Calcium dynamics of spines depend on their dendritic location.
AuthorsHolthoff K, Tsay D, Yuste R
JournalNeuron
PubMed ID11832229
'Dendritic spines are morphologically and functionally heterogeneous. To understand this diversity, we use two-photon imaging of layer 5 neocortical pyramidal cells and measure action potential-evoked [Ca(2+)]i transients in spines. Spine calcium kinetics are controlled by (i) the diameter of the parent dendrite, (ii) the length of the spine neck, and ... More
Action potential propagation in mitral cell lateral dendrites is decremental and controls recurrent and lateral inhibition in the mammalian olfactory bulb.
AuthorsMargrie TW, Sakmann B, Urban NN
JournalProc Natl Acad Sci U S A
PubMed ID11120888
'In the mammalian main olfactory bulb (MOB), the release of glutamate from lateral dendrites of mitral cells onto the dendrites of granule cells evokes recurrent and lateral inhibition of mitral cell activity. Whole-cell voltage recordings in the mouse MOB in vivo and in vitro show that recurrent and lateral inhibition ... More
Optical nanosensors for chemical analysis inside single living cells. 2. Sensors for pH and calcium and the intracellular application of PEBBLE sensors.
AuthorsClark HA, Kopelman R, Tjalkens R, Philbert MA
JournalAnal Chem
PubMed ID10565275
'Optical nanosensors, or PEBBLEs (probes encapsulated by biologically localized embedding), have been produced for intracellular measurements of pH and calcium. Five varieties of pH-sensitive sensors and three different calcium-selective sensors are presented and discussed. Each sensor combines an ion-selective fluorescent indicator and an ion-insensitive internal standard entrapped within an acrylamide ... More
High-speed, random-access fluorescence microscopy: I. High-resolution optical recording with voltage-sensitive dyes and ion indicators.
AuthorsBullen A, Patel SS, Saggau P
JournalBiophys J
PubMed ID9199810
'The design and implementation of a high-speed, random-access, laser-scanning fluorescence microscope configured to record fast physiological signals from small neuronal structures with high spatiotemporal resolution is presented. The laser-scanning capability of this nonimaging microscope is provided by two orthogonal acousto-optic deflectors under computer control. Each scanning point can be randomly ... More
SNARE complex oligomerization by synaphin/complexin is essential for synaptic vesicle exocytosis.
'Synaphin/complexin is a cytosolic protein that preferentially binds to syntaxin within the SNARE complex. We find that synaphin promotes SNAREs to form precomplexes that oligomerize into higher order structures. A peptide from the central, syntaxin binding domain of synaphin competitively inhibits these two proteins from interacting and prevents SNARE complexes ... More
Measurement of free Zn2+ ion concentration with the fluorescent probe mag-fura-2 (furaptra).
AuthorsSimons TJ
JournalJ Biochem Biophys Methods
PubMed ID8409208
'The fluorescent probe mag-fura-2, previously used to measure [Mg2+], can also be used to measure [Zn2+]. The peak in the excitation spectrum occurs at 323 nm for Zn2+, compared with 335 nm for Ca2+ and Mg2+. This allows simultaneous measurements of [Zn2+] and either [Ca2+] or [Mg2+], by using 3 ... More
Intracellular ionized calcium.
AuthorsJune CH, Rabinovitch PS
JournalMethods Cell Biol
PubMed ID7861962
Practical aspects of measuring [Ca2+] with fluorescent indicators.
AuthorsKao JP
JournalMethods Cell Biol
PubMed ID8201975
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
Differential modulation of SERCA2 isoforms by calreticulin.
AuthorsJohn LM, Lechleiter JD, Camacho P
JournalJ Cell Biol
PubMed ID9722609
In Xenopus laevis oocytes, overexpression of calreticulin suppresses inositol 1,4,5-trisphosphate-induced Ca2+ oscillations in a manner consistent with inhibition of Ca2+ uptake into the endoplasmic reticulum. Here we report that the alternatively spliced isoforms of the sarcoendoplasmic reticulum Ca2+-ATPase (SERCA)2 gene display differential Ca2+ wave properties and sensitivity to modulation by ... More
Cytosolic calcium transients: spatial localization and role in Drosophila photoreceptor cell function.
