THE EFFECTS OF MUSCLE LENGTH ON INTRACELLULAR CALCIUM TRANSIENTS IN MAMMALIAN CARDIAC-MUSCLE
THE EFFECTS OF MUSCLE LENGTH ON INTRACELLULAR CALCIUM TRANSIENTS IN MAMMALIAN CARDIAC-MUSCLE
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DOI：
10.1113/jphysiol.1982.sp014221
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发表时间：
1982-01-01
影响因子：
5.5
通讯作者：
KURIHARA, S
中科院分区：
文献类型：
--
作者：
ALLEN, DG;KURIHARA, S
将钙敏感的光蛋白Aequorin微量注射到大鼠和猫的心肌细胞内。由此产生的光发射是细胞内游离钙浓度([Ca~(2+)]i)的函数。监测伴随收缩的一过性钙离子浓度升高。在肌肉长度增加后，产生的张力立即增加，然后在几分钟内缓慢增加。随着肌肉长度的增加，每次收缩的[Ca~(2+)]i峰值最初没有变化，但随后呈现缓慢增加的趋势，其时间过程与缓慢张力变化的过程相似。作为这些缓慢变化的结果，张力-长度关系的形状取决于确定它的过程，而这种形状的变化可以归因于激活的变化。在肌肉长度增加后，立即缩短了钙瞬变。当在收缩过程中进行快速释放时，在释放后观察到短暂的[Ca~(2+)]i增加。如果肌钙蛋白与钙结合的常数是发展张力的函数，上述两个观察结果都可以解释。
The Ca-sensitive photoprotein aequorin was micro-injected into cells of rat and cat ventricular muscles. The resulting light emission is a function of intracellular free Ca concentration ([Ca2+]i). The transient increases in [Ca2+]i that accompany contraction were monitored. After an increase in muscle length, the developed tension increased immediately and then showed a slow increase over a period of minutes. The peak [Ca2+]i in each contraction was initially unchanged after an increase in muscle length but then showed a slow increase with a time course similar to that of the slow tension change. As a consequence of these slow changes, the shape of the tension-length relation depends on the procedure used to determine it and this change in shape can be attributed to changes in activation. Immediately after an increase in muscle length the Ca transient was abbreviated. When a quick release was performed during a contraction, a short-lived increase in the [Ca2+]i was observed following the release. The 2 previous observations can both be explained if the binding constant of troponin for Ca is a function of developed tension.