosphorylation. Using ... More
An apoplastic Ca2+ sensor regulates internal Ca2+ release in aequorin-transformed tobacco cells.
AuthorsCessna SG, Low PS
JournalJ Biol Chem
PubMed ID11139570
'Removal of Ca(2+) from tobacco suspension cell medium has two immediate effects on cytosolic Ca(2+) fluxes: (i) externally derived Ca(2+) influx (occurring in response to cold shock or hypo-osmotic shock) is inhibited, and (ii) organellar Ca(2+) release (induced by a fungally derived defense elicitor, caffeine, or hypo-osmotic shock) is elevated. ... More
Enhanced spontaneous Ca(2+) events in endothelial cells reflect signalling through myoendothelial gap junctions in pressurized mesenteric arteries.
AuthorsKansui Y, Garland CJ, Dora KA,
JournalCell Calcium
PubMed ID18191200
'Increases in global Ca(2+) in the endothelium are a crucial step in releasing relaxing factors to modulate arterial tone. In the present study we investigated spontaneous Ca(2+) events in endothelial cells, and the contribution of smooth muscle cells to these Ca(2+) events, in pressurized rat mesenteric resistance arteries. Spontaneous Ca(2+) ... More
Live imaging of neural structure and function by fibred fluorescence microscopy.
AuthorsVincent P, Maskos U, Charvet I, Bourgeais L, Stoppini L, Leresche N, Changeux JP, Lambert R, Meda P, Paupardin-Tritsch D
JournalEMBO Rep
PubMed ID17008931
'Only a few methods permit researchers to study selected regions of the central and peripheral nervous systems with a spatial and time resolution sufficient to image the function of neural structures. Usually, these methods cannot analyse deep-brain regions and a high-resolution method, which could repeatedly probe dynamic processes in any ... More
Dynamics of intracellular calcium in hair cells isolated from the semicircular canal of the frog.
AuthorsRispoli G, Martini M, Rossi ML, Mammano F
JournalCell Calcium
PubMed ID11440470
'Changes in cytosolic free Ca(2+) concentration ([Ca(2+)]i) were monitored optically in hair cells mechanically isolated from frog semicircular canals using the membrane-impermeant form of the Ca(2+)-selective dye Oregon Green 488 BAPTA-1 (OG, 100 microM). Cells stimulated by depolarization under whole-cell voltage clamp conditions revealed Ca(2+) entry at selected sites (hotspots) ... More
Intercellular calcium signaling in astrocytes via ATP release through connexin hemichannels.
AuthorsStout CE, Costantin JL, Naus CC, Charles AC
JournalJ Biol Chem
PubMed ID11790776
'Astrocytes are capable of widespread intercellular communication via propagated increases in intracellular Ca(2+) concentration. We have used patch clamp, dye flux, ATP assay, and Ca(2+) imaging techniques to show that one mechanism for this intercellular Ca(2+) signaling in astrocytes is the release of ATP through connexin channels ("hemichannels") in individual ... More
Action potential timing determines dendritic calcium during striatal up-states.
AuthorsKerr JN, Plenz D
JournalJ Neurosci
PubMed ID14749432
'Up-states represent a key feature of synaptic integration in cortex and striatum that involves activation of many synaptic inputs. In the striatum, the sparse firing and tight control of action potential timing is in contrast to the large intracellular membrane potential depolarizations observed during the up-state. One hallmark of striatal ... More
Focal Ca2+ transient detection in smooth muscle.
AuthorsYoung JS, Amos RJ, Brain KL,
JournalJ Vis Exp
PubMed ID19564842
'Ca2+ imaging of smooth muscle provides insight into cellular mechanisms that may not result in changes of membrane potential, such as the release of Ca2+ from internal stores, and allows multiple cells to be monitored simultaneously to assess, for example, coupling in syncytial tissue. Subcellular Ca2+ transients are common in ... More
alpha-Latrotoxin releases calcium in frog motor nerve terminals.
AuthorsTsang CW, Elrick DB, Charlton MP
JournalJ Neurosci
PubMed ID11102474
'alpha-Latrotoxin (alpha-LTX) is a neurotoxin that accelerates spontaneous exocytosis independently of extracellular Ca(2+). Although alpha-LTX increases spontaneous transmitter release at synapses, the mechanism is unknown. We tested the hypothesis that alpha-LTX causes transmitter release by mobilizing intracellular Ca(2+) in frog motor nerve terminals. Transmitter release was measured electrophysiologically and with ... More
Spatial-temporal patterning of metabotropic glutamate receptor-mediated inositol 1,4,5-triphosphate, calcium, and protein kinase C oscillations: protein kinase C-dependent receptor phosphorylation is not required.
AuthorsDale LB, Babwah AV, Bhattacharya M, Kelvin DJ, Ferguson SS
JournalJ Biol Chem
PubMed ID11461909
'The metabotropic glutamate receptors (mGluR), mGluR1a and mGluR5a, are G protein-coupled receptors that couple via G(q) to the hydrolysis of phosphoinositides, the release of Ca(2+) from intracellular stores, and the activation of protein kinase C (PKC). We show here that mGluR1/5 activation results in oscillatory G protein coupling to phospholipase ... 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
SERCA pump optimizes Ca2+ release by a mechanism independent of store filling in smooth muscle cells.
