ニューロンの興奮性の適応的調節は,電圧独立のカリウム伝導性によって行われます
S G Brickley1, V Revilla, S G Cull-Candy
1Department of Pharmacology, University College London, London WC1E 6BT, UK.
Nature
|May 9, 2001
まとめ
GABAA受容体によるトニック阻害は,小脳粒子の細胞機能に不可欠です. これらの受容体を失うと,ホメオスタティックな可塑性が生じ,K+伝導性が変化し,神経の興奮性を維持する.
科学分野:
- 神経科学は神経科学である.
- 細胞神経科学は細胞神経科学である.
- シナプスの可塑性
背景:
- ニューロンは,信号統合を調節するためにトニックシナプス入力を利用します.
- 小脳小粒細胞では,GABAの溢出が持続的なGABAA受容体媒介伝導性を生み出し,興奮性に影響を与えます.
研究 の 目的:
- 特定のGABAA受容体サブユニット (アルファ6とデルタ) が,小脳粒細胞におけるトニック伝導性を媒介する役割を調査する.
- これらのサブユニットがない粒状細胞の補償機構を理解するために.
主な方法:
- 小脳小粒細胞からの電気生理学的記録.
- GABAA受容体のアルファ6およびデルタサブユニットを除去するための遺伝子操作.
- 興奮性シナプス入力に対するニューロン応答の分析.
主要な成果:
- アルファ6およびデルタGABAA受容体サブユニットが欠けている小脳粒細胞では,トニック伝導性が欠けていた.
- 興奮性シナプス入力応答は,休憩時のリーク伝導率の増加のために変化しませんでした.
- この漏れ伝導性は,TASK-1カリウムチャネルの性質を示した.
結論:
- GABAA受容体によって媒介されるトニック抑制は,正常な小脳粒子の細胞機能に不可欠です.
- トニック阻害の喪失は,電圧独立のK+伝導性の変化を含むホメオスタティック可塑性を誘発する.
- この可塑性メカニズムは,トニック阻害の欠如にもかかわらず,神経の行動を維持します.
関連する概念動画
01:41Action Potentials
Overview
01:15Resting Potential Decay
The resting membrane potential of a neuron (-70mV) is sustained due to the selective ion permeability of the membrane. At the resting potential, the membrane is slightly permeable to ions like sodium (Na+) and chloride (Cl−) and highly permeable to potassium ions (K+). Differences in the ions' concentration inside the cell compared to the outside are maintained by membrane transport proteins like channels and pumps.
At rest, the K+ is the main ion that moves across the membrane through...
At rest, the K+ is the main ion that moves across the membrane through...
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...
01:26Voltage-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...
01:15Resting Potential Decay
The resting membrane potential of a neuron (-70mV) is sustained due to the selective ion permeability of the membrane. At the resting potential, the membrane is slightly permeable to ions like sodium (Na+) and chloride (Cl−) and highly permeable to potassium ions (K+). Differences in the ions' concentration inside the cell compared to the outside are maintained by membrane transport proteins like channels and pumps.
At rest, the K+ is the main ion that moves across the membrane through...
At rest, the K+ is the main ion that moves across the membrane through...