Although human pannexins (PanX) are homologous to gap junction molecules, their physiological function in vertebrates remains poorly understood. Our results demonstrate that overexpression of PanX1 results in the formation of Ca(2+)-permeable gap junction channels between adjacent cells, thus, allowing direct intercellular Ca(2+) diffusion and facilitating intercellular Ca(2+) wave propagation. More ... More
Impaired insulin secretion and glucose intolerance in synaptotagmin-7 null mutant mice.
JournalProceedings of the National Academy of Sciences of the United States of America
PubMed ID18308938
Vertebrates express at least 15 different synaptotagmins with the same domain structure but diverse localizations and tissue distributions. Synaptotagmin-1,-2, and -9 act as calcium sensors for the fast phrase of neurotransmitter release, and synaptotagmin-12 acts as a calcium-independent modulator of release. The exact functions of the remaining 11 synaptotagmins, however, ... More
High-throughput microfluidic mixing and multiparametric cell sorting for bioactive compound screening.
HyperCyt, an automated sample handling system for flow cytometry that uses air bubbles to separate samples sequentially introduced from multiwell plates by an autosampler. In a previously documented HyperCyt configuration, air bubble separated compounds in one sample line and a continuous stream of cells in another are mixed in-line for ... More
Drosophila Hsc70-4 is critical for neurotransmitter exocytosis in vivo.
AuthorsBronk P, Wenniger JJ, Dawson-Scully K, Guo X, Hong S, Atwood HL, Zinsmaier KE
JournalNeuron
PubMed ID11395008
'Previous in vitro studies of cysteine-string protein (CSP) imply a potential role for the clathrin-uncoating ATPase Hsc70 in exocytosis. We show that hypomorphic mutations in Drosophila Hsc70-4 (Hsc4) impair nerve-evoked neurotransmitter release, but not synaptic vesicle recycling in vivo. The loss of release can be restored by increasing external or ... More
Multiplex GPCR assay in reverse transfection cell microarrays.
AuthorsMishina YM, Wilson CJ, Bruett L, Smith JJ, Stoop-Myer C, Jong S, Amaral LP, Pedersen R, Lyman SK, Myer VE, Kreider BL, Thompson CM
JournalJ Biomol Screen
PubMed ID15140381
'G protein-coupled receptors (GPCRs) are a superfamily of proteins that include some of the most important drug targets in the pharmaceutical industry. Despite the success of this group of drugs, there remains a need to identify GPCR-targeted drugs with greater selectivity, to develop screening assays for validated targets, and to ... More
Identification of an intracellular trafficking and assembly pathway for HIV-1 gag.
AuthorsPerlman M, Resh MD
JournalTraffic
PubMed ID16683918
'Retroviral Gag proteins are membrane-bound polyproteins that are necessary and sufficient for virus-like particle (VLP) formation. It is not known how Gag traffics through the cell or how the site of particle production is determined. Here we use two techniques, biarsenical/tetracysteine (TC) labeling and release from a cycloheximide block, to ... More
A component of excitation-contraction coupling triggered in the absence of the T671-L690 and L720-Q765 regions of the II-III loop of the dihydropyridine receptor alpha(1s) pore subunit.
AuthorsAhern CA, Bhattacharya D, Mortenson L, Coronado R
JournalBiophys J
PubMed ID11720993
'We conducted a deletion analysis of two regions identified in the II-III loop of alpha(1S), residues 671-690, which were shown to bind to ryanodine receptor type 1 (RyR1) and stimulate RyR1 channels in vitro, and residues 720-765 or the narrower 724-743 region, which confer excitation-contraction (EC) coupling function to chimeric ... More
Functional cross-interaction of the fragments produced by the cleavage of distinct adhesion G-protein-coupled receptors.
AuthorsSilva JP, Lelianova V, Hopkins C, Volynski KE, Ushkaryov Y,
JournalJ Biol Chem
PubMed ID19124473
'The unusual adhesion G-protein-coupled receptors (aGPCRs) contain large extracellular N-terminal domains, which resemble cell-adhesion receptors, and C-terminal heptahelical domains, which may couple to G-proteins. These receptors are cleaved post-translationally between these domains into two fragments (NTF and CTF). Using the aGPCR latrophilin 1, we previously demonstrated that the fragments behave ... More
Pharmacology and functional properties of NTS2 neurotensin receptors in cerebellar granule cells.
AuthorsSarret P, Gendron L, Kilian P, Nguyen HM, Gallo-Payet N, Payet MD, Beaudet A
JournalJ Biol Chem
PubMed ID12084713
'The binding and signaling properties of neuronal NTS2 neurotensin (NT) receptors were examined in cultured rat cerebellar granule cells. As shown by reverse transcription-PCR, receptor autoradiography, and confocal microscopic localization of fluorescent NT, these cells selectively express the NTS2 receptor subtype. Accordingly, a single apparent class of (125)I-NT-binding sites, with ... More
The triad targeting signal of the skeletal muscle calcium channel is localized in the COOH terminus of the alpha(1S) subunit.
AuthorsFlucher BE, Kasielke N, Grabner M
JournalJ Cell Biol
PubMed ID11038191
'The specific localization of L-type Ca(2+) channels in skeletal muscle triads is critical for their normal function in excitation-contraction (EC) coupling. Reconstitution of dysgenic myotubes with the skeletal muscle Ca(2+) channel alpha(1S) subunit restores Ca(2+) currents, EC coupling, and the normal localization of alpha(1S) in the triads. In contrast, expression ... More
Knocking down type 2 but not type 1 calsequestrin reduces calcium sequestration and release in C2C12 skeletal muscle myotubes.
AuthorsWang Y, Xu L, Duan H, Pasek DA, Eu JP, Meissner G
JournalJ Biol Chem
PubMed ID16595676
'We examined the roles of type 1 and type 2 calsequestrins (CSQ1 and CSQ2) in stored Ca2+ release of C2C12 skeletal muscle myotubes. Transduction of C2C12 myoblasts with CSQ1 or CSQ2 small interfering RNAs effectively reduced the expression of targeted CSQ protein to near undetectable levels. As compared with control ... More
Exopolysaccharides from Burkholderia cenocepacia inhibit neutrophil chemotaxis and scavenge reactive oxygen species.
AuthorsBylund J, Burgess LA, Cescutti P, Ernst RK, Speert DP
JournalJ Biol Chem
PubMed ID16316987
'Bacteria belonging to the Burkholderia cepacia complex are important opportunistic pathogens in compromised hosts, particularly patients with cystic fibrosis or chronic granulomatous disease. Isolates of B. cepacia complex may produce large amounts of exopolysaccharides (EPS) that endow the bacteria with a mucoid phenotype and appear to facilitate bacterial persistence during ... More
PECAM-1 (CD31) regulates a hydrogen peroxide-activated nonselective cation channel in endothelial cells.
