Astrocyte-neurone crosstalk mediates dexmedetomidine sedation.

Orser, Beverley A; Brenna, Connor T A; Maze, Mervyn · Br J Anaesth · 2026

basic_science · Level V

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Abstract

As the clinical applications of dexmedetomidine expand, advances in neuroscientific research have provided further insights into its mechanisms of action. We provide a focused overview of the role that astrocytes play in the changes in neurotransmission that accompany the sedative action of dexmedetomidine. After activation of astrocytic α<sub>2</sub>A-adrenergic receptors, the subsequent rise in cytosolic calcium increases the permeability of bestrophin-1 channels, facilitating the release of γ-aminobutyric acid (GABA) that stimulates extrasynaptic GABA<sub>A</sub> receptors on glutamatergic neurones. This signalling cascade, involving multiple receptor systems, reduces neuronal excitability.