中枢シナプスにおけるNMDA受容体媒介のシナプス電流の発達調節
1Department of Physiology, University of California School of Medicine, San Francisco 94143.
Nature
|June 25, 1992
まとめ
幼少期の脳の可塑性は,N-メチル-D-アスパルテート (NMDA) 受容体を含む. この研究は,発達中のNMDA受容体の機能の変化を示し,若い脳におけるシナプス可塑性を制御する分子変化を示唆しています.
科学分野:
- 神経科学は神経科学である.
- 発達生物学 発達生物学について
- シナプスの可塑性
背景:
- 中枢神経系は,発達初期に有意な可塑性を発揮する.
- 急速な刺激性シナプス伝播は,N-メチル-D-アスパルテート (NMDA) および非NMDA受容体によって媒介されます.
- 以前の研究では,NMDA受容体の機能が生命の初期に一時的に改善することを示唆していたが,技術的な課題のために直接的な機能的証拠は欠けていた.
研究 の 目的:
- NMDA受容体媒介のシナプス伝達における発達変化を調査する.
- 脳発達初期にNMDA受容体電流の運動学が変化するかどうかを判断する.
- 発達中の中枢神経系におけるシナプス性可塑性の分子基礎を探求する.
主な方法:
- 上部コリキュルスの誘発されたおよびミニチュア刺激性ポストシナプス電流 (e.p.s.cs.) の電気生理学的記録.
- NMDA受容体媒介のe.p.s.c.の持続時間と幅の比較,発達初期と年老いた動物の間で.
- NMDA受容体チャネル運動を評価するために切断された膜パッチの分析.
主要な成果:
- 誘発されたNMDA受容体媒介のe.p.s.c.の持続期間は,より高齢の動物と比較して,発達初期に著しく長かった.
- ミニチュアNMDA受容体媒介型e.p.s.c.の振幅は,開発の過程で変化しませんでした.
- 切断されたパッチのNMDA受容体の運動特性は,誘発されたe.p.s.c.で観察された長期の時間経過を反映し,遅いチャネル運動性を示した.
結論:
- 発達中の上級コリキュルにおけるNMDA受容体媒介のシナプス電流の時間経過は,主に遅いNMDAチャネル特性によって決定されます.
- これらの発見は,NMDA受容体の分子特性が発達的に調節されていることを示しています.
- NMDA受容体の特性の発達的調節は,生命の初期にシナプス可塑性を制御する上で重要な役割を果たしている可能性が高い.
関連する概念動画
01:41Action Potentials
Overview
01:19The Role of Ion Channels in Neuronal Computation
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
01:19Ligand-gated Ion Channels
Ligand-gated ion channels are transmembrane proteins with a channel for ions to pass through and a binding site for a ligand. The channel opens only when a ligand attaches to the binding site.
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
01:30Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
01:21Electrochemical Gradient and Channel Proteins: An Overview
An electrochemical gradient is a fundamental concept in biology and chemistry. It regulates the movement of ions across cell membranes. This movement is influenced by two factors:
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to the...
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to the...
01:28Action Potential: Phases of Stimulation
The action potential is a complex electrical event that occurs in excitable cells, such as neurons and muscle cells. It consists of several distinct phases, each with specific characteristics.
Resting Phase:
In this phase, the cell's membrane is at its resting potential, typically around -70 millivolts (mV) for neurons. Inside the cell, there is a higher concentration of potassium ions (K+) and a lower concentration of sodium ions (Na+). Voltage-gated sodium channels are closed, and...
Resting Phase:
In this phase, the cell's membrane is at its resting potential, typically around -70 millivolts (mV) for neurons. Inside the cell, there is a higher concentration of potassium ions (K+) and a lower concentration of sodium ions (Na+). Voltage-gated sodium channels are closed, and...