AuthorsJi G, O'Brien CD, Feldman M, Manevich Y, Lim P, Sun J, Albelda SM, Kotlikoff MI
JournalJ Cell Biol
PubMed ID11927609
'Hydrogen peroxide (H2O2) released by neutrophils is an important mediator of endothelial cell (EC) injury and vascular inflammation via its effect on EC-free Ca2+, [Ca2+]i. Although the underlying mechanisms are not well understood, platelet endothelial cell adhesion molecule (PECAM)-1/CD-31 is a critical modulator of neutrophil-EC transmigration. PECAM-1 is also known ... More
Identification of specific ligands for orphan olfactory receptors. G protein-dependent agonism and antagonism of odorants.
AuthorsShirokova E, Schmiedeberg K, Bedner P, Niessen H, Willecke K, Raguse JD, Meyerhof W, Krautwurst D
JournalJ Biol Chem
PubMed ID15598656
'Olfactory receptors are the largest group of orphan G protein-coupled receptors with an infinitely small number of agonists identified out of thousands of odorants. The de-orphaning of olfactory receptor (OR) is complicated by its combinatorial odorant coding and thus requires large scale odorant and receptor screening and establishing receptor-specific odorant ... More
A new technique for simultaneous and in situ measurements of Ca2+ signals in arteriolar smooth muscle and endothelial cells.
AuthorsBurdyga T, Shmygol A, Eisner DA, Wray S
JournalCell Calcium
PubMed ID12767890
'We report here the first local and global Ca(2+) measurements made from in situ terminal arterioles. The advantages of the method are that there is minimal disturbance to the vessels, which retain their relationship to the tissue they are supplying (rat ureter) and the small size of vessel that can ... More
Signaling at the gliovascular interface.
AuthorsSimard M, Arcuino G, Takano T, Liu QS, Nedergaard M
JournalJ Neurosci
PubMed ID14534260
'Advances in fluorescent calcium indicating dyes over the past decade have identified calcium signaling as the tool by which astrocytes communicate among themselves and with neighboring neurons. Studies of astrocyte-neuron interactions have shown that calcium signaling is a potent modulator of the strength of both excitatory and inhibitory synapses. The ... More
Na+ channel-mediated Ca2+ entry leads to glutamate secretion in mouse neocortical preplate.
AuthorsPlatel JC, Boisseau S, Dupuis A, Brocard J, Poupard A, Savasta M, Villaz M, Albrieux M
JournalProc Natl Acad Sci U S A
PubMed ID16357207
'Before synaptogenesis, early excitability implicating voltage-dependent and transmitter-activated channels is known to be crucial for neuronal development. We previously showed that preplate (PP) neurons of the mouse neocortex express functional Na(+) channels as early as embryonic day 12. In this study, we investigated the role of these Na(+) channels in ... More
Effect of the insulin mimetic L-783,281 on intracellular Ca2+ and insulin secretion from pancreatic beta-cells.
'L-783,281, an antidiabetic fungal metabolite that has previously been shown to activate insulin signaling in CHO cells, was tested for its effect on intracellular Ca(2+) ([Ca(2+)](i)) and insulin secretion in single mouse pancreatic beta-cells. Application of 10 micromol/l L-783,281 for 40 s to isolated beta-cells in the presence of 3 ... More
Localisation, function and composition of primary Ca(2+) spark discharge region in isolated smooth muscle cells from guinea-pig mesenteric arteries.
AuthorsPucovský V, Bolton TB
JournalCell Calcium
PubMed ID16297446
'Smooth muscle cells (SMCs) contain numerous calcium release domains, grouped into regions discharging as a single unit. Laser scanning confocal microscopy, voltage clamp and immunocytochemistry of single SMCs from small mesenteric arteries of guinea-pig were used to study the localisation, function and macromolecular composition of such calcium discharge regions (CDRs). ... More
Evidence for a single heptahelical domain being turned on upon activation of a dimeric GPCR.
'G-protein-coupled receptors (GPCRs) have been shown to form dimers, but the relevance of this phenomenon in G-protein activation is not known. Among the large GPCR family, metabotropic glutamate (mGlu) receptors are constitutive dimers. Here we examined whether both heptahelical domains (HDs) are turned on upon full receptor activation. To that ... More
Epithelial membrane proteins induce membrane blebbing and interact with the P2X7 receptor C terminus.
Authors Wilson Heather L; Wilson Stuart A; Surprenant Annmarie; North R Alan;
JournalJ Biol Chem
PubMed ID12107182
'The binding of extracellular ATP to the P2X(7) receptor opens an integral cation-permeable channel; it also leads to membrane blebbing and, in certain immune cells, interleukin-1beta secretion and eventual death. The latter three effects are unique to the P2X(7) receptor; also unique among P2X receptors is the long intracellular C ... More
Activation and propagation of Ca(2+) release during excitation-contraction coupling in atrial myocytes.
AuthorsKockskämper J, Sheehan KA, Bare DJ, Lipsius SL, Mignery GA, Blatter LA
JournalBiophys J
PubMed ID11606273
'Fast two-dimensional confocal microscopy and the Ca(2+) indicator fluo-4 were used to study excitation-contraction (E-C) coupling in cat atrial myocytes which lack transverse tubules and contain both subsarcolemmal junctional (j-SR) and central nonjunctional (nj-SR) sarcoplasmic reticulum. Action potentials elicited by field stimulation induced transient increases of intracellular Ca(2+) concentration ([Ca(2+)](i)) ... More
Calmodulin kinases II and IV and calcineurin are involved in leukemia inhibitory factor-induced cardiac hypertrophy in rats.
AuthorsKato T, Sano M, Miyoshi S, Sato T, Hakuno D, Ishida H, Kinoshita-Nakazawa H, Fukuda K, Ogawa S
JournalCirc Res
PubMed ID11073891
'We recently reported that leukemia inhibitory factor (LIF) enhances Ca(2+)](i) through an increase in L-type Ca(2+) current (I(Ca,L)) in adult cardiomyocytes. The aim of this study was to investigate whether LIF activates Ca(2+)-dependent signaling molecules, such as calcineurin and calmodulin kinases II and IV (CaMKII and CaMKIV), and, if so, ... More
Spatially confined diffusion of calcium in dendrites of hippocampal neurons revealed by flash photolysis of caged calcium.
AuthorsKorkotian E, Segal M
JournalCell Calcium
PubMed ID17064764
'The extent of diffusion of a locally evoked calcium surge in dendrites of cultured hippocampal neurons was studied by flash photolysis of caged EGTA. Cells were transfected with pDsRed for visualization, preincubated with caged NP-EGTA (AM) and Fluo-4 (AM) at room temperature and imaged in a PASCAL confocal microscope. Pulses ... More
ETA receptors in the gerbil spiral modiolar artery.
AuthorsScherer EQ, Wangemann P
JournalAdv Otorhinolaryngol
PubMed ID11885662
'A reduction of blood flow in the spiral modiolar artery (SMA), which supplies the cochlea, is implicated in hearing loss and tinnitus. Endothelins are known to be the most potent endogenous vasoconstrictors. The purpose of the present study was to determine whether the SMA responds to endothelin, which receptor type ... More
Lysophosphatidic acid positively regulates the fluid flow-induced local Ca(2+) influx in bovine aortic endothelial cells.
