|excitatory amino acid||medical 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.
This entry appears with permission from the Dictionary of Cell and Molecular Biology
(11 Mar 2008)
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