カリックス型ターミナルにおけるグルタミン酸の放出におけるカルシウム感受性

J H Bollmann¹, B Sakmann, J G Borst

¹Max-Planck-Institute for Medical Research, Department of Cell Physiology, Jahnstrasse 29, D-69120 Heidelberg, Germany. jbollman@mpimf-heidelberg.mpg.de

Science (New York, N.Y.)

|August 11, 2000

まとめ

この研究は,ラットの聴覚脳幹シナプスにおける高カルシウム感受性を明らかにし,細胞内カルシウムのわずかな増加がグルタミン酸の放出を迅速に誘発し,シナプス機能に影響を与える.

科学分野:

神経科学は神経科学である.
シナプス生理学シナプス生理学
聴覚神経生物学聴覚神経生物学

背景:

シナプスの有効性は,シナプスの前の細胞内カルシウム濃度 ([Ca2+]i) によって調節されます.
神経伝達物質の放出におけるカルシウムの役割を理解することは,聴覚処理において極めて重要です.

研究の目的:

ネズミの聴覚脳幹シナプスでグルタミン酸の放出によるカルシウム感受性を定量化するために.
カルシウム誘発放出と生理学的アクションポテンシャル誘発放出を比較するために.

主な方法:

檻に閉じ込められたカルシウムのレーザー光分解は,プレシナプス [Ca2+]i.を正確に制御するために使用されました.
グルタミン酸の放出は,制御されたカルシウムトランジエントへの反応として測定されました.
放出のためのカルシウム濃度-反応曲線が生成されました.

主要な成果:

1マイクロモラまでの[Ca2+]i増加は,グルタミン酸の放出を誘発するのに十分であった.
放出可能な水泡池の急速な枯渇は,0.5ミリ秒以内に[Ca2+]i>30マイクロモールで発生しました.
生理学的放出パターンは[Ca2+]iが約10マイクロモラに増加することで再現できる.

結論:

聴覚脳幹のシナプスは,グルタミン酸の放出に対する高カルシウム感受性を示す.
段階的および遅延放出メカニズムの区別は,これまで考えられていたよりも顕著ではないかもしれません.

さらに関連する動画

08:39

Ex Vivo Release of Calcitonin Gene-Related Peptide from the Trigeminovascular System in Rodents

Published on: May 16, 2022

06:05

Advanced Glycation End-Products Sensitize Human Sensory-Like Neuron Cells to Capsaicin-Induced Calcium Influx

Published on: May 2, 2025

関連する概念動画

01:19

Ligand-gated Ion Channels

Ligand-gated ion channels are transmembrane proteins with a channel for ions to pass through and a binding site for a ligand. The channel opens only when a ligand attaches to the binding site.
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...

01:21

G-Protein Gated Ion Channels

GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...

01:30

Ligand-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...

01:24

Local Anesthetics: Differential Sensitivity of Nerve Fibers

Local anesthetics (LAs) block the sodium channels of nerve trunks, sensory nerve endings, and neuromuscular junctions. Although LAs can block all kinds of nerves, the sensitivity of nerve fibers differs according to nerve types and structures. LAs are known to block myelinated fibers faster than unmyelinated ones. Also, they block pain or sensory neurons at low concentrations without affecting the motor neurons involved in muscle contractions. This helps relieve labor pain without affecting the...

01:26

Chemical 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...

01:24

The Physiology of Taste

The perception of a salty flavor is facilitated by sodium ions within the oral salivary fluid. Upon consumption of a salty substance, salt crystals disassemble, leading to the liberation of its constituents—Na+ and Cl- ions. These ions subsequently dissolve into the salivary fluid present in the oral cavity. The external environment of the gustatory cells experiences an elevation in Na+ concentration, thereby establishing a potent concentration gradient. This gradient propels the diffusion of...

関連する実験動画