NEURONAL DEATH - IS THERE A ROLE FOR ASTROCYTES

Astrocytes are ubiquitous in the brain and have multiple functions. It is becoming increasingly clear that they play an important role in mo nitoring the neuromicroenvironment in CNS and in information processin g or signaling in the nervous system in normal conditions and respond to CNS injuries in a gradual and varied way. It is still debated wheth er such reactions are beneficial or detrimental. It was believed that reactive astrogliosis observed in most neurological disorders may regu late the removal of toxic compounds produced by damaged neurons and su pport neuronal growth by releasing trophic factors. However it was als o suggested that astrocytes contribute to a decline of neurologic func tion, for example by accumulation and release of excitotoxic aminoacid s after ischemia and oxidative stress, formation of epileptogenic scar s in response to CNS injury and metabolism of protoxins to potent toxi ns. In a number of metabolic diseases astrocytes, not neurons, may be the primary tar et. The astrocyte's role in normal and pathological co nditions will be discussed in the light of recent information about th eir metabolism, receptor distribution and release.