関: axon terminal、presynaptic nerve ending、presynaptic terminal、synaptic terminal

WordNet

a period of illness; "a bout of fever"; "a bout of depression"
a contest or fight (especially between boxers or wrestlers)
(neuroscience) of or involving synapses

PrepTutorEJDIC

一試合,一勝負 / (…している)一時的な期間;(…の)発作(fit)《+『of』+『名』》

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/09/01 12:36:58」(JST)

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Activity at an axon terminal: Neuron A is transmitting a signal at the axon terminal to neuron B (receiving). Features: 1. Mitochondrion. 2. Synaptic vesicle with neurotransmitters. 3. Autoreceptor. 4. Synapse with neurotransmitter released (serotonin). 5. Postsynaptic receptors activated by neurotransmitter (induction of a postsynaptic potential). 6. Calcium channel. 7. Exocytosis of a vesicle. 8. Recaptured neurotransmitter.

Axon terminals (also called synaptic boutons) are distal terminations of the branches of an axon. An axon nerve fiber is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses (called "action potentials") away from the neuron's cell body, or soma, in order to transmit those impulses to other neurons.

Neurons are interconnected in complex arrangements, and use electrochemical signals and neurotransmitter chemicals to transmit impulses from one neuron to the next; axon terminals are separated from neighboring neurons by a small gap called a synapse, across which impulses are sent. The axon terminal, and the neuron to which it is attached, is sometimes referred to as the "presynaptic" neuron.

Nerve impulse release

Neurotransmitters are packaged into synaptic vesicles that cluster beneath the axon terminal membrane on the presynaptic side of a synapse. The axonal terminals are specialized to release the electrical impulse of the presynaptic cell.^[1] The terminals release transmitter substances into a gap called the synaptic cleft between the terminals and the dendrites of the next neuron. The information is received by the dendrite receptors of the postsynaptic cell that are connected to it. Neurons don't touch each other, but communicate across the synapse.^[2]

The neurotransmitter molecule packages (vesicles) are created within the neuron, then travel down the axon to the distal axon terminal where they sit docked. Calcium ions then trigger a biochemical cascade which results in vesicles fusing with the presynaptic membrane and releasing their contents to the synaptic cleft within 180 µs of calcium entry.^[3] Triggered by the binding of the calcium ions, the synaptic vesicle proteins begin to move apart, resulting in the creation of a fusion pore. The presence of the pore allows for the release of neurotransmitter into the synaptic cleft.^[4]^[5] The process occurring at the axon terminal is exocytosis, which a cell uses to exude secretory vesicles out of the cell membrane. These membrane-bound vesicles contain soluble proteins to be secreted to the extracellular environment, as well as membrane proteins and lipids that are sent to become components of the cell membrane. Exocytosis in neuronal chemical synapses is Ca²⁺ triggered and serves interneuronal signalling.^{[citation needed]}

Mapping activity

Dr. Wade Regehr, professor of Neurobiology developed a method to physiologically see the synaptic activity that occurs in the brain. A dye alters the fluorenscence properties when attached to calcium. Using fluorescence-microscopy techniques calcium levels are detected, and therefore the influx of calcium in the presynaptic neuron.^[6] Regehr's laboratory specializes in pre-synaptic calcium dynamics which occurs at the axon terminals. Regehr studies the implication of calcium Ca²⁺ as it affects synaptic strength.^[7]^[8] By studying the physiological process and mechanisms, a further understanding is made of neurological disorders such as epilepsy, schizophrenia and major depressive disorder, as well as memory and learning.^[9]^[10]

References

^ "Axon Terminal". Medical Dictionary Online. Retrieved February 6, 2013.
^ Foster, Sally. "Axon Terminal - Synaptic Vesicle - Neurotransmitter". Retrieved February 6, 2013. ^{[self-published source?]}^{[unreliable medical source?]}
^ Llinás R, Steinberg IZ, Walton K (1981). "Relationship between presynaptic calcium current and postsynaptic potential in squid giant synapse". Biophysical Journal 33 (3): 323–51. doi:10.1016/S0006-3495(81)84899-0. PMC 1327434. PMID 6261850.
^ Carlson, 2007, p.56^{[verification needed]}
^ Chudler, Eric H. (November 24, 2011). "Neuroscience for kids Neurotransmitters and Neuroactive Peptides". Archived from the original on December 18, 2008. Retrieved February 6, 2013. ^{[self-published source?]}^{[unreliable medical source?]}
^ Sauber, Colleen. "Focus October 20-Neurobiology VISUALIZING THE SYNAPTIC CONNECTION". Archived from the original on 2006-09-01. Retrieved July 3, 2013.
^ Regehr, Wade (1999–2008). "Wade Regehr, Ph.D.". Retrieved July 3, 2013. ^{[self-published source?]}
^ President and Fellows of Harvard College (2008). "The Neurobiology Department at Harvard Medical School". Archived from the original on 20 December 2008. Retrieved July 3, 2013.
^ "NINDS Announces New Javits Neuroscience Investigator Awardees" (Press release). National Institute of Neurological Disorders and Stroke. May 4, 2005. Archived from the original on January 17, 2009. Retrieved February 6, 2013.
^ "Scholar Awards". The McKnight Endowment Fund for Neuroscience. Archived from the original on 2004-05-08. Retrieved July 3, 2013.

