SINGLE-CHANNEL CONDUCTANCES OF NMDA RECEPTORS EXPRESSED FROM CLONED CDNAS - COMPARISON WITH NATIVE RECEPTORS
SINGLE-CHANNEL CONDUCTANCES OF NMDA RECEPTORS EXPRESSED FROM CLONED CDNAS - COMPARISON WITH NATIVE RECEPTORS
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DOI：
10.1098/rspb.1992.0159
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发表时间：
1992-12-22
影响因子：
4.7
通讯作者：
COLQUHOUN, D
中科院分区：
文献类型：
--
作者：
STERN, P;BEHE, P;COLQUHOUN, D
为了阐明天然NMDA型谷氨酸受体的亚基组成，已在爪蟾卵母细胞中成对表达了NMDA受体的四个克隆亚基，并测量了它们的单通道特性。通道的电导率，和它们的特征模式的子级转换，原来是有用的诊断标准的亚基组成。NR 1-NR 2A和NR 1-NR 2B组合（其具有相同的TM 2序列）彼此非常相似。两者都有50 pS的开口和简短的40 pS的子水平（在1毫米的外部Ca 2+），具有相似的平均寿命和频率。它们也显示出与海马CA 1和齿状回细胞以及小脑颗粒细胞的通道的密切的定量相似性，除了NR 1-NR 2A组合具有比天然通道更低的甘氨酸敏感性。相比之下，NR 1-NR 2C组合产生具有类似（短暂）持续时间的36 pS和19 pS电导的通道;这些非常类似于先前在培养的大小脑神经元中观察到的38-18 pS通道（连同50 pS通道）。
To cast light on the subunit composition of native NMDA-type glutamate receptors, four cloned subunits of the NMDA receptor have been expressed, in pairs, in Xenopus oocytes, and their single-channel properties have been measured. The conductances of the channels, and their characteristic patterns of sublevel transitions, turn out to be useful diagnostic criteria for subunit composition. The NR1-NR2A and NR1-NR2B combinations (which have identical TM2 sequences) are verv similar to each other. Both have 50 pS openings and brief 40 pS sublevels (in 1 mm external Ca2+), with similar mean lifetimes and frequencies. They also show close quantitative resemblance to the channels of hippocampal CA1 and dentate gyrus cells and of cerebellar granule cells, except that the NR1-NR2A combination has a lower glycine sensitivity than the native channels. In contrast, the NR1-NR2C combination produces a channel with 36 pS and 19 pS conductances of similar (brief) duration; these closely resemble the 38-18 pS channels that have previously been observed in large cerebellar neurons in culture (together with 50 pS channels).