A light-dependent increase in free Ca2+ concentration in the salamander rod outer segment.
AuthorsMatthews HR, Fain GL
JournalJ Physiol
PubMed ID11306652
'1. The Ca(2+) indicator dye fluo-5F was excited by an argon ion laser to measure changes in free Ca(2+) concentration ([Ca2+]i) in the outer segments of isolated salamander rods rapidly exposed to a 0 Ca(2+), 0 Na(+) solution designed to minimise surface membrane Ca(2+) fluxes. Over 30-60 s of laser ... More
Catheter lock solutions influence staphylococcal biofilm formation on abiotic surfaces.
'BACKGROUND: Microbial biofilms form on central venous catheters and may be associated with systemic infections as well as decreased dialysis efficiency due to catheter thrombosis. The most widely used anticoagulant catheter lock solution in the US is sodium heparin. We have previously shown that sodium heparin in clinically relevant concentrations ... More
Dopaminergic regulation of dendritic calcium: fast multisite calcium imaging.
AuthorsZhou WL, Oikonomou KD, Short SM, Antic SD,
JournalMethods Mol Biol
PubMed ID23296782
'Optimal dopamine tone is required for the normal cortical function; however it is still unclear how cortical-dopamine-release affects information processing in individual cortical neurons. Thousands of glutamatergic inputs impinge onto elaborate dendritic trees of neocortical pyramidal neurons. In the process of ensuing synaptic integration (information processing), a variety of calcium ... More
The effect of light on outer segment calcium in salamander rods.
AuthorsMatthews HR, Fain GL
JournalJ Physiol
PubMed ID12949220
'Calcium acts as a second messenger in vertebrate rods, regulating the recovery phase of the light response and modulating sensitivity during light-adaptation. Since light not only decreases the outer segment calcium concentration ([Ca2+]i) by closing cyclic nucleotide-gated channels but can also increase [Ca2+]i by releasing Ca2+ from buffer sites or ... More
Imaging calcium entry sites and ribbon structures in two presynaptic cells.
AuthorsZenisek D, Davila V, Wan L, Almers W
JournalJ Neurosci
PubMed ID12684438
'We investigated the location of calcium entry sites and synaptic ribbons in the type-Mb goldfish bipolar neuron and the bullfrog saccular hair cell. Cells were loaded with a fast calcium indicator (Fluo-3 or Fluo-5F) and an excess of a high-affinity but slow Ca buffer (EGTA). The cell surface was imaged ... More
Control of firing patterns through modulation of axon initial segment T-type calcium channels.
Spontaneously active neurons typically fire either in a regular pattern or in bursts. While much is known about the subcellular location and biophysical properties of conductances that underlie regular spontaneous activity, less is known about those that underlie bursts. Here, we show that T-type Ca(2+) channels localized to the site ... More
Abnormal cytoplasmic calcium dynamics in central neurons of a dystonia mouse model.
AuthorsIwabuchi S, Kakazu Y, Koh JY, Harata NC,
Journal
PubMed ID23748075
Increased activities of cytoplasmic calcium and the excitatory neurotransmitter glutamate have been independently implicated in dystonia pathophysiology. However, cellular-level evidence linking these two features is not available. Here we show that glutamate-dependent changes in neuronal calcium dynamics occur in a knock-in mouse model of DYT1 dystonia, the most common hereditary ... More
Single cell and subcellular measurements of intracellular Ca²? concentration.
Increases in bulk average cytoplasmic Ca(2+) concentration ([Ca(2+)](c)) are derived from the combined activities of many Ca(2+) channels. Near (<100 nm) the mouth of each of these channels the local [Ca(2+)](c) rises and falls more quickly and reaches much greater values than occurs in the bulk cytoplasm. Even during apparently ... More
Characterizing the conductance underlying depolarization-induced slow current in cerebellar Purkinje cells.
AuthorsKim YS, Kang E, Makino Y, Park S, Shin JH, Song H, Launay P, Linden DJ,
JournalJ Neurophysiol
PubMed ID23197456
Brief strong depolarization of cerebellar Purkinje cells produces a slow inward cation current [depolarization-induced slow current (DISC)]. Previous work has shown that DISC is triggered by voltage-sensitive Ca influx in the Purkinje cell and is attenuated by blockers of vesicular loading and fusion. Here, we have sought to characterize the ... More
Spare respiratory capacity rather than oxidative stress regulates glutamate excitotoxicity after partial respiratory inhibition of mitochondrial complex I with rotenone.