AuthorsGómez-Viquez L, Guerrero-Serna G, García U, Guerrero-Hernández A
JournalBiophys J
PubMed ID12829491
'Thapsigargin-sensitive sarco/endoplasmic reticulum Ca(2+) pumps (SERCAs) are involved in maintaining and replenishing agonist-sensitive internal stores. Although it has been assumed that release channels act independently of SERCA pumps, there are data suggesting the opposite. Our aim was to study the relationship between SERCA pumps and the release channels in smooth ... More
The anticonvulsant, antihyperalgesic agent gabapentin is an agonist at brain gamma-aminobutyric acid type B receptors negatively coupled to voltage-dependent calcium channels.
'Gabapentin (Neurontin, Pfizer Global R & D) is a novel anticonvulsant, antihyperalgesic, and antinociceptive agent with a poorly understood mechanism of action. In this study, we show that gabapentin (EC50 2 microM) inhibited up to 70 to 80% of the total K+-evoked Ca2+ influx via voltage-dependent calcium channels (VD-CCs) in ... More
Ventricle-directed migration in the developing cerebral cortex.
AuthorsNadarajah B, Alifragis P, Wong RO, Parnavelas JG
JournalNat Neurosci
PubMed ID11850632
'It is believed that postmitotic neurons migrate away from their sites of origin in the germinal zones to populate distant targets. Contrary to this notion, we found, using time-lapse imaging of brain slices, populations of neurons positioned at various levels of the developing neocortex that migrate towards the cortical ventricular ... More
Mechanisms of calcium elevation in the micromeres of sea urchin embryos.
AuthorsYazaki I, Abe M, Santella L, Koyama Y
JournalBiol Cell
PubMed ID15050370
'The micromeres, the first cells to be specified in sea urchin embryos, are generated by unequal cleavage at the fourth cell division. The micromeres differentiate autonomously to form spicules and dispatch signals to induce endomesoderm in the neighbouring macromeres cells in the embryo. Using a calcium indicator Fura-2/AM and a ... More
Functional organization of sensory input to the olfactory bulb glomerulus analyzed by two-photon calcium imaging.
AuthorsWachowiak M, Denk W, Friedrich RW
JournalProc Natl Acad Sci U S A
PubMed ID15184670
'Glomeruli in the olfactory bulb are anatomically discrete modules receiving input from idiotypic olfactory sensory neurons. To examine the functional organization of sensory inputs to individual glomeruli, we loaded olfactory sensory neurons with a Ca(2+) indicator and measured odorant-evoked presynaptic Ca(2+) signals within single glomeruli by using two-photon microscopy in ... More
Synchronous hyperactivity and intercellular calcium waves in astrocytes in Alzheimer mice.
'Although senile plaques focally disrupt neuronal health, the functional response of astrocytes to Alzheimer''s disease pathology is unknown. Using multiphoton fluorescence lifetime imaging microscopy in vivo, we quantitatively imaged astrocytic calcium homeostasis in a mouse model of Alzheimer''s disease. Resting calcium was globally elevated in the astrocytic network, but was ... 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
Targeted bulk-loading of fluorescent indicators for two-photon brain imaging in vivo.
AuthorsGaraschuk O, Milos RI, Konnerth A
JournalNat Protoc
PubMed ID17406260
'One of the challenges for modern neuroscience is to understand the rules of concerted neuronal function in vivo. This question can be addressed using noninvasive high-resolution imaging techniques like two-photon microscopy. This protocol describes a versatile approach for in vivo two-photon calcium imaging of neural networks, stained with membrane-permeant fluorescent-indicator ... More
Detecting action potentials in neuronal populations with calcium imaging.
AuthorsSmetters D, Majewska A, Yuste R
JournalMethods
PubMed ID10356353
'The study of neural circuits requires methods for simultaneously recording the activity of populations of neurons. Here, using calcium imaging of neocortical brain slices we take advantage of the ubiquitous distribution of calcium channels in neurons to develop a method to reconstruct the action potentials occurring in a population of ... 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
K+ channel blockers and Ca2+ signals in basket cell terminals.
AuthorsRobertson B, Southan A
JournalJ Physiol
PubMed ID10517792
Confocal Ca2+ imaging of organelles, cells, tissues, and organs.
AuthorsWilliams DA, Bowser DN, Petrou S
JournalMethods Enzymol
PubMed ID10506988
High-speed, miniaturized fluorescence microscopy in freely moving mice.
AuthorsFlusberg BA, Nimmerjahn A, Cocker ED, Mukamel EA, Barretto RP, Ko TH, Burns LD, Jung JC, Schnitzer MJ,
JournalNat Methods
PubMed ID18836457
A central goal in biomedicine is to explain organismic behavior in terms of causal cellular processes. However, concurrent observation of mammalian behavior and underlying cellular dynamics has been a longstanding challenge. We describe a miniaturized (1.1 g mass) epifluorescence microscope for cellular-level brain imaging in freely moving mice, and its ... More
Astrocytes going live: advances and challenges.