AuthorsOhata H, Ikeuchi T, Kamada A, Yamamoto M, Momose K
JournalCirc Res
PubMed ID11349002
'Using real-time confocal microscopy, we have demonstrated that lysophosphatidic acid (LPA), a bioactive phospholipid existing in plasma, positively regulates fluid flow-induced [Ca(2+)](i) response in fluo 4-loaded, cultured, bovine aortic endothelial cells. The initial increase in [Ca(2+)](i) was localized to a circular area with a diameter of <4 microm and spread ... More
Targeted overexpression of sarcolipin in the mouse heart decreases sarcoplasmic reticulum calcium transport and cardiac contractility.
AuthorsBabu GJ, Bhupathy P, Petrashevskaya NN, Wang H, Raman S, Wheeler D, Jagatheesan G, Wieczorek D, Schwartz A, Janssen PM, Ziolo MT, Periasamy M
JournalJ Biol Chem
PubMed ID16365042
'The role of sarcolipin (SLN) in cardiac physiology was critically evaluated by generating a transgenic (TG) mouse model in which the SLN to sarco(endoplasmic)reticulum (SR) Ca(2+) ATPase (SERCA) ratio was increased in the ventricle. Overexpression of SLN decreases SR calcium transport function and results in decreased calcium transient amplitude and ... More
Differential G protein-coupled cannabinoid receptor signaling by anandamide directs blastocyst activation for implantation.
AuthorsWang H, Matsumoto H, Guo Y, Paria BC, Roberts RL, Dey SK
JournalProc Natl Acad Sci U S A
PubMed ID14645706
'Mammalian fertility absolutely depends on synchronized development of the blastocyst to the stage when it is competent to implant, and the uterus to the stage when it is receptive to implantation. However, the molecular basis for the reciprocal interaction between the embryo and the uterus remains largely unexplored. One potentially ... More
Antagonist activity of meta-chlorophenylpiperazine and partial agonist activity of 8-OH-DPAT at the 5-HT(7) receptor.
AuthorsWood M, Chaubey M, Atkinson P, Thomas DR
JournalEur J Pharmacol
PubMed ID10822046
'This study compared the use of adapter G-proteins to link G(s) coupled G-protein receptors to a Ca(2+) signal, enabling high throughput functional studies using a fluorescent imaging plate reader (FLIPR, Molecular Devices).The pharmacological profile of the human 5-hydroxytryptamine (5-HT(7)) receptor was studied using the adapter G-proteins G(alpha16) and G(qs5) and ... More
Calcium oscillation linked to pacemaking of interstitial cells of Cajal: requirement of calcium influx and localization of TRP4 in caveolae.
AuthorsTorihashi S, Fujimoto T, Trost C, Nakayama S
JournalJ Biol Chem
PubMed ID11897792
'Interstitial cells of Cajal (ICC) are considered to be pacemaker cells in gastrointestinal tracts. ICC generate electrical rhythmicity (dihydropyridine-insensitive) as slow waves and drive spontaneous contraction of smooth muscles. Although cytosolic Ca(2+) has been assumed to play a key role in pacemaking, Ca(2+) movements in ICC have not yet been ... More
Multidrug transporter activity in lymphocytes.
AuthorsElliott JI, Raguz S, Higgins CF,
JournalBr J Pharmacol
PubMed ID15492020
'Multidrug transporters play a dual role in haematopoietic cells, mediating the efflux of xenobiotics and regulating cell migration. For several reasons including the lack of specific antibodies, reports of multidrug transporter distribution on lymphocytes conflict. Murine B cells have been reported to completely lack transporter activity. Through analysis of parental ... More
Bisandrographolide from Andrographis paniculata activates TRPV4 channels.
AuthorsSmith PL, Maloney KN, Pothen RG, Clardy J, Clapham DE
JournalJ Biol Chem
PubMed ID16899456
'Many transient receptor potential (TRP) channels are activated or blocked by various compounds found in plants; two prominent examples include the activation of TRPV1 channels by capsaicin and the activation of TRPM8 channels by menthol. We sought to identify additional plant compounds that are active on other types of TRP ... More
Diacylglycerol analogues activate second messenger-operated calcium channels exhibiting TRPC-like properties in cortical neurons.
AuthorsTu P, Kunert-Keil C, Lucke S, Brinkmeier H, Bouron A,
JournalJ Neurochem
PubMed ID19094061
'The lipid diacylglycerol (DAG) analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) was used to verify the existence of DAG-sensitive channels in cortical neurons dissociated from E13 mouse embryos. Calcium imaging experiments showed that OAG increased the cytosolic concentration of Ca(2+) ([Ca(2+)]i) in nearly 35% of the KCl-responsive cells. These Ca(2+) responses disappeared in a ... More
Errors caused by combination of Di-4 ANEPPS and Fluo3/4 for simultaneous measurements of transmembrane potentials and intracellular calcium.
AuthorsJohnson PL, Smith W, Baynham TC, Knisley SB
JournalAnn Biomed Eng
PubMed ID10468240
'Intracellular calcium concentration and transmembrane potentials are two important measurements used to study the mechanisms of cardiac activity. Fluorescent dyes have been used to measure these separately but not simultaneously in cardiac tissue. Fluo-3 and Fluo-4 (a recently improved version of Fluo-3) have been used to measure changes in intracellular ... More
Adrenergic stimulation of rat resistance arteries affects Ca(2+) sparks, Ca(2+) waves, and Ca(2+) oscillations.
AuthorsMauban JR, Lamont C, Balke CW, Wier WG
JournalAm J Physiol Heart Circ Physiol
PubMed ID11299247
'Confocal laser scanning microscopy and fluo 4 were used to visualize local and whole cell Ca(2+) transients within individual smooth muscle cells (SMC) of intact, pressurized rat mesenteric small arteries during activation of alpha1-adrenoceptors. A method was developed to record the Ca(2+) transients within individual SMC during the changes in ... More
Cysteine-string protein increases the calcium sensitivity of neurotransmitter exocytosis in Drosophila.
AuthorsDawson-Scully K, Bronk P, Atwood HL, Zinsmaier KE
JournalJ Neurosci
PubMed ID10934253
'Previous studies suggest that the vesicular cysteine-string protein (CSP) may modulate presynaptic Ca(2+) channel activity in fast neurotransmitter release. To test this hypothesis, we analyzed the dynamics of presynaptic Ca(2+) ion influx with the Ca(2+) indicator fluo-4 AM at csp mutant neuromuscular junctions of Drosophila. From 24 to 30 degrees ... More
Concepts in imaging and microscopy. Exploring biological structure and function with confocal microscopy.
AuthorsDailey M, Marrs G, Satz J, Waite M
JournalBiol Bull
PubMed ID10573836
'Confocal microscopy is providing new and exciting opportunities for imaging cell structure and physiology in thick biological specimens, in three dimensions, and in time. The utility of confocal microscopy relies on its fundamental capacity to reject out-of-focus light, thus providing sharp, high-contrast images of cells and subcellular structures within thick ... More
Carbenoxolone inhibition of voltage-gated Ca channels and synaptic transmission in the retina.
