Astrocyte–Neuron Networks: A Multilane Highway of Signaling for Homeostatic Brain Function

Abstract

Research on glial cells over the past 30 years has confirmed the critical role of astrocytes in pathophysiological brain states. However, most of our knowledge about astrocyte physiology and of the interactions between astrocytes and neurons is based on the premises that astrocytes constitute a homogeneous cell type, without considering the particular properties of the circuits or brain nuclei in which the astrocytes are located. Therefore, we argue that more-sophisticated experiments are required to elucidate the specific features of astrocytes in different brain regions, and even within different layers of a particular circuit. Thus, in addition to considering the diverse mechanisms used by astrocytes to communicate with neurons and synaptic partners, it is necessary to take into account the cellular heterogeneity that likely contributes to the outcomes of astrocyte–neuron signaling. In this review article, we briefly summarize the current data regarding the anatomical, molecular and functional properties of astrocyte–neuron communication, as well as the heterogeneity within this communication.

Pathological ATPergic Signaling in Major Depression and Bipolar Disorder

“…Astrocytes to a large extent define synaptic connectivity. Indirect effects are exerted by changes in astrocytic functions due to modifications in K + uptake and redistribution; Cl − and water fluxes; Na + /K + , Na + /Ca 2+ , or Na + /HCO 3 − exchange; neurotransmitter uptake; etc (Verkhratsky et al, 2017;Mederos et al, 2018;Illes et al, 2019). Astrocytes also directly modify synaptic transmission, because they contact and partially ensheathe synapses with their perisynaptic processes (Allen and Eroglu, 2017).…”

Adenosine inhibits human astrocyte proliferation independently of adenosine receptor activation

“…Astrocytes are essential in maintaining brain homeostasis, supporting neuronal development and survival by providing trophic factors, regulating the turnover of neurotransmitters and maintaining extracellular ions concentration (see Mederos et al, ; Guttenplan & Liddelow ). In situations of brain injury, resulting from trauma or hypoxia as in stroke, astrocytes became activated into so called reactive astrocytes.…”

“…Astrocytes are essential for maintaining brain homeostasis, by supporting neuronal development and survival, regulating extracellular ions concentration, uptaking neurotransmitters and adenosine, regulating the CNS immune system and modulating neurotransmission (see Mederos, González‐Arias, & Perea, ; Guttenplan & Liddelow ). Another role of astrocytes is preservation of tissue integrity after injury, which involves their activation into so called reactive astrocytes.…”

Autophagy in Astrocytes: Importance for Metabolism

“…Moreover, astrocytes can release gliotransmitters in response to neuronal activity, modulating synaptic activity and strength. The important participation of astrocytes in synapses was coined as tripartite synapse, a concept which has broaden to multipartite synapse due the discover of microglia involvement in it [13][14][15].…”