Watanabe M, Inoue Y, Sakimura K, Mishina M
Department of Anatomy, Hokkaido University School of Medicine, Sapporo, Japan.
J Comp Neurol. 1993 Dec 15;338(3):377-90. doi: 10.1002/cne.903380305.
The distributions of five NMDA receptor channel subunit mRNAs in the mouse forebrain at postnatal day 21 were semiquantitatively examined by in situ hybridization with subunit-specific oligonucleotide probes. In contrast to ubiquitous distribution of the zeta 1 subunit mRNA throughout the forebrain, distributions of four epsilon subunit mRNAs were highly variable from nucleus to nucleus. The telencephalon (except for the septum) expressed the epsilon 1 and epsilon 2 subunit mRNAs. Various combinations of the epsilon 1, epsilon 2, epsilon 3, and epsilon 4 subunit mRNAs were present in different nuclei of the septum, the olfactory bulb, and the thalamus. In the hypothalamus, the suprachiasmatic nucleus expressed distinct signals for the epsilon 3 subunit mRNA alone, whereas other nuclei showed faint signals for the epsilon 1, epsilon 2, and epsilon 4 subunit mRNAs. Moreover, different signal levels of the epsilon subunit mRNAs were found in various regions. The hippocampal CA1 region expressed higher signals for the epsilon 1 and epsilon 2 subunit mRNAs than the CA3 region and the dentate gyrus. In the cerebral cortex, signal levels of the epsilon 1 subunit mRNA were higher in the laminae II/III, IV, and VI than the lamina V, whereas those of the epsilon 2 subunit mRNA were highest in laminae II/III and lowest in laminae IV and V. Different signal levels between the epsilon 1 and epsilon 2 subunit mRNAs were also discerned in the amygdala, the caudate-putamen, and the thalamus. The distinct anatomical distributions and differential signal levels of the epsilon subunit mRNAs strongly suggest different subunit organizations of the NMDA receptor channel in different forebrain neurons, which may result in functional diversity of the channel in vivo.
通过使用亚基特异性寡核苷酸探针进行原位杂交，对出生后第21天小鼠前脑的五种NMDA受体通道亚基mRNA的分布进行了半定量检测。与ζ1亚基mRNA在前脑普遍分布不同，四种ε亚基mRNA的分布在不同核团之间差异很大。端脑（除隔区外）表达ε1和ε2亚基mRNA。ε1、ε2、ε3和ε4亚基mRNA的不同组合存在于隔区、嗅球和丘脑的不同核团中。在下丘脑，视交叉上核仅表达ε3亚基mRNA的明显信号，而其他核团对ε1、ε2和ε4亚基mRNA显示微弱信号。此外，在不同区域发现了ε亚基mRNA的不同信号水平。海马CA1区表达的ε1和ε2亚基mRNA信号高于CA3区和齿状回。在大脑皮层，ε1亚基mRNA的信号水平在II/III层、IV层和VI层高于V层，而ε2亚基mRNA的信号水平在II/III层最高，在IV层和V层最低。在杏仁核、尾状核-壳核和丘脑中也可辨别出ε1和ε2亚基mRNA之间不同的信号水平。ε亚基mRNA独特的解剖学分布和不同的信号水平强烈提示不同前脑神经元中NMDA受体通道的亚基组成不同，这可能导致该通道在体内具有功能多样性。
