N-methyl-D-aspartate activates different channels than do kainate and quisqualate.
N-methyl-D-aspartate activates different channels than do kainate and quisqualate.
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N-甲基-D-天冬氨酸激活的通道与红藻氨酸和使君子氨酸不同。
DOI：
10.1073/pnas.86.6.2083
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发表时间：
1989
影响因子：
11.1
通讯作者：
Bennett,MV
中科院分区：
文献类型：
--
作者：
Lerma,J;Kushner,L;Zukin,RS;Bennett,MV
在哺乳动物中枢神经系统中，兴奋性氨基酸递质L-谷氨酸激活三种不同的受体，N-甲基-D-天冬氨酸（NMDA）、红藻氨酸和使君子酸受体。本文件解决的问题，这三个受体是否独立运作的渠道，或者他们是否共享渠道，可能有几个电导子状态。非洲爪蟾卵母细胞提供了一个表达外源性mRNA的系统，允许详细研究受体的结构和功能。在卵母细胞注射大鼠脑mRNA，NMDA的通道激活的化学计量不同于红藻氨酸和使君子酸。NMDA激活其自身的通道，如由NMDA诱发的电流与由使君子酸或红藻氨酸诱发的电流的简单总和或接近总和所示。与总和的偏差归因于缺乏选择性，其中一种受体的激动剂在另一种受体上充当弱拮抗剂。分离通道的进一步指示是，通过Mg 2+或苯环利定阻断NMDA通道对阻断期间诱发的红藻氨酸或使君子酸反应没有影响。红藻氨酸和使君子酸的相互作用更为复杂，但它们可以解释为这些激动剂对其自身受体缺乏完全特异性。
In the mammalian central nervous system, the excitatory amino acid transmitter L-glutamate activates three pharmacologically distinguishable receptors, the N-methyl-D-aspartate (NMDA), kainate, and quisqualate receptors. The present paper addresses the issue of whether these three receptors operate independent channels or whether they share channels that may have several conductance substates. The Xenopus oocyte provides a system for expression of exogenous mRNAs that permits detailed study of receptor structure and function. In oocytes injected with rat brain mRNA, NMDA has a stoichiometry of channel activation different from that for kainate and quisqualate. NMDA activates its own channels as indicated by simple summation or near-summation of currents evoked by NMDA with those evoked by quisqualate or kainate. Deviations from summation are ascribable to lack of selectivity in which an agonist at one receptor acts as a weak antagonist at another receptor. A further indication of separate channels is that block of NMDA channels by Mg2+ or phencyclidine has no effect on kainate or quisqualate responses evoked during the block. Interactions of kainate and quisqualate are more complex, but they can be explained by lack of complete specificity of these agonists for their own receptors.