The role of astrocytic ephrins and Eph receptors in astrocyte function, synaptic plasticity, and memory formation

Astrocytes play essential roles in brain functions, including regulating neurotransmitter reuptake, modulating synaptic activity through gliotransmission and signaling molecules, supporting neuronal metabolism, and influencing neuronal morphology. Astrocytes can modulate specific neuronal circuits, respond to environmental changes, and exhibit computational capabilities. Through these processes, astrocytes contribute to neuronal plasticity and memory formation. Among the key regulators of astrocytic function are Eph receptors and their interacting ephrin proteins. Eph receptors and ephrins control critical astrocytic processes and directly influence neuronal functions, including transmission and morphology. These effects include regulating glutamate transmission by controlling synaptic glutamate levels and d-serine-dependent modulation of glutamate receptors, as well as shaping dendritic spine morphology and affecting the number of synapses. Through these mechanisms, astrocytic Eph receptors and ephrins modulate synaptic plasticity and are central regulators of long-term memory formation.