Journal ArticleDOI
Local Ca2+ detection and modulation of synaptic release by astrocytes
Maria Amalia Di Castro,Julien Chuquet,Nicolas Liaudet,Khaleel Bhaukaurally,Mirko Santello,David Bouvier,Pascale Tiret,Andrea Volterra +7 more
TLDR
Evidence is provided that astrocytes are integrated in local synaptic functioning in adult brain through GTP- and inositol-1,4,5-trisphosphate–dependent signaling and is relevant for basal synaptic function.Abstract:
Astrocytes communicate with synapses by means of intracellular calcium ([Ca(2+)](i)) elevations, but local calcium dynamics in astrocytic processes have never been thoroughly investigated. By taking advantage of high-resolution two-photon microscopy, we identify the characteristics of local astrocyte calcium activity in the adult mouse hippocampus. Astrocytic processes showed intense activity, triggered by physiological transmission at neighboring synapses. They encoded synchronous synaptic events generated by sparse action potentials into robust regional (∼12 μm) [Ca(2+)](i) elevations. Unexpectedly, they also sensed spontaneous synaptic events, producing highly confined (∼4 μm), fast (millisecond-scale) miniature Ca(2+) responses. This Ca(2+) activity in astrocytic processes is generated through GTP- and inositol-1,4,5-trisphosphate-dependent signaling and is relevant for basal synaptic function. Thus, buffering astrocyte [Ca(2+)](i) or blocking a receptor mediating local astrocyte Ca(2+) signals decreased synaptic transmission reliability in minimal stimulation experiments. These data provide direct evidence that astrocytes are integrated in local synaptic functioning in adult brain.read more
Citations
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Journal ArticleDOI
Disruption in Connexin-Based Communication Is Associated with Intracellular Ca2+ Signal Alterations in Astrocytes from Niemann-Pick Type C Mice
Pablo J. Sáez,Juan A. Orellana,Natalia Vega-Riveros,Vania Figueroa,Vania Figueroa,Diego Hernández,Juan Francisco Castro,Andrés D. Klein,Jean X. Jiang,Silvana Zanlungo,Juan C. Sáez,Juan C. Sáez +11 more
TL;DR: Npc1−/− astrocytes present features of connexin based channels compatible with those of reactive astroCytes and hemichannels that might be a novel therapeutic target to reduce neuroinflammation in NPC disease.
Journal ArticleDOI
Pro-maturational Effects of Human iPSC-Derived Cortical Astrocytes upon iPSC-Derived Cortical Neurons.
Anne Hedegaard,Jimena Monzón-Sandoval,Sarah E. Newey,Emma S. Whiteley,Caleb Webber,Caleb Webber,Colin J. Akerman +6 more
TL;DR: Interactions between human astrocytes and neurons derived from a common cortical progenitor pool are examined, thereby recapitulating aspects of in vivo cortical development and laying the foundation for future investigations intoAstrocyte-to-neuron interactions in human health and disease.
Journal ArticleDOI
More than just summed neuronal activity: how multiple cell types shape the BOLD response
TL;DR: The contributions of each cell type to the regulation of cerebral blood flow and metabolism are reviewed, and situations where a simplified interpretation of the BOLD response as reporting local excitatory activity may misrepresent important biological phenomena are discussed.
Journal ArticleDOI
NMDA receptor activation: two targets for two co-agonists.
TL;DR: How the spatial distribution of co-agonist sources and uptake mechanisms, together with diffusional properties of the synaptic environment, could shape NMDAR co-agonists supply and therefore NMDar-dependent plasticity is discussed.
Journal ArticleDOI
Astrocyte calcium microdomains are inhibited by bafilomycin A1 and cannot be replicated by low-level Schaffer collateral stimulation in situ.
Min-Yu Sun,Prakash Devaraju,Alison X. Xie,Isabelle Holman,Emmelyn Samones,Thomas R. Murphy,Todd A. Fiacco +6 more
TL;DR: The findings suggest that spontaneous microdomain astrocyte Ca(2+) elevations are not driven by neuronal action potentials but require quantal release of neurotransmitter which cannot be replicated by stimulation of Schaffer collaterals.
References
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Journal ArticleDOI
Tripartite synapses: astrocytes process and control synaptic information
TL;DR: There is an emerging view, which is reviewed herein, in which brain function actually arises from the coordinated activity of a network comprising both neurons and glia, rather than the classically accepted paradigm that brain function results exclusively from neuronal activity.
Journal ArticleDOI
Control of synapse number by glia.
TL;DR: It is shown that few synapses form in the absence of glial cells and that the fewsynapses that do form are functionally immature, and that CNS synapse number can be profoundly regulated by nonneuronal signals.
Journal ArticleDOI
Long-term potentiation depends on release of d -serine from astrocytes
Christian Henneberger,Thomas Papouin,Thomas Papouin,Stéphane H. R. Oliet,Stéphane H. R. Oliet,Dmitri A. Rusakov +5 more
TL;DR: It is demonstrated that Ca2+-dependent release of d-serine from an astrocyte controls NMDAR-dependent plasticity in many thousands of excitatory synapses nearby.
Journal ArticleDOI
Definition of the Readily Releasable Pool of Vesicles at Hippocampal Synapses
TL;DR: It is found that hypertonic solutions do not act through changes in intracellular calcium, which means that the synaptic release probability depends on the size of the readily releasable pool.
Journal ArticleDOI
Neuronal Synchrony Mediated by Astrocytic Glutamate through Activation of Extrasynaptic NMDA Receptors
TL;DR: The results reveal a distinct mechanism for neuronal excitation and synchrony and highlight a functional link between astrocytic glutamate and extrasynaptic NMDA receptors.