Stecher J, Müller W E, Hoyer S
Department of Pathochemistry and General Neurochemistry, University of Heidelberg, Federal Republic of Germany.
J Neural Transm (Vienna). 1997;104(2-3):281-9. doi: 10.1007/BF01273188.
The hippocampal NMDA-receptor is predominantly involved to establish long-term potentiation (LTP) which is assumed to underlie fundamental molecular mechanisms of learning and memory. In the present study, NMDA-receptor density was investigated in parietotemporal cerebral cortex and in hippocampus of commonly bred naive adult male Wistar rats which had performed well or poorly in the passive avoidance paradigm. NMDA-receptor binding was determined in saturation experiments using (3H) MK-801 as a ligand and data for KD and Bmax were calculated from Scatchard plots. In general, higher NMDA receptor density was found in the hippocampus as compared to parietotemporal cerebral cortex. This regional difference became particularly obvious in good performers but was abolished in poor performers. In the hippocampus, a significantly higher NMDA-receptor density could be found in rats which had performed well in the passive avoidance task as compared to poor performers. In contrast, no such differences could be found in parietotemporal cerebral cortex. The data may indicate that the reduction in hippocampal NMDA-receptor density is of functional importance, for cognitive abilities in both physiological and pathophysiological conditions.
海马体N-甲基-D-天冬氨酸受体主要参与建立长期增强作用（LTP），长期增强作用被认为是学习和记忆基本分子机制的基础。在本研究中，对在被动回避范式中表现良好或不佳的普通饲养的成年雄性Wistar大鼠的颞顶叶大脑皮层和海马体中的N-甲基-D-天冬氨酸受体密度进行了研究。使用(3H) MK-801作为配体，通过饱和实验测定N-甲基-D-天冬氨酸受体结合，并从Scatchard图计算KD和Bmax的数据。一般来说，与颞顶叶大脑皮层相比，海马体中发现的N-甲基-D-天冬氨酸受体密度更高。这种区域差异在表现良好的大鼠中尤为明显，但在表现不佳的大鼠中消失。在海马体中，与表现不佳的大鼠相比，在被动回避任务中表现良好的大鼠中可以发现显著更高的N-甲基-D-天冬氨酸受体密度。相比之下，在颞顶叶大脑皮层中未发现此类差异。这些数据可能表明，海马体N-甲基-D-天冬氨酸受体密度的降低在生理和病理生理条件下对认知能力具有重要的功能意义。
