Electrophysiological Characterization of AMPA and NMDA Receptors in Rat Dorsal Striatum
Electrophysiological Characterization of AMPA and NMDA Receptors in Rat Dorsal Striatum
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DOI：
10.4196/kjpp.2009.13.3.209
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发表时间：
2009-06-01
影响因子：
2
通讯作者：
Sung, Ki-Wug
中科院分区：
文献类型：
--
作者：
Jeun, Seung Hyun;Cho, Hyeong Seok;Sung, Ki-Wug
纹状体接受来自皮质和丘脑的突触能传入，这些突触传递由α-氨基-3-羟基-5-甲基-4-异恶唑丙酸酯（AMPA）和N-甲基-D-天冬氨酸（NMDA）受体介导。本研究的目的是通过分析背侧纹状体的NMDA/AMPA比率和使用全细胞电压钳方法对AMPA和NMDA兴奋性突触后电流（EPSC）的整流来表征谷氨酸受体。受体拮抗剂用于分离受体或亚单位特异性EPSC，例如（DL）-2-氨基-5-膦酰基戊酸（APV），一种NMDA受体拮抗剂，艾芬地尔，一种NR 2B拮抗剂，CNQX，一种AMPA受体拮抗剂和IEM-1460，一种GluR 2-缺乏的AMPA受体阻断剂。AMPA和NMDA EPSC分别记录在-70和+40 mV。整流指数通过EPSC在+50和-50 mV之间的电流比计算。NMDA/AMPA比率为0.20 +/- 0.05，GluR 2缺失/GluR 2含亚基的AMPA受体比率为0.26 +/- 0.05，NR 2B/NR 2A亚基的NMDA受体比率为0.32 +/- 0.03。在存在APV以及APV和IEM-1460的组合的情况下，矫正指数（对照2.39 +/- 0.27）降低（分别为1.02 +/- 0.11和0.93 +/- 0.09）。这些结果表明，纹状体谷氨酸受体的主要成分是含GluR 2的AMPA受体和含NR 2A的NMDA受体。本研究结果为皮质纹状体突触传递和可塑性研究提供了有用的信息。
The striatum receives glutamatergic afferents from the cortex and thalamus, and these synaptic transmissions are mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) and N-methyl-D-aspartate (NMDA) receptors. The purpose of this study was to characterize glutamate receptors by analyzing NMDA/AMPA ratio and rectification of AMPA and NMDA excitatory postsynaptic currents (EPSCs) using a whole-cell voltage-clamp method in the dorsal striatum. Receptor antagonists were used to isolate receptor or subunit specific EPSC, such as (DL)-2-amino-5-phosphonovaleric acid (APV), an NMDA receptor antagonist, ifenprodil, an NR2B antagonist, CNQX, an AMPA receptor antagonist and IEM-1460, a GluR2-lacking AMPA receptor blocker. AMPA and NMDA EPSCs were recorded at - 70 and + 40 mV, respectively. Rectification index was calculated by current ratio of EPSCs between + 50 and - 50 mV. NMDA/AMPA ratio was 0.20 +/- 0.05, AMPA receptor ratio of GluR2-lacking/GluR2-containing subunit was 0.26 +/- 0.05 and NMDA receptor ratio of NR2B/NR2A subunit was 0.32 +/- 0.03. The rectification index (control 2.39 +/- 0.27) was decreased in the presence of both APV and combination of APV and IEM-1460 (1.02 +/- 0.11 and 0.93 +/- 0.09, respectively). These results suggest that the major components of the striatal glutamate receptors are GluR2-containing AMPA receptors and NR2A-containing NMDA receptors. Our results may provide useful information for corticostriatal synaptic transmission and plasticity studies.