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
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Disk-shaped amperometric enzymatic biosensor for in vivo detection of D-serine.
David Polcari,Annie Kwan,Marion R. Van Horn,Laurence Danis,Loredano Pollegioni,Edward S. Ruthazer,Janine Mauzeroll +6 more
TL;DR: The development of a disk-shaped amperometric enzymatic biosensor for detection of D-serine based on a 25 μm diameter platinum disk microelectrode with an electrodeposited poly-m-phenylenediamine (PPD) layer and an R. gracilis D-amino acid oxidase (RgDAAO) layer is reported.
Journal ArticleDOI
Confocal microscopy for astrocyte in vivo imaging: Recycle and reuse in microscopy.
TL;DR: The surgical procedure and experimental setup that allowed us to record intracellular calcium variations in astrocytes evoked by sensory stimulation, and to monitor intact neuronal dendritic spines andAstrocytic processes as well as blood vessel dynamics, constitute a useful, convenient, and affordable tool for brain studies in vivo.
Journal ArticleDOI
Specific and behaviorally consequential astrocyte Gq GPCR signaling attenuation in vivo with iβARK.
Jun Nagai,Arash Bellafard,Zhe Qu,Xinzhu Yu,Xinzhu Yu,Matthias Ollivier,Mohitkumar R. Gangwani,Blanca Diaz-Castro,Giovanni Coppola,Giovanni Coppola,Sarah M. Schumacher,Peyman Golshani,Viviana Gradinaru,Baljit S. Khakh +13 more
TL;DR: In this paper, a 122-residue inhibitory peptide from β-adrenergic receptor kinase 1 (iβARK; and inactive D110A control) was used to attenuate astrocyte G-protein-coupled receptors (GPCRs) signaling.
Journal ArticleDOI
Local Resting Ca2+ Controls the Scale of Astroglial Ca2+ Signals.
Claire King,Kirsten Bohmbach,Daniel Minge,Andrea Delekate,Kaiyu Zheng,James P. Reynolds,Cordula Rakers,Andre Zeug,Gabor C. Petzold,Gabor C. Petzold,Dmitri A. Rusakov,Christian Henneberger,Christian Henneberger,Christian Henneberger +13 more
TL;DR: This work employs time-resolved two-photon excitation fluorescence imaging in acute hippocampal slices and in cortex in vivo to find that resting [Ca2+] predicts the scale (amplitude) and the maximum (peak) of astroglial Ca2+ elevations, uncovering a basic generic rule of Ca 2+ signal formation in astrocytes.
Journal ArticleDOI
Astroglial Ca2+-Dependent Hyperexcitability Requires P2Y1 Purinergic Receptors and Pannexin-1 Channel Activation in a Chronic Model of Epilepsy.
Mario Wellmann,Carla Álvarez-Ferradas,Carla Álvarez-Ferradas,Carola J. Maturana,Juan C. Sáez,Juan C. Sáez,Christian Bonansco +6 more
TL;DR: It is suggested that P2Y1R and Panx1 HCs play a pivotal role in astroglial pathophysiology, which would explain the upregulation of glutamatergic neurotransmission in the epileptic brain and thus represents a new potential pharmacological target for the treatment of drug-refractory epilepsy.
References
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Journal ArticleDOI
Tripartite synapses: astrocytes process and control synaptic information
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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.