MICRODOMAINS OF HIGH CALCIUM-CONCENTRATION IN A PRESYNAPTIC TERMINAL
MICRODOMAINS OF HIGH CALCIUM-CONCENTRATION IN A PRESYNAPTIC TERMINAL
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DOI：
10.1126/science.1350109
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发表时间：
1992-05-01
期刊：
影响因子：
56.9
通讯作者：
SILVER, RB
中科院分区：
文献类型：
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作者：
LLINAS, R;SUGIMORI, M;SILVER, RB
所有神经元突触前末梢释放神经递质都需要增加细胞内钙浓度。然而，钙发挥作用的机制尚不清楚。将低灵敏度钙依赖性发光蛋白（n-水母发光蛋白-J）注入巨型鱿鱼突触的突触前末端，以选择性检测高钙浓度微区。在发射器释放期间，光发射发生在特定点或量子发射域，这些点或量子发射域在长时间刺激期间保持在同一位置。在递质分泌过程中，细胞内钙浓度微区出现在质膜的细胞质表面，数量级为 200 至 300 微摩尔，这支持了这样的观点，即负责递质释放的突触囊泡融合是由活性区低亲和力钙结合位点的激活触发的。
Increases in intracellular calcium concentration are required for the release of neurotransmitter from presynaptic terminals in all neurons. However, the mechanism by which calcium exerts its effect is not known. A low-sensitivity calcium-dependent photoprotein (n-aequorin-J) was injected into the presynaptic terminal of the giant squid synapse to selectively detect high calcium concentration microdomains. During transmitter release, light emission occurred at specific points or quantum emission domains that remained in the same place during protracted stimulation. Intracellular calcium concentration microdomains on the order of 200 to 300 micromolar occur against the cytoplasmic surface of the plasmalemma during transmitter secretion, supporting the view that the synaptic vesicular fusion responsible for transmitter release is triggered by the activation of a low-affinity calcium-binding site at the active zone.