在扩张性心肌病中,肉质细胞网膜的收缩性和Ca2+释放活性在扩张性心肌病中
A D'Agnolo1, G B Luciani, A Mazzucco
1Institute of Cardiovascular Surgery, University of Padua, Italy.
Circulation
|February 1, 1992
概括
异常扩张性心肌病显示正常的收缩性蛋白质,但异常的质网膜释释放道. 这表明激发 - 收缩合在疾病中发挥了作用.
科学领域:
- 心血管生理学心血管生理学
- 分子心脏病学分子心脏病学
- 肌肉生物学 肌肉生物学
背景情况:
- 异常扩张性心肌病 (IDC) 影响心肌功能.
- 在非失败和IDC心脏中,对质网膜 (SR) Ca2+释放和收缩器官敏感性的比较分析至关重要.
研究的目的:
- 为了比较SR的Ca2+释放活性和IDC和无IDC的人类心脏收缩器械的敏感性.
- 调查激发 - 收缩合在IDC病变发生过程中的作用.
主要方法:
- 使用了从人类心脏 (非失败和IDC) 中化学剥离的心肌纤维.
- 同度张力测量评估了收缩装置的Ca2+敏感性和通过咖啡因挑战释放的SR Ca2+.
- 研究了不同拉伸长度 (130%和150%的静止长度) 的纤维.
主要成果:
- 在正常心肌和IDC心肌之间在130%的休息时间内没有观察到Ca2+敏感性或合作性的显著差异.
- 增加拉伸 (150%) 在两组中都提高了Ca2+敏感性,但在IDC中降低了希尔系数.
- 在IDC中,Ca2+释放的咖啡因值显著增加,表明SR功能发生了变化,而释放范围和速率相似.
结论:
- 收缩性和调节性蛋白质在IDC中没有改变.
- 在SR Ca2+释放通道的关门机制中的异常表明激发-收缩合在IDC病变发生过程中发挥了作用.
- 在IDC中增加咖啡因值可能是由于SR膜特性发生变化.
相关概念视频
Muscle Contraction
Muscle Contraction
In skeletal muscles, acetylcholine is released by nerve terminals at the motor endplate—the point of synaptic communication between motor neurons and muscle fibers. The binding of acetylcholine to its receptors on the sarcolemma allows entry of sodium ions into the cell and triggers an action potential in the muscle cell. Thus, electrical signals from the brain are transmitted to the muscle. Subsequently, the enzyme acetylcholinesterase breaks down acetylcholine to prevent excessive muscle...
Relaxation of Skeletal Muscles
The period of muscle contraction primarily influences the duration of stimulation at the neuromuscular junction (NMJ), the presence of free calcium ions in the sarcoplasm, and the availability of energy or ATP to support contractions.
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
Specialized Characteristics of Cardiac Muscles
The primary role of cardiac muscles is to propel blood throughout the cardiovascular system. The cardiac muscle cells, or cardiomyocytes, exhibit specialized characteristics that allow them to perform this function.
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy reserves in...
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy reserves in...
Smooth Muscle Contraction
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...
Cardiomyopathy III: Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy, or HCM, is an autosomal dominant genetic disorder characterized by asymmetric left ventricular hypertrophy without ventricular dilation. It is more common in men and is typically diagnosed in young, athletic adults.EtiologyHCM is primarily genetic and is caused by mutations in genes encoding sarcomeric proteins. Researchers have identified over 1400 mutations across at least 11 different genes. Among these, the most frequently occurring mutations are found in the...