AuthorsYadava N, Nicholls DG,
JournalJ Neurosci
PubMed ID17611283
Partial inhibition of mitochondrial respiratory complex I by rotenone reproduces aspects of Parkinson's disease in rodents. The hypothesis that rotenone enhancement of neuronal cell death is attributable to oxidative stress was tested in an acute glutamate excitotoxicity model using primary cultures of rat cerebellar granule neurons. As little as 5 ... 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
Overexpression of cytosolic group IVA phospholipase A2 protects cells from Ca2+-dependent death.
The calcium ionophore ionomycin induces apoptosis-like events in the human embryonic kidney cell line at early times. Plasma membrane blebbing, mitochondrial depolarization, externalization of phosphatidylserine, and nuclear permeability changes can all be observed within 15 min of treatment. However, there is no activation of caspases or chromatin condensation. Expression of ... More
Time course and magnitude of the calcium release induced by bright light in salamander rods.
AuthorsMatthews HR, Fain GL
JournalJ Physiol
PubMed ID12154182
Changes in fluorescence were measured with an argon ion laser from the outer segments of isolated salamander rods containing the Ca(2+)-sensitive fluorescent dye fluo-5F. When the outer segments were exposed to a 0Ca(2+)/0Na(+) solution designed to minimise surface membrane Ca(2+) fluxes, exposure to intense light from the laser evoked a ... More
Simultaneous monitoring of ionophore- and inhibitor-mediated plasma and mitochondrial membrane potential changes in cultured neurons.
AuthorsNicholls DG
JournalJ Biol Chem
PubMed ID16551630
Although natural and synthetic ionophores are widely exploited in cell studies, for example, to influence cytoplasmic free calcium concentrations and to depolarize in situ mitochondria, their inherent lack of membrane selectivity means that they affect the ion permeability of both plasma and mitochondrial membranes. A similar ambiguity affects the interpretation ... More
The relationship between intracellular [Ca(2+)] and Ca(2+) wave characteristics in permeabilised cardiomyocytes from the rabbit.
AuthorsLoughrey CM, MacEachern KE, Neary P, Smith GL
JournalJ Physiol
PubMed ID12231644
Spontaneous sarcoplasmic reticulum (SR) Ca(2+) release and propagated intracellular Ca(2+) waves are a consequence of cellular Ca(2+) overload in cardiomyocytes. We examined the relationship between average intracellular [Ca(2+)] and Ca(2+) wave characteristics. The amplitude, time course and propagation velocity of Ca(2+) waves were measured using line-scan confocal imaging of beta-escin-permeabilised ... More
Effects of electrical shocks on Cai2+ and Vm in myocyte cultures.
AuthorsFast VG, Cheek ER, Pollard AE, Ideker RE
JournalCirc Res
PubMed ID15155528
Changes in intracellular calcium concentration (DeltaCa(i)2+) induced by electrical shocks may play an important role in defibrillation, but high-resolution DeltaCa(i)2+ measurements in a multicellular cardiac tissue and their relationship to corresponding Vm changes (DeltaVm) are lacking. Here, we measured shock-induced DeltaCa(i)2+ and DeltaV(m) in geometrically defined myocyte cultures. Cell strands ... More
Measurement of cytoplasmic calcium concentration in the rods of wild-type and transducin knock-out mice.
A 10 microm spot of argon laser light was focused onto the outer segments of intact mouse rods loaded with fluo-3, fluo-4 or fluo-5F, to estimate dark, resting free Ca(2+) concentration ([Ca(2+)](i)) and changes in [Ca(2+)](i) upon illumination. Dye concentration was adjusted to preserve the normal physiology of the rod, ... More
The RAB3-RIM Pathway Is Essential for the Release of Neuromodulators.
Authors
JournalNeuron
PubMed ID31679900
Quantitative analysis of dense-core vesicle fusion in rodent CNS neurons.
Authors
JournalSTAR Protoc
PubMed ID33659902
Pool size estimations for dense-core vesicles in mammalian CNS neurons.