Ion Channels and Electrophysiological Properties of Astrocytes: Implications for Emergent Stimulation Technologies

Abstract

Astrocytes comprise a heterogeneous cell population characterized by distinct morphologies, protein expression and function. Unlike neurons, astrocytes do not generate action potentials, however, they are electrically dynamic cells with extensive electrophysiological heterogeneity and diversity. Astrocytes are hyperpolarized cells with low membrane resistance. They are heavily involved in the modulation of K+ and express an array of different voltage-dependent and voltage-independent channels to help with this ion regulation. In addition to these K+ channels, astrocytes also express several different types of Na+ channels; intracellular Na+ signaling in astrocytes has been linked to some of their functional properties. The physiological hallmark of astrocytes is their extensive intracellular Ca2+ signaling cascades, which vary at the regional, subregional, and cellular levels. In this review article, we highlight the physiological properties of astrocytes and the implications for their function and influence of network and synaptic activity. Furthermore, we discuss the implications of these differences in the context of optogenetic and DREADD experiments and consider whether these tools represent physiologically relevant techniques for the interrogation of astrocyte function.

Optogenetic Activation of Astrocytes—Effects on Neuronal Network Function

“…Optogenetic activation of Gq-signaling in astrocytes in our experiments did not result in such strong and fast changes in synaptic plasticity. As an explanation, it can be proposed that due to quite low membrane resistance in astrocytes (due to the presence of gap-junctions [40]) more time is needed for more gentle activation by light in comparison with DREADD (Designer Receptors Exclusively Activated by Designer Drugs). In another study, activation of G-protein coupled receptors in astrocytes was performed by expression of melanopsin.…”

Unraveling Aβ-Mediated Multi-Pathway Calcium Dynamics in Astrocytes: Implications for Alzheimer’s Disease Treatment From Simulations

“…This may indicate the destructive nature of Aβ to synchronization oscillation of astrocyte network. Besides, astrocyte RMP displays extensive heterogeneity in the central nervous system (McNeill et al, 2021). To a certain extent, our model also reflects the characteristics of astrocytes with different RMP.…”

α9-Containing Nicotinic Receptors in Cancer

“…In astrocytes, whose membrane resting potential is critically lower than that measured in neurons, ionic influx through ligand-gated channels may be largely responsible for the increased intracellular Ca 2+ levels that modulates Ca 2+ -gated channels locally, and activates various Ca 2+ -dependent signaling mechanisms (Mcneill et al, 2021).…”