AuthorsVessey JP, Lalonde MR, Mizan HA, Welch NC, Kelly ME, Barnes S
JournalJ Neurophysiol
PubMed ID15028741
'We show that carbenoxolone, a drug used to block hemichannels in the retina to test the ephaptic model of horizontal cell inhibitory feedback, has strong inhibitory effects on voltage-gated Ca channels. Carbenoxolone (100 microM) reduced photoreceptor-to-horizontal cell synaptic transmission by 92%. Applied to patch-clamped, isolated cone photoreceptors, carbenoxolone inhibited Ca ... More
Mitochondrial and plasma membrane potential of cultured cerebellar neurons during glutamate-induced necrosis, apoptosis, and tolerance.
'A failure of mitochondrial bioenergetics has been shown to be closely associated with the onset of apoptotic and necrotic neuronal injury. Here, we developed an automated computational model that interprets the single-cell fluorescence for tetramethylrhodamine methyl ester (TMRM) as a consequence of changes in either delta psi(m) or delta psi(p), ... More
Development of an intact cell reporter gene beta-lactamase assay for G protein-coupled receptors for high-throughput screening.
'G protein-coupled receptors (GPCRs) are involved in a large variety of physiological disorders, and are thus important pharmaceutical drug targets. Here, we describe the development and characterization of a beta-lactamase reporter gene assay as a functional readout for the ligand-induced activation of the human bradykinin B1 receptor, expressed recombinantly in ... More
Arginine vasopressin stimulates H+-ATPase in MDCK cells via V1 (cell Ca2+) and V2 (cAMP) receptors.
AuthorsOliveira-Souza M, Musa-Aziz R, Malnic G, De Mello Aires M
JournalAm J Physiol Renal Physiol
PubMed ID12965889
'The effect of arginine vasopressin (AVP) and/or atrial natriuretic peptide (ANP) on the regulation of intracellular pH (pHi) via H+-ATPase and of cytosolic calcium ([Ca2+]i) was investigated in Madin-Darby canine kidney (MDCK) cells by the fluorescent probes BCECF-AM and fluo-4-AM, respectively. The pHi recovery rate was examined after intracellular acidification ... More
Smooth muscle cell response to mechanical injury involves intracellular calcium release and ERK1/ERK2 phosphorylation.
AuthorsMoses S, Dreja K, Lindqvist A, Lövdahl C, Hellstrand P, Hultgårdh-Nilsson A
JournalExp Cell Res
PubMed ID11525642
'We have investigated possible signaling pathways coupled to injury-induced ERK1/2 activation and the subsequent initiation of vascular rat smooth muscle cell migration and proliferation. Aortic smooth muscle cells were cultured to confluency and subjected to in vitro injury under serum-free conditions. In fluo-4-loaded cells, injury induced a rapid wave of ... More
Venom from the ectoparasitic wasp Nasonia vitripennis increases Na+ influx and activates phospholipase C and phospholipase A2 dependent signal transduction pathways in cultured insect cells.
AuthorsRivers DB, Rocco MM, Frayha AR
JournalToxicon
PubMed ID11602274
'The mode of action of venom from the ectoparasitic wasp Nasonia vitripennis in eliciting cell death was examined using an in vitro approach with BTI-TN-5B1-4 cells, and the cell responses were compared to those evoked by the extensively studied wasp toxin mastoparan. Wasp venom increased plasma membrane permeability to Na+, ... More
The mitochondrial membrane potential and Ca2+ oscillations in smooth muscle.
AuthorsChalmers S, McCarron JG,
JournalJ Cell Sci
PubMed ID18073239
'Ca2+ uptake by mitochondria might both modulate the cytosolic Ca2+ concentration ([Ca2+]c) and depolarize the mitochondrial membrane potential (delta Psi m) to limit ATP production. To investigate how physiological Ca2+ signaling might affect energy production, delta Psi m was examined during Ca2+ oscillations in smooth muscle cells. In single, voltage-clamped ... More
Localized neurotransmitter release for use in a prototype retinal interface.
AuthorsPeterman MC, Bloom DM, Lee C, Bent SF, Marmor MF, Blumenkranz MS, Fishman HA
JournalInvest Ophthalmol Vis Sci
PubMed ID12824264
'PURPOSE: Current neural prostheses use electricity as the mode of stimulation, yet information transfer in neural circuitry is primarily through chemical transmitters. To address this disparity, this study was conducted to devise a prototype interface for a retinal prosthetic based on localized chemical delivery. The goal was to determine whether ... More
Membrane phosphatidylserine distribution as a non-apoptotic signalling mechanism in lymphocytes.
AuthorsElliott JI, Surprenant A, Marelli-Berg FM, Cooper JC, Cassady-Cain RL, Wooding C, Linton K, Alexander DR, Higgins CF
JournalNat Cell Biol
PubMed ID16025105
'Phosphatidylserine (PS) exposure is normally associated with apoptosis and the removal of dying cells. We observed that PS is exposed constitutively at high levels on T lymphocytes that express low levels of the transmembrane tyrosine phosphatase CD45RB. CD45 was shown to be a negative regulator of PS translocation in response ... More
NAADP controls cross-talk between distinct Ca2+ stores in the heart.
AuthorsMacgregor A, Yamasaki M, Rakovic S, Sanders L, Parkesh R, Churchill GC, Galione A, Terrar DA
JournalJ Biol Chem
PubMed ID17387177
'In cardiac muscle the sarcoplasmic reticulum (SR) plays a key role in the control of contraction, releasing Ca(2+) in response to Ca(2+) influx across the sarcolemma via voltage-gated Ca(2+) channels. Here we report evidence for an additional distinct Ca(2+) store and for actions of nicotinic acid adenine dinucleotide phosphate (NAADP) ... More
Graded alpha1-adrenoceptor activation of arteries involves recruitment of smooth muscle cells to produce 'all or none' Ca(2+) signals.
AuthorsZang WJ, Balke CW, Wier WG
JournalCell Calcium
PubMed ID11292389
'Confocal laser scanning microscopy and Fluo-4 were used to visualize Ca(2+) transients within individual smooth muscle cells (SMC) of rat resistance arteries during alpha(1)-adrenoceptor activation. The typical spatio-temporal pattern of [Ca(2+)] in an artery after exposure to a maximally effective concentration of phenylephrine (PE, 10.0 microM) was a large, brief, ... More
Fluorescence imaging of amyloid formation in living cells by a functional, tetracysteine-tagged alpha-synuclein.
'Alpha-synuclein is a major component of intraneuronal protein aggregates constituting a distinctive feature of Parkinson disease. To date, fluorescence imaging of dynamic processes leading to such amyloid deposits in living cells has not been feasible. To address this need, we generated a recombinant alpha-synuclein (alpha-synuclein-C4) bearing a tetracysteine target for ... More
Ca(2+) sparks and BK currents in gallbladder myocytes: role in CCK-induced response.
AuthorsPozo MJ, Pérez GJ, Nelson MT, Mawe GM
JournalAm J Physiol Gastrointest Liver Physiol
PubMed ID11751170
'We sought to elucidate the regulation of gallbladder smooth muscle (GBSM) excitability by localized Ca(2+) release events (sparks) and large-conductance Ca(2+)-dependent (BK) channels by determining whether sparks exist in GBSM and, if so, whether they activate BK channels. Sparks were identified in isolated GBSM loaded with fluo 4. Each spark ... More
A store-operated calcium channel in Drosophila S2 cells.
