excitatory amino acidmedical dictionary

<biochemistry> The naturally occurring amino acids L glutamate and L aspartate and their synthetic analogues, notably kainate, quisqualate and NMDA. They have the properties of excitatory neurotransmitters in the CNS, may be involved in long-term potentiation and can act as excitotoxins.

at least three classes of EAA receptor have been identified, the agonists of the N type receptor are L aspartate, NMDA and ibotenate, the agonists of the Q type receptor are L glutamate and quisqualate, agonists of the K type are L glutamate and kainate. All three receptor types are found widely in the CNS and particularly the telencephalon, N and Q type receptors tend to occur together and may interact, their distribution is complementary to the K type receptors. The ion fluxes through the Q and K receptors are relatively brief, whereas the flux through the N type is longer and carries a significant amount of calcium. Additionally the N type receptor is blockaded by magnesium near the resting potential and thus shows voltage gated ion channel properties, leading to a regenerative response, this is why N type receptors have been linked to long-term potentiation.

Invertebrate glutamate receptors may not have the same properties as those described above.

This entry appears with permission from the Dictionary of Cell and Molecular Biology

(11 Mar 2008)