AuthorsNimmerjahn A,
JournalJ Physiol
PubMed ID19204050
Astrocytes are one of the most numerous cell types in the CNS. They have emerged as sophisticated cells participating in a large and diverse variety of functions vital for normal brain development, adult physiology and pathology. Recent in vivo studies have provided exciting new insight into astrocyte physiology in the ... More
Two-photon imaging of calcium accumulation in rat cerebellar granule cells.
AuthorsPellistri F, Cupello A, Esposito A, Marchetti C, Robello M
JournalNeuroreport
PubMed ID15106836
Topical accumulation of calcium ions in neurites and cell bodies of rat cerebellar granule cells was studied by two-photon microscopy in neurons loaded with the Ca-sensitive fluorescent indicator Oregon Green 488 Bapta. High potassium caused a rapid surge of internal calcium ([Ca2+]i) in the cell body, followed by a plateau. ... More
Supralinear Ca2+ influx into dendritic tufts of layer 2/3 neocortical pyramidal neurons in vitro and in vivo.
AuthorsWaters J, Larkum M, Sakmann B, Helmchen F
JournalJ Neurosci
PubMed ID13679425
Pyramidal neurons in layer 2/3 of the neocortex are central to cortical circuitry, but the intrinsic properties of their dendrites are poorly understood. Here we study layer 2/3 apical dendrites in parallel experiments in acute brain slices and in anesthetized rats using whole-cell recordings and Ca2+ imaging. We find that ... More
Postsynaptic Induction of BDNF-Mediated Long-Term Potentiation.
AuthorsKovalchuk Y, Hanse E, Kafitz KW, Konnerth A
JournalScience
PubMed ID11872844
Brain-derived neurotrophic factor (BDNF) and other neurotrophins are critically involved in long-term potentiation (LTP). Previous reports point to a presynaptic site of neurotrophin action. By imaging dentate granule cells in mouse hippocampal slices, we identified BDNF-evoked Ca2+ transients in dendrites and spines, but not at presynaptic sites. Pairing a weak ... More
From the Cover: Visually evoked activity in cortical cells imaged in freely moving animals.
We describe a miniaturized head-mounted multiphoton microscope and its use for recording Ca(2+) transients from the somata of layer 2/3 neurons in the visual cortex of awake, freely moving rats. Images contained up to 20 neurons and were stable enough to record continuously for >5 min per trial and 20 ... More
Impairment of LTD and cerebellar learning by Purkinje cell-specific ablation of cGMP-dependent protein kinase I.
AuthorsFeil R, Hartmann J, Luo C, Wolfsgruber W, Schilling K, Feil S, Barski JJ, Meyer M, Konnerth A, De Zeeuw CI, Hofmann F
JournalJ Cell Biol
PubMed ID14568994
The molecular basis for cerebellar plasticity and motor learning remains controversial. Cerebellar Purkinje cells (PCs) contain a high concentration of cGMP-dependent protein kinase type I (cGKI). To investigate the function of cGKI in long-term depression (LTD) and cerebellar learning, we have generated conditional knockout mice lacking cGKI selectively in PCs. ... More
Filopodia that extend from neuronal growth cones sample the environment for extracellular guidance cues, but the signals they transmit to growth cones are unknown. Filopodia were observed generating localized transient elevations of intracellular calcium ([Ca2+]i) that propagate back to the growth cone and stimulate global Ca2+ elevations. The frequency of ... More
Induction of synaptic long-term potentiation after opioid withdrawal.
AuthorsDrdla R, Gassner M, Gingl E, Sandkühler J,
JournalScience
PubMed ID19590003
mu-Opioid receptor (MOR) agonists represent the gold standard for the treatment of severe pain but may paradoxically also enhance pain sensitivity, that is, lead to opioid-induced hyperalgesia (OIH). We show that abrupt withdrawal from MOR agonists induces long-term potentiation (LTP) at the first synapse in pain pathways. Induction of opioid ... More
In vivo single-cell excitability probing of neuronal ensembles in the intact and awake developing Xenopus brain.
AuthorsDunfield D, Haas K,
JournalNat Protoc
PubMed ID20379139
Sensory experience can elicit long-lasting plasticity of both single neurons and ensemble neural circuit response properties during embryonic development. To investigate their relationship, one must image functional responses of large neuronal populations simultaneously with single-cell resolution. In this protocol, we describe a noninvasive approach to assay functional plasticity of individual ... More
In vivo dendritic calcium imaging with a fiberoptic periscope system.
AuthorsMurayama M, Larkum ME,
JournalNat Protoc
PubMed ID19798087
Dendritic recordings in freely moving animals present great challenges using the current approaches. Here we present in detail a microendoscopic technique (the 'periscope' method) for measuring intracellular calcium activity directly from the apical dendrites of L5 pyramidal neurons from the pia down to depths of approximately 700 mum in anesthetized ... More
Calcium imaging of living astrocytes in the mouse spinal cord following sensory stimulation.
