What Is the Role of Astrocyte Calcium in Neurophysiology?

Agulhon, Cendra; Petravicz, Jeremy; McMullen, Allison B.; Sweger, Elizabeth J.; Minton, Suzanne K.; Taves, Sarah; Casper, Kristen B.; Fiacco, Todd A.; McCarthy, Ken D.

doi:10.1016/j.neuron.2008.09.004

Cited by 511 publications

(430 citation statements)

References 119 publications

(309 reference statements)

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“…For example the functions of nAChRs on glia, especially on astrocytes, which occupy about half of the total volume of the brain and are critical for understanding the full picture of various brain functions [91,92] , have received considerably less attention to date than for receptors expressed in neurons. However evidence suggests that astrocytic nAChRs may be involved in neuroprotection.…”

Section: Perspectivesmentioning

confidence: 99%

Nicotinic acetylcholine receptor-mediated calcium signaling in the nervous system

2009

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Based on the composition of the five sub units forming functional neuronal nicotinic acetylcholine receptors (nAChRs), they are grouped into either heteromeric (comprising both α and β subunits) or homomeric (comprising only α subunits) receptors. The nAChRs are known to be differentially permeable to calcium ions, with the α7 nAChR subtype having one of the highest permeabilities to calcium. Calcium influx through nAChRs, particularly through the α-bungarotoxin-sensitive α7-containing nAChRs, is a very efficient way to raise cytoplasmic calcium levels. The activation of nAChRs can mediate three types of cytoplasmic calcium signals: (1) direct calcium influx through the nAChRs, (2) indirect calcium influx through voltage-dependent calcium channels (VDCCs) which are activated by the nAChR-mediated depolarization, and (3) calciuminduced calcium release (CICR) (triggered by the first two sources) from the endoplasmic reticulum (ER) through the ryanodine receptors and inositol (1,4,5)-triphosphate receptors (IP 3 Rs). Downstream signaling events mediated by nAChRmediated calcium responses can be grouped into instantaneous effects (such as neurotransmitter release, which can occur in milliseconds after nAChR activation), short-term effects (such as the recovery of nAChR desensitization through cellular signaling cascades), and long-term effects (such as neuroprotection via gene expression). In addition, nAChR activity can be regulated by cytoplasmic calcium levels, suggesting a complex reciprocal relationship. Further advances in imaging techniques, animal models, and more potent and subtype-selective ligands for neuronal nAChRs would help in understanding the neuronal nAChR-mediated calcium signaling, and lead to the development of improved therapeutic treatments.

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Section: Perspectivesmentioning

confidence: 99%

Nicotinic acetylcholine receptor-mediated calcium signaling in the nervous system

2009

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“…It is likely that Ca 2+ waves are instrumental in tripartite synaptic interactions of astrocytes and neuronal synapses [23]- [25].…”

Section: Ca 2+mentioning

confidence: 99%

Influence of Macrocolumnar EEG on Ca Waves

Ingber¹

2012

SSRN Journal

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Abstract-A "smoking gun" for explicit top-down neocortical mechanisms that directly drive bottom-up processes that describe memory, attention, etc. The top-down mechanism considered are macrocolumnar EEG firings in neocortex, as described by a statistical mechanics of neocortical interactions (SMNI), developed as a magnetic vector potential A. The bottom-up process considered are Ca 2+ waves prominent in synaptic and extracellar processes that are considered to greatly influence neuronal firings. Here, the complimentary effects are considered, i.e., the influence of A on Ca 2+ momentum, p. The canonical momentum of a charged particle in an electromagnetic field, Π = p + qA (SI units), is calculated, where the charge of Ca 2+ is q = 2e, e is the magnitude of the charge of an electron, valid in both classical and quantum mechanics. It is shown that A is large enough to influence p. This suggests that, instead of the common assumption that Ca 2+ waves contribute to neuronal activity, they may in fact at times be caused by the influence of A of larger-scale EEG.Index Terms-short-term memory, astrocytes, neocortical dynamics, vector potential I. SMOKING GUN FOR TOP-DOWN PROCESSESThere is a growing awareness of the importance of multiple scales in many physical and biological systems, including neuroscience [1], [2]. As yet, there does not seem to be any "smoking gun" for explicit top-down mechanisms that directly drive bottom-up processes that describe memory, attention, etc. Of course, there are many top-down type studies demonstrating that neuromodulator [3] and neuronal firing states, e.g., as defined by EEG frequencies, can modify the milieu or context of individual synaptic and neuronal activity, which is still consistent with ultimate bottom-up paradigms. However, there is a logical difference between top-down milieu as conditioned by some prior external or internal conditions, and some direct top-down processes that direct cause bottom-up interactions specific to STM. Here, the operative word is "cause". A. Magnetism Influences in Living SystemsThere is a body of evidence that suggests a specific topdown mechanism for neocortical STM processing.An example of a direct physical mechanism that affects neuronal processing not part of "standard" sensory influences is the strong possibility of magnetic influences in birds at quantum levels of interaction [4]- [6]. It should be noted that this is just a proposed mechanism [7].The strengths of magnetic fields in neocortex may be at a threshold to directly influence synaptic interactions with astrocytes, as proposed for long-term memory (LTM) [ rise to even stronger magnetic fields. Columnar excitatory and inhibitory processes largely take place in different neocortical laminae, providing possibilities for more specific mechanisms. II. SMNI CONTEXTSince 1981 about 30 papers on a statistical mechanics of neocortical interactions (SMNI) has been detailed properties of short-term memory, long-term memory, EEG analyses, and other properties of neocortex [11]-[16].This disc...

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“…The basic idea of the structural organization of the network, in terms of the introduction of a management subnet, is borrowed from neurobiological studies [6][7][8][9].…”

Section: The Statement Of the Problemmentioning

confidence: 99%

“…In the first experiment as a model of switches Comms, the model of a neuron «Integrate Fig. 3 The scheme of processing streams of data units of software modules and Fire» [15] resistant to interference was taken, as well as models of interaction between the synapse and astrocyte through the sharing of neurotransmitter of works [7][8][9] were taken.…”

Section: Examples Of Solutions Of Neurodynamic Problemsmentioning

confidence: 99%

The Model of the Cybernetic Network and Its Realization on the Cluster of Universal and Graphic Processors

Krasnov¹,

Калачев²,

Nadezhdin³

et al. 2017

Proceedings of the Scientific-Practical Conference "Research and Development - 2016"

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The model of the cybernetic network consisting of information and management subnets is offered. For each subnets, its active structural elements and also a way of their association in the general heterogeneous multicoherent network are described. The main functions of active structural elements of such network are considered. For the creation of the model, the object-oriented approach is used. The description of functionalities of main classes intended for the work on clusters of universal and graphic processors is submitted. The approbation of the developed model is executed by a solution of neurobiological tasks.

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What Is the Role of Astrocyte Calcium in Neurophysiology?

Cited by 511 publications

References 119 publications

Nicotinic acetylcholine receptor-mediated calcium signaling in the nervous system

Nicotinic acetylcholine receptor-mediated calcium signaling in the nervous system

Influence of Macrocolumnar EEG on Ca Waves

The Model of the Cybernetic Network and Its Realization on the Cluster of Universal and Graphic Processors

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