An isolated pool of vesicles recycles at rest and drives spontaneous neurotransmission
An isolated pool of vesicles recycles at rest and drives spontaneous neurotransmission
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DOI：
10.1016/j.neuron.2004.12.056
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发表时间：
2005-02-17
期刊：
影响因子：
16.2
通讯作者：
Kavalali, ET
中科院分区：
文献类型：
--
作者：
Sara, Y;Virmani, T;Kavalali, ET
突触囊泡的自发融合是所有突触的共同特性。为了追踪海马突触中自发融合小泡的起源，我们用荧光苯乙烯染料、抗突触结合蛋白-1抗体或辣根过氧化物酶标记小泡。我们可以证明，突触囊泡在休息时循环，在自发的外吞-内吞作用后，它们聚集在一个有限大小的不情愿释放的池中。有趣的是，与用活性标记的囊泡相比，该自发标记池中的囊泡更可能自发地再融合。我们发现，在休息时阻断囊泡再填充选择性地耗尽自发融合囊泡的神经递质，而不显著改变诱发传递。此外，在囊泡陷阱蛋白小突触泡蛋白（VAMP）的情况下，活性依赖性和自发回收囊泡可以混合，这表明小突触泡蛋白在两个池的分离中的作用。总之，这些结果表明，自发回收囊泡和活性依赖性回收囊泡来自不同的池，相互之间的串扰有限。
Spontaneous synaptic vesicle fusion is a common property of all synapses. To trace the origin of spontaneously fused vesicles in hippocampal synapses, we tagged vesicles with fluorescent styryl dyes, antibodies against synaptotagmin-1, or horseradish peroxidase. We could show that synaptic vesicles recycle at rest, and after spontaneous exo-endocytosis, they populate a reluctantly releasable pool of limited size. Interestingly, vesicles in this spontaneously labeled pool were more likely to re-fuse spontaneously compared to vesicles labeled with activity. We found that blocking vesicle refilling at rest selectively depleted neurotransmitter from spontaneously fusing vesicles without significantly altering evoked transmission. Furthermore, in the absence of the vesicle SNARE protein synaptobrevin (VAMP), activity-dependent and spontaneously recycling vesicles could mix, suggesting a role for synaptobrevin in the separation of the two pools. Taken together these results suggest that spontaneously recycling vesicles and activity-dependent recycling vesicles originate from distinct pools with limited cross-talk with each other.