Target type: molecularfunction
Enables the transmembrane transfer of an ion by a channel that opens when glutamate is bound by the channel complex or one of its constituent parts on the extracellular side of the plasma membrane. [GOC:mtg_transport, ISBN:0815340729]
Extracellularly glutamate-gated ion channel activity represents a fundamental process in neuronal communication. It involves the opening of ion channels in response to the binding of glutamate, a primary excitatory neurotransmitter, to its receptors located on the outer surface of the cell membrane. This activity plays a crucial role in mediating synaptic transmission, neuronal excitability, and plasticity, ultimately shaping brain function and behavior. The mechanism involves the following steps:
1. Glutamate, released from presynaptic neurons, binds to specific glutamate receptors, namely ionotropic glutamate receptors (iGluRs), located on the postsynaptic membrane.
2. This binding event triggers a conformational change in the receptor protein, leading to the opening of an ion channel embedded within the receptor.
3. The opening of the channel allows the passage of ions, predominantly sodium (Na+) and calcium (Ca2+), across the cell membrane.
4. The influx of these positively charged ions depolarizes the postsynaptic neuron, making it more likely to fire an action potential, thereby propagating the signal.
5. Different iGluR subtypes exist, each with specific properties and ion permeability, contributing to the diverse effects of glutamate signaling. For instance, AMPA and kainate receptors mediate fast excitatory neurotransmission, while NMDA receptors play a vital role in synaptic plasticity and learning.
6. The precise regulation of glutamate-gated ion channel activity is crucial for maintaining neuronal homeostasis. Dysregulation of this process can lead to various neurological disorders, including epilepsy, stroke, and neurodegenerative diseases.
7. Understanding the intricate molecular mechanisms underlying extracellularly glutamate-gated ion channel activity is essential for developing novel therapeutic strategies targeting these pathways for the treatment of brain disorders.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Glutamate receptor ionotropic, kainate 2 | A glutamate receptor ionotropic, kainate 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q13002] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid | alpha-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 | |
| kainic acid | Kainic Acid: (2S-(2 alpha,3 beta,4 beta))-2-Carboxy-4-(1-methylethenyl)-3-pyrrolidineacetic acid. Ascaricide obtained from the red alga Digenea simplex. It is a potent excitatory amino acid agonist at some types of excitatory amino acid receptors and has been used to discriminate among receptor types. Like many excitatory amino acid agonists it can cause neurotoxicity and has been used experimentally for that purpose. | dicarboxylic acid; L-proline derivative; non-proteinogenic L-alpha-amino acid; pyrrolidinecarboxylic acid | antinematodal drug; excitatory amino acid agonist |
| glutamic acid | glutamic 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 |
| sym 2081 | |||
| ly 293558 | tezampanel: structure given in first source; an AMPA receptor antagonist | ||
| alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid | |||
| ly382884 | benzoic acids | ||
| 4-bromohomoibotenic acid, (rs)-isomer | |||
| 2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline | 2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline: structure given in first source; neuroprotectant for cerebral ischemia; AMPA receptor antagonist | naphthalenes; sulfonic acid derivative | |
| ubp 310 | UBP 310: a GluR5 antagonist; structure in first source | ||
| ubp 302 | |||
| dysiherbaine | dysiherbaine : A furopyran that is (3aR,7aR)-hexahydro-2H-furo[3,2-b]pyran substituted by carboxy, (2S)-2-amino-2-carboxyethyl, hydroxy and methylamino groups at positions 2, 2, 6, and 7, respectively (the 2R,3aR,6S,7R,7aR-stereoisomer). A convulsant isolated from the marine sponge Dysidea herbacea that has high affinity for kainate ionotropic glutamate receptors. dysiherbaine: an exitotoxic amino acid; structure in first source | amino dicarboxylic acid; furopyran; hydroxy carboxylic acid; secondary amino compound | animal metabolite; excitatory amino acid agonist; marine metabolite; neurotoxin |