Hofer M, Constantine-Paton M
Department of Biology, Yale University, New Haven, CT 06511.
Prog Brain Res. 1994;102:277-85. doi: 10.1016/S0079-6123(08)60546-4.
There is evidence from a number of studies that the molecular and biophysical properties of NMDA receptors are altered during normal development. A temporal correlation with changes in NMDA receptor efficacy and periods of synaptic plasticity has been demonstrated in several systems, suggesting that NMDA receptors have a critical function in determining periods of synaptic plasticity. Data from our laboratory demonstrate reduced NMDA sensitivity of the tectal evoked potential following chronic application of NMDA to the tadpole tectum, a treatment that may mimic a naturally occurring mechanism for limiting neuronal plasticity to certain stages of development. Our analysis of the expression pattern of mRNA coding for various glutamate receptor subunits in the rat retinocollicular system establishes that differential regulation of NMDA receptor subunits at the mRNA level could be a molecular basis for changes in biophysical and pharmacological properties of the NMDA receptor complex. However, even though the NMDA receptor is the best studied candidate to function as a 'plasticity switch', there are large gaps in our understanding of the complete set of factors that control the ability of synapses to rearrange during development.
多项研究表明，在正常发育过程中，NMDA受体的分子和生物物理特性会发生改变。在多个系统中已证实，NMDA受体效能的变化与突触可塑性时期存在时间相关性，这表明NMDA受体在确定突触可塑性时期方面具有关键作用。我们实验室的数据表明，在蝌蚪视顶盖长期应用NMDA后，视顶盖诱发电位的NMDA敏感性降低，这种处理可能模拟了一种自然发生的机制，即将神经元可塑性限制在发育的特定阶段。我们对大鼠视网膜-视顶盖系统中编码各种谷氨酸受体亚基的mRNA表达模式的分析表明，NMDA受体亚基在mRNA水平上的差异调节可能是NMDA受体复合物生物物理和药理学特性变化的分子基础。然而，尽管NMDA受体是作为“可塑性开关”功能研究得最为深入的候选者，但在我们对控制突触在发育过程中重新排列能力的全套因素的理解上仍存在很大差距。
