アプリシア・シナプスにおける前・後シナプスメカニズムと前・後シナプスメカニズムの関わりと,前・後シナプスメカニズムの関わりと,前・後シナプスメカニズムの関わりと,前・後シナプスの関わりと,前・後シナプスの関わりと,前・後シナプスの関わ
J X Bao1, E R Kandel, R D Hawkins
1Center for Neurobiology and Behavior, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
まとめ
シナプスの可塑性の1つの形態であるポストテタニック・ポテンテーション (PTP) は,通常,プレシナプスとして見られます. この研究は,PTPが,長期にわたって維持されてきたプレシナプスのみ理論に挑戦し,ポストシナプスメカニズムも含んでいることを明らかにしています.
科学分野:
- 神経科学は神経科学である.
- 細胞生物学 細胞生物学
- シナプスの可塑性
背景:
- ポストテタニック増強 (PTP) は,短期間のシナプス可塑性の確立された形態です.
- PTPは伝統的に,神経伝達物質の放出に影響を与えるシナプス前メカニズムにのみ起因する.
研究 の 目的:
- アプリシアの感官運動ニューロンシナプスにおけるPTPの基礎となる正確なメカニズムを調査する.
- PTPはプレシナプス成分のみか,ポストシナプス要因が関与するかどうかを判断する.
主な方法:
- 実験では,細胞培養でAplysia感覚運動ニューロンシナプスを利用しました.
- カルシウムケレーターのプレシナプスおよびポストシナプス注射が行われました.
- PTPへの影響を評価するために,ポストシナプスハイパーポラライゼーションを誘導した.
主要な成果:
- プレシナプスカルシウムケレーションにより,PTPが減少し,自発的な刺激性ポストシナプスポテンシャルの頻度は増加したが,幅は増加しなかった.
- 急速なカルシウムケレーターのポストシナプス注射もPTPを減少させた.
- 同様に,ポストシナプスハイパーポラライゼーションはPTPを減少させ,ポストシナプス関わりを示した.
結論:
- これらのシナプスのPTPは,プレシナプスメカニズムによってのみ媒介されるわけではありません.
- ポストシナプス誘導機構はPTPに大きく貢献する.
- これらの発見は,短期間のシナプス可塑性についての理解を修正することを必要としています.
関連する概念動画
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Long-term Potentiation
Long-term potentiation, or LTP, is one of the ways by which synaptic plasticity—changes in the strength of chemical synapses—can occur in the brain. LTP is the process of synaptic strengthening that occurs over time between pre and postsynaptic neuronal connections. The synaptic strengthening of LTP works in opposition to the synaptic weakening of long-term depression (LTD) and together are the main mechanisms that underlie learning and memory.
Hebbian LTP
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Hebbian LTP
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Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
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Postsynaptic potential (PSP) refers to a change in the electrical potential of a neuron when neurotransmitters released by presynaptic neurons bind to postsynaptic receptors. This potential can either be excitatory, leading to depolarization and ultimately action potential generation, or inhibitory, leading to hyperpolarization and suppression of the postsynaptic neuron.
There are two types of receptors: ionotropic and metabotropic.
The ionotropic receptor is the membrane protein that has an...
There are two types of receptors: ionotropic and metabotropic.
The ionotropic receptor is the membrane protein that has an...
Integration of Synaptic Events
Synaptic integration mainly includes the summation of graded potentials. Graded potentials, regardless of their type, cause subtle alterations in membrane voltage, resulting in either depolarization or hyperpolarization. These incremental changes, when combined or summed, can propel the neuron toward its threshold. Consider, for example, a membrane experiencing a +15 mV shift, causing it to depolarize from -70 mV to -55 mV. In this scenario, graded potentials govern the membrane's ability to...


