Astrocytes, classically considered as supportive cells for neurons without a direct role in brain information processing, are emerging as relevant elements in brain physiology through their ability to regulate neuronal activity and synaptic transmission and plasticity. In relation to the key role of astrocyte-neuron interactions in synaptic physiology, accumulating evidence suggests that dysfunctions of neuron-astrocyte signaling may be linked to the pathology of various neurological and neurodegenerative diseases. In this article, we summarize the evidence supporting the importance of astrocyte-neuron communication in synaptic physiology, which have led to reveal astrocytes as integral elements of synaptic function. We also discuss how this novel view of astrocytic functions on brain physiology is prompting us to reconsider the possible astrocytic roles in brain diseases, and specifically in depression.
