Synaptic plasticity is the ability of synapses to modulate synaptic strength in response to dynamic changes within, as well as environmental changes. Although there is a considerable body of knowledge on protein expression and receptor migration in different categories of synaptic plasticity, the contribution and impact of presynaptic vesicle release and neurotransmitter levels towards plasticity remain largely unclear. Herein, nanoelectrochemistry using carbon fiber nanoelectrodes with excellent spatio-temporal resolution was applied for real-time monitoring of presynaptic vesicle release of dopamine inside single synapses of dopaminergic neurons, and exocytotic variations in quantity and kinetics under repetitive electrical stimuli. We found that the presynaptic terminal tends to maintain synaptic strength by rapidly recruiting vesicles, changing the dynamics of exocytosis, and maintaining sufficient neurotransmitter release in following stimuli. Except for small clear synaptic vesicles, dense core vesicles are involved in exocytosis to sustain the neurotransmitter level in later periods of repetitive stimuli. These data indicate that vesicles use a potential regulatory mechanism to establish short-term plasticity, and provide new directions for exploring the synaptic mechanisms in connection and plasticity.

中文翻译：

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纳米电化学揭示突触前神经元如何调节囊泡释放以维持重复刺激下的突触可塑性

突触可塑性是突触调节突触强度以响应内部动态变化以及环境变化的能力。尽管对不同类别的突触可塑性中的蛋白质表达和受体迁移有相当多的了解，但突触前囊泡释放和神经递质水平对可塑性的贡献和影响仍不清楚。在此，利用具有优异时空分辨率的碳纤维纳米电极的纳米电化学技术用于实时监测多巴胺能神经元单个突触内突触前囊泡释放的多巴胺，以及重复电刺激下胞吐的数量和动力学变化。我们发现突触前末梢倾向于通过快速招募囊泡、改变胞吐作用的动力学以及在后续刺激中保持足够的神经递质释放来维持突触强度。除了小的透明突触小泡外，致密的核心小泡参与胞吐作用，以在重复刺激的后期维持神经递质水平。这些数据表明囊泡利用潜在的调节机制来建立短期可塑性，为探索突触连接和可塑性机制提供了新的方向。