Delint-Ramírez Ilse, Salcedo-Tello Pamela, Bermudez-Rattoni Federico
Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, D.F., México.
J Neurochem. 2008 Aug;106(4):1658-68. doi: 10.1111/j.1471-4159.2008.05523.x.
NMDA receptors (NMDARs) activation in the hippocampus and insular cortex is necessary for spatial memory formation. Recent studies suggest that localization of NMDARs to lipid rafts enhance their signalization, since the kinases that phosphorylate its subunits are present in larger proportion in lipid raft membrane microdomains. We sought to determine the possibility that NMDAR translocation to synaptic lipid rafts occurs during plasticity processes such as memory formation. Our results show that water maze training induces a rapid recruitment of NMDAR subunits (NR1, NR2A, NR2B) and PSD-95 to synaptic lipid rafts and decrease in the post-synaptic density plus an increase of NR2B phosphorylation at tyrosine 1472 in the rat insular cortex. In the hippocampus, spatial training induces selective translocation of NR1 and NR2A subunits to lipid rafts. These results suggest that NMDARs translocate from the soluble fraction of post-synaptic membrane (non-raft PSD) to synaptic lipid raft during spatial memory formation. The recruitment of NMDA receptors and other proteins to lipid rafts could be an important mechanism for increasing the efficiency of synaptic transmission during synaptic plasticity process.
海马体和岛叶皮质中的N-甲基-D-天冬氨酸受体（NMDARs）激活对于空间记忆形成是必要的。最近的研究表明，NMDARs定位于脂筏可增强其信号传导，因为磷酸化其亚基的激酶在脂筏膜微区中所占比例更大。我们试图确定在诸如记忆形成等可塑性过程中，NMDARs易位至突触脂筏的可能性。我们的结果表明，水迷宫训练可诱导NMDAR亚基（NR1、NR2A、NR2B）和突触后密度蛋白95（PSD-95）快速募集至突触脂筏，并使突触后致密物减少，同时大鼠岛叶皮质中酪氨酸1472位点的NR2B磷酸化增加。在海马体中，空间训练可诱导NR1和NR2A亚基选择性易位至脂筏。这些结果表明，在空间记忆形成过程中，NMDARs从突触后膜的可溶性部分（非脂筏PSD）易位至突触脂筏。NMDA受体和其他蛋白质募集至脂筏可能是在突触可塑性过程中提高突触传递效率的重要机制。
