Optical monitoring of glutamate release at multiple synapses in situ detects changes following LTP induction
Optical monitoring of glutamate release at multiple synapses in situ detects changes following LTP induction
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DOI：
10.1186/s13041-020-00572-x
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发表时间：
2020-03-13
期刊：
影响因子：
3.6
通讯作者：
Rusakov, Dmitri A.
中科院分区：
文献类型：
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作者：
Kopach, Olga;Zheng, Kaiyu;Rusakov, Dmitri A.
大脑中的信息处理和记忆形成依赖于突触前轴突特化释放主要的兴奋性神经递质谷氨酸。突触记忆的经典Hebbian范式，即传递的长时程增强（LTP），已被广泛地与突触后受体电流的增加相关联。LTP诱导是否以及在多大程度上也增强突触前谷氨酸释放一直是争论的主题。在这里，我们利用最近开发的遗传编码的光学传感器谷氨酸（iGluSnFR）监测其释放在急性海马切片CA 3-CA 1突触，诱导LTP之前和之后。我们试图通过快速帧扫描模式下的双光子激发成像来同时追踪多个突触的释放事件。因此，我们检测到一个显着增加的平均iGluSnFR信号增强过程中，持续长达90分钟。这种增加可能反映了释放谷氨酸的量增加，或者，减少谷氨酸结合到高亲和力的谷氨酸转运蛋白与iGluSnFR竞争。
Information processing and memory formation in the brain relies on release of the main excitatory neurotransmitter glutamate from presynaptic axonal specialisations. The classical Hebbian paradigm of synaptic memory, long-term potentiation (LTP) of transmission, has been widely associated with an increase in the postsynaptic receptor current. Whether and to what degree LTP induction also enhances presynaptic glutamate release has been the subject of debate. Here, we took advantage of the recently developed genetically encoded optical sensors of glutamate (iGluSnFR) to monitor its release at CA3-CA1 synapses in acute hippocampal slices, before and after the induction of LTP. We attempted to trace release events at multiple synapses simultaneously, by using two-photon excitation imaging in fast frame-scanning mode. We thus detected a significant increase in the average iGluSnFR signal during potentiation, which lasted for up to 90 min. This increase may reflect an increased amount of released glutamate or, alternatively, reduced glutamate binding to high-affinity glutamate transporters that compete with iGluSnFR.