Drosophila phototransduction is a phosphoinositide-mediated and Ca(2+)-regulated signaling cascade ideal for the dissection of feedback regulatory mechanisms. To study the roles of intracellular Ca2+ ([Ca2+]i) in this process, we developed novel techniques for the measurement of [Ca2+]i in intact photoreceptors. We genetically engineered flies that express a UV-specific rhodopsin in ... More
Multiphoton fluorescence excitation: new spectral windows for biological nonlinear microscopy.
AuthorsXu C, Zipfel W, Shear JB, Williams RM, Webb WW
JournalProc Natl Acad Sci U S A
PubMed ID8855254
Intrinsic, three-dimensionally resolved, microscopic imaging of dynamical structures and biochemical processes in living preparations has been realized by nonlinear laser scanning fluorescence microscopy. The search for useful two-photon and three-photon excitation spectra, motivated by the emergence of nonlinear microscopy as a powerful biophysical instrument, has now discovered a virtual artist's ... More
Calcium binding to fluorescent calcium indicators: calcium green, calcium orange and calcium crimson.
AuthorsEberhard M, Erne P
JournalBiochem Biophys Res Commun
PubMed ID1930217
The recently introduced fluorescent calcium sensitive indicators calcium green, calcium orange and calcium crimson suggest important improvements and advantages to detect small calcium transients at low indicator concentrations. Thermodynamic dissociation constants and dissociation rate constants of calcium green, calcium orange and calcium crimson were measured by use of fluorescence titration ... More
Nuclear translocation of cytosolic phospholipase A2 is induced by ATP depletion.
AuthorsSheridan AM, Sapirstein A, Lemieux N, Martin BD, Kim DK, Bonventre JV
JournalJ Biol Chem
PubMed ID11395512
Phospholipase A(2) (PLA(2)) enzymes may play a role in cellular injury due to ATP depletion. Renal Madin-Darby canine kidney cells were subjected to ATP depletion to assess the effects of cellular energy metabolism on cytosolic PLA(2) (cPLA(2)) regulation. ATP depletion results in a decrease in soluble cPLA(2) activity and an ... More
Properties of tri- and tetracarboxylate Ca2+ indicators in frog skeletal muscle fibers.
AuthorsZhao M, Hollingworth S, Baylor SM
JournalBiophys J
PubMed ID8789107
Recently a number of lower-affinity fluorescent Ca2+ indicators have become available with principal absorbance bands at visible wavelengths. This article evaluates these indicators, as well as two shorter wavelength indicators, mag-fura-5 and mag-indo-1, for their suitability as rapid Ca2+ indicators in frog skeletal muscle fibers. With three lower-affinity tricarboxylate indicators ... More
Action potential backpropagation and multiglomerular signaling in the rat vomeronasal system.
AuthorsMa J, Lowe G
JournalJ Neurosci
PubMed ID15496670
In the accessory olfactory bulb (AOB), sensory neurons expressing a given vomeronasal receptor (VR) gene send divergent projections to many glomeruli, and second-order neurons (mitral cells) link to multiple glomeruli via branched primary dendrites. We used calcium imaging and paired somadendritic patch-clamp recording to track backpropagated action potentials (APs) in ... 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
In vitro ischemia promotes calcium influx and intracellular calcium release in hippocampal astrocytes.
AuthorsDuffy S, MacVicar BA
JournalJ Neurosci
PubMed ID8613811
The intracellular calcium concentration ([Ca2+])i of astrocytes within rat hippocampal slices was measured during simultaneous hypoxia and hypoglycemia to examine the early intracellular signaling events induced by this in vitro model of ischemia. Hypoxia-hypoglycemia for 3.3-7.5 min evoked [Ca2+]i increases in astrocytes iontophoretically loaded with calcium orange (11/14 slices; 2.5 ... More
Adrenergic calcium signaling in astrocyte networks within the hippocampal slice.
AuthorsDuffy S, MacVicar BA
JournalJ Neurosci
PubMed ID7643199
Norepinephrine (NE) and glutamate (Glu) initiate intracellular calcium ([Ca2+]i) transients, oscillations, and intracellular [Ca2+]i waves in cultured astrocytes. To further elucidate the significance of NE- and Glu-evoked astrocytic [Ca2+]i signaling to neuron-astrocyte communication in the mature CNS, [Ca2+]i of astrocyte networks within hippocampal slices (P21-42) was measured during bath application ... More