AuthorsYeromin AV, Roos J, Stauderman KA, Cahalan MD
JournalJ Gen Physiol
PubMed ID14744989
'Using whole-cell recording in Drosophila S2 cells, we characterized a Ca(2+)-selective current that is activated by depletion of intracellular Ca2+ stores. Passive store depletion with a Ca(2+)-free pipette solution containing 12 mM BAPTA activated an inwardly rectifying Ca2+ current with a reversal potential >60 mV. Inward currents developed with a ... More
Propagation of pacemaker activity in the guinea-pig antrum.
AuthorsHennig GW, Hirst GD, Park KJ, Smith CB, Sanders KM, Ward SM, Smith TK
JournalJ Physiol
PubMed ID14754999
'Cyclical periods of depolarization (slow waves) underlie peristaltic contractions involved in mixing and emptying of contents in the gastric antrum. Slow waves originate from a myenteric network of interstitial cells of Cajal (ICC-MY). In this study we have visualized the sequence and propagation of Ca(2+) transients associated with pacemaker potentials ... More
Calcium signaling components of oscillating invertebrate neurons in vitro.
AuthorsLevi R, Samoilova M, Selverston AI
JournalNeuroscience
PubMed ID12676158
'We have studied the Ca(2+) dynamics of bursting-spiking neurons in the lobster stomatogastric ganglion. Neurons in this ganglion undergo spontaneous oscillations in membrane voltage with a period of 1-10 s in situ. We found that neurons isolated from the ganglion and filled with the fluorescent calcium indicator Fluo-4 show simultaneous ... More
Conformational coupling of DHPR and RyR1 in skeletal myotubes is influenced by long-range allosterism: evidence for a negative regulatory module.
AuthorsLee EH, Lopez JR, Li J, Protasi F, Pessah IN, Kim DH, Allen PD
JournalAm J Physiol Cell Physiol
PubMed ID13679303
'Four ryanodine receptor type 1 and 2 chimeras (R4, R9, R10, and R16) and their respective wild-type ryanodine receptors (type 1 and 2; wtRyR1 and wtRyR2) were expressed in dyspedic 1B5 to identify possible negative regulatory modules of the Ca2+ release channel that are under the influence of the dihydropyridine ... More
Endothelin-1-induced vasospasms of spiral modiolar artery are mediated by rho-kinase-induced Ca(2+) sensitization of contractile apparatus and reversed by calcitonin gene-related Peptide.
AuthorsScherer EQ, Herzog M, Wangemann P
JournalStroke
PubMed ID12468798
'BACKGROUND AND PURPOSE: Vasospasms of the spiral modiolar artery may cause an ischemic stroke of the inner ear that manifests itself by a sudden hearing loss. Previously we have shown that endothelin-1 (ET-1) induces vasospasms of the spiral modiolar artery. Here we tested the hypotheses that ET-1-induced vasospasms are (1) ... More
Calcium is a key signaling molecule in beta-lapachone-mediated cell death.
AuthorsTagliarino C, Pink JJ, Dubyak GR, Nieminen AL, Boothman DA
JournalJ Biol Chem
PubMed ID11279125
'beta-Lapachone (beta-Lap) triggers apoptosis in a number of human breast and prostate cancer cell lines through a unique apoptotic pathway that is dependent upon NQO1, a two-electron reductase. Downstream signaling pathway(s) that initiate apoptosis following treatment with beta-Lap have not been elucidated. Since calpain activation was suspected in beta-Lap-mediated apoptosis, ... More
Lipopolysaccharide improves cardiomyocyte survival and function after serum deprivation.
AuthorsChao W, Shen Y, Zhu X, Zhao H, Novikov M, Schmidt U, Rosenzweig A
JournalJ Biol Chem
PubMed ID15793310
'Toll-like receptor-4 (TLR4) and its signaling molecule interleukin-1 receptor-associated kinase (IRAK-1) play an important role in host defense and tissue inflammation. Intriguingly, systemic administration of lipopolysaccharide (LPS), the agonist for TLR4, confers a cardio-protective effect against ischemic injury. However, the mechanisms leading to the cardiac protection remain largely unknown. The ... More
The CatSper channel mediates progesterone-induced Ca2+ influx in human sperm.
AuthorsStrünker T, Goodwin N, Brenker C, Kashikar ND, Weyand I, Seifert R, Kaupp UB,
JournalNature
PubMed ID21412338
'In the oviduct, cumulus cells that surround the oocyte release progesterone. In human sperm, progesterone stimulates a Ca(2+) increase by a non-genomic mechanism. The Ca(2+) signal has been proposed to control chemotaxis, hyperactivation and acrosomal exocytosis of sperm. However, the underlying signalling mechanism has remained mysterious. Here we show that ... More
SparkMaster: automated calcium spark analysis with ImageJ.
AuthorsPicht E, Zima AV, Blatter LA, Bers DM,
JournalAm J Physiol Cell Physiol
PubMed ID17376815
'Ca sparks are elementary Ca-release events from intracellular Ca stores that are observed in virtually all types of muscle. Typically, Ca sparks are measured in the line-scan mode with confocal laser-scanning microscopes, yielding two-dimensional images (distance vs. time). The manual analysis of these images is time consuming and prone to ... More
Real-time analysis of the role of Ca(2+) in flagellar movement and motility in single sea urchin sperm.
AuthorsWood CD, Nishigaki T, Furuta T, Baba SA, Darszon A
JournalJ Cell Biol
PubMed ID15928204
'Eggs of many marine and mammalian species attract sperm by releasing chemoattractants that modify the bending properties of flagella to redirect sperm paths toward the egg. This process, called chemotaxis, is dependent on extracellular Ca(2+). We used stroboscopic fluorescence imaging to measure intracellular Ca(2+) concentration ([Ca(2+)]i) in the flagella of ... More
Activity-dependent long-term potentiation of intrinsic excitability in hippocampal CA1 pyramidal neurons.
AuthorsXu J, Kang N, Jiang L, Nedergaard M, Kang J
JournalJ Neurosci
PubMed ID15716411
'The efficiency of neural circuits is enhanced not only by increasing synaptic strength but also by increasing intrinsic excitability. In contrast to the detailed analysis of long-term potentiation (LTP), less attention has been given to activity-dependent changes in the intrinsic neuronal excitability. By stimulating hippocampal CA1 pyramidal neurons with synaptic ... More
Signaling pathways transduced through the elastin receptor facilitate proliferation of arterial smooth muscle cells.
AuthorsMochizuki S, Brassart B, Hinek A
JournalJ Biol Chem
PubMed ID12244048
'In this report we demonstrate that soluble peptides, elastin degradation products stimulate proliferation of arterial smooth muscle cells. We show that these effects are due to generation of intracellular signals transduced through the cell surface elastin receptor, which consists of peripheral 67-kDa elastin-binding protein (EBP) (spliced variant of beta-galactosidase), immobilized ... More
Cell-type specific calcium responses in acute rat hippocampal slices.
