[Glutamate--a transmitter in the tensionfield between toxin and trophine]

Glutamate is the most important excitatory transmitter in the central nervous system. A tremendous complexity in the actions of this excitatory transmitter was found and an equally great complexity in the molecular structures of the receptors activated by glutamate. The glutamate receptor system influences nearly all other neurotransmitter systems. Glutamate also plays a central role in important processes of the central nervous system like the long-term potentiation in the hippocampus and the central sensitization for pain stimuli in the spinal cord, which is predominantly mediated by NMDA-receptors. But there are actions of glutamate beyond its function as an excitatory transmitter. Glutamate also has a trophic influence on neurons--depending upon the developmental stage. The excitotoxicity of glutamate mediated by NMDA-receptors is the common ultimate mechanism of acute and chronic nerve cell death and plays an important role in many acute neurologic diseases. The modulation of the glutamate system for example by antagonist of the glutamate-receptors might be a possible way in therapy of many different diseases of the central nervous system.