ラピッドタイムコースのミニチュアで, cerebellar synapses in situで刺激的な電流を誘発した
R A Silver1, S F Traynelis, S G Cull-Candy
1Department of Pharmacology, University College London, UK.
Nature
|January 9, 1992
まとめ
小脳における神経伝達には,主にL-グルタミン酸を使用します. この研究は,高速な非N-メチル-D-アスパルテート受容体電流と,小脳粒細胞におけるより遅いN-メチル-D-アスパルテートチャネル開口を明らかにし,代替理論に挑戦しています.
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
- 神経生理学 神経生理学とは
背景:
- 小脳小粒細胞は,モス繊維端から神経伝達を受けます.
- L-グルタミン酸は,この信号伝達経路を媒介する神経伝達物質であると考えられています.
- 以前の研究では,これらの細胞におけるシナプス電流の異なるメカニズムが提案されました.
研究 の 目的:
- 神経伝達が小脳小粒細胞に伝わる正確なメカニズムと運動を研究する.
- ミニチュア刺激性ポストシナプス電流 (m.e.p.s.c.) の構成要素を特徴づけること.
- 粒状細胞のシナプス電流におけるNMDAチャネルの関与に関する最近の仮説を評価する.
主な方法:
- m.e.p.s.c.および誘発電流の高解像度の電気生理学的記録
- 粒状細胞のユニークな特性 (小さなソマ,限られたプロセス,短いデンドライト) を活用するために,薄い小脳切片を使用しました.
- 現在の時間経過,薬理学,振幅分布を分析した.
主要な成果:
- 非N-メチル-D-アスパルテート (非NMDA) 受容体の異常速度の電流 (上昇時間 <100 μs,衰退 τ = 1.0 ms) を特定しました.
- 非NMDAコンポーネントに続いて直接解明可能な50 pSのN-メチル-D-アスパルテート (NMDA) チャンネル開口が観察されました.
- NMDAチャネルによるm.e.p.s.c.の唯一のメディエーションと新しい時間経過を支持する証拠は見つかりませんでした.
- 非NMDAコンポーネントは,歪んだ振幅分布を示し,量子解析に影響を与えました.
結論:
- 脳小胞粒細胞への神経伝達には,NMDA以外の成分を素早く摂取し,その後NMDAチャネルの開通を伴う.
- 発見は,これらのシナプス電流のための唯一のNMDAチャネルメディエーションの仮説を否定する.
- シナプス電流運動の差異は,異なるシナプス機能または電位フィルタリング効果から生じる可能性があります.
関連する概念動画
01:41Action Potentials
Overview
01:28Electrical Synapses
Electrical synapses found in all nervous systems play important and unique roles. In these synapses, the presynaptic and postsynaptic membranes are very close together (3.5 nm) and are actually physically connected by channel proteins forming gap junctions.
Gap junctions allow the current to pass directly from one cell to the next. In contrast, in the chemical synapse, the neurotransmitters carry the information through the synaptic cleft from one neuron to the next. They consist of two...
Gap junctions allow the current to pass directly from one cell to the next. In contrast, in the chemical synapse, the neurotransmitters carry the information through the synaptic cleft from one neuron to the next. They consist of two...
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...
01:23Propagation of Action Potentials
The propagation of an action potential refers to the process by which a nerve impulse, or "action potential," travels along a neuron.
Neurons (nerve cells) have a resting membrane potential, with a slightly negative charge inside compared to outside. This is maintained by ion channels, such as sodium (Na+) and potassium (K+) channels, which control the flow of ions. When a stimulus, like a touch or a signal from another neuron, triggers the neuron, sodium channels open, allowing sodium ions to...
Neurons (nerve cells) have a resting membrane potential, with a slightly negative charge inside compared to outside. This is maintained by ion channels, such as sodium (Na+) and potassium (K+) channels, which control the flow of ions. When a stimulus, like a touch or a signal from another neuron, triggers the neuron, sodium channels open, allowing sodium ions to...
01:27Fast Reactions
Fast reactions occurring in times shorter than the time needed to mix reactants pose a unique challenge for investigation. In a liquid-phase continuous-flow system, reactants A and B are swiftly pushed into the mixing chamber, where mixing occurs within 1 ms. The reaction mixture then flows through an observation tube, and one measures light absorption to determine species concentrations at various points of the tube. This method is most appropriate when relatively large volumes of reactants...