Page last updated: 2024-10-24

intracellular glutamate homeostasis

Definition

Target type: biologicalprocess

A homeostatic process involved in the maintenance of a steady state level of glutamate within a cell. [GOC:tb]

Glutamate, the primary excitatory neurotransmitter in the central nervous system, is crucial for normal neuronal function. Maintaining precise glutamate homeostasis is essential for synaptic plasticity, learning, and memory. Disruptions in this delicate balance can lead to various neurological disorders. Here is a detailed description of the intricate biological processes involved in intracellular glutamate homeostasis:

**1. Glutamate Uptake and Release:**
* Glutamate is synthesized from glutamine via the enzyme glutaminase in neurons.
* Released glutamate from presynaptic terminals binds to postsynaptic receptors, triggering neuronal signaling.
* The rapid removal of glutamate from the synaptic cleft is essential to prevent excessive neuronal excitation and excitotoxicity.
* This removal occurs via two primary mechanisms:
* **Reuptake:** High-affinity glutamate transporters, primarily EAAT1 and EAAT2 (also known as GLT-1 and GLAST), located on astrocytes and neurons, actively transport glutamate back into these cells.
* **Diffusion:** Glutamate can also diffuse out of the synaptic cleft into the extracellular space.

**2. Glutamate Metabolism within Neurons and Astrocytes:**
* **Astrocytes:** Once taken up by astrocytes, glutamate is converted into glutamine by the enzyme glutamine synthetase. Glutamine is then transported back to neurons where it serves as the precursor for glutamate synthesis.
* **Neurons:** Glutamate can be metabolized by several enzymes, including glutamate dehydrogenase (GDH) and transaminases, into other metabolites such as α-ketoglutarate, which enters the tricarboxylic acid (TCA) cycle for energy production.

**3. Regulation of Glutamate Homeostasis:**
* **Glutamate transporters:** The activity of glutamate transporters is tightly regulated by various factors, including neuronal activity, calcium levels, and the availability of substrates like glutamine.
* **Glutamate receptors:** Activation of specific glutamate receptors, like NMDA receptors, can regulate glutamate transporter activity and intracellular glutamate levels.
* **Enzymes involved in glutamate metabolism:** The activity of enzymes involved in glutamate metabolism is also subject to regulation, ensuring appropriate levels of glutamate and its precursors.

**4. Consequences of Glutamate Imbalance:**
* **Excitotoxicity:** Excessive glutamate accumulation in the synapse can lead to neuronal death, a phenomenon known as excitotoxicity. This is implicated in neurological disorders such as stroke, Alzheimer's disease, and Huntington's disease.
* **Neurodevelopmental disorders:** Abnormal glutamate signaling during early brain development can contribute to neurodevelopmental disorders like autism spectrum disorder and intellectual disability.

**5. Therapeutic Targets for Glutamate Homeostasis:**
* The tight regulation of glutamate homeostasis makes it an attractive target for developing therapies for neurological disorders.
* Strategies include:
* Enhancing glutamate transporter activity
* Targeting enzymes involved in glutamate metabolism
* Modulating glutamate receptor activity
* Developing drugs to protect against excitotoxicity'
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Proteins (5)

ProteinDefinitionTaxonomy
Cystine/glutamate transporterA cystine/glutamate transporter that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q9UPY5]Homo sapiens (human)
Metabotropic glutamate receptor 2A metabotropic glutamate receptor 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q14416]Homo sapiens (human)
Excitatory amino acid transporter 3An excitatory amino acid transporter 3 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P43005]Homo sapiens (human)
Glutaminase kidney isoform, mitochondrialA glutaminase kidney isoform, mitochondrial that is encoded in the genome of human. [PRO:DNx, UniProtKB:O94925]Homo sapiens (human)
Acetyl-CoA carboxylase 2An acetyl-CoA carboxylase 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:O00763]Homo sapiens (human)

Compounds (63)

CompoundDefinitionClassesRoles
alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acidalpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid: An IBOTENIC ACID homolog and glutamate agonist. The compound is the defining agonist for the AMPA subtype of glutamate receptors (RECEPTORS, AMPA). It has been used as a radionuclide imaging agent but is more commonly used as an experimental tool in cell biological studies.non-proteinogenic alpha-amino acid
alpha-methyl-4-carboxyphenylglycine
ibotenic acidIbotenic Acid: A neurotoxic isoxazole (similar to KAINIC ACID and MUSCIMOL) found in AMANITA mushrooms. It causes motor depression, ataxia, and changes in mood, perceptions and feelings, and is a potent excitatory amino acid agonist.non-proteinogenic alpha-amino acidneurotoxin
4-carboxy-3-hydroxyphenylglycine4-carboxy-3-hydroxyphenylglycine: weak agonist at metabotropic glutamate receptors; occludes the action of 1-aminocyclopentyl-1,3-dicarboxylate in hippocampushydroxybenzoic acid
1-aminoindan-1,5-dicarboxylic acid1-aminoindan-1,5-dicarboxylic acid: structure given in first source
mesalaminemesalamine : A monohydroxybenzoic acid that is salicylic acid substituted by an amino group at the 5-position.

