Page last updated: 2024-10-24
excitatory chemical synaptic transmission
Definition
Target type: biologicalprocess
Synaptic transmission that results in an excitatory postsynaptic potential. [GOC:dos]
Excitatory chemical synaptic transmission is a fundamental process in the nervous system that allows neurons to communicate with each other. It involves the release of neurotransmitters from a presynaptic neuron, which bind to receptors on a postsynaptic neuron, causing a change in the postsynaptic neuron's membrane potential. Here's a detailed description of the process:
1. **Action Potential Arrival:** The process begins with an action potential arriving at the presynaptic terminal, the end of the presynaptic neuron's axon. This electrical signal depolarizes the presynaptic terminal.
2. **Calcium Influx:** Depolarization of the presynaptic terminal opens voltage-gated calcium channels. Calcium ions (Ca2+) flow into the presynaptic terminal down their concentration gradient.
3. **Vesicle Fusion and Neurotransmitter Release:** The influx of Ca2+ triggers the fusion of synaptic vesicles containing neurotransmitters with the presynaptic membrane. This fusion process releases the neurotransmitters into the synaptic cleft, the narrow gap between the pre- and postsynaptic neurons.
4. **Neurotransmitter Binding:** The released neurotransmitters diffuse across the synaptic cleft and bind to specific receptors on the postsynaptic membrane. These receptors are often ionotropic, meaning they are directly linked to ion channels.
5. **Postsynaptic Potential Generation:** Binding of neurotransmitters to their receptors causes a change in the postsynaptic membrane potential. In excitatory synapses, this change is typically a depolarization, known as an excitatory postsynaptic potential (EPSP). This depolarization brings the postsynaptic neuron closer to its threshold for firing an action potential.
6. **Neurotransmitter Removal:** To prevent prolonged signaling, neurotransmitters are quickly removed from the synaptic cleft. This removal can occur through various mechanisms, including:
* **Reuptake:** The presynaptic neuron actively reabsorbs the released neurotransmitter, returning it to the presynaptic terminal.
* **Enzymatic Degradation:** Enzymes in the synaptic cleft break down the neurotransmitter, rendering it inactive.
* **Diffusion:** Some neurotransmitters simply diffuse away from the synaptic cleft.
7. **Postsynaptic Response:** The EPSP, along with other inputs the postsynaptic neuron receives, determines whether the postsynaptic neuron will fire an action potential. If the combined inputs reach the threshold for firing, the postsynaptic neuron will generate its own action potential, continuing the signal transmission.
Excitatory chemical synaptic transmission is essential for various functions, including:
* **Sensory perception:** Transmitting signals from sensory organs to the brain.
* **Motor control:** Sending signals from the brain to muscles.
* **Learning and memory:** Strengthening or weakening synaptic connections.
* **Thought and cognition:** Processing information in the brain.
Many neurological disorders are linked to disruptions in excitatory synaptic transmission. For example, epilepsy involves excessive neuronal activity, often due to imbalances in excitatory and inhibitory signaling. Alzheimer's disease, Parkinson's disease, and other neurodegenerative disorders are also associated with changes in synaptic function.