UpToDate Contents

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1. 痙攣発作およびてんかんの病態生理 pathophysiology of seizures and epilepsy
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English Journal

Modulation of excitatory synaptic transmission in rat hippocampal CA3 neurons by triphenyltin, an environmental pollutant.

Wakita M1, Oyama Y2, Takase Y3, Akaike N4.
Chemosphere.Chemosphere.2015 Feb;120:598-607. doi: 10.1016/j.chemosphere.2014.09.073. Epub 2014 Oct 27.
Triphenyltin (TPT) is an organometallic compound that poses a known environmental hazard to some fish and mollusks, as well as mammals. However, its neurotoxic mechanisms in the mammalian brain are still unclear. Thus, we have investigated mechanisms through which TPT modulates glutamatergic synapti
PMID 25462303

Monoamine receptor agonists, acting preferentially at presynaptic autoreceptors and heteroreceptors, downregulate the cell fate adaptor FADD in rat brain cortex.

García-Fuster MJ1, García-Sevilla JA2.
Neuropharmacology.Neuropharmacology.2015 Feb;89:204-14. doi: 10.1016/j.neuropharm.2014.09.018. Epub 2014 Oct 5.
FADD is a crucial adaptor of death receptors that can engage apoptosis or survival actions (e.g. neuroplasticity) through its phosphorylated form (p-FADD). Although FADD was shown to participate in receptor mechanisms related to drugs of abuse, little is known on its role in the signaling of classic
PMID 25286119

Developmental Reduction of Asynchronous GABA Release from Neocortical Fast-Spiking Neurons.

Jiang M, Yang M, Yin L, Zhang X, Shu Y.
Cerebral cortex (New York, N.Y. : 1991).Cereb Cortex.2015 Jan;25(1):258-70. doi: 10.1093/cercor/bht236. Epub 2013 Aug 22.
Delayed asynchronous release (AR) evoked by bursts of presynaptic action potentials (APs) occurs in certain types of hippocampal and neocortical inhibitory interneurons. Previous studies showed that AR provides long-lasting inhibition and desynchronizes the activity in postsynaptic cells. However, w
PMID 23968835

Japanese Journal

微小神経終末部におけるCa^<2+>チャネルサブタイプ

正代清光,村山伸樹
電子情報通信学会技術研究報告. MBE, MEとバイオサイバネティックス 107(460), 51-54, 2008-01-18
中枢神経系には電位依存性Ca^<2+>チャネルとして、5種類の持続型高域値(HVA)Ca〜<2+>チャネルのサブタイプ(L,N,P,Q,R-型)と低域値(LVA)Ca^<2+>チャネルが存在し、後者はT型Ca^<2+>チャネルとも呼ばれる。本研究では、Gly作動性神経終末が投射する脊髄背側交連核(SDCN)ニューロンを機械的に単離して、'シナプス・ブ …
NAID 110006623835

Synaptophysin Expression in Rat Retina Following Acute High Intraocular Pressure

Dan Chen,Jian-Bin Tong,Hui Wang,Le-Ping Zeng,Jin Zhou,Ju-Fang Huang,Xue-Gang Luo
ACTA HISTOCHEMICA ET CYTOCHEMICA advpub(0), 0812180046, 2008
… In the present study, we investigated the protein and mRNA expression of synaptophysin (SYN), an important molecule closely related to synaptic activities, synaptogenesis and synaptic plasticity. … (3) in the outer nuclear layer bouton-like vesicle-containing structures were observed by electron microscopy. …
NAID 130000070510

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★リンクテーブル★

リンク元	「シナプスボタン」「presynaptic nerve ending」「presynaptic terminal」「synaptic terminal」
関連記事	「bout」「synaptic」「bouton」