Mesalamine: An anti-inflammatory agent, structurally related to the SALICYLATES, which is active in INFLAMMATORY BOWEL DISEASE. It is considered to be the active moiety of SULPHASALAZINE. (From Martindale, The Extra Pharmacopoeia, 30th ed)
amino acid;
aromatic amine;
monocarboxylic acid;
monohydroxybenzoic acid;
phenols
non-steroidal anti-inflammatory drug
4-carboxyphenylglycine4-carboxyphenylglycine: RN given for (+-)-isomer; RN for cpd without isomeric designation not available 3/93; glutamate receptor antagonistalpha-amino acid
sulfapyridinesulfapyridine : A sulfonamide consisting of pyridine with a 4-aminobenzenesulfonamido group at the 2-position.

Sulfapyridine: Antibacterial, potentially toxic, used to treat certain skin diseases.
pyridines;
substituted aniline;
sulfonamide;
sulfonamide antibiotic
antiinfective agent;
dermatologic drug;
drug allergen;
environmental contaminant;
xenobiotic
sulfasalazinesulfasalazine : An azobenzene consisting of diphenyldiazene having a carboxy substituent at the 4-position, a hydroxy substituent at the 3-position and a 2-pyridylaminosulphonyl substituent at the 4'-position.

Sulfasalazine: A drug that is used in the management of inflammatory bowel diseases. Its activity is generally considered to lie in its metabolic breakdown product, 5-aminosalicylic acid (see MESALAMINE) released in the colon. (From Martindale, The Extra Pharmacopoeia, 30th ed, p907)
cysteinecysteine;
cysteine zwitterion;
L-alpha-amino acid;
proteinogenic amino acid;
serine family amino acid
EC 4.3.1.3 (histidine ammonia-lyase) inhibitor;
flour treatment agent;
human metabolite
aspartic acidaspartic acid : An alpha-amino acid that consists of succinic acid bearing a single alpha-amino substituent

Aspartic Acid: One of the non-essential amino acids commonly occurring in the L-form. It is found in animals and plants, especially in sugar cane and sugar beets. It may be a neurotransmitter.

L-aspartic acid : The L-enantiomer of aspartic acid.
aspartate family amino acid;
aspartic acid;
L-alpha-amino acid;
proteinogenic amino acid
Escherichia coli metabolite;
mouse metabolite;
neurotransmitter
d-glutamateD-alpha-amino acid;
glutamic acid
Escherichia coli metabolite;
mouse metabolite
glutamic acidglutamic acid : An alpha-amino acid that is glutaric acid bearing a single amino substituent at position 2.

Glutamic Acid: A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.
glutamic acid;
glutamine family amino acid;
L-alpha-amino acid;
proteinogenic amino acid
Escherichia coli metabolite;
ferroptosis inducer;
micronutrient;
mouse metabolite;
neurotransmitter;
nutraceutical
quisqualic acidQuisqualic Acid: An agonist at two subsets of excitatory amino acid receptors, ionotropic receptors that directly control membrane channels and metabotropic receptors that indirectly mediate calcium mobilization from intracellular stores. The compound is obtained from the seeds and fruit of Quisqualis chinensis.non-proteinogenic alpha-amino acid
1-amino-1,3-dicarboxycyclopentane, (trans)-isomer
d-aspartic acidaspartic acid;
D-alpha-amino acid
mouse metabolite
L-2-aminoadipic acidL-2-aminoadipic acid : The L-enantiomer of 2-aminoadipic acid.2-aminoadipic acidEscherichia coli metabolite;
human metabolite
sym 2081
alpha-aminopimelic acid2-aminopimelic acid : An amino dicarboxylic acid that is heptanedioic acid in which a hydrogen at position 2 is replaced by an amino group. It is a component of the cell wall peptidoglycan of bacteria.

