Glutamate: Difference between revisions
>Thomas m Fixed an inaccuracy describing glutamate receptor categories; added citation. |
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[[File:L-Glutamate.svg|250px|thumb|right|L-glutamate molecule]] | [[File:L-Glutamate.svg|250px|thumb|right|L-glutamate molecule]] | ||
'''Glutamate''', also known as '''glutamic acid''', is one of the principal excitatory neurotransmitters in the human central nervous system (CNS). | '''Glutamate''', also known as '''glutamic acid''', is one of the principal excitatory neurotransmitters in the human central nervous system (CNS). | ||
It is the most abundant neurotransmitter in vertebrates and is involved in every major excitatory function, accounting in total for well over 90% of the synaptic connections in the human brain.<ref>Meldrum | It is the most abundant neurotransmitter in vertebrates and is involved in every major excitatory function, accounting in total for well over 90% of the synaptic connections in the human brain.<ref name="Meldrum2000">{{cite journal|last1=Meldrum|first1=Brian S.|title=Glutamate as a Neurotransmitter in the Brain: Review of Physiology and Pathology|journal=The Journal of Nutrition|volume=130|issue=4|year=2000|pages=1007S–1015S|issn=0022-3166|doi=10.1093/jn/130.4.1007S}}</ref> | ||
Because of its role in synaptic plasticity, glutamate is involved in cognitive functions such as learning and memory.<ref name="McEnteeCrook1993">{{cite journal|last1=McEntee|first1=William J.|last2=Crook|first2=Thomas H.|title=Glutamate: its role in learning, memory, and the aging brain|journal=Psychopharmacology|volume=111|issue=4|year=1993|pages=391–401|issn=0033-3158|doi=10.1007/BF02253527}}</ref> | |||
Neuropharmacology | The receptors for glutamate can be divided into metabotropic and ionotropic glutamate receptors. Ionotopic glutamate receptors fall into three major classes, known as AMPA receptors (GluA1-GluA4), [[NMDA receptor|NMDA receptors]] (GluN1-GluN3), and kainate receptors (GluK1-GluK5).{{citation needed}}<ref name="CollingridgeOlsen2009">{{cite journal|last1=Collingridge|first1=Graham L.|last2=Olsen|first2=Richard W.|last3=Peters|first3=John|last4=Spedding|first4=Michael|title=A nomenclature for ligand-gated ion channels|journal=Neuropharmacology|volume=56|issue=1|year=2009|pages=2–5|issn=00283908|doi=10.1016/j.neuropharm.2008.06.063}}</ref> | ||
Glutamate is a major constituent of a wide variety of proteins which makes it one of the most abundant amino acids in the human body.<ref name="Meldrum2000">{{cite journal|last1=Meldrum|first1=Brian S.|title=Glutamate as a Neurotransmitter in the Brain: Review of Physiology and Pathology|journal=The Journal of Nutrition|volume=130|issue=4|year=2000|pages=1007S–1015S|issn=0022-3166|doi=10.1093/jn/130.4.1007S}}</ref> It also serves as a metabolic precursor for the neurotransmitter [[GABA]], the main inhibitory neurotransmitter. | |||
Glutamate is a major constituent of a wide variety of proteins which makes it one of the most abundant amino acids in the human body.<ref>Meldrum | |||
==Chemistry== | ==Chemistry== | ||
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*'''Agonists''' | *'''Agonists''' | ||
A glutamate [[agonist]] is a chemical that binds to and activates a glutamate [[receptor]] and triggers a response, displaying full efficacy at that receptor. An example of this is [[theanine]], a weak agonist of the NMDA receptor.<ref>Wakabayashi | A glutamate [[agonist]] is a chemical that binds to and activates a glutamate [[receptor]] and triggers a response, displaying full efficacy at that receptor. An example of this is [[theanine]], a weak agonist of the NMDA receptor.<ref name="WakabayashiNumakawa2011">{{cite journal|last1=Wakabayashi|first1=Chisato|last2=Numakawa|first2=Tadahiro|last3=Ninomiya|first3=Midori|last4=Chiba|first4=Shuichi|last5=Kunugi|first5=Hiroshi|title=Behavioral and molecular evidence for psychotropic effects in l-theanine|journal=Psychopharmacology|volume=219|issue=4|year=2011|pages=1099–1109|issn=0033-3158|doi=10.1007/s00213-011-2440-z}}</ref> | ||
*'''Positive Allosteric Modulators''' | *'''Positive Allosteric Modulators''' | ||
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*'''Antagonists''' | *'''Antagonists''' | ||
A glutamate receptor [[antagonist]] is a type of receptor drug that inhibits action at glutamate receptors. [[Alcohol|Ethanol]] acts as an antagonist of the NMDA, AMPA and kainate glutamate receptors, along with several antiepileptic drugs.{{citation needed}} The nootropic compound [[theanine]] is an antagonist of the AMPA and kainate receptors.<ref>Kakuda | A glutamate receptor [[antagonist]] is a type of receptor drug that inhibits action at glutamate receptors. [[Alcohol|Ethanol]] acts as an antagonist of the NMDA, AMPA and kainate glutamate receptors, along with several antiepileptic drugs.{{citation needed}} The nootropic compound [[theanine]] is an antagonist of the AMPA and kainate receptors.<ref name="Kakuda2002">{{cite journal|last1=Kakuda|first1=Takami|title=Neuroprotective Effects of the Green Tea Components Theanine and Catechins|journal=Biological & Pharmaceutical Bulletin|volume=25|issue=12|year=2002|pages=1513–1518|issn=0918-6158|doi=10.1248/bpb.25.1513}}</ref> Many [[dissociatives|dissociative]] drugs are antagonists of the NMDA glutamate receptor, including [[ketamine]], [[MXE]], [[PCP]] and [[DXM]]. [[Tramadol]] and [[ibogaine]] are dual antagonists of the NMDA glutamate receptor and [[opioid]] receptors.{{citation needed}} | ||
*'''Negative Allosteric Modulators''' | *'''Negative Allosteric Modulators''' |