AuthorsCirillo G, De Luca D, Papa M,
JournalNeural Plast
PubMed ID23091738
Astrocytic Ca(2+) dynamics have been extensively studied in ex vivo models; however, the recent development of two-photon microscopy and astrocyte-specific labeling has allowed the study of Ca(2+) signaling in living central nervous system. Ca(2+) waves in astrocytes have been described in cultured cells and slice preparations, but evidence for astrocytic ... More
Remote excitation of neuronal circuits using low-intensity, low-frequency ultrasound.
AuthorsTyler WJ, Tufail Y, Finsterwald M, Tauchmann ML, Olson EJ, Majestic C,
JournalPLoS ONE
PubMed ID18958151
Possessing the ability to noninvasively elicit brain circuit activity yields immense experimental and therapeutic power. Most currently employed neurostimulation methods rely on the somewhat invasive use of stimulating electrodes or photon-emitting devices. Due to its ability to noninvasively propagate through bone and other tissues in a focused manner, the implementation ... More
Mitochondrial DNA mutations affect calcium handling in differentiated neurons.
Mutations in the mitochondrial genome are associated with a wide range of neurological symptoms, but many aspects of the basic neuronal pathology are not understood. One candidate mechanism, given the well-established role of mitochondria in calcium buffering, is a deficit in neuronal calcium homoeostasis. We therefore examined calcium responses in ... More
High-speed in vivo calcium imaging reveals neuronal network activity with near-millisecond precision.
Two-photon calcium imaging of neuronal populations enables optical recording of spiking activity in living animals, but standard laser scanners are too slow to accurately determine spike times. Here we report in vivo imaging in mouse neocortex with greatly improved temporal resolution using random-access scanning with acousto-optic deflectors. We obtained fluorescence ... More
Radially expanding transglial calcium waves in the intact cerebellum.
Multicellular glial calcium waves may locally regulate neural activity or brain energetics. Here, we report a diffusion-driven astrocytic signal in the normal, intact brain that spans many astrocytic processes in a confined volume without fully encompassing any one cell. By using 2-photon microscopy in rodent cerebellar cortex labeled with fluorescent ... More
Multianalyte single-cell analysis with multiple cell lines using a fiber-optic array.
AuthorsWhitaker RD, Walt DR,
JournalAnal Chem
PubMed ID17973503
A single-cell drug screening method is described that produces rich single-cell data and discriminates between single-cell responses from clonal populations stimulated with different agonists. Ligand-induced receptor activation is commonly detected by observing intracellular Ca2+ oscillations using high-throughput screening (HTS) methods. In most cases, HTS results in an average signal from ... More
Intercellular calcium communication regulates platelet aggregation and thrombus growth.
AuthorsNesbitt WS, Giuliano S, Kulkarni S, Dopheide SM, Harper IS, Jackson SP
JournalJ Cell Biol
PubMed ID12668663
The ability of platelets to form stable adhesion contacts with other activated platelets (platelet cohesion or aggregation) at sites of vascular injury is essential for hemostasis and thrombosis. In this study, we have examined the mechanisms regulating cytosolic calcium flux during the development of platelet-platelet adhesion contacts under the influence ... More
Intraglomerular inhibition: signaling mechanisms of an olfactory microcircuit.
AuthorsMurphy GJ, Darcy DP, Isaacson JS
JournalNat Neurosci
PubMed ID15696160
Microcircuits composed of principal neuron and interneuron dendrites have an important role in shaping the representation of sensory information in the olfactory bulb. Here we establish the physiological features governing synaptic signaling in dendrodendritic microcircuits of olfactory bulb glomeruli. We show that dendritic gamma-aminobutyric acid (GABA) release from periglomerular neurons ... More
Calcium mediates bidirectional growth cone turning induced by myelin-associated glycoprotein.
AuthorsHenley JR, Huang KH, Wang D, Poo MM
JournalNeuron
PubMed ID15603734
Cytoplasmic second messengers, Ca2+ and cAMP, regulate nerve growth cone turning responses induced by many guidance cues, but the causal relationship between these signaling pathways has been unclear. We here report that, for growth cone turning induced by a gradient of myelin-associated glycoprotein (MAG), cAMP acts by modulating MAG-induced Ca2+ ... More
Organelle selection determines agonist-specific Ca2+ signals in pancreatic acinar and beta cells.
AuthorsYamasaki M, Masgrau R, Morgan AJ, Churchill GC, Patel S, Ashcroft SJ, Galione A
JournalJ Biol Chem
PubMed ID14660554
How different extracellular stimuli can evoke different spatiotemporal Ca2+ signals is uncertain. We have elucidated a novel paradigm whereby different agonists use different Ca2+-storing organelles ("organelle selection") to evoke unique responses. Some agonists select the endoplasmic reticulum (ER), and others select lysosome-related (acidic) organelles, evoking spatial Ca2+ responses that mirror ... More
Distribution of nifedipine- and omega-conotoxin GVIA-sensitive Ca2+ channels in cultured rat neocortical neurons.
