突触传递逆行性信号分子的实时电化学监测

Real-time Electrochemical Detection of Retrograde Messengers in Synaptic Transmission

神经系统是人体重要的指挥系统,神经细胞之间的信息交流主要依赖于突触前分泌的神经递质等顺行性信号分子以及突触后释放的逆行性信号分子。一氧化氮(NO)是一种重要的逆行性信号分子,能够调节突触强度和突触可塑性以适应不同的生理需求。然而,目前鲜有逆行性信号分子释放检测的报道。为了实现突触后释放逆行性信号分子NO的实时监测,本研究在碳纤维电极表面修饰铂纳米颗粒,构建了一种具有高时空分辨率、高灵敏度、响应快速的超微电化学传感器。首先采用L-精氨酸和谷氨酸刺激海马神经元,证明了海马神经元合成NO以及细胞膜上N-甲基-D-天冬氨酸受体结合谷氨酸后释放NO的能力。在此基础上,利用高钾溶液刺激突触前神经元胞体模拟神经冲动,诱导突触前释放神经递质谷氨酸,成功检测到突触后神经元产生的NO信号。本研究结果直接证实了突触传递过程伴随着逆行性信号分子释放,建立的方法为研究神经系统反馈调节和突触可塑性机制提供了有力的工具。

Nervous system is a significant command system,and the communication between neurons depends on anterograde messengers such as neurotransmitters released from presynaptic neurons and retrograde messengers from postsynaptic cells.As an important kind of retrograde messengers,nitric oxide can regulate synaptic strength for different physiological needs.Whereas,most current researches focus on presynaptic exocytosis of neurotransmitters but ignore the detection of retrograde messengers.To monitor retrograde messenger nitric oxide released from postsynaptic neurons,we developed an electrochemical sensor with rapid response,high sensitivity and spatio-temporal resolution by modifying platinum nanoparticles on carbon fiber microelectrodes.The ability of hippocampal neurons to synthesize and secrete nitric oxide was firstly evidenced by successful detection of nitric oxide released from L-arginine-or glutamate-stimulated neurons.On this basis,the neuronal transmission was initiated by stimulating presynaptic neuron with high potassium solution,and the nitric oxide released from postsynaptic neurons was monitored in real time.The results demonstrated that synaptic transmission was accompanied with the release of retrograde messengers.This method has promising potential in exploring synaptic feedback regulation and plasticity in nervous system.