顺序依赖的反极化是由内源的动力潜力持续时间梯度调节的,而不是心室肌肉中的电合
Grace A Blair1,2, Madeline Depman1,2, William P Adams2
1Graduate Program in Translational Biology Medicine and Health, Virginia Tech Roanoke VA USA.
Journal of the American Heart Association
|December 24, 2024
概括
电气合不会显著影响作用电位持续时间 (APD) 的异质性. 相反,内生梯度和刺激器件是心脏组织中APD变化的主要驱动因素.
科学领域:
- 心脏电生理学 心脏电生理学
- 计算生物学 计算生物学
- 药理学 药理学是指药理学的学科.
背景情况:
- 之前的研究表明,电联会影响激活时间 (AT) 和作用电位持续时间 (APD) 之间的关系.
- 然而,缺乏直接的实验证据来测试这一假设及其对APD异质性的影响.
研究的目的:
- 调查电气合的急性变化是否影响APD异质性.
- 确定其他因素 (如导电和再极化动态) 对APD异质性的影响.
主要方法:
- 经Langendorff穿透的几内亚猪心脏在表心节奏调节后被光学地图化.
- 心脏被用影响间隙连接 (carbenoxolone) 的药物治疗,触觉合 (曼尼托,德克斯),通道 (flecainide) 或通道 (E4031).
- 量化APD异质性的指标包括APD的标准偏差和AT-APD关系.
主要成果:
- APD的标准偏差随着碳醇,曼尼托尔和改变的激活序列而增加.
- AT-APD斜率基本上对药物干预不敏感,但根据激活序列而异.
- APD异质性测量受选择的度量,刺激器件和内生APD梯度的影响,模拟表明后者是比AT更强的决定因素.
结论:
- APD对导电的依赖是最小的.
- APD异质性主要由内源梯度和刺激器件决定,而不是电气合.
- 实验方法和固有的组织特性在观察到的APD异质性中起着比直接电联调制更重要的作用.
相关概念视频
01:30Cardiac Action Potential
961
Cardiac action potentials are essential for proper heart function, enabling the rhythmic contractions needed for adequate blood circulation. Nodal cells and Purkinje fibers, specialized for electrical conduction, generate these action potentials.
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
961
01:19Electrophysiology of Normal Cardiac Rhythm
2.1K
The normal cardiac rhythm is a synchronized electrical activity that facilitates the regular and coordinated contraction of the heart muscle. This process is essential for efficient blood circulation throughout the body. The fundamental elements involved in establishing and maintaining this rhythm include the unique electrical properties of cardiac muscle cells, the sinoatrial (SA) node's pacemaker function, the specialized conducting system, and the ionic mechanisms underlying each phase...
2.1K
01:28Action Potential: Phases of Stimulation
5.0K
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...
5.0K
01:41Action Potentials
128.8K
Overview
128.8K
01:24Generation of Action Potential in Skeletal Muscles
4.1K
Every cell in the body maintains a membrane potential due to an uneven distribution of positive and negative charges across its plasma membrane. The membrane potential is measured in millivolts and quantifies the difference in charge across the membrane.
Like neurons, muscle cells are also regarded as excitable due to their capacity to change in response to stimuli, primarily due to voltage-gated ion channels embedded in their plasma membranes, which get activated by alterations in the...
Like neurons, muscle cells are also regarded as excitable due to their capacity to change in response to stimuli, primarily due to voltage-gated ion channels embedded in their plasma membranes, which get activated by alterations in the...
4.1K
01:25Correlation between ECG and Cardiac Cycle
3.4K
The electrical signals recorded on an electrocardiogram (ECG) occur before the mechanical processes of contraction and relaxation during the cardiac cycle.
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...
3.4K