AuthorsWang G, Hashiguchi T, Sakamoto Y, Takigawa M, Kameyama M
JournalNeuroscience
PubMed ID10465432
L- and N-type voltage-dependent calcium channels are widely distributed in neurons of the CNS. To investigate their subcellular distributions on CNS neurons, intracellular calcium concentration ([Ca2+]i) increase in response to high potassium ([K+]) solution was detected in primary cultured rat neocortical neurons using the calcium indicator dye Oregon Green with ... More
Quantitative two-photon Ca2+ imaging via fluorescence lifetime analysis.
AuthorsWilms CD, Schmidt H, Eilers J
JournalCell Calcium
PubMed ID16690123
Two-photon microscopy (TPM) revolutionized Ca2+ imaging by allowing recordings in the depth of intact tissue and live organisms. A serious limitation in TPM, however, is the lack of an accurate and straightforward approach for the quantification of Ca2+ signals, an ability that became an invaluable tool in fluorescence microscopy. Here, ... More
Sulforhodamine 101 as a specific marker of astroglia in the neocortex in vivo.
AuthorsNimmerjahn A, Kirchhoff F, Kerr JN, Helmchen F
JournalNat Methods
PubMed ID15782150
Glial cells have been identified as key signaling components in the brain; however, methods to investigate their structure and function in vivo have been lacking. Here, we describe a new, highly selective approach for labeling astrocytes in intact rodent neocortex that allows in vivo imaging using two-photon microscopy. The red ... More
Efficient generation of retinal progenitor cells from human embryonic stem cells.
AuthorsLamba DA, Karl MO, Ware CB, Reh TA
JournalProc Natl Acad Sci U S A
PubMed ID16908856
The retina is subject to degenerative conditions, leading to blindness. Although retinal regeneration is robust in lower vertebrates, regeneration does not occur in the adult mammalian retina. Thus, we have developed efficient methods for deriving retinal neurons from human embryonic stem (hES) cells. Under appropriate culture conditions, up to 80% ... More
Activation of metabotropic glutamate receptor mGlu5 on nuclear membranes mediates intranuclear Ca2+ changes in heterologous cell types and neurons.
AuthorsO'Malley KL, Jong YJ, Gonchar Y, Burkhalter A, Romano C
JournalJ Biol Chem
PubMed ID12736269
Nuclear Ca2+ plays a critical role in many cellular functions although its mode (s) of regulation is unclear. This study shows that the metabotropic glutamate receptor, mGlu5, mobilizes nuclear Ca2+ independent of cytosolic Ca2+ regulation. Immunocytochemical, ultrastructural, and subcellular fractionation techniques revealed that the metabotropic glutamate receptor, mGlu5, can be ... More
Quantification of spread of cerebellar long-term depression with chemical two-photon uncaging of glutamate.
AuthorsWang SS, Khiroug L, Augustine GJ
JournalProc Natl Acad Sci U S A
PubMed ID10890882
Localized, chemical two-photon photolysis of caged glutamate was used to map the changes in alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors caused by long-term synaptic depression (LTD) in cerebellar Purkinje cells. LTD produced by pairing parallel fiber activity with depolarization was accompanied by a decline in the response of Purkinje cells to uncaged ... More
Distinct roles of Galpha(q) and Galpha11 for Purkinje cell signaling and motor behavior.
AuthorsHartmann J, Blum R, Kovalchuk Y, Adelsberger H, Kuner R, Durand GM, Miyata M, Kano M, Offermanns S, Konnerth A
JournalJ Neurosci
PubMed ID15175381
G-protein-coupled metabotropic glutamate group I receptors (mGluR1s) mediate synaptic transmission and plasticity in Purkinje cells and, therefore, critically determine cerebellar motor control and learning. Purkinje cells express two members of the G-protein G(q) family, namely G(q) and G11. Although in vitro coexpression of mGluR1 with either Galpha11 or Galpha(q) produces ... More
Homeostatic regulation of eye-specific responses in visual cortex during ocular dominance plasticity.
Experience-dependent plasticity is crucial for the precise formation of neuronal connections during development. It is generally thought to depend on Hebbian forms of synaptic plasticity. In addition, neurons possess other, homeostatic means of compensating for changes in sensory input, but their role in cortical plasticity is unclear. We used two-photon ... More
Modeling the dependence of the period of intracellular Ca2+ waves on SERCA expression.
AuthorsFalcke M, Li Y, Lechleiter JD, Camacho P
JournalBiophys J
PubMed ID12944265
Contrary to intuitive expectations, overexpression of sarco-endoplasmic reticulum (ER) Ca(2+) ATPases (SERCAs) in Xenopus oocytes leads to a decrease in the period and an increase in the amplitude of intracellular Ca(2+) waves. Here we examine these experimental findings by modeling Ca(2+) release using a modified Othmer-Tang-model. An increase in the ... More
In vivo calcium imaging of circuit activity in cerebellar cortex.
