Nonlinear summation of contractions in striated muscle. II. Potentiation of intracellular Ca2+ movements in single barnacle muscle fibres
Nonlinear summation of contractions in striated muscle. II. Potentiation of intracellular Ca2+ movements in single barnacle muscle fibres
复制标题
横纹肌收缩的非线性总和。
DOI：
10.1007/bf01756198
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发表时间：
1986
影响因子：
2.7
通讯作者：
K. Hainaut
中科院分区：
文献类型：
--
作者：
J. Duchateau;K. Hainaut
摘要非线性总和的收缩研究在单个藤壶（藤壶nubilus）肌肉纤维，加载了发光蛋白水母发光蛋白。结果表明，水母发光蛋白瞬变的非线性求和确实存在，并且对于短脉冲间隔（25-250 ms），观察到瞬变的超过线性求和，这表明在第二响应中胞质Ca 2+浓度的增加。这种增强的Ca 2+浓度不仅是由于与前一个条件瞬变的总和，而是由于第二个瞬变本身的放大。此外，第二Ca 2+反应的扩大不是延长释放或减缓细胞内细胞器再摄取的结果。相反，发现Ca 2+释放增强，并且对于短去极化（20 ms），其半重摄取时间减少。由第二标准去极化触发的增强的Ca 2+释放与在条件反应中达到的胞质Ca 2+浓度的水平相关，并且例如，在丹曲林钠存在下似乎更大，已知丹曲林钠在单次抽搐中减少Ca 2+运动。它的结论是，收缩增强非线性的总和收缩过程中观察到的，是与细胞内Ca 2+运动，相互作用，以调节收缩过程中的胞浆Ca 2+浓度的增强。
SummaryNonlinear summation of contractions is studied in single barnacle (Balanus nubilus) muscle fibres, loaded with the photoprotein aequorin. The results indicate that nonlinear summation of aequorin transients is indeed present and for short interpulse intervals (25–250 ms), a more-than-linear summation of transients, which suggest an increase of the cytosolic Ca2+ concentration in the second response, is observed. This augmented Ca2+ concentration is not merely due to summation with the preceding conditioning transient, but to an enlargement of the second transient in its own right. Furthermore, the enlargement of the second Ca2+ response is not the result of prolonged release, or slowing of re-uptake by intracellular organelles. On the contrary, Ca2+ release is found to be enhanced and for short depolarizations (20 ms), its time to half re-uptake is reduced. The intensified Ca2+ release, triggered by the second standard depolarization, is related to the level of cytosolic Ca2+ concentration reached in the conditioning response and, for example, appears to be larger in the presence of Dantrolene-sodium, which is known to reduce Ca2+ movements in a single twitch. It is concluded that contractile potentiation observed during nonlinear summation of contractions, is associated with a potentiation of intracellular Ca2+ movements, which interact to regulate the cytosolic Ca2+ concentration during contraction.
DOI：
10.1085/jgp.83.1.75
发表时间：
1984
期刊：
The Journal of general physiology
影响因子：
--
作者：
Ridgway,EB;Gordon,AM
通讯作者：
Gordon,AM