alpha-aminopimelic acid: antagonizes glutamate-induced inhibitions of Helix neurones
amino dicarboxylic acid;
non-proteinogenic alpha-amino acid
bacterial metabolite
1-amino-1,3-dicarboxycyclopentane1-amino-1,3-dicarboxycyclopentane: RN given refers to (cis)-isomer
dihydrokainatedicarboxylic acid
alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid
serine o-sulfateL-serine O-sulfate : A non-proteinogenic L-alpha-amino acid that is the O-sulfo derivative of L-serine.

serine O-sulfate: RN given refers to (L)-isomer
L-serine derivative;
non-proteinogenic L-alpha-amino acid;
O-sulfoamino acid
alpha-amino-3-(hydroxy)-5-methyl-4-isoxazoleacetic acidalpha-amino-3-(hydroxy)-5-methyl-4-isoxazoleacetic acid: RN given refers to cpd without isomeric designation; structure given in first source
homocysteic acidhomocysteic acid : A non-proteinogenic alpha-amino acid that is homocysteine in which the thiol group has benn oxidised to the corresponding sulfonic acid.

homocysteic acid: promotes growth in hypophysectomized rats; RN given refers to parent cpd

L-homocysteic acid : A homocysteic acid with L-configuration.
homocysteic acidNMDA receptor agonist
2-amino-4-phosphonobutyric acid(2S)-2-amino-4-phosphonobutanoic acid : A non-proteinogenc L-alpha-amino acid that is L-alpha-aminobutyric acid in which one of the hydrogens of the terminal methyl group has been replaced by a dihydroxy(oxido)-lambda(5)-phosphanyl group. It is a potent and selective agonist for the group III metabotropic glutamate receptors (mGluR4/6/7/8).non-proteinogenic L-alpha-amino acid;
phosphonic acids
metabotropic glutamate receptor agonist
eglumetadeglumetad: LY-354740 is the active isomer, LY-366563 is the inactive isomer, and LY 314582 is the racemate; structure given in first sourceL-alpha-amino acid
hinokininhinokinin : A lignan that is dihydrofuran-2(3H)-one (gamma-butyrolactone) substituted by a 3,4-methylenedioxybenzyl group at positions 3 and 4 (the 3R,4R-diastereoisomer).

hinokinin: suppresses expression of both HBsAg and HBeAg
benzodioxoles;
gamma-lactone;
lignan
trypanocidal drug
3-hydroxyaspartic acid, (threo-l)-isomer(3S)-3-hydroxy-L-aspartic acid : The (3S)-diastereomer of 3-hydroxy-L-aspartic acid.3-hydroxy-L-aspartic acidmetabolite
3,5-dihydroxyphenylglycine(S)-3,5-dihydroxyphenylglycine : A glycine derivative that is L-alpha-phenylglycine substituted at positions 3 and 5 on the phenyl ring by hydroxy groups.amino acid zwitterion;
non-proteinogenic L-alpha-amino acid;
resorcinols
alpha-methyl-4-carboxyphenylglycine(S)-alpha-methyl-4-carboxyphenylglycine : A non-proteinogenic alpha-amino acid that is alanine in which the alpha-hydrogen is replaced by a 4-carboxyphenyl group (the S-enantiomer). It is a non-selective group I/group II metabotropic glutamate receptor (mGluR) antagonist.

alpha-methyl-4-carboxyphenylglycine: glutamate receptor antagonist
non-proteinogenic alpha-amino acidmetabotropic glutamate receptor antagonist
cp-640186CP-640186: a potent inhibitor of mammalian Acetyl-coenzyme A carboxylases & can reduce body weight and improve insulin sensitivity in test animals; structure in first sourceanthracenes;
bipiperidines;
morpholines;
N-acylpiperidine
6-methyl-2-(phenylethynyl)pyridine2-methyl-6-(phenylethynyl)pyridine : A methylpyridine that coinsists of 2-methylp[yridine bearing an additional phenylethynyl group at position 6. Potent and highly selective non-competitive antagonist at the mGlu5 receptor subtype (IC50 = 36 nM) and a positive allosteric modulator at mGlu4 receptors. Centrally active following systemic administration in vivo. Reverses mechanical hyperalgesia in the inflamed rat hind paw.