AuthorsSullivan MR, Nimmerjahn A, Sarkisov DV, Helmchen F, Wang SS
JournalJ Neurophysiol
PubMed ID16079125
In vivo two-photon calcium imaging provides the opportunity to monitor activity in multiple components of neural circuitry at once. Here we report the use of bulk-loading of fluorescent calcium indicators to record from axons, dendrites, and neuronal cell bodies in cerebellar cortex in vivo. In cerebellar folium crus IIa of ... More
Calcium signaling regulates translocation and activation of Rac.
AuthorsPrice LS, Langeslag M, ten Klooster JP, Hordijk PL, Jalink K, Collard JG
JournalJ Biol Chem
PubMed ID12888567
Rac is activated in response to various stimuli including growth factors and by adhesion to the extracellular matrix. However, how these stimuli ultimately result in Rac activation is poorly understood. The increase in intracellular calcium [Ca2+]i represents a ubiquitous second messenger system in cells, linking receptor activation to downstream signaling ... More
Real-time imaging of nuclear permeation by EGFP in single intact cells.
AuthorsWei X, Henke VG, Strübing C, Brown EB, Clapham DE
JournalBiophys J
PubMed ID12547812
The NPC is the portal for the exchange of proteins, mRNA, and ions between nucleus and cytoplasm. Many small molecules (<10 kDa) permeate the nucleus by simple diffusion through the pore, but molecules larger than 70 kDa require ATP and a nuclear localization sequence for their transport. In isolated Xenopus ... More
Depolarization-induced slow calcium transients activate early genes in skeletal muscle cells.
AuthorsCarrasco MA, Riveros N, Ríos J, Müller M, Torres F, Pineda J, Lantadilla S, Jaimovich E
JournalAm J Physiol Cell Physiol
PubMed ID12529240
The signaling mechanisms by which skeletal muscle electrical activity leads to changes in gene expression remain largely undefined. We have reported that myotube depolarization induces calcium signals in the cytosol and nucleus via inositol 1,4,5-trisphosphate (IP(3)) and phosphorylation of both ERK1/2 and cAMP-response element-binding protein (CREB). We now describe the ... More
Highly ordered arrangement of single neurons in orientation pinwheels.
AuthorsOhki K, Chung S, Kara P, Hübener M, Bonhoeffer T, Reid RC
JournalNature
PubMed ID16906137
In the visual cortex of higher mammals, neurons are arranged across the cortical surface in an orderly map of preferred stimulus orientations. This map contains 'orientation pinwheels', structures that are arranged like the spokes of a wheel such that orientation changes continuously around a centre. Conventional optical imaging first demonstrated ... More
Dependence of calcium influx in neocortical cells on temporal structure of depolarization, number of spikes, and blockade of NMDA receptors.
AuthorsBalaban P, Chistiakova M, Malyshev A, Volgushev M
JournalJ Neurosci Res
PubMed ID15114620
Increase of intracellular [Ca(2+)] evoked by action potentials in a cell can induce long-term synaptic plasticity even without concomitant presynaptic stimulation. We used optical recording of the fluorescence of a Ca(2+)-indicator Oregon Green to investigate whether differences in results obtained with modifications of that purely postsynaptic induction protocol could be ... More
Phasic characteristic of elementary Ca(2+) release sites underlies quantal responses to IP(3).
AuthorsCallamaras N, Parker I
JournalEMBO J
PubMed ID10899115
Ca(2+) liberation by inositol 1,4,5-trisphosphate (IP(3)) is 'quantal', in that low [IP(3)] causes only partial Ca(2+) release, but further increasing [IP(3)] evokes more release. This characteristic allows cells to generate graded Ca(2+) signals, but is unexpected, given the regenerative nature of Ca(2+)-induced Ca(2+) release through IP(3) receptors. Two models have ... More
Emission ratiometry for simultaneous calcium and action potential measurements with coloaded dyes in rabbit hearts: reduction of motion and drift.
AuthorsKong W, Walcott GP, Smith WM, Johnson PL, Knisley SB
JournalJ Cardiovasc Electrophysiol
PubMed ID12625615
INTRODUCTION: Optical measurements of the cardiac calcium transient (Ca) and transmembrane action potential (AP) may be performed simultaneously with emission ratiometry to lessen motion artifacts and photobleaching effects. We examined changes in emission spectrum in perfused rabbit hearts coloaded with Rh237 and a green-emitting Ca dye (Fluo-4 or Oregon Green ... More
Inhibition of inositol 1,4,5-trisphosphate-induced Ca2+ release by cAMP-dependent protein kinase in a living cell.
AuthorsTertyshnikova S, Fein A
JournalProc Natl Acad Sci U S A
PubMed ID9465064
Interaction of intracellular free calcium ([Ca2+]i) and cAMP signaling mechanisms was examined in intact single megakaryocytes by using a combination of single-cell fluorescence microscopy to measure [Ca2+]i and flash photolysis of caged Ca2+, inositol 1,4, 5-trisphosphate (IP3), or cAMP to elevate rapidly the concentration of these compounds inside the cell. ... More
Potentiation of fractional sarcoplasmic reticulum calcium release by total and free intra-sarcoplasmic reticulum calcium concentration.
