Page last updated: 2024-10-24

neuron projection terminus

Definition

Target type: cellularcomponent

The specialized, terminal region of a neuron projection such as an axon or a dendrite. [GOC:jl]

The neuron projection terminus, also known as the axon terminal or synaptic bouton, is a specialized structure at the end of a neuron's axon responsible for transmitting signals to other neurons or target cells. It's a highly complex cellular compartment, characterized by the following features:

**1. Synaptic Vesicles:**
- Abundant, small membrane-bound sacs filled with neurotransmitters, the chemical messengers that transmit signals across synapses.
- These vesicles are clustered near the presynaptic membrane, the portion of the axon terminal facing the target cell.
- They undergo exocytosis, releasing neurotransmitters into the synaptic cleft, the narrow space between the presynaptic and postsynaptic membranes.

**2. Presynaptic Membrane:**
- Specialized membrane of the axon terminal facing the target cell.
- Contains a high density of voltage-gated calcium channels, which open in response to an action potential arriving at the terminal.
- Calcium influx triggers the fusion of synaptic vesicles with the presynaptic membrane, releasing neurotransmitters into the synaptic cleft.

**3. Synaptic Cleft:**
- The narrow gap between the presynaptic and postsynaptic membranes.
- It's filled with extracellular matrix, which helps regulate the diffusion of neurotransmitters and other molecules.
- Neurotransmitters diffuse across the cleft, binding to receptors on the postsynaptic membrane of the target cell.

**4. Postsynaptic Density:**
- A dense protein structure on the postsynaptic membrane of the target cell.
- Contains receptors for neurotransmitters, as well as other signaling molecules and enzymes involved in signal transduction.
- Upon binding to neurotransmitters, these receptors trigger changes in the postsynaptic cell, leading to a response.

**5. Cytoskeleton:**
- A network of protein filaments that provides structural support and helps transport materials within the axon terminal.
- Microtubules and microfilaments ensure the precise positioning of synaptic vesicles and other organelles.

**6. Mitochondria:**
- Provide energy for the metabolic processes occurring within the axon terminal.
- They are essential for maintaining the high energy demands of neurotransmitter synthesis, vesicle cycling, and signal transduction.

**7. Enzymes and Proteins:**
- The axon terminal contains numerous enzymes and proteins involved in:
- Neurotransmitter synthesis
- Vesicle trafficking
- Receptor regulation
- Signal transduction pathways

**8. Synaptic Scaffolding Proteins:**
- A network of proteins that organize and maintain the structure of the synapse.
- They provide anchors for receptors, enzymes, and other signaling molecules, ensuring their proper localization and function.

These intricate components of the neuron projection terminus work in a coordinated manner to ensure efficient and reliable communication between neurons. The process involves the release of neurotransmitters from the presynaptic terminal, their diffusion across the synaptic cleft, and their binding to receptors on the postsynaptic cell. This intricate interplay ultimately leads to changes in the target cell's activity, contributing to the complex functions of the nervous system.'
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Proteins (5)

ProteinDefinitionTaxonomy
Disks large homolog 4A disks large homolog 4 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P78352]Homo sapiens (human)
Tyrosine-protein phosphatase non-receptor type 9A tyrosine-protein phosphatase non-receptor type 9 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P43378]Homo sapiens (human)
Excitatory amino acid transporter 2An excitatory amino acid transporter 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P43004]Homo sapiens (human)
Ubiquitin carboxyl-terminal hydrolase isozyme L1A ubiquitin carboxyl-terminal hydrolase isozyme L1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P09936]Homo sapiens (human)
NeprilysinA neprilysin that is encoded in the genome of human. [PRO:WCB, UniProtKB:P08473]Homo sapiens (human)

Compounds (41)

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
thiorphanThiorphan: A potent inhibitor of membrane metalloendopeptidase (ENKEPHALINASE). Thiorphan potentiates morphine-induced ANALGESIA and attenuates naloxone-precipitated withdrawal symptoms.N-acyl-amino acid
losartanlosartan : A biphenylyltetrazole where a 1,1'-biphenyl group is attached at the 5-position and has an additional trisubstituted imidazol-1-ylmethyl group at the 4'-position

Losartan: An antagonist of ANGIOTENSIN TYPE 1 RECEPTOR with antihypertensive activity due to the reduced pressor effect of ANGIOTENSIN II.
biphenylyltetrazole;
imidazoles
angiotensin receptor antagonist;
anti-arrhythmia drug;
antihypertensive agent;
endothelin receptor antagonist
vitamin k 3Vitamin K 3: A synthetic naphthoquinone without the isoprenoid side chain and biological activity, but can be converted to active vitamin K2, menaquinone, after alkylation in vivo.1,4-naphthoquinones;
vitamin K
angiogenesis inhibitor;
antineoplastic agent;
EC 3.4.22.69 (SARS coronavirus main proteinase) inhibitor;
human urinary metabolite;
nutraceutical
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
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
captoprilcaptopril : A L-proline derivative in which L-proline is substituted on nitrogen with a (2S)-2-methyl-3-sulfanylpropanoyl group. It is used as an anti-hypertensive ACE inhibitor drug.

