まとめ
アプリシアの2つの内部ニューロンは,単一のフォロワー細胞で刺激と抑制の両方を制御します. 単一の神経伝達物質であるアセチルコリンが2つの異なる受容体に作用して,これらの対極的な効果を生成します.
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:
- 内ニューロンは,神経回路の活動を調節する上で重要な役割を果たします.
- シナプス伝達メカニズムを理解することは,神経科学にとって根本的なものです.
研究 の 目的:
- アプリシアの単一のインターニューロンが刺激と阻害の両方を媒介するメカニズムを調査する.
- これらの二重反応に関与する異なったポストシナプス受容体を特徴づける.
主な方法:
- Aplysiaのブカル・ギャングリオンニューロンからの電気生理学的記録.
- 特定されたインターニューロンにおける単一のアクションポテンシャルの後のシナプスポテンシャル分析.
- アセチルコリンとコレリン阻害剤のイオノフォレティックな適用.
主要な成果:
- 特定されたインターニューロンは,フォロワー細胞で二相性 (デポラライズ・ハイパーポラライズ) シナプスポテンシャルを誘発した.
- 逆転ポテンシャルとイオン伝導量が異なる2つの異なるポストシナプス受容体が特定されました.
- 刺激成分はナトリウム伝導性を含み,抑制成分は塩化物伝導性を含んでいた.
- 両方のシナプスポテンシャル成分はアセチルコリンと特定のコレリン作用剤によって模倣され,差異的にブロックされました.
結論:
- 複数の受容体タイプに作用する単一の神経伝達物質は,反対のポストシナプス効果を媒介することができます.
- このメカニズムは,Aplysia.のニューロンの出力を調節するための洗練された方法を提供します.
- これらの受容体の異なる性質は,神経細胞のコミュニケーションの微調整を可能にします.
関連する概念動画
01:32Postsynaptic Potential (PSP)
Postsynaptic potential (PSP) refers to a change in the electrical potential of a neuron when neurotransmitters released by presynaptic neurons bind to postsynaptic receptors. This potential can either be excitatory, leading to depolarization and ultimately action potential generation, or inhibitory, leading to hyperpolarization and suppression of the postsynaptic neuron.
There are two types of receptors: ionotropic and metabotropic.
The ionotropic receptor is the membrane protein that has an...
There are two types of receptors: ionotropic and metabotropic.
The ionotropic receptor is the membrane protein that has an...
01:26Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
01:26Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
01:28Integration of Synaptic Events
Synaptic integration mainly includes the summation of graded potentials. Graded potentials, regardless of their type, cause subtle alterations in membrane voltage, resulting in either depolarization or hyperpolarization. These incremental changes, when combined or summed, can propel the neuron toward its threshold. Consider, for example, a membrane experiencing a +15 mV shift, causing it to depolarize from -70 mV to -55 mV. In this scenario, graded potentials govern the membrane's ability to...
01:29Excitatory and Inhibitory Effects of Neurotransmitters
When an action potential reaches the presynaptic axon terminal, it releases neurotransmitters from the neuron into the synaptic cleft at a chemical synapse. The released neurotransmitter can be excitatory or inhibitory. The critical criteria commonly used to determine whether a molecule is a neurotransmitter at a chemical synapse are the molecule's presence in the presynaptic neuron. Second, its release is in response to strong presynaptic depolarization. And lastly, the presence of specific...
02:47The Synapse
Neurons communicate with one another by passing on their electrical signals to other neurons. A synapse is the location where two neurons meet to exchange signals. At the synapse, the neuron that sends the signal is called the presynaptic cell, while the neuron that receives the message is called the postsynaptic cell. Note that most neurons can be both presynaptic and postsynaptic, as they both transmit and receive information.