Self-Structuring of Motile Astrocytic Processes within the Network of a Single Astrocyte

Bernhard J Mitterauer

doi:10.4236/abb.2015.612074

Abstract

Dynamic structuring and functions of perisynaptic astrocytic processes and of the gap junction network within a single astrocyte are outlined. Motile perisynaptic astrocytic processes are generating microdomains. By contacting and retracting of their endfeet an appropriate receptor pattern is selected that modulates the astrocytic receptor sheath for its activation by neurotransmitter substances, ions, transporters, etc. This synaptic information processing occurs in three distinct time scales of milliseconds to seconds, seconds to minutes, hours or longer. Simultaneously, the interconnecting gap junctions are activated by building a network within the astrocyte. Frequently activated gap junction cycles become embodied in gap junction plaques. The gap junction network formation and gap junction plaques are governed and controlled in the same time scales as synaptic information processing. Biomimetic computer systems may represent an alternative to limitations of brainphysiological research. The model proposed allows the interpretation of affective psychoses and schizophrenia as time disorders basically determined by a shortened, prolonged or lacking time scale of synaptic information processing.

Highlights

Introduction and HypothesisGlial-neuronal synaptic units are composed of the pre- and post-synapse as the neuronal components and the astrocyte as the glial component, termed tripartite synapse [1]
Searching for principles that may govern neuro-glial interactions in the tripartite synapse and its gap junction network and that enable the autonomous operation within a single astrocyte, my hypothesis is as follows: Motile perisynaptic astrocytic processes (PSAPs) are generating microdomains interconnected by gap junctions that embody an autonomous network
According to Verkhratsky and Nedergaard [3], the PSAPs act as an astroglial cradle representing the fundamental mechanism contributing to synaptic connectivity, synaptic plasticity, and information processing in the nervous system

Summary

Introduction and Hypothesis

Glial-neuronal synaptic units are composed of the pre- and post-synapse as the neuronal components and the astrocyte as the glial component, termed tripartite synapse [1] This concept is very fruitful in research on synaptic. Searching for principles that may govern neuro-glial interactions in the tripartite synapse and its gap junction network and that enable the autonomous operation within a single astrocyte, my hypothesis is as follows: Motile perisynaptic astrocytic processes (PSAPs) are generating microdomains interconnected by gap junctions that embody an autonomous network. Gap junctions interconnecting PSAPs are able to build cyclic pathways which, when frequently activated, become embodied in gap junction plaques This feedback structure within a time period of synaptic activation feeds forward to the PSAP movement pattern that selects astrocytic receptors modifying the glia-neuronal interaction period based on the frequently working astrocytic receptor pattern. Some implications for interdisciplinary research and neuropsychiatric diseases are suggested

Dynamic Microdomain Generation by Perisynaptic Astrocytic Processes

Synaptic Modulation by Motile Perisynaptic Astrocytic Processes

Findings

Discussion and Prospects