AuthorsDallwig R, Deitmer JW
JournalJ Neurosci Methods
PubMed ID12007985
'The identification of glial cells and neurons in brain slices is often difficult or uncertain. We have previously found that cultured rat cerebellar astrocytes and presumed astrocytes in acute brain slices, but not neurons, respond with cytosolic Ca(2+) transients following Ca(2+) influx in low external K+ concentrations (<1 mM; Cell ... More
All three ryanodine receptor isoforms generate rapid cooling responses in muscle cells.
AuthorsProtasi F, Shtifman A, Julian FJ, Allen PD
JournalAm J Physiol Cell Physiol
PubMed ID14592807
'The rapid cooling (RC) response in muscle is an increase in cytoplasmic Ca2+ concentration ([Ca2+]i) that is probably caused by Ca2+ release from the sarcoplasmic reticulum (SR). However, the molecular bases of this response have not been completely elucidated. Three different isoforms of the SR Ca2+ release channels, or ryanodine ... More
Agonist-induced calcium response in single human platelets assayed in a microfluidic device.
'To facilitate drug discovery directed toward platelet-specific targets, we developed a platelet isolation and fluorophore-loading method that yields functionally responsive platelets in which we were able to detect agonist-induced calcium flux using a microfluidics-based screening platform. The platelet preparation protocol was designed to minimize preparation-induced platelet activation and to optimize ... More
Calcium waves in agarose gel with cell organelles: implications of the velocity curvature relationship.
AuthorsWussling MH, Krannich K, Drygalla V, Podhaisky H
JournalBiophys J
PubMed ID11371442
'Calcium oscillations and waves have been observed not only in several types of living cells but also in less complex systems of isolated cell organelles. Here we report the determination of apparent Ca2+ diffusion coefficients in a novel excitable medium of agarose gel with homogeneously distributed vesicles of skeletal sarcoplasmic ... More
Opposing actions of inositol 1,4,5-trisphosphate and ryanodine receptors on nuclear factor of activated T-cells regulation in smooth muscle.
AuthorsGomez MF, Stevenson AS, Bonev AD, Hill-Eubanks DC, Nelson MT,
JournalJ Biol Chem
PubMed ID12145283
'The nuclear factor of activated T-cells (NFAT), originally identified in T-cells, has since been shown to play a role in mediating Ca(2+)-dependent gene transcription in diverse cell types outside of the immune system. We have previously shown that nuclear accumulation of NFATc3 is induced in ileal smooth muscle by platelet-derived ... More
AuthorsMetkar SS, Wang B, Catalan E, Anderluh G, Gilbert RJ, Pardo J, Froelich CJ,
JournalPLoS One
PubMed ID21931672
'The cytotoxic cell granule secretory pathway is essential for host defense. This pathway is fundamentally a form of intracellular protein delivery where granule proteases (granzymes) from cytotoxic lymphocytes are thought to diffuse through barrel stave pores generated in the plasma membrane of the target cell by the pore forming protein ... More
Prostaglandin E2 enhances osteoclastic differentiation of precursor cells through protein kinase A-dependent phosphorylation of TAK1.
AuthorsKobayashi Y, Mizoguchi T, Take I, Kurihara S, Udagawa N, Takahashi N
JournalJ Biol Chem
PubMed ID15647289
'Prostaglandin E2 (PGE2) synergistically enhances the receptor activator for NF-kappa B ligand (RANKL)-induced osteoclastic differentiation of the precursor cells. Here we investigated the mechanisms of the stimulatory effect of PGE2 on osteoclast differentiation. PGE2 enhanced osteoclastic differentiation of RAW264.7 cells in the presence of RANKL through EP2 and EP4 prostanoid ... More
Cardiac alternans do not rely on diastolic sarcoplasmic reticulum calcium content fluctuations.
AuthorsPicht E, DeSantiago J, Blatter LA, Bers DM,
JournalCirc Res
PubMed ID16946134
'Cardiac alternans are thought to be a precursor to life-threatening arrhythmias. Previous studies suggested that alterations in sarcoplasmic reticulum (SR) Ca2+ content are either causative or not associated with myocyte Ca2+ alternans. However, those studies used indirect measures of SR Ca2+. Here we used direct continuous measurement of intra-SR free ... More
Propagation of intercellular calcium waves in retinal astrocytes and Müller cells.
AuthorsNewman EA
JournalJ Neurosci
PubMed ID11264297
'Intercellular Ca(2+) waves are believed to propagate through networks of glial cells in culture in one of two ways: by diffusion of IP(3) between cells through gap junctions or by release of ATP, which functions as an extracellular messenger. Experiments were conducted to determine the mechanism of Ca(2+) wave propagation ... More
Group V phospholipase A2 induces leukotriene biosynthesis in human neutrophils through the activation of group IVA phospholipase A2.
AuthorsKim YJ, Kim KP, Han SK, Munoz NM, Zhu X, Sano H, Leff AR, Cho W
JournalJ Biol Chem
PubMed ID12124392
'We reported previously that exogenously added human group V phospholipase A(2) (hVPLA(2)) could elicit leukotriene B(4) (LTB(4)) biosynthesis in human neutrophils (Han, S. K., Kim, K. P., Koduri, R., Bittova, L., Munoz, N. M., Leff, A. R., Wilton, D. C., Gelb, M. H., and Cho, W. (1999) J. Biol. Chem. ... More
Analysis of calcium channels in single spines using optical fluctuation analysis.
AuthorsSabatini BL, Svoboda K
JournalNature
PubMed ID11117746
'Most synapses form on small, specialized postsynaptic structures known as dendritic spines. The influx of Ca2+ ions into such spines--through synaptic receptors and voltage-sensitive Ca2+ channels (VSCCs)--triggers diverse processes that underlie synaptic plasticity. Using two-photon laser scanning microscopy, we imaged action-potential-induced transient changes in Ca2+ concentration in spines and dendrites ... More
Performance of in-line microfluidic mixers in laminar flow for high-throughput flow cytometry.
AuthorsJackson WC, Bennett TA, Edwards BS, Prossnitz E, Lopez GP, Sklar LA
JournalBiotechniques
PubMed ID12139249
'We describe a micromixing approach that is compatible with commercial autosamplers, flow cytometry, and other detection schemes that require the mixing of components that have been introduced into laminarflow. The scheme is based on high-throughput flow cytometry (HyperCyt) where samples from multi-well plates that have been picked up by an ... More
Tissue engineering of vascularized cardiac muscle from human embryonic stem cells.
AuthorsCaspi O, Lesman A, Basevitch Y, Gepstein A, Arbel G, Habib IH, Gepstein L, Levenberg S
JournalCirc Res
PubMed ID17218605
'Transplantation of a tissue-engineered heart muscle represents a novel experimental therapeutic paradigm for myocardial diseases. However, this strategy has been hampered by the lack of sources for human cardiomyocytes and by the scarce vasculature in the ischemic area limiting the engraftment and survival of the transplanted muscle. Beyond the necessity ... More
Applications of cytotoxicity assays and pre-lethal mechanistic assays for assessment of human hepatotoxicity potential.
