LTP of AMPA and NMDA Receptor–Mediated Signals: Evidence for Presynaptic Expression and Extrasynaptic Glutamate Spill-Over

摘要: We have addressed the expression of long-term potentiation (LTP) in hippocampal CA1 by comparing AMPA and NMDA receptor-(AMPAR- NMDAR-) mediated postsynaptic signals. find that NMDAR-mediated signals accompanies LTP AMPAR-mediated signals, is associated with a change variability implying an increase quantal content. Further, tetanic can be elicited when prevented. propose mainly expressed presynaptically, that, while AMPARs respond only to glutamate from immediately apposed terminals, NMDARs also sense released terminals presynaptic neighboring cells. increases rate depression use-dependent blocker MK-801, release probability. These findings argue for contribution extrasynaptic spill-over onto NMDARs.