Subcellular location of astrocytic calcium stores favors extrasynaptic neuron–astrocyte communication

Patrushev, Ilya; Gavrilov, Nikolay; Турлапов, Вадим; Semyanov, Alexey

doi:10.1016/j.ceca.2013.08.003

Cited by 111 publications

(134 citation statements)

References 45 publications

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“…The tissue volume fraction (VF) occupied by astroglial processes in the hippocampal neuropil ranges between 5 and 10% 26,29,32,33 . The VF distribution provides a key descriptor of astroglial morphology because individual astrocytes occupy adjacent tissue domains with little overlap while their processes fill the volume in a sponge-like manner 23,34 .…”

Section: Resultsmentioning

confidence: 99%

Disentangling astroglial physiology with a realistic cell model in silico

et al. 2018

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Electrically non-excitable astroglia take up neurotransmitters, buffer extracellular K+ and generate Ca2+ signals that release molecular regulators of neural circuitry. The underlying machinery remains enigmatic, mainly because the sponge-like astrocyte morphology has been difficult to access experimentally or explore theoretically. Here, we systematically incorporate multi-scale, tri-dimensional astroglial architecture into a realistic multi-compartmental cell model, which we constrain by empirical tests and integrate into the NEURON computational biophysical environment. This approach is implemented as a flexible astrocyte-model builder ASTRO. As a proof-of-concept, we explore an in silico astrocyte to evaluate basic cell physiology features inaccessible experimentally. Our simulations suggest that currents generated by glutamate transporters or K+ channels have negligible distant effects on membrane voltage and that individual astrocytes can successfully handle extracellular K+ hotspots. We show how intracellular Ca2+ buffers affect Ca2+ waves and why the classical Ca2+ sparks-and-puffs mechanism is theoretically compatible with common readouts of astroglial Ca2+ imaging.

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Section: Resultsmentioning

confidence: 99%

Disentangling astroglial physiology with a realistic cell model in silico

et al. 2018

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“…It appears that in most cases, mitochondria, microtubules and endoplasmic reticulum are virtually absent from PAPs (Bernardinelli et al, 2014a; Reichenbach et al, 2010). Recently, quantitative three‐dimensional EM data have suggested that cellular organelles associated with Ca 2+ signaling indeed tend to occur inside astroglia at some distance from the nearby excitatory synapses (Patrushev et al, 2013). However, PAPs do seem to contain individual ribosomes and glycogen granules, together with actin and actin binding proteins (Bernardinelli et al, 2014a; Derouiche and Frotscher, 2001; Fiala et al, 2003; Molotkov et al, 2013; Safavi‐Abbasi et al, 2001; Seidel et al, 1995).…”

Section: Molecular Makeup Of Perisynaptic Astroglial Processes: Majormentioning

confidence: 99%

“…The actual three‐dimensional distances between astrocytic membranes and dendritic spines can vary from the immediate contact to hundreds of nanometers (Lushnikova et al, 2009; Medvedev et al, 2014; Patrushev et al, 2013; Spacek and Harris, 1998). Although PAPs can be found in all brain regions, only a proportion of synapses are actually in immediate contact with them.…”

Section: Astroglial Coverage Of Synapsesmentioning

confidence: 99%

Morphological plasticity of astroglia: Understanding synaptic microenvironment

Heller

Rusakov

2015

Glia

130

137

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Memory formation in the brain is thought to rely on the remodeling of synaptic connections which eventually results in neural network rewiring. This remodeling is likely to involve ultrathin astroglial protrusions which often occur in the immediate vicinity of excitatory synapses. The phenomenology, cellular mechanisms, and causal relationships of such astroglial restructuring remain, however, poorly understood. This is in large part because monitoring and probing of the underpinning molecular machinery on the scale of nanoscopic astroglial compartments remains a challenge. Here we briefly summarize the current knowledge regarding the cellular organisation of astroglia in the synaptic microenvironment and discuss molecular mechanisms potentially involved in use‐dependent astroglial morphogenesis. We also discuss recent observations concerning morphological astroglial plasticity, the respective monitoring methods, and some of the newly emerging techniques that might help with conceptual advances in the area. GLIA 2015;63:2133–2151

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“…(figure 2). These transporters create substantial ion fluxes; the PAPs and perisynaptic astroglial compartments are generally poor in organelles [22], and in particular they are almost completely devoid of endoplasmic reticulum [28] making transmembrane ion fluxes fundamental for local ion signalling mediated by both Ca 2þ and Na þ [29,30].…”

Section: (B) Physiologymentioning

confidence: 99%

Astroglial cradle in the life of the synapse

Verkhratsky¹

2014

Phil. Trans. R. Soc. B

213

179

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Astroglial perisynaptic sheath covers the majority of synapses in the central nervous system. This glial coverage evolved as a part of the synaptic structure in which elements directly responsible for neurotransmission (exocytotic machinery and appropriate receptors) concentrate in neuronal membranes, whereas multiple molecules imperative for homeostatic maintenance of the synapse (transporters for neurotransmitters, ions, amino acids, etc.) are shifted to glial membranes that have substantially larger surface area. The astrocytic perisynaptic processes act as an 'astroglial cradle' essential for synaptogenesis, maturation, isolation and maintenance of synapses, representing the fundamental mechanism contributing to synaptic connectivity, synaptic plasticity and information processing in the nervous system. Multiple components of the central synapseThe power of the brain lies in the intercellular connections; some tens of trillions of these connections create the neural web that is the substrate for information processing. The connectivity of neural networks is immensely plastic and it is constantly remodelled under the influence of the environment and experience; this remarkable plasticity underlies learning. Intercellular connections in the nervous system are represented by chemical and electrical synapses, with the former predominantly established between neurons and the latter between neuroglia. Chemical transmission in the brain is not confined to synapses, it also operates in a 'volume transmission' mode when neurotransmitters diffuse through interstitial space, finding their multiple targets between neurons and neuroglial cells.Synaptic structures evolved over the last approximately 600 million years, after the first diffuse nervous system appeared in primitive animals such as hydras and comb jellies; this first nervous system was composed from cells of a single cell type, the neurons, which establish a neuronal net through synaptic contacts. Subsequent evolution of the nervous system progressed by the way of great diversification and specialization of cells. The first glial-like cells emerged in nematodes, they became specialized in annelids and attained a high degree of morphological and functional heterogeneity in arthropods. In basal chordates, the new type of glial cells, the radial glia, replaced parenchymal glial cells, which signalled an advent of layered organization of the central nervous system (CNS). Increase in the size of the CNS instigated re-emergence and diversification of astrocytes and appearance of myelin [1]. The brain and the spinal cord of mammals contain hundreds of distinct types of neurons and many types of neuroglia. Similarly, there are many types of synapses established between neuronal terminals and effector organs in the periphery or between neuronal terminals and other neurons and between neurons and some NG2 glial cells [2] in the CNS as well as in sympathetic ganglia or enteric plexuses.Synapses in the CNS are composed of several distinct components (figure 1), which incl...

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Subcellular location of astrocytic calcium stores favors extrasynaptic neuron–astrocyte communication

Cited by 111 publications

References 45 publications

Disentangling astroglial physiology with a realistic cell model in silico

Disentangling astroglial physiology with a realistic cell model in silico

Morphological plasticity of astroglia: Understanding synaptic microenvironment

Astroglial cradle in the life of the synapse

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