Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
Cell Rep. 2012 Apr 19;1(4):291-8. doi: 10.1016/j.celrep.2012.02.004. Epub 2012 Mar 22.
An increase in the number of AMPA-type glutamate receptors (AMPARs) is critical for long-term potentiation (LTP), synaptic plasticity regarded as a basal mechanism of learning and memory. However, when and how each type of AMPAR reaches the postsynaptic membrane remain unclear. We have developed experimental methods to form postsynaptic-like membrane (PSLM) on a glass surface to precisely visualize the location and movement of receptors. We observed fluorescence-labeled AMPAR subunits (GluA1-3) around PSLM with total internal reflection fluorescence microscopy. The increases of GluA1, 2, and 3 in PSLM showed different time courses after LTP induction. GluA1 increased first, and was exocytosed to the periphery of PSLM soon after LTP induction. GluA2 and GluA3 initially decreased, and then increased. Exocytosis of GluA2 and GluA3 occurred primarily in non-PSLM, and later than exocytosis of GluA1. Thus, GluA1-3 appear to increase in the postsynaptic membrane through distinct pathways during LTP.
AMPA 型谷氨酸受体 (AMPAR) 的数量增加对于长时程增强 (LTP) 至关重要，而 LTP 被认为是学习和记忆的基础机制之一。然而，每种类型的 AMPAR 何时以及如何到达突触后膜尚不清楚。我们已经开发了实验方法，在玻璃表面形成类似于突触后的膜 (PSLM)，以精确观察受体的位置和运动。我们使用全内反射荧光显微镜观察荧光标记的 AMPAR 亚基 (GluA1-3) 在 PSLM 周围的荧光。LTP 诱导后，PSLM 中 GluA1、2 和 3 的增加呈现出不同的时程。GluA1 首先增加，并在 LTP 诱导后很快被外排到 PSLM 的外围。GluA2 和 GluA3 最初减少，然后增加。GluA2 和 GluA3 的外排主要发生在非 PSLM 中，并且晚于 GluA1 的外排。因此，在 LTP 过程中，GluA1-3 似乎通过不同的途径增加到突触后膜中。
