Astrocytes are the most numerous cell type within the central nervous system. Early during development they act as guiding structures for migratory neurons; later they are not only the main source for nutrients and growth factors in the brain, but they are also communication partners of neighboring neurons. For this purpose astrocytes are equipped with several types of transmitter receptors and the capacity to release neuroactive substances. In addition, they form an extended syncytium via gap junction channels which allows fast intercellular signaling pathways. The pivotal involvement of astrocytes in brain function during disease situations is the topic of many studies. Here, we will review the role of astrocytic gap junctions, astroglial metabolism and neuron-astrocyte signaling. Identification of the molecular mechanisms of these three functions will improve our understanding of neuroprotection.