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
Weak effect of neuromodulators on climbing fiber-activated [Ca(2+)](i) increases in rat cerebellar Purkinje neurons.
AuthorsPisani A, Ross WN
JournalBrain Res
PubMed ID10411989
'The effect of several neuromodulators (carbachol (CCh), serotonin (5-HT), noradrenaline (NE), and dopamine (DA)) on the climbing fiber (CF)-induced [Ca(2+)](i) increase in the dendrites of cerebellar Purkinje cells was examined in slices from the rat cerebellum. Purkinje cells were filled with the Ca(2+) indicator bis-fura-2 with patch electrodes on the ... More
Electrophysiological recordings and calcium measurements in striatal large aspiny interneurons in response to combined O2/glucose deprivation.
AuthorsPisani A, Calabresi P, Centonze D, Marfia GA, Bernardi G
JournalJ Neurophysiol
PubMed ID10322086
'Electrophysiological recordings and calcium measurements in striatal large aspiny interneurons in response to combined O2/glucose deprivation. The effects of combined O2/glucose deprivation were investigated on large aspiny (LA) interneurons recorded from a striatal slice preparation by means of simultaneous electrophysiological and optical recordings. LA interneurons were visually identified and impaled ... More
The role of mitochondria in presynaptic calcium handling at a ribbon synapse.
AuthorsZenisek D, Matthews G
JournalNeuron
PubMed ID10707986
'Mitochondria are thought to be important in clearing calcium from synaptic terminals. It is unclear, however, whether the principal role of mitochondria in pre-synaptic calcium handling is to take up Ca2+ directly or to fuel Ca2+ removal by other mechanisms. We used patch clamp techniques and fluorescence imaging to examine ... More
Dissociation of force decline from calcium decline by preload in isolated rabbit myocardium.
AuthorsMonasky MM, Varian KD, Davis JP, Janssen PM,
JournalPflugers Arch
PubMed ID18057959
It is well known that the rate of intracellular calcium ([Ca2+]i) decline is an important factor governing relaxation in unloaded myocardium. However, it remains unclear to what extent, under near physiological conditions, the intracellular calcium transient amplitude and kinetics contribute to the length-dependent increase in force and increase in duration ... More
Increased phosphorylation of tropomyosin, troponin I, and myosin light chain-2 after stretch in rabbit ventricular myocardium under physiological conditions.
AuthorsMonasky MM, Biesiadecki BJ, Janssen PM,
JournalJ Mol Cell Cardiol
PubMed ID20298699
After a change in muscle length, there is an immediate intrinsic response in the amount of developed force, followed by a slower response. Although it has been well documented that the slow force response is at least in part generated by modification of calcium handling, it is unclear whether regulation ... More
Synergistic release of Ca2+ from IP3-sensitive stores evoked by synaptic activation of mGluRs paired with backpropagating action potentials.
AuthorsNakamura T, Barbara JG, Nakamura K, Ross WN
JournalNeuron
PubMed ID10595522
Increases in postsynaptic [Ca2+]i can result from Ca2+ entry through ligand-gated channels or voltage-gated Ca2+ channels, or through release from intracellular stores. Most attention has focused on entry through the N-methyl-D-aspartate (NMDA) receptor in causing [Ca2+]i increases since this pathway requires both presynaptic stimulation and postsynaptic depolarization, making it a ... More
Transfer of visual motion information via graded synapses operates linearly in the natural activity range.
AuthorsKurtz R, Warzecha AK, Egelhaaf M
JournalJ Neurosci
PubMed ID11517283
Synaptic transmission between a graded potential neuron and a spiking neuron was investigated in vivo using sensory stimulation instead of artificial excitation of the presynaptic neuron. During visual motion stimulation, individual presynaptic and postsynaptic neurons in the brain of the fly were electrophysiologically recorded together with concentration changes of presynaptic ... More
Calexcitin interaction with neuronal ryanodine receptors.
Calexcitin (CE), a Ca2+- and GTP-binding protein, which is phosphorylated during memory consolidation, is shown here to co-purify with ryanodine receptors (RyRs) and bind to RyRs in a calcium-dependent manner. Nanomolar concentrations of CE released up to 46% of the 45Ca label from microsomes preloaded with 45CaCl2. This release was ... More
T-jump study of calcium binding kinetics of calcium chelators.
AuthorsNaraghi M
JournalCell Calcium
PubMed ID9481476
Recent experimental studies have investigated the kinetic competition between calcium chelators and the secretion apparatus at a fast central synapse. Simultaneously, mathematical modelling studies indicate the importance of a quantitative knowledge of the binding kinetics of the chelators in studying fast physiological processes operating on a millisecond time scale. Using ... More
Serotonin modulates spike backpropagation and associated [Ca2+]i changes in the apical dendrites of hippocampal CA1 pyramidal neurons.