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Proteins (6)
| Protein | Definition | Taxonomy |
|---|---|---|
| Glutamate receptor ionotropic, NMDA 2C | A glutamate receptor ionotropic, NMDA 2C that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q14957] | Homo sapiens (human) |
| Glutamate receptor ionotropic, NMDA 2B | A glutamate receptor ionotropic, NMDA 2B that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q13224] | Homo sapiens (human) |
| Glutamate receptor ionotropic, NMDA 2A | A glutamate receptor ionotropic, NMDA 2A that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q12879] | Homo sapiens (human) |
| Glutamate receptor ionotropic, NMDA 1 | A glutamate receptor ionotropic, NMDA 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q05586] | Homo sapiens (human) |
| Potassium voltage-gated channel subfamily KQT member 3 | A voltage-gated potassium channel subunit KCNQ3 that is encoded in the genome of human. [] | Homo sapiens (human) |
| Glutamate receptor ionotropic, NMDA 2D | A glutamate receptor ionotropic, NMDA 2D that is encoded in the genome of human. [PRO:DNx, UniProtKB:O15399] | Homo sapiens (human) |
Compounds (70)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| spermine | polyazaalkane; tetramine | antioxidant; fundamental metabolite; immunosuppressive agent | |
| 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 | |
| 6,7-dichloroquinoxaline-2,3-dione | quinoxaline derivative | ||
| tacrine | tacrine : A member of the class of acridines that is 1,2,3,4-tetrahydroacridine substituted by an amino group at position 9. It is used in the treatment of Alzheimer's disease. Tacrine: A cholinesterase inhibitor that crosses the blood-brain barrier. Tacrine has been used to counter the effects of muscle relaxants, as a respiratory stimulant, and in the treatment of Alzheimer's disease and other central nervous system disorders. | acridines; aromatic amine | EC 3.1.1.7 (acetylcholinesterase) inhibitor |
| N-(2-aminoethyl)-5-chloro-1-naphthalenesulfonamide | naphthalenes; sulfonic acid derivative | ||
| amantadine | amant: an antiviral compound consisting of an adamantane derivative chemically linked to a water-solube polyanioic matrix; structure in first source | adamantanes; primary aliphatic amine | analgesic; antiparkinson drug; antiviral drug; dopaminergic agent; NMDA receptor antagonist; non-narcotic analgesic |
| arcaine | 1,4-diguanidinobutane : A guanidine derivative consisting of butane having guanidino groups at the 1- and 4-positions. arcaine: RN given refers to parent cpd; structure | guanidines | |
| chlorpromazine | chlorpromazine : A substituted phenothiazine in which the ring nitrogen at position 10 is attached to C-3 of an N,N-dimethylpropanamine moiety. Chlorpromazine: The prototypical phenothiazine antipsychotic drug. Like the other drugs in this class chlorpromazine's antipsychotic actions are thought to be due to long-term adaptation by the brain to blocking DOPAMINE RECEPTORS. Chlorpromazine has several other actions and therapeutic uses, including as an antiemetic and in the treatment of intractable hiccup. | organochlorine compound; phenothiazines; tertiary amine | anticoronaviral agent; antiemetic; dopaminergic antagonist; EC 3.4.21.26 (prolyl oligopeptidase) inhibitor; phenothiazine antipsychotic drug |
| clofibric acid | clofibric acid : A monocarboxylic acid that is isobutyric acid substituted at position 2 by a p-chlorophenoxy group. It is a metabolite of the drug clofibrate. Clofibric Acid: An antilipemic agent that is the biologically active metabolite of CLOFIBRATE. | aromatic ether; monocarboxylic acid; monochlorobenzenes | anticholesteremic drug; antilipemic drug; antineoplastic agent; herbicide; marine xenobiotic metabolite; PPARalpha agonist |
| racemethorphan | 6-methoxy-11-methyl-1,3,4,9,10,10a-hexahydro-2H-10,4a-(epiminoethano)phenanthrene : An organic heterotetracyclic compound that is 1,3,4,9,10,10a-hexahydro-2H-10,4a-(epiminoethano)phenanthrene which is substituted by a methoxy group at position 6 and a methyl group at position 11. | aromatic ether; morphinane alkaloid; morphinane-like compound; organic heterotetracyclic compound | |
