まとめ
研究者らは,ニワトリとネズミの感覚神経細胞で新しいカルシウムチャネルを発見した. このチャネルは,時間および電圧に依存するユニークな性質を示し,興奮性膜におけるカルシウム伝導性の無活性化を説明します.
科学分野:
- 神経科学は神経科学である.
- 細胞生理学 細胞生理学
- イオンチャネル生物学
背景:
- カルシウムチャネルは,興奮しやすい膜の細胞機能に不可欠です.
- ニューロンのバースト発火モードは,カルシウム伝導度によって影響を受け,休憩ポテンシャルで不活性化されることが多いが,ハイパーポラライゼーションによって活性化される.
研究 の 目的:
- 感覚神経細胞の無活性化行動に責任を負う新しいタイプのカルシウムチャネルを特定し,特徴づけること.
- この新しいカルシウムチャネルの時間および電圧に依存する性質を調査するために.
主な方法:
- 鶏とネズミの感覚神経細胞の隔離された膜パッチからの電気生理学的記録.
- カルシウムチャネル運動学と無活性化特性を研究するための電圧クランプ技術.
主要な成果:
- 異なる時間および電圧に依存する特性を有する新しいカルシウムチャネルの証拠.
- このチャネルは, -50 から +10 mV の間の 3-6 ms の開口を示し,爆発的に発生します.
- 不活性化は,デポラライゼーション電圧のステップに続く長期の閉塞によって特徴付けられ,短めの開口を持つ共存する,電圧に敏感でないチャネルと区別されます.
結論:
- カルシウム伝導性の不活性化に起因する可能性が高い新しいカルシウムチャネルタイプが,感覚神経細胞で特定されました.
- この発見は,神経刺激性と機能的状態の変化を制御するメカニズムに関する新しい洞察を提供します.
関連する概念動画
01:21The Resting Membrane Potential
Overview
01:24Resting Membrane Potential
The relative difference in electrical charge, or voltage, between the inside and the outside of a cell membrane, is called the membrane potential. It is generated by differences in permeability of the membrane to various ions and the concentrations of these ions across the membrane.
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
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.
01:26Voltage-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...
01:30Ligand-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...
01:26Voltage-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...