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Astrocytes generate local calcium (Ca(2+)) signals that are thought to regulate their functions. Visualization of these signals in the intact brain requires an imaging method with high spatiotemporal resolution. Here, we describe such a method using transgenic mice expressing the ultrasensitive ratiometric Ca(2+) indicator yellow Cameleon-Nano 50(More)
The endoplasmic reticulum (ER) and mitochondria accumulate Ca(2+) within their lumens to regulate numerous cell functions. However, determining the dynamics of intraorganellar Ca(2+) has proven to be difficult. Here we describe a family of genetically encoded Ca(2+) indicators, named calcium-measuring organelle-entrapped protein indicators (CEPIA), which(More)
IP(3) signaling in Purkinje cells is involved in the regulation of cell functions including LTD. We have used a GFP-tagged pleckstrin homology domain to visualize IP(3) dynamics in Purkinje cells. Surprisingly, IP(3) production was observed in response not only to mGluR activation, but also to AMPA receptor activation in Purkinje cells in culture.(More)
Glutamate is the major neurotransmitter in the brain, mediating point-to-point transmission across the synaptic cleft in excitatory synapses. Using a glutamate imaging method with fluorescent indicators, we show that synaptic activity generates extrasynaptic glutamate dynamics in the vicinity of active synapses. These glutamate dynamics had magnitudes and(More)
In many excitatory glutamatergic synapses, both ionotropic glutamate receptors (iGluRs) and metabotropic glutamate receptors (mGluRs) are closely distributed on the postsynaptic membrane. However, the functional significance of the close distribution of the two types of glutamate receptors has not been fully clarified. In this study, we examined the(More)
Brain injury induces phenotypic changes in astrocytes, known as reactive astrogliosis, which may influence neuronal survival. Here we show that brain injury induces inositol 1,4,5-trisphosphate (IP3)-dependent Ca(2+) signaling in astrocytes, and that the Ca(2+) signaling is required for astrogliosis. We found that type 2 IP3 receptor knockout (IP3R2KO) mice(More)
The maintenance of synaptic functions is essential for neuronal information processing, but cellular mechanisms that maintain synapses in the adult brain are not well understood. Here, we report an activity-dependent maintenance mechanism of parallel fiber (PF)-Purkinje cell (PC) synapses in the cerebellum. When postsynaptic metabotropic glutamate receptor(More)
Astrocytes play a pivotal role in the regulation of neurite growth, but the intracellular signaling mechanism in astrocytes that mediates this regulation remains unclarified. We studied the relationship between spontaneous Ca(2+) oscillations in astrocytes and the astrocyte-mediated neurite growth. We generated Ca(2+) signal-deficient astrocytes in which(More)
Genetically identical cells in a uniform external environment can exhibit different phenotypes, which are often masked by conventional measurements that average over cell populations. Although most studies on this topic have used microorganisms, differentiated mammalian cells have rarely been explored. Here, we report that only approximately 40% of clonal(More)
Intracellular Ca(2+) signaling, and related mechanisms involving inositol 1,4,5-trisphosphate (IP(3)), nitric oxide, and the excitatory neurotransmitter glutamate, play a major role in the regulation of cellular function in the brain. Due to the complex morphology of central neurons, the correct spatiotemporal distribution of signaling molecules is(More)