期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2005
卷号：102
期号：17
页码：6166-6171
DOI：10.1073/pnas.0501881102
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Synaptic plasticity at neuronal connections has been well characterized functionally by using electrophysiological approaches, but the structural basis for this phenomenon remains controversial. We have studied the dynamic interactions between presynaptic and postsynaptic structures labeled with FM 4-64 and a membrane-targeted GFP, respectively, in hippocampal slices. Under conditions of reduced neuronal activity (1 {micro}M tetrodotoxin), we observed extension of glutamate receptor-dependent processes from dendritic spines of CA1 pyramidal cells to presynaptic boutons. The formation of these spine head protrusions is blocked by -amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor antagonists and by agents that reduce the release of glutamate from presynaptic terminals. Moreover, spine head protrusions form in response to exogenously applied glutamate, with clear directionality toward the glutamate electrode. Our results suggest that spontaneously released glutamate is sufficient to activate nearby spines, which can then lead to the growth of new postsynaptic processes connecting to a presynaptic site. Spines thus can compare their recent history with that of neighboring synapses and modify local connectivity accordingly.
