Activation of pig oocytes by intracytoplasmic injection of strontium and barium.
AuthorsOkada K, Miyano T, Miyake M
JournalZygote
PubMed ID12828415
'Ovulated mouse oocytes are activated by exposure to culture medium containing Sr2+ or Ba2+ or by intracytoplasmic injection of the divalent cations. It is known that in vitro matured pig oocytes are activated by the intracytoplasmic injection of Ca2+. In this study, we examined the effect of exposure and of ... More
Pharmacological profile of store-operated channels in cerebral arteriolar smooth muscle cells.
AuthorsFlemming R, Xu SZ, Beech DJ
JournalBr J Pharmacol
PubMed ID12839869
'1. In this study, we determined a pharmacological profile of store-operated channels (SOCs) in smooth muscle cells of rabbit pial arterioles. Ca(2+)-indicator dyes, fura-PE3 or fluo-4, were used to track [Ca(2+)](i) and 10 micro M methoxyverapamil (D600) was present in all experiments on SOCs to prevent voltage-dependent Ca(2+) entry. Store ... More
Novel fluo-4 analogs for fluorescent calcium measurements.
AuthorsMartin VV, Beierlein M, Morgan JL, Rothe A, Gee KR
JournalCell Calcium
PubMed ID15488600
We report new fluorescent calcium indicators based on fluo-4. Attachment of a carboxamide or methylenecarboxamide moiety to the BAPTA chelator portion of fluo-4 allowed for the attachment of dextrans, protein-reactive moieties, and biotin. In particular, a high affinity fluo-4 dextran conjugate was prepared and shown to be functional in brain ... More
Monitoring presynaptic calcium dynamics in projection fibers by in vivo loading of a novel calcium indicator.
AuthorsKreitzer AC, Gee KR, Archer EA, Regehr WG
JournalNeuron
PubMed ID10939328
Fluorometric calcium measurements have revealed presynaptic residual calcium (Ca(res)) to be an important regulator of synaptic strength. However, in the mammalian brain, it has not been possible to monitor Ca(res) in fibers that project from one brain region to another. Here, we label neuronal projections by injecting dextran-conjugated calcium indicators ... More
IP3-dependent nuclear Ca2+ signalling in the mammalian heart.
AuthorsZima AV, Bare DJ, Mignery GA, Blatter LA,
JournalJ Physiol
PubMed ID17761776
In cardiac myocytes the type-2 inositol 1,4,5-trisphosphate receptor (IP(3)R2) is the predominant isoform expressed. The IP(3)R2 channel is localized to the SR and to the nuclear envelope. We studied IP(3)-dependent nuclear Ca(2+) signals ([Ca(2+)](Nuc)) in permeabilized atrial myocytes and in isolated cardiac nuclei. In permeabilized myocytes IP(3) (20 microm) and ... More
Biolistic delivery of Ca2+ dyes into plant and algal cells.
In eukaryotes, changes in cytosolic Ca2+ concentrations ([Ca2+]cyt) are associated with a number of environmental and developmental stimuli. However, measuring [Ca2+]cyt changes in single plant or algal cells is often problematic. Although a wide range of Ca2+-sensitive fluorescent dyes is available, they are often difficult to introduce into plant cells. ... More
Retrograde inhibition of presynaptic calcium influx by endogenous cannabinoids at excitatory synapses onto Purkinje cells.
AuthorsKreitzer AC, Regehr WG
JournalNeuron
PubMed ID11301030
Brief depolarization of cerebellar Purkinje cells was found to inhibit parallel fiber and climbing fiber EPSCs for tens of seconds. This depolarization-induced suppression of excitation (DSE) is accompanied by altered paired-pulse plasticity, suggesting a presynaptic locus. Fluorometric imaging revealed that postsynaptic depolarization also reduces presynaptic calcium influx. The inhibition of ... More
Fast calcium signals in Drosophila motor neuron terminals.
AuthorsMacleod GT, Hegström-Wojtowicz M, Charlton MP, Atwood HL
JournalJ Neurophysiol
PubMed ID12424301
Drosophila is a powerful model for neuroscientists, but physiological techniques have not kept pace with advances in molecular genetics. We introduce a reliable assay for intracellular calcium dynamics in Drosophila larval motor neuron terminals, and a new physiological solution that improves the longevity of the larval preparation. By loading calcium ... More
Acetylcholine and calcium signalling regulates muscle fibre formation in the zebrafish embryo.
