The Cytoplasmic Domain of Rat Synaptotagmin I Enhances Synaptic Transmission
The Cytoplasmic Domain of Rat Synaptotagmin I Enhances Synaptic Transmission
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DOI：
10.1007/s10571-014-0040-2
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发表时间：
2014-07-01
影响因子：
4
通讯作者：
Tong, Liang
中科院分区：
文献类型：
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作者：
Hua, Shao-Ying;Syed, Ali;Tong, Liang
突触聚集素是突触囊泡的一种完整的膜蛋白，在神经递质释放的时间控制中起着钙传感器的作用。尽管在生化实验中，突触素促进脂膜融合，但过表达突触素会抑制神经传递。从未观察到突触素对突触传递的易化作用。为了确定突触聚集素在体内是否可以加速突触传递，我们将大鼠突触聚集素I胞浆区(CD-Syt)注射到小龙虾运动轴突内，并检测了CD-Syt对突触反应的影响。我们证实CD-Syt可以加速神经肌肉的传递。注射制剂具有较大的突触电位和较短的上升时间。不同钙浓度的实验表明，CD-Syt增加了神经肌肉突触的最大突触反应。对神经肌肉突触的短期可塑性的进一步测试表明，CD-Syt增加了释放准备好的囊泡的释放概率。
Synaptotagmin, an integral membrane protein of synaptic vesicles, functions as a calcium sensor in the temporal control of neurotransmitter release. Although synaptotagmin facilitates lipid membrane fusion in biochemical experiments, overexpression of synaptotagmin inhibits neurotransmission. A facilitatory effect of synaptotagmin on synaptic transmission was never observed. To determine whether synaptotagmin may accelerate synaptic transmission in vivo, we injected the cytoplasmic domain of rat synaptotagmin I (CD-syt) into crayfish motor axons and tested the effect of CD-syt on synaptic response. We confirmed that CD-syt accelerates neuromuscular transmission. The injected preparation had larger synaptic potentials with shorter rise time. Experiments with varying calcium concentrations showed that CD-syt increased the maximum synaptic response of the neuromuscular synapses. Further tests on short-term plasticity of neuromuscular synapses revealed that CD-syt increases the release probability of the release-ready vesicles.