Sun L, Shipley M T, Lidow M S
Department of Oral and Craniofacial Biological Sciences, University of Maryland, Baltimore, Maryland 21201, USA.
Synapse. 2000 Mar 1;35(3):212-21. doi: 10.1002/(SICI)1098-2396(20000301)35:3<212::AID-SYN6>3.0.CO;2-O.
Quantitative reverse transcriptase - polymerase chain reaction was used to analyze the relative expressions of NR1, NR2A, NR2B, NR2C, NR2D, and NR3 subunits of the NMDA receptor in the piriform, entorhinal, visual, and motor cortices as well as in the olfactory bulb of adult rat. The analysis detected clear differences in the relative proportions of the NMDA receptor subunits between the five forebrain regions examined. These differences were particularly striking when the piriform and motor cortices were compared. In the piriform cortex, NR1 was the predominant transcript. The expression of NR2A was only slightly higher than half of that of NR1. NR2B was expressed even at lower levels ( approximately 30% of NR1). NR2C and NR3 were expressed at levels which were approximately 15% of those of NR1. NR2D had the lowest levels of expression ( approximately 3% of NR1). In contrast, NR2B was the predominant transcript in the motor cortical region, where it was expressed at the levels close to 135% of those of NR1 message. NR2A had the levels of expression of approximately 50% of those of NR1. The NR2C expression was close to 25% that of NR1, and the NR2D and NR3 transcripts were totally absent from this cortical area. These findings suggest a significant regional variability of the NMDA receptors in the adult rat forebrain.
采用定量逆转录聚合酶链反应分析成年大鼠梨状皮质、内嗅皮质、视觉皮质、运动皮质以及嗅球中N-甲基-D-天冬氨酸（NMDA）受体的NR1、NR2A、NR2B、NR2C、NR2D和NR3亚基的相对表达。分析检测到在所检查的五个前脑区域之间，NMDA受体亚基的相对比例存在明显差异。当比较梨状皮质和运动皮质时，这些差异尤为显著。在梨状皮质中，NR1是主要转录本。NR2A的表达仅略高于NR1的一半。NR2B的表达水平更低（约为NR1的30%）。NR2C和NR3的表达水平约为NR1的15%。NR2D的表达水平最低（约为NR1的3%）。相比之下，NR2B是运动皮质区域的主要转录本，其表达水平接近NR1信使水平的135%。NR2A的表达水平约为NR1的50%。NR2C的表达接近NR1的25%，该皮质区域完全没有NR2D和NR3转录本。这些发现表明成年大鼠前脑NMDA受体存在显著的区域变异性。