| felbamate | felbamate : The bis(carbamate ester) of 2-phenylpropane-1,3-diol. An anticonvulsant, it is used in the treatment of epilepsy. Felbamate: A PEGylated phenylcarbamate derivative that acts as an antagonist of NMDA RECEPTORS. It is used as an anticonvulsant, primarily for the treatment of SEIZURES in severe refractory EPILEPSY. | carbamate ester | anticonvulsant; neuroprotective agent |
| ifenprodil | ifenprodil: NMDA receptor antagonist | piperidines | |
| ketamine | ketamine : A member of the class of cyclohexanones in which one of the hydrogens at position 2 is substituted by a 2-chlorophenyl group, while the other is substituted by a methylamino group. Ketamine: A cyclohexanone derivative used for induction of anesthesia. Its mechanism of action is not well understood, but ketamine can block NMDA receptors (RECEPTORS, N-METHYL-D-ASPARTATE) and may interact with sigma receptors. | cyclohexanones; monochlorobenzenes; secondary amino compound | analgesic; environmental contaminant; intravenous anaesthetic; neurotoxin; NMDA receptor antagonist; xenobiotic |
| kynurenic acid | kynurenic acid : A quinolinemonocarboxylic acid that is quinoline-2-carboxylic acid substituted by a hydroxy group at C-4. Kynurenic Acid: A broad-spectrum excitatory amino acid antagonist used as a research tool. | monohydroxyquinoline; quinolinemonocarboxylic acid | G-protein-coupled receptor agonist; human metabolite; neuroprotective agent; nicotinic antagonist; NMDA receptor antagonist; Saccharomyces cerevisiae metabolite |
| memantine | adamantanes; primary aliphatic amine | antidepressant; antiparkinson drug; dopaminergic agent; neuroprotective agent; NMDA receptor antagonist | |
| methoctramine | aromatic ether; tetramine | muscarinic antagonist | |
| orphenadrine | orphenadrine : A tertiary amino compound which is the phenyl-o-tolylmethyl ether of 2-(dimethylamino)ethanol. Orphenadrine: A muscarinic antagonist used to treat drug-induced parkinsonism and to relieve pain from muscle spasm. | ether; tertiary amino compound | antidyskinesia agent; antiparkinson drug; H1-receptor antagonist; muscarinic antagonist; muscle relaxant; NMDA receptor antagonist; parasympatholytic |
| pentamidine | pentamidine : A diether consisting of pentane-1,5-diol in which both hydroxyl hydrogens have been replaced by 4-amidinophenyl groups. A trypanocidal drug that is used for treatment of cutaneous leishmaniasis and Chagas disease. Pentamidine: Antiprotozoal agent effective in trypanosomiasis, leishmaniasis, and some fungal infections; used in treatment of PNEUMOCYSTIS pneumonia in HIV-infected patients. It may cause diabetes mellitus, central nervous system damage, and other toxic effects. | aromatic ether; carboxamidine; diether | anti-inflammatory agent; antifungal agent; calmodulin antagonist; chemokine receptor 5 antagonist; EC 2.3.1.48 (histone acetyltransferase) inhibitor; NMDA receptor antagonist; S100 calcium-binding protein B inhibitor; trypanocidal drug; xenobiotic |
| procyclidine | procyclidine : A tertiary alcohol that consists of propan-1-ol substituted by a cyclohexyl and a phenyl group at position 1 and a pyrrolidin-1-yl group at position 3. Procyclidine: A muscarinic antagonist that crosses the blood-brain barrier and is used in the treatment of drug-induced extrapyramidal disorders and in parkinsonism. | pyrrolidines; tertiary alcohol | antidyskinesia agent; antiparkinson drug; muscarinic antagonist |
| phencyclidine | phencyclidine : A member of the class of piperidines that is piperidine in which the nitrogen is substituted with a 1-phenylcyclohexyl group. Formerly used as an anaesthetic agent, it exhibits both hallucinogenic and neurotoxic effects. Phencyclidine: A hallucinogen formerly used as a veterinary anesthetic, and briefly as a general anesthetic for humans. Phencyclidine is similar to KETAMINE in structure and in many of its effects. Like ketamine, it can produce a dissociative state. It exerts its pharmacological action through inhibition of NMDA receptors (RECEPTORS, N-METHYL-D-ASPARTATE). As a drug of abuse, it is known as PCP and Angel Dust. | benzenes; piperidines | anaesthetic; neurotoxin; NMDA receptor antagonist; psychotropic drug |
