AMPARs mediate the briefest synaptic currents in the brain by virtue of their rapid gating kinetics. However, at the mossy fiber-to-unipolar brush cell synapse in the cerebellum, AMPAR-mediated EPSCs last for hundreds of milliseconds, and it has been proposed that this time course reflects slow diffusion from a complex synaptic space. We show that upon release of glutamate, synaptic AMPARs were desensitized by transmitter by >90%. As glutamate levels subsequently fell, recovery of transmission occurred due to the presence of the AMPAR accessory protein stargazin that enhances the AMPAR response to low levels of transmitter. This gradual increase in receptor activity following desensitization accounted for the majority of synaptic transmission at this synapse. Moreover, the amplitude, duration, and shape of the synaptic response was tightly controlled by plasma membrane glutamate transporters, indicating that clearance of synaptic glutamate during the slow EPSC is dictated by an uptake process.

中文翻译：

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慢的AMPAR突触传递由Stargazin和谷氨酸转运蛋白确定。

AMPAR由于其快速的门控动力学而介导了大脑中最短暂的突触电流。但是，在小脑的长满苔藓的纤维与单极刷状细胞突触之间，AMPAR介导的EPSC持续数百毫秒，并且有人提出，该时间过程反映了从复杂突触空间的缓慢扩散。我们表明，一旦释放谷氨酸，突触的AMPARs就会通过递质> 90％脱敏。随着谷氨酸水平的下降，由于AMPAR辅助蛋白stargazin的存在而增强了AMPAR对低水平递质的反应，从而恢复了传播。脱敏后受体活性的这种逐渐增加占该突触处的大多数突触传递的原因。而且，振幅，持续时间，