[Glutamic acid as an excitatory neurotransmitter].

The role of L-glutamic acid (Glu) as an excitatory neurotransmitter is reviewed. The idea that Glu is a main excitatory transmitter in the central nervous system (CNS) is now well supported by several lines of evidence, including its excitatory action, presence in the CNS, release, uptake mechanisms and suppression of synaptic transmission by its antagonists. Receptors for Glu are classified into ionotropic and metabotropic receptors. The former is further classified into non-NMDA and NMDA subgroups. The non-NMDA receptor mediates signal transduction between central neurons. Activation of the NMDA receptor causes an increase in intracellular calcium concentration in the postsynaptic neuron and thereby induces plastic changes such as, memory and learning. The function of the metabotropic receptor is yet to be elucidated.