Functional and Pharmacological Differences Between Recombinant N -Methyl- d -Aspartate Receptors

作者：Stefano Vicini, Jianfeng Wang, Jin Hong Li, Wei Jian Zhu, Yue Hua Wang, Jian Hong Luo, Barry B. Wolfe, Dennis R. Grayson · 发表于：Journal of Neurophysiology · 年份：1998 · DOI：10.1152/jn.1998.79.2.555 · 被引用次数：680 · 研究领域：Neuroscience and Neuropharmacology Research、Ion channel regulation and function、Receptor Mechanisms and Signaling

N-methyl-D-aspartic acid (NMDA) receptors transiently transfected into mammalian HEK-293 cells were characterized with subunit-specific antibodies and electrophysiological recordings. Deactivation time course recorded in response to fast-glutamate pulses were studied in isolated and lifted cells, as well as in outside-out membrane patches excised from cells expressing recombinant NR1 subunits in combination with the NR2A, NR2B, NR2C, or NR2D NMDA receptor subunits. Transfected cells were preidentified by the fluorescence emitted from the coexpressed Aequorea victoria jellyfish Green Lantern protein. Currents generated by NR1/NR2A channels displayed double exponential deactivation time course being faster than that in NR1/NR2B or NR1/NR2C channels. However, a large decay variability was observed within each cotransfection, suggesting that mechanisms additional to subunit composition may also regulate deactivation time course. NR1/NR2D channels displayed slowly deactivating currents. Channel deactivation was fast and comparable among receptors obtained by cotransfecting five distinct spliced variants of the NR1 subunit, each with the NR2A subunit. Additionally, recovery from desensitization was slower for NR1/NR2B than for NR1/NR2A channels. The average deactivation time course of responses to brief L-glutamate applications in cells where NR1/NR2A/NR2B cDNAs were cotransfected at variable ratio was intermediate between those of the NR1/NR2A and NR1/NR2B channels. Although immun...