| 2,3-dihydroxyquinoxaline | 2,3-dihydroxyquinoxaline: fluorescent oxalic acid deriv. | ||
| 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 |
| bezafibrate | aromatic ether; monocarboxylic acid; monocarboxylic acid amide; monochlorobenzenes | antilipemic drug; environmental contaminant; geroprotector; xenobiotic | |
| flupirtine | flupirtine: RN given refers to parent cpd without isomeric designation | aminopyridine | |
| eliprodil | 1-(4-chlorophenyl)-2-[4-(4-fluorobenzyl)piperidin-1-yl]ethanol : A member of the class of piperidines that is piperidine substituted by a 2-(4-chlorophenyl)-2-hydroxyethyl group at position 1 and by a 4-fluorobenzyl group at position 4. | monochlorobenzenes; monofluorobenzenes; piperidines; secondary alcohol; tertiary amino compound | |
| fenofibric acid | fenofibric acid : A monocarboxylic acid that is 2-methylpropanoic acid substituted by a 4-(4-chlorobenzoyl)phenoxy group at position 2. It is a metabolite of the drug fenofibrate. fenofibric acid: RN given refers to parent cpd without isomeric designation; structure | aromatic ketone; chlorobenzophenone; monocarboxylic acid | drug metabolite; marine xenobiotic metabolite |
| 25-hydroxycholesterol | 25-hydroxy steroid; oxysterol | human metabolite | |
| budipine | budipine: RN given refers to parent cpd; structure in Negwer, 5th ed, #6541 | diarylmethane | |
| rosiglitazone | aminopyridine; thiazolidinediones | EC 6.2.1.3 (long-chain-fatty-acid--CoA ligase) inhibitor; ferroptosis inhibitor; insulin-sensitizing drug | |
| 6,7-dichloroquinoxaline-2,3-dione | |||
| pregnenolone sulfate | pregnenolone sulfate: RN given refers to (3 beta)-isomer | steroid sulfate | EC 2.7.1.33 (pantothenate kinase) inhibitor; human metabolite |
| ezogabine | ezogabine : A substituted aniline that is benzene-1,2,4-triamine bearing ethoxycarbonyl and 4-fluorobenzyl substituents at positions N-1 and N-4 respectively. An anticonvulsant used to treat seizures associated with epilepsy in adults. ezogabine: structure in first source | carbamate ester; organofluorine compound; secondary amino compound; substituted aniline | anticonvulsant; potassium channel modulator |
| 24-hydroxycholesterol | (24S)-24-hydroxycholesterol : A 24-hydroxycholesterol that has S configuration at position 24. It is the major metabolic breakdown product of cholesterol in the brain. | 24-hydroxycholesterol | biomarker; human blood serum metabolite; mouse metabolite |
| ly 293558 | tezampanel: structure given in first source; an AMPA receptor antagonist | ||
| besonprodil | besonprodil: CI-1041 is also known as PD19680; NMDA receptor antagonist for treatment of Parkinson's disease; structure in first source | ||
| philanthotoxin 343 | philanthotoxin 343: structure given in first source (see article's footnote); identical to philanthotoxin 433 except that the number of methylene groups between the respective amine moieties is 3,4,3 instead of 4,3,3 | N-acyl-amino acid | |
| dizocilpine | secondary amino compound; tetracyclic antidepressant | anaesthetic; anticonvulsant; neuroprotective agent; nicotinic antagonist; NMDA receptor antagonist | |
| memantine hydrochloride | hydrochloride | antidepressant; antiparkinson drug; dopaminergic agent; neuroprotective agent; NMDA receptor antagonist | |
| esketamine | esketamine : The S- (more active) enantiomer of ketamine. | ketamine | analgesic; intravenous anaesthetic; NMDA receptor antagonist |
| cns 5161 | CNS 5161: structure in first source | ||
| bms204352 | BMS204352: a calcium-sensitive opener of maxi-K potassium channels; structure in first source | ||
| cp 101,606 | traxoprodil mesylate: a selective NMDA antagonist; structure given in first source | ||
| 6-methyl-2-(phenylethynyl)pyridine | 2-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 |
| dexoxadrol | |||
| 7-chloro-thiokynurenate | 7-chlorothiokynurenic acid: glycine site antagonist of NMDA receptor | ||
| N-(2,4,6-trimethylphenyl)-3-bicyclo[2.2.1]heptanecarboxamide | monoterpenoid | ||
