Copyright © 2005 Sage Publications

In the central nervous system, neurons are greatly out-numbered by supporting glial cells that play essential roles in daily function and in the response to all forms of CNS insults such as injury, ischemia, infection, or degenerative disease. The loss of CNS functions after injury or disease is ultimately due to the dysfunction or death of neurons. Nevertheless, glial cells, as the pri-mary responders to CNS insults, are in a position to be key determinants of clinical outcome. Achieving a better understanding of glial cell roles during the complex mul-ticellular interactions that unfold after CNS insults is an important goal in developing new ideas for potential therapeutic interventions. Reactive Astrocytes: Friend or Foe? Astrocytes are ubiquitous glia whose finely branchin