AuthorsShannon TR, Ginsburg KS, Bers DM
JournalBiophys J
PubMed ID10620297
Our aim was to measure the influence of sarcoplasmic reticulum (SR) calcium content ([Ca](SRT)) and free SR [Ca] ([Ca](SR)) on the fraction of SR calcium released during voltage clamp steps in isolated rabbit ventricular myocytes. [Ca](SRT), as measured by caffeine application, was progressively increased by conditioning pulses. Sodium was absent ... More
Release of calcium from stores alters the morphology of dendritic spines in cultured hippocampal neurons.
AuthorsKorkotian E, Segal M
JournalProc Natl Acad Sci U S A
PubMed ID10518577
The ability to monitor ongoing changes in the shape of dendritic spines has important implications for the understanding of the functional correlates of the great variety of shapes and sizes of dendritic spines in central neurons. We have monitored and three-dimensionally reconstructed dendritic spines in cultured hippocampal neurons over several ... More
Differential calcium-dependent modulation of NMDA currents in CA1 and CA3 hippocampal pyramidal cells.
AuthorsGrishin AA, Gee CE, Gerber U, Benquet P
JournalJ Neurosci
PubMed ID14724233
Neuronal Ca2+ influx via NMDA receptors (NMDARs) is essential for the development and plasticity of synapses but also triggers excitotoxic cell death when critical intracellular levels are exceeded. Therefore, finely equilibrated mechanisms are necessary to ensure that NMDAR function is maintained within a homeostatic range. Here we describe a pronounced ... More
Rapid measurements of intracellular calcium using a fluorescence plate reader.
AuthorsLin K, Sadée W, Quillan JM
JournalBiotechniques
PubMed ID10023544
Intracellular calcium is a universal second messenger that can serve as a broad-based measure of receptor activity. Recent developments in multi-well plate fluorescence readers facilitate measurement of intracellular free-calcium levels and reduce reliance on slower, more cumbersome or expensive data collection methods. In this report, we describe a rapid 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
Activation of TRPM7 channels by phospholipase C-coupled receptor agonists.
AuthorsLangeslag M, Clark K, Moolenaar WH, van Leeuwen FN, Jalink K
JournalJ Biol Chem
PubMed ID17095511
TRPM7 is a ubiquitously expressed nonspecific cation channel that has been implicated in cellular Mg(2+) homeostasis. We have recently shown that moderate overexpression of TRPM7 in neuroblastoma N1E-115 cells elevates cytosolic Ca(2+) levels and enhances cell-matrix adhesion. Furthermore, activation of TRPM7 by phospholipase C (PLC)-coupled receptor agonists caused a further ... More
Sodium-calcium exchange affects local calcium signal decay and the rate of exocytotic secretion in single chromaffin cells.
AuthorsTang YM, Travis ER, Wightman RM, Schneider AS
JournalJ Neurochem
PubMed ID10646522
The effects of Na+ deprivation on local calcium signal decay and the rate of exocytotic secretion were measured in single bovine chromaffin cells to determine whether Na-Ca exchange influences the local cytosolic Ca2+ signal for neurohormone release. Na+ replacement with N-methylglucamine caused a marked slowing of the decay of the ... More
Long-term depression of climbing fiber-evoked calcium transients in Purkinje cell dendrites.
AuthorsWeber JT, De Zeeuw CI, Linden DJ, Hansel C
JournalProc Natl Acad Sci U S A
PubMed ID12601151
In recent years much has been learned about the molecular requirements for inducing long-term synaptic depression (LTD) in various brain regions. However, very little is known about the consequences of LTD induction for subsequent signaling events in postsynaptic neurons. We have addressed this issue by examining homosynaptic LTD at the ... More
Distinct glycoprotein Ib/V/IX and integrin alpha IIbbeta 3-dependent calcium signals cooperatively regulate platelet adhesion under flow.
AuthorsNesbitt WS, Kulkarni S, Giuliano S, Goncalves I, Dopheide SM, Yap CL, Harper IS, Salem HH, Jackson SP
JournalJ Biol Chem
PubMed ID11713259
We have investigated the calcium signaling relationship between the two major platelet adhesion receptors, glycoprotein Ib/V/IX (GPIb/V/IX) and integrin alpha(IIb)beta(3), involved in regulating platelet adhesion on von Willebrand factor (vWf) under flow. Our studies demonstrate that GPIb engagement of immobilized vWf elicits a transient calcium spike that may function to ... More
Distance-dependent scaling of calcium transients evoked by backpropagating spikes and synaptic activity in dendrites of hippocampal interneurons.