| n-(6-chloropyridin-3-yl)-4-fluorobenzamide | N-(6-chloropyridin-3-yl)-4-fluorobenzamide: structure in first source | ||
| (3-chlorophenyl)(6,7-dimethoxy-1-((4-methoxyphenoxy)methyl)-3,4-dihydroisoquinolin-2(1h)-yl)methanone | (3-chlorophenyl)(6,7-dimethoxy-1-((4-methoxyphenoxy)methyl)-3,4-dihydroisoquinolin-2(1H)-yl)methanone: a positive modulator of GluN2C/GluN2D subunit-selective NMDA receptor | ||
| 4-(5-(4-bromophenyl)-3-(6-methyl-2-oxo-4-phenyl-1,2-dihydroquinolin-3-yl)-4,5-dihydro-1h-pyrazol-1-yl)-4-oxobutanoic acid | 4-(5-(4-bromophenyl)-3-(6-methyl-2-oxo-4-phenyl-1,2-dihydroquinolin-3-yl)-4,5-dihydro-1H-pyrazol-1-yl)-4-oxobutanoic acid: structure in first source | ||
| tcn 201 | |||
| l 745870 | 3-((4-(4-chlorophenyl)piperazin-1-yl)methyl)-1H-pyrrolo(2,3-b)pyridine: selective for D(4) receptors; structure in first source | piperazines | |
| levorphanol | Levorphanol: A narcotic analgesic that may be habit-forming. It is nearly as effective orally as by injection. | morphinane alkaloid | |
| dextromethorphan | dextromethorphan : A 6-methoxy-11-methyl-1,3,4,9,10,10a-hexahydro-2H-10,4a-(epiminoethano)phenanthrene in which the sterocenters at positions 4a, 10 and 10a have S-configuration. It is a prodrug of dextrorphan and used as an antitussive drug for suppressing cough. Dextromethorphan: Methyl analog of DEXTRORPHAN that shows high affinity binding to several regions of the brain, including the medullary cough center. This compound is an NMDA receptor antagonist (RECEPTORS, N-METHYL-D-ASPARTATE) and acts as a non-competitive channel blocker. It is one of the widely used ANTITUSSIVES, and is also used to study the involvement of glutamate receptors in neurotoxicity. | 6-methoxy-11-methyl-1,3,4,9,10,10a-hexahydro-2H-10,4a-(epiminoethano)phenanthrene | antitussive; environmental contaminant; neurotoxin; NMDA receptor antagonist; oneirogen; prodrug; xenobiotic |
| dextrorphan | Dextrorphan: Dextro form of levorphanol. It acts as a noncompetitive NMDA receptor antagonist, among other effects, and has been proposed as a neuroprotective agent. It is also a metabolite of DEXTROMETHORPHAN. | morphinane alkaloid | |
| licostinel | licostinel: a glycine site NMDA receptor antagonist; structure given in first source | ||
| ro 25-6981 | Ro 25-6981 : A member of the class of piperidines that is 4-benzylpiperidine substituted by a 3-hydroxy-3-(4-hydroxyphenyl)-2-methylpropyl group at position 1 (the 1R,2S-stereoisomer). It is a potent antagonist of the GluN2B subunit of the N-methyl-D-aspartate (NMDA) receptor. Ro 25-6981: blocks NMDA receptors containg NR2B subunit; structure in first source | benzenes; phenols; piperidines; secondary alcohol; tertiary amino compound | anticonvulsant; antidepressant; neuroprotective agent; NMDA receptor antagonist |
| eaa-090 | EAA-090: a potent N-methyl-D-aspartate antagonist; structure in first source | dialkylarylamine; tertiary amino compound | |
| pd 174494 | PD 174494: structure in first source | piperidines | |
| fpl 15896ar | |||
| 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)piperidine | 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)piperidine: an excitatory amino acid antagonist | ||
| (4-benzylpiperidin-1-yl)-(6-hydroxy-1h-indol-2-yl)methanone | (4-benzylpiperidin-1-yl)-(6-hydroxy-1H-indol-2-yl)methanone: an NR2B-subunit selective antagonist; structure in first source | ||
| tqx 173 | |||
| (1rs,1's)-peaqx | |||
| gw 9578 | GW 9578: a peroxisome proliferator-activated receptor alpha agonist; structure in first source | ||
| ica 27243 | N-(6-Chloropyridin-3-yl)-3,4-difluorobenzamide: a KCNQ2/3 channel activator; structure in first source | ||
| etoxadrol | etoxadrol: was heading 1975-94 (see under PIPERIDINES 1975-90); use PIPERIDINES to search ETOXADROL 1975-90; dissociative anesthetic with some cardiovascular effects | ketal | |
| methoxydine | 1-(1-(4-methoxyphenyl)cyclohexyl)piperidine: a glutamate NMDA receptor ligand; structure in first source | ||
| a 803467 | A 803467: an Nav1.8 sodium channel blocker; structure in first source | ||
| nitd 609 | NITD 609: an antimalarial and coccidiostat; structure in first source | ||
| wms 1410 |