RT Journal Article SR Electronic T1 Postsynaptic Density-95 Mimics and Occludes Hippocampal Long-Term Potentiation and Enhances Long-Term Depression JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 5503 OP 5506 DO 10.1523/JNEUROSCI.23-13-05503.2003 VO 23 IS 13 A1 Stein, Valentin A1 House, David R. C. A1 Bredt, David S. A1 Nicoll, Roger A. YR 2003 UL http://www.jneurosci.org/content/23/13/5503.abstract AB Previous studies have shown that overexpression of the protein PSD-95 (postsynaptic density-95) selectively enhances AMPA receptor-mediated synaptic responses in hippocampal pyramidal cells. To determine whether this effect is related to synaptic plasticity at these synapses, we examined whether PSD-95 expression mimics long-term potentiation (LTP), and also whether it influences LTP and long-term depression (LTD) in hippocampal slice cultures. Using simultaneous recording from transfected or infected cells and control pyramidal cells, we found that PSD-95, similar to LTP, increases the amplitude and frequency of miniature EPSCs. It also converts silent synapses to functional synapses, as does LTP. In addition, LTP is completely occluded in cells expressing PSD-95, whereas LTD is greatly enhanced. These results suggest that common mechanisms are involved in controlling synaptic AMPA receptors by PSD-95 and synaptic plasticity.