AuthorsRozsa B, Zelles T, Vizi ES, Lendvai B
JournalJ Neurosci
PubMed ID14736852
Although interactions between backpropagating action potentials and synaptic stimulations have been extensively studied in pyramidal neurons, dendritic propagation and the summation of these signals in interneurons are not nearly as well known. In this study, two-photon imaging was used to explore the basic properties of dendritic calcium signaling in CA1 ... More
Functional imaging with cellular resolution reveals precise micro-architecture in visual cortex.
AuthorsOhki K, Chung S, Ch'ng YH, Kara P, Reid RC
JournalNature
PubMed ID15660108
Neurons in the cerebral cortex are organized into anatomical columns, with ensembles of cells arranged from the surface to the white matter. Within a column, neurons often share functional properties, such as selectivity for stimulus orientation; columns with distinct properties, such as different preferred orientations, tile the cortical surface in ... More
Development and dissipation of Ca(2+) gradients in adrenal chromaffin cells.
AuthorsMarengo FD, Monck JR
JournalBiophys J
PubMed ID11023887
We used pulsed laser imaging to measure the development and dissipation of Ca(2+) gradients evoked by the activation of voltage-sensitive Ca(2+) channels in adrenal chromaffin cells. Ca(2+) gradients appeared rapidly (<5 ms) upon membrane depolarization and dissipated over several hundred milliseconds after membrane repolarization. Dissipation occurred with an initial fast ... More
A comparison of fluorescent Ca2+ indicator properties and their use in measuring elementary and global Ca2+ signals.
AuthorsThomas D, Tovey SC, Collins TJ, Bootman MD, Berridge MJ, Lipp P
JournalCell Calcium
PubMed ID11032777
Quantifying the magnitude of Ca2+ signals from changes in the emission of fluorescent indicators relies on assumptions about the indicator behaviour in situ. Factors such as osmolarity, pH, ionic strength and protein environment can affect indicator properties making it advantageous to calibrate indicators within the required cellular or subcellular environment. ... More
Synergistic adhesive interactions and signaling mechanisms operating between platelet glycoprotein Ib/IX and integrin alpha IIbbeta 3. Studies in human platelets ans transfected Chinese hamster ovary cells.
AuthorsYap CL, Hughan SC, Cranmer SL, Nesbitt WS, Rooney MM, Giuliano S, Kulkarni S, Dopheide SM, Yuan Y, Salem HH, Jackson SP
JournalJ Biol Chem
PubMed ID10967111
This study investigates three aspects of the adhesive interaction operating between platelet glycoprotein Ib/IX and integrin alpha(IIb)beta(3). These include the following: 1) examining the sufficiency of GPIb/IX and integrin alpha(IIb)beta(3) to mediate irreversible cell adhesion on immobilized von Willebrand factor (vWf) under flow; 2) the ability of the vWf-GPIb interaction ... More
Inter-bouton variability of synaptic strength correlates with heterogeneity of presynaptic Ca(2+) signals.
AuthorsKirischuk S, Grantyn R
JournalJ Neurophysiol
PubMed ID12364541
The elevation of presynaptic calcium concentration is a crucial step in excitation-secretion coupling. However, the amplitudes of action-potential-induced presynaptic calcium transients can display high variability among different terminals. The aim of this study was to clarify whether, at individual boutons, synaptic strength correlates with the average amplitude of presynaptic calcium ... More
Estimating intracellular calcium concentrations and buffering without wavelength ratioing.
AuthorsMaravall M, Mainen ZF, Sabatini BL, Svoboda K
JournalBiophys J
PubMed ID10777761
We describe a method for determining intracellular free calcium concentration ([Ca(2+)]) from single-wavelength fluorescence signals. In contrast to previous single-wavelength calibration methods, the proposed method does not require independent estimates of resting [Ca(2+)] but relies on the measurement of fluorescence close to indicator saturation during an experiment. Consequently, it is ... More
Single-bouton-mediated synaptic transmission: postsynaptic conductance changes in their relationship with presynaptic calcium signals.
AuthorsKirischuk S, Veselovsky N, Grantyn R
JournalPflugers Arch
PubMed ID10555571
Most central neurons contact their dendritic targets at several sites. However, it is not known whether all synapses formed by a single parent axon make the same contribution to the postsynaptic response. In order to answer this question it is necessary to isolate the synaptic currents generated by individual axon ... More
Evidence that Ca2+-waves in Xenopus melanotropes depend on calcium-induced calcium release: a fluorescence correlation microscopy and linescanning study.
The neuroendocrine melanotrope cell displays Ca2+ oscillations that are build up by several discrete Ca2+ rises ('steps'). Each step is linked to Ca2+-entry across the plasma membrane via voltage-operated calcium channels and associated with a fast Ca2+-wave travelling from the plasma membrane to the central parts of the cell. Previously, ... More
Presynaptic mitochondrial calcium sequestration influences transmission at mammalian central synapses.
AuthorsBillups B, Forsythe ID
JournalJ Neurosci
PubMed ID12122046
Beyond their role in generating ATP, mitochondria have a high capacity to sequester calcium. The interdependence of these functions and limited access to presynaptic compartments makes it difficult to assess the role of sequestration in synaptic transmission. We addressed this important question using the calyx of Held as a model ... More