デンドリット型電圧ゲートナトリウムチャネルの分子同一性
Andrea Lorincz1, Zoltan Nusser
1Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary. lorincz@koki.hu
Science (New York, N.Y.)
|May 15, 2010
まとめ
Nav1.6ナトリウムチャネルサブユニットは,ピラミッド型のニューロンのデンドライトに存在し,脳の可塑性にとって不可欠なアクションポテンシャルの逆転伝播を可能にします. この発見は, dendritic 興奮性の鍵となる分子を特定しています.
科学分野:
- 神経科学は神経科学である.
- 分子生物学は分子生物学である.
- 細胞電気生理学 細胞電気生理学
背景:
- アクションポテンシャル (AP) が dendritic tree に侵入することは,シナプス性可塑性とニューロンネットワーク形成に不可欠です.
- 皮質のピラミッド細胞 (PCs) でのAPの逆伝播を司る電圧ゲートナトリウム (Nav) チャンネルの分子同一性は不明である.
研究 の 目的:
- 皮質のピラミッド細胞におけるデンドリートナブチャネルの分子基板を特定する.
- dendritic ツリー内の特定された Nav チャンネルサブユニットのサブセルラー分布を特徴付けるために.
主な方法:
- 高感度電子顕微鏡免疫ゴールド技術を使用しました.
- ヒッポカンパのCA1PC近辺および遠端デンドライト,および軸索初期セグメントにおける定量化されたNavサブユニット密度.
主要な成果:
- ヒッポキャンパスのCA1PCの近辺および遠辺デンドライトの両方で,Nav1.6サブユニットを特定しました.
- デンドライトのNav1.6サブユニット密度は,アクソン初期セグメントよりも (35-80倍) signicantly lowerでした.
- dendrites の近距離軸に沿って Nav1.6 密度の漸進的な減少が観察され, dendritic スパインのラベリングはありません.
結論:
- Nav1.6サブユニットは,ピラミッド型の細胞デンドライト内の特定のサブ細胞分布を示しています.
- Nav1.6は,デンドリット刺激性とAPの逆伝播を可能にする重要な分子成分として特定されています.
- この発見は,シナプス性可塑性とニューロンアンサンブル形成の基礎となるメカニズムについての洞察を提供します.
関連する概念動画
01:26Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
01:26Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
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.
01:24Non-gated Ion Channels
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
01:24Non-gated Ion Channels
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
01:12Mechanically-gated Ion Channels
Mechanically-gated ion channels are proteins found in eukaryotic and prokaryotic cell membranes that open in response to mechanical stress. Tension, compression, swelling, and shear stress can alter the conformation of the protein, opening a transmembrane channel that allows the passage of ions for signal transmission. In eukaryotes, mechanically-gated channels are distributed in several regions like the neurons, lungs, skin, bladder, and heart, where they play critical roles in numerous...