Target type: cellularcomponent
A synapse of a mossy fiber onto the dendrite of a granule cell; each mossy fiber can have up to 50 rosettes. [NIF_Subcellular:nlx_subcell_091021, Wikipedia:Mossy_fiber_(cerebellum)]
The mossy fiber rosette is a specialized synaptic structure found in the hippocampus, a brain region crucial for learning and memory. It is formed by the presynaptic terminals of mossy fibers, axons of granule cells in the dentate gyrus, and their postsynaptic targets, the dendrites of CA3 pyramidal neurons.
The mossy fiber rosette is characterized by its unique morphology:
* **Presynaptic terminal:** The mossy fiber terminal is enlarged and contains numerous synaptic vesicles filled with neurotransmitters, primarily glutamate. It also exhibits a characteristic "rosette" shape, with a central core and radiating arms.
* **Postsynaptic dendrite:** The postsynaptic dendrite of the CA3 pyramidal neuron is highly branched and forms numerous synapses with the mossy fiber terminal.
* **Synaptic cleft:** The space between the presynaptic terminal and the postsynaptic dendrite is called the synaptic cleft. It is filled with extracellular matrix and contains molecules that regulate synaptic transmission.
**Key features of the mossy fiber rosette:**
* **High density of synapses:** Each rosette can contain hundreds of synapses, creating a highly localized and powerful synaptic input.
* **Presence of specialized proteins:** The mossy fiber rosette contains unique proteins, such as synaptotagmin-like protein 1 (Slp1), which are thought to play a role in synaptic plasticity.
* **Large synaptic boutons:** The presynaptic terminals of mossy fibers are exceptionally large, suggesting a significant release of neurotransmitters.
* **Non-conventional synaptic transmission:** The mossy fiber rosette exhibits non-conventional synaptic transmission, meaning that it can release multiple neurotransmitters, including glutamate and GABA.
**Functional significance:**
The mossy fiber rosette is thought to play a critical role in:
* **Learning and memory:** It contributes to the formation of new memories and the consolidation of existing ones.
* **Synaptic plasticity:** It exhibits high levels of synaptic plasticity, meaning that its strength can be modified by experience.
* **Excitatory transmission:** It primarily mediates excitatory transmission from the dentate gyrus to the CA3 region.
In summary, the mossy fiber rosette is a complex and specialized synaptic structure that plays a crucial role in hippocampal function and contributes to learning, memory, and synaptic plasticity. Its unique morphology and molecular composition allow for highly localized and powerful synaptic input, making it a key component of the hippocampal circuitry.'
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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 |