在KA-AMPA-接的谷氨酸受体通道中,Ca2+的透性取决于子单元组成
M Hollmann1, M Hartley, S Heinemann
1Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037.
概括
非NMDA受体,通常通过单价离子,当特定的子单元 (GluR1,GluR3) 存在时可以导电. 这一发现表明谷氨酸可能通过这些非NMDA受体激活依赖事件.
科学领域:
- 神经科学是一个神经科学.
- 分子生物学分子生物学
- 生物化学 生物化学
背景情况:
- 离子通道链接的谷氨酸受体对于神经元信号传递至关重要.
- 两个主要类别是NMDA受体和非NMDA受体.
- 传统上,人们认为非NMDA受体只能导出单价离子.
研究的目的:
- 为了研究非NMDA受体通道对二价离子的透性.
- 为了确定特定的谷氨酸受体子单元是否影响离子透性.
- 探索非NMDA受体调解流入的潜力.
主要方法:
- 在Xenopus卵细胞中,谷氨酸受体子单元 (GluR1,GluR2,GluR3) 的表达.
- 酸 (KA) 和α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) 的应用在封闭的道中.
- 测量离子电流,特别是电流,在生理休息潜力.
主要成果:
- 在KA和AMPA刺激时,表达GluR1,GluR3或GluR1+GluR3的卵细胞表现出向内电流.
- 表达GluR1+GluR2或GluR3+GluR2的卵细胞没有显示出的透性.
- GluR2亚单元的存在似乎阻止了离子电导率.
结论:
- 非NMDA受体子单元的某些组合 (特别是那些缺乏GluR2的) 可以导出离子.
- 非NMDA受体的谷氨酸激活可以导致表达这些特定子单元的神经元中的流入.
- 这种通过非NMDA受体的流入可能会触发细胞内依赖事件.
更多相关视频
相关概念视频
The 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.
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...
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...
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,...
Sensory organs,...
Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
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...
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...
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...