AuthorsXu JJ, Diaz D, O'Brien PJ
JournalChem Biol Interact
PubMed ID15522265
'While drug toxicity (especially hepatotoxicity) is the most frequent reason cited for withdrawal of an approved drug, no simple solution exists to adequately predict such adverse events. Simple cytotoxicity assays in HepG2 cells are relatively insensitive to human hepatotoxic drugs in a retrospective analysis of marketed pharmaceuticals. In comparison, a ... More
Cytotoxic T lymphocytes kill multiple targets simultaneously via spatiotemporal uncoupling of lytic and stimulatory synapses.
AuthorsWiedemann A, Depoil D, Faroudi M, Valitutti S
JournalProc Natl Acad Sci U S A
PubMed ID16832064
'A longstanding paradox in the activation of cytotoxic T lymphocytes (CTL) arises from the observation that CTL recognize and rapidly destroy target cells with exquisite sensitivity despite the fact that cytokine production requires sustained signaling at the immunological synapse. Here we solve this paradox by showing that CTL establish sustained ... More
P2X7 mediates superoxide production in primary microglia and is up-regulated in a transgenic mouse model of Alzheimer's disease.
AuthorsParvathenani LK, Tertyshnikova S, Greco CR, Roberts SB, Robertson B, Posmantur R
JournalJ Biol Chem
PubMed ID12551918
'Primary rat microglia stimulated with either ATP or 2''- and 3''-O-(4-benzoylbenzoyl)-ATP (BzATP) release copious amounts of superoxide (O(2)(-)*). ATP and BzATP stimulate O(2)(-)* production through purinergic receptors, primarily the P2X(7) receptor. O(2)(-)* is produced through the activation of the NADPH oxidase. Although both p42/44 MAPK and p38 MAPK were activated ... More
Reactive oxygen species mediate the potentiating effects of ATP on GABAergic synaptic transmission in the immature hippocampus.
AuthorsSafiulina VF, Afzalov R, Khiroug L, Cherubini E, Giniatullin R
JournalJ Biol Chem
PubMed ID16787924
'Reactive oxygen species (ROS) constitute important signaling molecules in the central nervous system. They regulate a number of different functions both under physiological conditions and under pathological conditions. Here we tested the hypothesis that in the immature hippocampus ATP, the most diffuse neurotransmitter in the brain, modulates synaptic transmission via ... More
An initial and rapid step of lytic granule secretion precedes microtubule organizing center polarization at the cytotoxic T lymphocyte/target cell synapse.
'It is presently assumed that lethal hit delivery by cytotoxic T lymphocytes (CTLs) is mechanistically linked to centrosome polarization toward target cells, leading to dedicated release of lytic granules within a confined secretory domain. Here we provide three lines of evidence showing that this mechanism might not apply as a ... More
Glial cell inhibition of neurons by release of ATP.
AuthorsNewman EA
JournalJ Neurosci
PubMed ID12629170
'ATP is released by neurons and functions as a neurotransmitter and modulator in the CNS. Here I show that ATP released from glial cells can also serve as a potent neuromodulator, inhibiting neurons in the retina of the rat. Activation of glial cells by focal ejection of ATP, ATPgammaS, dopamine, ... More
Cross-tolerance to otherwise lethal N-methyl-D-aspartate and oxygen-glucose deprivation in preconditioned cortical cultures.
AuthorsTauskela JS, Comas T, Hewitt K, Monette R, Paris J, Hogan M, Morley P
JournalNeuroscience
PubMed ID11720781
'In vitro ischemic preconditioning induced by subjecting rat cortical cultures to nonlethal oxygen-glucose deprivation protects against a subsequent exposure to otherwise lethal oxygen-glucose deprivation. We provide evidence that attenuation of the postsynaptic N-methyl-D-aspartate (NMDA) receptor- and Ca(2+)-dependent neurotoxicity underlies oxygen-glucose deprivation tolerance. It is demonstrated that extended tolerance to otherwise ... More
Calicum microdomains form within neutrophils at the neutrophil-tumor cell synapse: role in antibody-dependent target cell apoptosis.
AuthorsClark AJ, Diamond M, Elfline M, Petty HR,
JournalCancer Immunol Immunother
PubMed ID19593564
'Ca(2+) messages are broadly important in cellular signal transduction. In immune cells, Ca(2+) signaling is an essential step in many forms of activation. Neutrophil-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) is one form of leukocyte activation that plays an important role in tumor cell killing in vitro and in patient care. Using ... More
A truncated P2X7 receptor variant (P2X7-j) endogenously expressed in cervical cancer cells antagonizes the full-length P2X7 receptor through hetero-oligomerization.
AuthorsFeng YH, Li X, Wang L, Zhou L, Gorodeski GI
JournalJ Biol Chem
PubMed ID16624800
'A truncated naturally occurring variant of the human receptor P2X7 was identified in cancer cervical cells. The novel protein (P2X7-j), a polypeptide of 258 amino acids, lacks the entire intracellular carboxyl terminus, the second transmembrane domain, and the distal third of the extracellular loop of the full-length P2X7 receptor. The ... More
Ca2+ sparks are initiated by Ca2+ entry in embryonic mouse skeletal muscle and decrease in frequency postnatally.
AuthorsChun LG, Ward CW, Schneider MF
JournalAm J Physiol Cell Physiol
PubMed ID12724135
'"Spontaneous" Ca2+ sparks and ryanodine receptor type 3 (RyR3) expression are readily detected in embryonic mammalian skeletal muscle but not in adult mammalian muscle, which rarely exhibits Ca2+ sparks and expresses predominantly RyR1. We have used confocal fluorescence imaging and systematic sampling of enzymatically dissociated single striated muscle fibers containing ... More
Muscarinic receptors control K+ secretion in inner ear strial marginal cells.
AuthorsWangemann P, Liu J, Scherer EQ, Herzog M, Shimozono M, Scofield MA
JournalJ Membr Biol
PubMed ID11547340
'K+ secretion in strial marginal cells (SMC) of stria vascularis (SV) is stimulated by beta1-adrenergic receptors. The aim of the present study was to determine, whether SMC from the gerbil inner ear contain muscarinic receptors that inhibit K+ secretion. Receptors were identified with pharmacological tools in functional studies where K+ ... 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
Contributions of Ca2+ to galectin-1-induced exposure of phosphatidylserine on activated neutrophils.
AuthorsKarmakar S, Cummings RD, McEver RP
JournalJ Biol Chem
PubMed ID15929990
'Apoptotic cells redistribute phosphatidylserine (PS) to the cell surface by both Ca(2+)-dependent and -independent mechanisms. Binding of dimeric galectin-1 (dGal-1) to glycoconjugates on N-formyl-Met-Leu-Phe (fMLP)-activated neutrophils exposes PS and facilitates neutrophil phagocytosis by macrophages, yet it does not initiate apoptosis. We asked whether dGal-1 initiated Ca(2+) fluxes that are required ... More
Zinc is a novel intracellular second messenger.
