THE TIME COURSE OF GLUTAMATE IN THE SYNAPTIC CLEFT
THE TIME COURSE OF GLUTAMATE IN THE SYNAPTIC CLEFT
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DOI：
10.1126/science.1359647
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发表时间：
1992-11-27
期刊：
影响因子：
56.9
通讯作者：
WESTBROOK, GL
中科院分区：
文献类型：
--
作者：
CLEMENTS, JD;LESTER, RAJ;WESTBROOK, GL
神经递质从突触间隙的峰值浓度和清除率是突触功能的重要决定因素，但神经递质浓度的时间过程是未知的在大脑中的突触。通过对突触传递过程中N-甲基-D-天冬氨酸（NMDA）受体的快速解离竞争性拮抗剂的位移进行动力学分析，估计间隙中游离谷氨酸的时程。在培养的海马突触中，谷氨酸在1.1毫摩尔时达到峰值，并以1.2毫秒的时间常数衰减。这一时间过程意味着递质使突触后NMDA受体饱和。然而，谷氨酸从α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）受体解离得快得多。因此，游离谷氨酸的时间进程预测，解离有助于衰减的AMPA受体介导的突触后电流。
The peak concentration and rate of clearance of neurotransmitter from the synaptic cleft are important determinants of synaptic function, yet the neurotransmitter concentration time course is unknown at synapses in the brain. The time course of free glutamate in the cleft was estimated by kinetic analysis of the displacement of a rapidly dissociating competitive antagonist from N-methyl-D-aspartate (NMDA) receptors during synaptic transmission. Glutamate peaked at 1.1 millimolar and decayed with a time constant of 1.2 milliseconds at cultured hippocampal synapses. This time course implies that transmitter saturates postsynaptic NMDA receptors. However, glutamate dissociates much more rapidly from alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Thus, the time course of free glutamate predicts that dissociation contributes to the decay of the AMPA receptor-mediated postsynaptic current.