Measurements of intracellular calcium concentration in heart muscle: the effects of inotropic interventions and hypoxia.
Measurements of intracellular calcium concentration in heart muscle: the effects of inotropic interventions and hypoxia.
复制标题
心肌细胞内钙浓度的测量：正性肌力干预和缺氧的影响。
DOI：
10.1016/s0022-2828(84)80700-2
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发表时间：
1984
影响因子：
5
通讯作者：
Orchard,CH
中科院分区：
文献类型：
--
作者：
Allen,DG;Orchard,CH
描述了水母发光蛋白作为心室肌细胞内钙指示剂的用途。如果在变力性干预期间测量与每次收缩相关的细胞内钙浓度增加（钙瞬变），则可以区分两类变力性干预。一类导致与张力变化平行的钙瞬变的变化。第二类导致钙瞬变和张力的变化，其幅度或方向不同。在后一类中，收缩蛋白对钙的敏感性发生变化，并代表变力机制的重要部分。当氧化磷酸化被抑制在一个孤立的哺乳动物乳头肌，张力下降，但钙瞬变的幅度不受影响。与糖酵解速率增加相关的乳酸产生引起的细胞内酸中毒是这种张力下降的可能机制。当氧化磷酸化和糖酵解都被抑制时，钙瞬变和产生的张力都迅速下降到零。这种严重的收缩性衰竭可能是ATP水解自由能下降的结果，因此肌浆网不能再积累钙。在静息[Ca2+] i没有显著增加的情况下发生肌挛缩，可能是由于低[ATP]引起的僵直。
The use of aequorin as an intracellular calcium indicator in ventricular muscle is described. If the increase of intracellular calcium concentration associated with each contraction (the calcium transient) is measured during inotropic interventions, it is possible to distinguish two classes of inotropic intervention. One class leads to changes in the calcium transient which parallel the changes in tension. The second class lead to changes in the calcium transient and tension which are different in magnitude or direction. In this latter class changes in the sensitivity of the contractile proteins to calcium are occurring and represent an important part of the inotropic mechanisms. When oxidative phosphorylation is inhibited in an isolated mammalian papillary muscle, tension declines but the amplitude of the calcium transients is unaffected. Intracellular acidosis caused by lactate production associated with the increased rate of glycolysis is the probable mechanism of this decline in by lactate production associated with the increased rate of glycolysis is the probable mechanism of this decline in tension. When both oxidative phosphorylation and glycolysis are inhibited, both the calcium transient and the developed tension decline rapidly to zero. This profound contractile failure may be a consequence of a decline in the free energy of hydrolysis of ATP so that the sarcoplasmic reticulum can no longer accumulate calcium. Hypoxic contractures occur in the absence of significant increases in resting [Ca2+]iand are probably due to rigor produced by the low [ATP].