Postsynaptic Ca2+ Influx Mediated by Three Different Pathways during Synaptic Transmission at a Calyx-Type Synapse
Postsynaptic Ca2+ Influx Mediated by Three Different Pathways during Synaptic Transmission at a Calyx-Type Synapse
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花萼型突触突触传递过程中三种不同途径介导的突触后 Ca2 流入
DOI：
10.1523/jneurosci.18-24-10409.1998
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
B. Sakmann
中科院分区：
文献类型：
--
作者：
Johann H. Bollmann;F. Helmchen;J. Borst;B. Sakmann
在大鼠脑干切片的一个巨大的萼型突触上进行全细胞记录和Ca2+通量测量，以确定谷氨酸受体（GluR）通道和电压依赖性Ca2+通道（VDCCs）在突触传递过程中对突触后Ca2+内流的贡献。单个突触前动作电位（AP）诱发EPSP，随后是单个AP。EPSP - AP序列引起突触后Ca2+内流约3.0 pC，主要通过vdcc（约70%）和nmda -型（高达30%）通道，但也通过ampa -型（<5%）GluR通道。在−80 mV下，AMPA受体（AMPAR）和NMDA受体（NMDAR）通道介导的分数Ca2+电流（Pf）分别为1.3和11-12%。通过GluR通道的Ca2+内流的时间过程模拟表明，AMPAR通道的少量贡献仅发生在EPSP的前几毫秒，而通过NMDAR通道的内流则占主导地位。nmdar介导的Ca2+内流定位于突触前末端覆盖的区域，而VDCCs介导的Ca2+内流分布更为均匀。由于时间和空间的差异，通过三种不同途径进入的钙离子可能激活突触后细胞中不同的胞内靶点。
Whole-cell recordings and Ca2+ flux measurements were made at a giant calyx-type synapse in rat brainstem slices to determine the contribution of glutamate receptor (GluR) channels and voltage-dependent Ca2+ channels (VDCCs) to postsynaptic Ca2+ influx during synaptic transmission. A single presynaptic action potential (AP) evoked an EPSP, followed by a single AP. The EPSP–AP sequence caused a postsynaptic Ca2+ influx of ∼3.0 pC, primarily through VDCCs (∼70%) and NMDA-type (up to 30%) channels but also through AMPA-type (<5%) GluR channels. At −80 mV, the fractional Ca2+ current (Pf) mediated by AMPA receptor (AMPAR) and NMDA receptor (NMDAR) channels was 1.3 and 11–12%, respectively. Simulations of the time course of Ca2+ influx through GluR channels suggested that the small contribution of AMPAR channels occurred only during the first few milliseconds of an EPSP, whereas influx through NMDAR channels dominated later. The NMDAR-mediated Ca2+ influx was localized in regions covered by the presynaptic terminal, whereas the Ca2+ influx mediated by VDCCs was more homogeneously distributed. Because of the temporal and spatial differences, calcium ions entering through the three different pathways are likely to activate different intracellular targets in the postsynaptic cell.
影响因子：
15.9
作者：
SHARP, AA;ONEIL, MB;MARDER, E
通讯作者：
MARDER, E
海马神经元突触 NMDA 受体的甘氨酸调节。
DOI：
10.1152/jn.1996.76.5.3415
发表时间：
1996
期刊：
Journal of neurophysiology.
影响因子：
--
作者：
Wilcox,KS;Fitzsimonds,RM;Johnson,B;Dichter,MA
通讯作者：
Dichter,MA