6-methyl-2-(phenylethynyl)pyridine: an mGlu5 antagonist
acetylenic compound;
methylpyridines
anxiolytic drug;
metabotropic glutamate receptor antagonist
susalimodsusalimod: analogue of sulphasalazine, was designed for use in the treatment of rheumatoid arthritis
4-methylglutamic acid, threo-(l)-isomer
2-amino-3-phenylmethoxybutanedioic acidaspartic acid derivative
sib 1757SIB 1757: a selective mGluR5 antagonist; structure in first source
l-2-(carboxypropyl)glycine
2-(2,3-dicarboxycyclopropyl)glycine
2r,4r-4-aminopyrrolidine-2,4-dicarboxylatepyrrolidinedicarboxylic acid
upf 596UPF 596: structure in first source
dl-threo-beta-benzyloxyaspartate
sib 1893SIB 1893: a selective mGluR5 antagonist; structure in first source
4-carboxy-3-hydroxyphenylglycine
1-amino-1,3-dicarboxycyclopentane, cis-(1s,3s)-isomer
ampa, (r)-isomer
1-aminocyclopentane-1,3,4-tricarboxylic acid1-aminocyclopentane-1,3,4-tricarboxylic acid: metabolic glutamate receptor (mGluR) antagonist; structure in first source
ly 341495xanthenes
n-(4-(2-methoxyphenoxy)phenyl)-n-(2,2,2-trifluoroethylsulfonyl)pyrid-3-ylmethylamineN-(4-(2-methoxyphenoxy)phenyl)-N-(2,2,2-trifluoroethylsulfonyl)pyrid-3-ylmethylamine: a metabotropic glutamate 2 receptor potentiator; structure in first source
ly 404039LY404039 : An organic heterobicyclic compound that is (1S,5R)-2-thiabicyclo[3.1.0]hexane carrying oxo, oxo, amino, carboxy, and carboxy groups at positions 2, 2, 4S, 4S, and 6S, respectively. It is a potent agonist of group II metabotropic glutamate receptors mGluR2 mGluR3 (Ki = 149 nM and 92 nM, respectively) and exhibits antipsychotic and anxiolytic efficacy in animal models.bridged compound;
dicarboxylic acid;
non-proteinogenic amino acid derivative;
organic heterobicyclic compound;
sulfone
antipsychotic agent;
anxiolytic drug;
dopamine agonist;
metabotropic glutamate receptor agonist
mgs 0028MGS 0028: a group II mGluR agonist; structure in first source
biphenyl-indanone abiphenyl-indanone A: an mGluR2 agonist; structure in first sourcebiphenyls
ly 389795LY 389795: a group II metabotropic glutamate receptor agonist; structure in first source
ly 379268LY 379268 : An organic heterobicyclic compound that is (1R,5S)-2-oxabicyclo[3.1.0]hexane carrying amino, carboxy, and carboxy groups at positions 4R, 4R and 6R, respectively. It is a potent agonist of group II metabotropic glutamate receptors mGluR2 and mGluR3 (EC50 = 2.69 nM and 4.48 nM, respectively) that exhibits antipsychotic-like action in animal models of schizophrenia.

LY 379268: group II metabotropic glutamate receptor agonist; structure in first source
amino dicarboxylic acid;
bridged compound;
organic heterobicyclic compound
antipsychotic agent;
anxiolytic drug;
metabotropic glutamate receptor agonist;
neuroprotective agent
erastinerastin : A member of the class of quinazolines that is quinazolin-4(3H)-one in which the hydrogens at positions 2 and 3 are replaced by 1-{4-[(4-chlorophenoxy)acetyl]piperazin-1-yl}ethyl and 2-ethoxyphenyl groups, respectively. It is an inhibitor of voltage-dependent anion-selective channels (VDAC2 and VDAC3) and a potent ferroptosis inducer.

erastin: an antineoplastic agent; structure in first source
aromatic ether;
diether;
monochlorobenzenes;
N-acylpiperazine;
N-alkylpiperazine;
quinazolines;
tertiary carboxamide
antineoplastic agent;
ferroptosis inducer;
voltage-dependent anion channel inhibitor
a 794282
l-beta-threo-benzyl-aspartateL-beta-threo-benzyl-aspartate: structure in first source
sp 2033-fluoro-5-(2-(2-(fluoromethyl)thiazol-4-yl)ethynyl)benzonitrile: a radioligand for mGlu5 receptor; structure in first source
3,5-dichloro-2-hydroxy-N-(2-methoxy-5-phenylphenyl)benzenesulfonamidebiphenyls
jnj-404118131-butyl-3-chloro-4-(4-phenyl-1-piperidinyl)-(1H)-pyridone: an mGlu2 receptor modulator; structure in first source
ucph 1012-amino-4-(4-methoxyphenyl)-7-(naphthalen-1-yl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile: structure in first source
ml289ML289: metabotropic glutamate receptor 3 probe
cb-839