AuthorsBrennan C, Mangoli M, Dyer CE, Ashworth R
JournalJ Cell Sci
PubMed ID16249237
Nerve activity is known to be an important regulator of muscle phenotype in the adult, but its contribution to muscle development during embryogenesis remains unresolved. We used the zebrafish embryo and in vivo imaging approaches to address the role of activity-generated signals, acetylcholine and intracellular calcium, in vertebrate slow muscle ... More
Transmitter-evoked local calcium release stabilizes developing dendrites.
AuthorsLohmann C, Myhr KL, Wong RO
JournalNature
PubMed ID12110889
In the central nervous system, dendritic arborizations of neurons undergo dynamic structural remodelling during development. Processes are elaborated, maintained or eliminated to attain the adult pattern of synaptic connections. Although neuronal activity influences this remodelling, it is not known how activity exerts its effects. Here we show that neurotransmission-evoked calcium ... More
Imaging calcium dynamics in the nervous system by means of ballistic delivery of indicators.
AuthorsKettunen P, Demas J, Lohmann C, Kasthuri N, Gong Y, Wong RO, Gan WB
JournalJ Neurosci Methods
PubMed ID12234633
The use of fluorescence-based calcium indicators has, over the years, unraveled important calcium-dependent mechanisms underlying neuronal function and development. However, difficulties associated with the loading of calcium indicators have limited their widespread use, particularly for the study of neuronal processing in the adult nervous system. Here, we show that in ... More
Regulation of mechanical interactions between fibroblasts and the substratum by stretch-activated Ca2+ entry.
AuthorsMunevar S, Wang YL, Dembo M
JournalJ Cell Sci
PubMed ID14627625
Ca2+ ions have long been implicated in regulating various aspects of cell movements. We found that stretching forces applied through flexible substrata induced increases in both intracellular Ca2+ concentration and traction forces of NIH3T3 fibroblasts. Conversely, application of gadolinium, an inhibitor of stretch-activated ion channels, or removal of extracellular free ... More
Optical single-channel recording by imaging Ca2+ flux through individual ion channels: theoretical considerations and limits to resolution.
AuthorsShuai J, Parker I
JournalCell Calcium
PubMed ID15755490
Recent developments in microscopy and fluorescent indicators now make it possible to monitor the activity and localization of membrane ion channels by imaging Ca(2+) flux through individual channels. Such optical approaches have advantages over electrophysiological single-channel techniques in that they are less invasive, provide spatial information and can simultaneously and ... More
Live-cell imaging methods for the study of vagal afferents within the nucleus of the solitary tract.
AuthorsRogers RC, Nasse JS, Hermann GE
JournalJ Neurosci Methods
PubMed ID16099514
Substantial evidence suggests that vagal afferent functions are modulated by agonists acting on afferent terminals in the solitary nucleus (NST). Actions of these agonists are implied through intracellular recordings from cultured nodose ganglion cells or second order NST neurons. While high-quality data have been obtained using these methods, techniques in ... More
Optical single-channel recording: imaging Ca2+ flux through individual ion channels with high temporal and spatial resolution.
AuthorsDemuro A, Parker I
JournalJ Biomed Opt
PubMed ID15847568
Developments in imaging technology now enable visualization of the functioning of individual ion channels in living cells: something previously possible only by the electrophysiological patch-clamp technique. We review techniques that track channel gating via changes in intracellular [Ca2+] resulting from openings of Ca(2+)-permeable channels. Spatial and temporal resolution are optimized ... More
Presynaptic calcium measurements at physiological temperatures using a new class of dextran-conjugated indicators.
AuthorsBeierlein M, Gee KR, Martin VV, Regehr WG
JournalJ Neurophysiol
PubMed ID15212445
Presynaptic calcium (Ca(pre)) has been studied extensively because of its role in triggering and modulating neurotransmitter release. Although calcium regulation and calcium-driven processes can be strongly temperature dependent, technical difficulties have limited most studies of Ca(pre) to temperatures well below the physiological range. Here we assessed the use of membrane-permeant ... More
Na+-dependent sources of intra-axonal Ca2+ release in rat optic nerve during in vitro chemical ischemia.
AuthorsNikolaeva MA, Mukherjee B, Stys PK
JournalJ Neurosci
PubMed ID16251444
The contribution of intracellular stores to axonal Ca2+ overload during chemical ischemia in vitro was examined by confocal microscopy. Ca2+ accumulation was measured by fluo-4 dextran (low-affinity dye, KD approximately 4 microM) or by Oregon Green 488 BAPTA-1 dextran (highaffinity dye, KD approximately 450 nM). Axonal Na+ was measured using ... More