AuthorsSandler VM, Ross WN
JournalJ Neurophysiol
PubMed ID9914282
The effect of serotonin (5-HT) on somatic and dendritic properties was analyzed in pyramidal neurons from the CA1 region in slices from the rat hippocampus. Bath-applied 5-HT (10 microM) hyperpolarized the soma and apical dendrites and caused a conductance increase at both locations. In the dendrites (200-300 microm from the ... More
Effect of CGP 36742 on the extracellular level of neurotransmitter amino acids in the thalamus.
AuthorsNyitrai G, Szárics E, Kovács I, Kékesi KA, Juhász G, Kardos J
JournalNeurochem Int
PubMed ID10397367
We have evaluated the effect of the brain penetrating GABAb antagonist, CGP 36742 on GABAb receptors using in vivo microdialysis in the ventrobasal thalamus of freely moving rat. When a solution of 1 mM CGP 36742 in ACSF was dialyzed into the ventrobasal thalamus, 2-3-fold increases of extracellular Glu, Asp ... More
Ryanodine-sensitive stores regulate the excitability of AH neurons in the myenteric plexus of guinea-pig ileum.
AuthorsHillsley K, Kenyon JL, Smith TK
JournalJ Neurophysiol
PubMed ID11110808
Myenteric afterhyperpolarizing (AH) neurons are primary afferent neurons within the gastrointestinal tract. Stimulation of the intestinal mucosa evokes action potentials (AP) that are followed by a slow afterhyperpolarization (AHP(slow)) in the soma. The role of intracellular Ca(2+) ([Ca(2+)](i)) and ryanodine-sensitive Ca(2+) stores in modulating the electrical activity of myenteric AH ... More
Estradiol increases spine density and NMDA-dependent Ca2+ transients in spines of CA1 pyramidal neurons from hippocampal slices.
AuthorsPozzo-Miller LD, Inoue T, Murphy DD
JournalJ Neurophysiol
PubMed ID10085365
To investigate the physiological consequences of the increase in spine density induced by estradiol in pyramidal neurons of the hippocampus, we performed simultaneous whole cell recordings and Ca2+ imaging in CA1 neuron spines and dendrites in hippocampal slices. Four- to eight-days in vitro slice cultures were exposed to 17beta-estradiol (EST) ... More
Two-dimensional determination of the cellular Ca2+ binding in bovine chromaffin cells.
AuthorsNaraghi M, Müller TH, Neher E
JournalBiophys J
PubMed ID9746506
The spatiotemporal profile of intracellular calcium signals is determined by the flux of calcium ions across different biological membranes as well as by the diffusional mobility of calcium and different calcium buffers in the cell. To arrive at a quantitative understanding of the determinants of these signals, one needs to ... More
Exocytosis and endocytosis of small vesicles in PC12 cells studied with TEPIQ (two-photon extracellular polar-tracer imaging-based quantification) analysis.
AuthorsLiu TT, Kishimoto T, Hatakeyama H, Nemoto T, Takahashi N, Kasai H
JournalJ Physiol
PubMed ID16150796
We investigated exocytosis of PC12 cells using two-photon excitation imaging and extracellular polar tracers (TEP imaging) in the lateral membranes not facing the glass-cover slip. Upon photolysis of a caged Ca2+ compound, TEP imaging with FM1-43 (a polar membrane tracer) detected massive exocytosis of vesicles with a time constant of ... More
Role of intracellular Ca(2+) stores shaping normal activity in brain.
AuthorsNyitrai G, Kovács I, Szárics E, Skuban N, Juhász G, Kardos J
JournalJ Neurosci Res
PubMed ID10467262
The role of intracellular Ca(2+) stores in the control of brain activity was investigated in microdialysis experiments by monitoring changes in the extracellular concentration of amino acids (AA) in the hippocampus of the rat after intracerebroventricular (icv) administration of the intracellular Ca(2+) release blocker, dantrolene in vivo, as well as ... More
Early and simultaneous emergence of multiple hippocampal biomarkers of aging is mediated by Ca2+-induced Ca2+ release.
AuthorsGant JC, Sama MM, Landfield PW, Thibault O
JournalJ Neurosci
PubMed ID16571755
Age-dependent changes in multiple Ca2+-related electrophysiological processes in the hippocampus appear to be consistent biomarkers of aging, and several also correlate with cognitive decline. These findings have led to the hypothesis that a common mechanism of Ca2+ dyshomeostasis underlies aspects of aging-dependent brain impairment. However, some key predictions of this ... More
Frequency-dependent acceleration of relaxation involves decreased myofilament calcium sensitivity.
AuthorsVarian KD, Janssen PM
JournalAm J Physiol Heart Circ Physiol
PubMed ID17209002
The force-frequency relationship is an intrinsic modulator of cardiac contractility and relaxation. Force of contraction increases with frequency, while simultaneously a frequency-dependent acceleration of relaxation occurs. While frequency dependency of calcium handling and sarcoplasmic reticulum calcium load have been well described, it remains unknown whether frequency-dependent changes in myofilament calcium ... More