Mechanisms of calcium release in sarcoplasmic reticulum.
Mechanisms of calcium release in sarcoplasmic reticulum.
复制标题
肌浆网钙释放机制。
DOI：
10.1016/0024-3205(76)90001-1
复制
发表时间：
1976
期刊：
影响因子：
6.1
通讯作者：
N. Malan
中科院分区：
文献类型：
--
作者：
G. Inesi;N. Malan
自从肌浆网(SR)膜的囊泡碎片出现在肌肉匀浆的微体部分(1，2)后，肌浆网(SR)在骨骼肌松弛中的作用已被广泛研究。结果表明，分离的SR囊泡在体外表现出ATP依赖性的钙转运，使培养液中的Ca~(2+)浓度降低到与生理条件下肌原纤维松弛相适应的水平(3)和速率(4，5)。然而，钙释放的问题长期以来一直难以捉摸。在这一点上，众所周知，骨骼肌SR能够储存足够激活肌原纤维的钙。因此，可以简单地假设，在膜兴奋时，从SR释放钙，从而增加肌浆中的钙浓度并启动收缩。最近的各种实验表明，从SR释放钙可以通过不同的机制发生，引起人们极大的兴趣，并可能与生理相关。这些机制将在这里讨论。
The involvement of Sarcoplasmic Reticulum (SR) in relaxation of skeletal muscle has been studied extensively since vesicular fragments of SR membrane were found in the microsomal fraction of muscle homogenates (1,2). It was shown that the isolated SR vesicles exhibit ATP dependent calcium transport in vitro, reducing the Ca2+concentration in the medium to levels (3) and at rates (4,5) compatible with relaxation of myofibrils in physiological conditions (6).The question of calcium release, however, has been elusive for a long time. In this regard it is known that skeletal muscle SR is able to store an amount of calcium which is sufficient for activation of myofibrils. Therefore, it is simply assumed that upon membrane excitation calcium is released from SR, thereby raising the Ca2+concentration in the myoplasm and initiating contraction.Recently various experiments were performed demonstrating that calcium release from SR can occur by different mechanisms of great interest and possibly of physiological relevance. These mechanisms will be discussed here.