Captopril: A potent and specific inhibitor of PEPTIDYL-DIPEPTIDASE A. It blocks the conversion of ANGIOTENSIN I to ANGIOTENSIN II, a vasoconstrictor and important regulator of arterial blood pressure. Captopril acts to suppress the RENIN-ANGIOTENSIN SYSTEM and inhibits pressure responses to exogenous angiotensin.
alkanethiol;
L-proline derivative;
N-acylpyrrolidine;
pyrrolidinemonocarboxylic acid
antihypertensive agent;
EC 3.4.15.1 (peptidyl-dipeptidase A) inhibitor
sym 2081
dihydrokainatedicarboxylic acid
celastrolmonocarboxylic acid;
pentacyclic triterpenoid
anti-inflammatory drug;
antineoplastic agent;
antioxidant;
EC 5.99.1.3 [DNA topoisomerase (ATP-hydrolysing)] inhibitor;
Hsp90 inhibitor;
metabolite
sq 28603SQ 28603: a selective neutral endopeptidase inhibitor
kelatorphankelatorphan: inhibitor of enkephalin metabolism; structure given in first source
(3-(n-hydroxy)carboxamido-2-benzylpropanoyl)glycine
2-(4-morpholinyl)-4h-1-benzopyran-4-one2-(4-morpholinyl)-4H-1-benzopyran-4-one: an aminochromone; exhibits both antiproliferative and antichemotactic activity in vitro
cgs 26303CGS 26303: a potent non-peptidic inhibitor of neutral endopeptidase capable of protecting atrial natriuretic peptide from enzymatic degradation; structure given in first source
bb3497BB3497: peptide deformylase inhibitor; structure in first source
cryptotanshinonecryptotanshinone: from Salvia miltiorrhizaabietane diterpenoidanticoronaviral agent
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
candoxatrilatcandoxatrilat : A dicarboxylic acid monoamide obtained by formal condensation between the amino group of cis-4-aminocyclohexanecarboxylic acid and the cyclopentanecarboxylic acid group of 1-[(2S)-2-carboxy-3-(2-methoxyethoxy)propyl]cyclopentanecarboxylic acid. A potent inhibitor of neutral endopeptidase (NEP, neprilysin, EC 3.4.24.11), it is used as its 2,3-dihydro-1H-inden-5-yl ester prodrug in the treatment of chronic heart failure.

candoxatrilat: USAN lists candoxatrilat (UK-73,967) with RN 123122-54-3
actinoninactinonin: natural hydroxamic acid, pseudopeptide antibiotic isolated from Streptomyces species; structure
phosphoramidonphosphoramidon : A dipeptide isolated from the cultures of Streptomyces tanashiensis.

phosphoramidon: a membrane metallo-endopeptidase & endothelin-converting enzyme inhibitor; thermolysin inhibitor from culture filtrate of Streptomyces tanashiensis; structure
deoxyaldohexose phosphate;
dipeptide
bacterial metabolite;
EC 3.4.24.11 (neprilysin) inhibitor;
EC 3.4.24.71 (endothelin-converting enzyme 1) inhibitor
cefsulodincefsulodin : A pyridinium-substituted semi-synthetic, broad-spectrum, cephalosporin antibiotic.

Cefsulodin: A pyridinium-substituted semisynthetic, broad-spectrum antibacterial used especially for Pseudomonas infections in debilitated patients.
cephalosporin;
organosulfonic acid;
primary carboxamide
antibacterial drug
omapatrilatomapatrilat: structure in first sourcedipeptide
4,5,6,7-tetrachloroindan-1,3-dione4,5,6,7-tetrachloroindan-1,3-dione: inhibits ubiquitin C-terminal hydrolase L1
2-amino-3-phenylmethoxybutanedioic acidaspartic acid derivative
sitagliptinsitagliptin : A triazolopyrazine that exhibits hypoglycemic activity.triazolopyrazine;
trifluorobenzene
EC 3.4.14.5 (dipeptidyl-peptidase IV) inhibitor;
environmental contaminant;
hypoglycemic agent;
serine proteinase inhibitor;
xenobiotic
thiorphan
l-ccg iii
dl-threo-beta-benzyloxyaspartate
ceftriaxone1,2,4-triazines;
1,3-thiazoles;
cephalosporin;
oxime O-ether
antibacterial drug;
drug allergen;
EC 3.5.2.6 (beta-lactamase) inhibitor
uk 81,252sampatrilat: structure in first source
acetyl isogambogic acidacetyl isogambogic acid: structure in first source
cgs 35066CGS 35066: an endothelin-converting enzyme-1 inhibitor; structure in first source
degrasyndegrasyn: a JAK2 kinase inhibitor that induces rapid degradation of c-Myc protein in MM-1 multiple myeloma and other tumor cell lines; structure in first source
vialinin avialinin A: free radical scavenger from an edible mushroom in China; structure in first source
l-beta-threo-benzyl-aspartateL-beta-threo-benzyl-aspartate: 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
tat-nr2b9cTat-NR2B9c: a synthetic peptide consisting of the C-terminal 9 amino acids of the NR2B subunit of the NMDA receptor fused to the cell membrane protein transduction domain of the HIV-1-Tat protein
ldn 57444LDN 57444: inhibitor of ubiquitin C-terminal hydrolase-L1; structure in first source
quininibquininib : A styrylquinoline that is trans-2-styrylquinoline in which the the phenyl group has been substituted at position 2 by a hydroxy group. It is an anti-angiogenic compound that exerts a dose-dependent antagonism of the cysteinyl leukotriene pathway, preferentially antagonising cysteinyl leukotriene receptor 1. The major species at pH 7.3

quininib: has antiangiogenic activity; structure in first source
phenols;
styrylquinoline
angiogenesis inhibitor