中介导电性Ca2+激活通道通过功能合与球肌细胞中拉伸激活非选择性阴离子通道来激活
Tomohiro Numata1,2, Kaori Sato-Numata1,2, Masami Yoshino2
1Department of Integrative Physiology, Graduate School of Medicine, Akita University, Akita, Japan.
Frontiers in insect science
|March 12, 2024
概括
离子通道的合作门调节肌肉收缩. 这项研究表明,板卵管中的中间导电性激活 (IK) 通道被拉伸激活 (SA) 离子通道激活,揭示了节律性收缩的机制.
科学领域:
- 生理学 生理学 生理学
- 分子生物学分子生物学
- 生物物理学的生物物理.
背景情况:
- 离子通道的合作关对于肌肉收缩和心脏节奏等生理过程至关重要.
- 膜变形激活拉伸激活 (SA) 离子通道,导致Ca2+的流入.
- 这种Ca2+的流入随后激活了局部Ca2+敏感的K+通道,微调肌肉收缩.
研究的目的:
- 鉴定和表征卵管肌细胞中内源性表达的中间导电活性 (IK) 通道.
- 评估细胞外Ca2+在激活IK通道活动中的功能相关性.
- 为了研究SA和IK通道活动之间的关系,以响应机械刺激.
主要方法:
- 补丁电生理学被用来记录来自板卵管肌细胞的单通道数据.
- 细胞外Ba2+被用来区分IK通道与大导电激活 (BK) 通道.
- 实验涉及操纵细胞外Ca2+度,并使用Gd3+阻断离子通道.
主要成果:
- 鉴定出中间导电性活性 (IK) 通道,其单通道导电性为62 pS,并确认其内源表达.
- IK通道活性取决于细胞内Ca2+度,而不是电压依赖.
- 在没有细胞外Ca2+或Gd3+的情况下,IK通道活动被废除,这表明Ca2+流入是激活所需的.
- 发现IK通道活动在空间和功能上与SA通道活动相结合,两者都增加了膜拉伸.
- 机械拉伸的IK通道活性取决于细胞外Ca2+的存在.
结论:
- 介导电导性激活 (IK) 通道在卵管肌细胞中内源地表达.
- IK通道活动是由邻近的拉伸激活 (SA) 阴离子通道的活动调节的,需要Ca2+的流入.
- 在SA和IK通道之间的功能合可能是板卵管中自发节律收缩的分子机制的基础.
相关概念视频
Excitation-Contraction Coupling in Skeletal Muscles
8.2K
Excitation-contraction coupling is a series of events that occur between generating an action potential and initiating a muscle contraction. It occurs at the triad, a structure found in skeletal muscle fibers that comprise a T-tubule and terminal cisternae of the sarcoplasmic reticulum on each side. These triads are visible in longitudinally sectioned muscle fibers. They are typically located at the A-I junction — the junction between the A and I bands of the sarcomere.
When an action...
When an action...
8.2K
Feedback Regulation of Calcium Concentration
3.4K
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
3.4K
The Role of Ion Channels in Neuronal Computation
3.2K
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....
3.2K
Ligand-Gated Ion Channel Receptor: Gating Mechanism
2.2K
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...
2.2K
Voltage-gated Ion Channels
8.2K
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...
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...
8.2K
Smooth Muscle Contraction
2.9K
Smooth muscle contraction is a complex process vital for various bodily functions, from maintaining blood vessel tension to facilitating the movement of food through the digestive tract. Unlike striated muscles, smooth muscle contraction begins more slowly and lasts longer.
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
2.9K


