Astrocytes in the nucleus of the solitary tract: Contributions to neural circuits controlling physiology - PubMed (original) (raw)

Review

Astrocytes in the nucleus of the solitary tract: Contributions to neural circuits controlling physiology

Alastair J MacDonald et al. Physiol Behav. 2020.

Abstract

The nucleus of the solitary tract (NTS) is the primary brainstem centre for the integration of physiological information from the periphery transmitted via the vagus nerve. In turn, the NTS feeds into downstream circuits regulating physiological parameters. Astrocytes are glial cells which have key roles in maintaining CNS tissue homeostasis and regulating neuronal communication. Recently an increasing number of studies have implicated astrocytes in the regulation of synaptic transmission and physiology. This review aims to highlight evidence for a role for astrocytes in the functions of the NTS. Astrocytes maintain and modulate NTS synaptic transmission contributing to the control of diverse physiological systems namely cardiovascular, respiratory, glucoregulatory, and gastrointestinal. In addition, it appears these cells may have a role in central control of feeding behaviour. As such these cells are a key component of signal processing and physiological control by the NTS.

Keywords: Astrocyte; Autonomic; Brainstem; Feeding; Glucose; Glutamate.

Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.

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Conflict of interest statement

Declaration of Competing Interest The authors of this manuscript declare no conflict of interest.

Figures

Fig 1

Fig. 1

A simplified schematic of astrocyte modulation of synaptic transmission in the NTS. 1) Astrocytes respond to synaptic glutamate via AMPA-receptors (AMPA-R) expressed on the cell surface; 2) Astrocytes clear glutamate from the synapse to restrain neuronal firing and maintain presynaptic glutamate levels via EAAT2; 3) Astrocytes provide fuel to neurons in the form of lactate in order to maintain fidelity of synaptic transmission; 4) Astrocytes provide tonic modulation to synaptic transmission in the form of purinergic gliotransmission (release of ATP which may be converted to adenosine in the synaptic cleft) and 5) altering post-synaptic excitability by modulating presence of the a-type potassium current (IKA) which restrains action potential firing. Abbreviations: Ado = adenosine, ATP = adenosine triphosphate, EAAT2 = excitatory amino acid transporter 2, MCT = monocarboxylate transporter, NTS= nucleus of the solitary tract, ST = solitary tract, VGKC = voltage gated potassium channel.

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