Intrinsic kinetics determine the time course of neuronal synaptic transporter currents.
Intrinsic kinetics determine the time course of neuronal synaptic transporter currents.
复制标题
内在动力学决定神经元突触转运蛋白电流的时间进程。
DOI：
10.1073/pnas.0510476103
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发表时间：
2006
影响因子：
11.1
通讯作者：
Jahr,CraigE
中科院分区：
文献类型：
--
作者：
Wadiche,JacquesI;Tzingounis,AnastassiosV;Jahr,CraigE
Efficient clearance of synaptically released glutamate from the extracellular space is an absolute requirement for maintaining information processing in the central nervous system. In the cerebellum, clearance of glutamate relies on uptake by Bergmann glial cells and Purkinje cells (PCs). Uptake by PCs can be monitored by recording the synaptic transport current (STC) mediated by the PC-specific transporter excitatory amino acid transporter 4 (EAAT4). The slow time course of the PC STC has been used to argue that glutamate clearance is protracted. We find, however, that the time course of the STC is not affected by altering the amount of glutamate released at individual synapses or by partial transporter blockade, manipulations that would be expected to change the duration of the extracellular glutamate transient. Ion substitution experiments and kinetic modeling of the PC transporter current suggest that physiological levels of intracellular Na+and glutamate slow the cycling rate of transporters and thereby lengthen the time course of STCs. The model predicts that PC transporters bind glutamate quickly but that the actual cycling rate of EAAT4 in physiological conditions is slow; therefore, the STC reflects the intrinsic kinetics of the glutamate transporter, not the rate of glutamate clearance.
