Disorders afflicting the nervous system account for more hospitalizations, more long-term care, and more chronic suffering than nearly all other disorders combined (Cowan and Kandel, 2001). The emotional and economic losses are enormous.
Effective treatment is mostly unavailable, and prevention is difficult due to insufficient understanding of the causes. When brain tissue is diseased, complex processes start and nerve cells often continue to die after the initiating stimulus has stopped. Among the most exciting mechanisms are those controlling extracellular glutamate (Danbolt 2001).
The mechanisms controlling glutamate are hard to study because glutamate is involved in so many different and interconnected processes. Glutamate mediates most of the excitatory (stimulating, activating) signals in the central nervous system. This does not only include signals involved in perception, cognition and movements, but also for cell survival, elimination, migration and differentiation, as well as for synapse formation and elimination.
Further, glutamate affects brain energy consumption, free radical formation, cell volume and water transport. Whenever brain tissue is studied, it changes.