AuthorsYamasaki S, Sakata-Sogawa K, Hasegawa A, Suzuki T, Kabu K, Sato E, Kurosaki T, Yamashita S, Tokunaga M, Nishida K, Hirano T
JournalJ Cell Biol
PubMed ID17502426
'Zinc is an essential trace element required for enzymatic activity and for maintaining the conformation of many transcription factors; thus, zinc homeostasis is tightly regulated. Although zinc affects several signaling molecules and may act as a neurotransmitter, it remains unknown whether zinc acts as an intracellular second messenger capable of ... More
Purine receptors and Ca(2+) signalling in the human blood-brain barrier endothelial cell line hCMEC/D3.
AuthorsBintig W, Begandt D, Schlingmann B, Gerhard L, Pangalos M, Dreyer L, Hohnjec N, Couraud PO, Romero IA, Weksler BB, Ngezahayo A,
JournalPurinergic Signal
PubMed ID21956217
'The expression and physiology of purine receptors of the human blood-brain barrier endothelial cells were characterised by application of molecular biological, gene-silencing and Ca(2+)-imaging techniques to hCMEC/D3 cells. Reverse transcription polymerase chain reaction showed the expression of the G-protein-coupled receptors P2Y(2)-, P2Y(6)-, P2Y(11)- as well as the ionotropic P2X(4)-, P2X(5)- ... More
PDGF-induced coupling of function with metabolism in microvascular pericytes of the retina.
AuthorsSakagami K, Kodama T, Puro DG
JournalInvest Ophthalmol Vis Sci
PubMed ID11431464
'PURPOSE. The aim of this study was to test the hypothesis that platelet-derived growth factor (PDGF)-BB regulates the physiology of retinal pericytes, which are contractile cells located on the abluminal surface of capillaries. The expression of PDGF-BB and its cognate receptor in retinal vessels suggests a vasoactive function. However, although ... More
Trogocytosis by Entamoeba histolytica contributes to cell killing and tissue invasion.
AuthorsRalston KS, Solga MD, Mackey-Lawrence NM, Somlata, Bhattacharya A, Petri WA,
Journal
PubMed ID24717428
'Entamoeba histolytica is the causative agent of amoebiasis, a potentially fatal diarrhoeal disease in the developing world. The parasite was named '
Purinergic and muscarinic modulation of the cell cycle and calcium signaling in the chick retinal ventricular zone.
AuthorsPearson R, Catsicas M, Becker D, Mobbs P
JournalJ Neurosci
PubMed ID12196580
'Spontaneous calcium transients occur in the ventricular zone of the chick retina and result from the endogenous release of neurotransmitters in the absence of action potentials. Calcium transients resulting from the activation of purinergic and muscarinic receptors occur in a mixed population of interphase and mitotic cells, whereas those produced ... More
Altering the speract-induced ion permeability changes that generate flagellar Ca2+ spikes regulates their kinetics and sea urchin sperm motility.
AuthorsWood CD, Nishigaki T, Tatsu Y, Yumoto N, Baba SA, Whitaker M, Darszon A
JournalDev Biol
PubMed ID17467684
'Speract, an egg-derived sperm-activating peptide, induces changes in intracellular Ca2+, Na+, pH, cAMP, cGMP, and membrane potential in sperm of the sea urchin Strongylocentrotus purpuratus. Ca2+ is a key regulator of motility in all sperm and, in many marine species, is required for generating turns interspersed with straighter swimming paths ... More
Synthesis and structure-activity relationships of 3,8-diazabicyclo[4.2.0]octane ligands, potent nicotinic acetylcholine receptor agonists.
AuthorsFrost JM, Bunnelle WH, Tietje KR, Anderson DJ, Rueter LE, Curzon P, Surowy CS, Ji J, Daanen JF, Kohlhaas KL, Buckley MJ, Henry RF, Dyhring T, Ahring PK, Meyer MD
JournalJ Med Chem
PubMed ID17181167
'A series of potent neuronal nicotinic acetylcholine receptor (nAChR) ligands based on a 3,8-diazabicyclo[4.2.0]octane core have been synthesized and evaluated for affinity and agonist efficacy at the human high affinity nicotine recognition site (halpha4beta2) and in a rat model of persistent nociceptive pain (formalin model). Numerous analogs in this series ... More
Physiological study of interstitial cells of Cajal identified by vital staining.
AuthorsRich A, Hanani M, Ermilov LG, Malysz J, Belzer V, Szurszewski JH, Farrugia G
JournalNeurogastroenterol Motil
PubMed ID11975719
'Interstitial cells of Cajal (ICC) form networks that intercalate between the enteric nervous system and smooth muscle cells and play a fundamental role in the control of gastrointestinal motility by initiating rhythmic electrical activity. In this report, we used a method to examine the physiological and morphological properties of ICC ... More
Proton-mediated feedback inhibition of presynaptic calcium channels at the cone photoreceptor synapse.
AuthorsVessey JP, Stratis AK, Daniels BA, Da Silva N, Jonz MG, Lalonde MR, Baldridge WH, Barnes S
JournalJ Neurosci
PubMed ID15843613
'Generation of center-surround antagonistic receptive fields in the outer retina occurs via inhibitory feedback modulation of presynaptic voltage-gated calcium channels in cone photoreceptor synaptic terminals. Both conventional and unconventional neurotransmitters, as well as an ephaptic effect, have been proposed, but the intercellular messaging that mediates the inhibitory feedback signal from ... More
Bending the MDCK cell primary cilium increases intracellular calcium.
AuthorsPraetorius HA, Spring KR
JournalJ Membr Biol
PubMed ID11687880
'We tested the hypothesis that the primary cilium of renal epithelia is mechanically sensitive and serves as a flow sensor in MDCK cells using differential interference contrast and fluorescence microscopy. Bending the cilium, either by suction with a micropipette or by increasing the flow rate of perfusate, causes intracellular calcium ... More
The spatial distribution of inositol 1,4,5-trisphosphate receptor isoforms shapes Ca2+ waves.
AuthorsHernandez E, Leite MF, Guerra MT, Kruglov EA, Bruna-Romero O, Rodrigues MA, Gomes DA, Giordano FJ, Dranoff JA, Nathanson MH
JournalJ Biol Chem
PubMed ID17284437
'Cytosolic Ca(2+) is a versatile second messenger that can regulate multiple cellular processes simultaneously. This is accomplished in part through Ca(2+) waves and other spatial patterns of Ca(2+) signals. To investigate the mechanism responsible for the formation of Ca(2+) waves, we examined the role of inositol 1,4,5-trisphosphate receptor (InsP3R) isoforms ... More
Beta 1-subunits are required for regulation of coupling between Ca2+ transients and Ca2+-activated K+ (BK) channels by protein kinase C.
AuthorsHagen BM, Bayguinov O, Sanders KM
JournalAm J Physiol Cell Physiol
PubMed ID12867357
'Colonic myocytes have spontaneous, localized, Ins (1,4,5) trisphosphate (IP3) receptor-dependent Ca2+ transients that couple to the activation of Ca2+-dependent K+ channels and spontaneous transient outward currents (STOCs). We previously reported that the coupling strength between spontaneous Ca2+ transients and large conductance Ca2+ activated K+ (BK) channels is regulated by Ca2+ ... More