Communication between astrocytes and neurons: a complex language.

In recent years, accumulating evidence suggests the existence of bidirectional communication between astrocytes and neurons, indicating an important active role of astrocytes in the physiology of the nervous system. As a consequence of this evidence, a new concept of the synaptic physiology--"the tripartite synapse"--has been proposed, in which the synapse is formed by three functional elements, i.e. the pre- and postsynaptic elements and the surrounding astrocytes. In the present article we review and discuss the current knowledge on the cellular mechanisms and physiological properties of this communication that displays highly complex characteristics. We are beginning to realize that the communication between astrocytes and neurons uses a quite complex language.