title: NMDA receptor antagonists sustain LTP and spatial memory: active processes mediate LTP decay.
abstract: Although long-term potentiation (LTP) is long-lasting, it is not permanent and decays within weeks after its induction. Little is known about the processes underlying this decay. Here we assessed the contribution of synaptic activity to LTP decay by determining the effect of the competitive NMDA receptor antagonist CPP on the decay of perforant path-dentate LTP. CPP blocked decay over a one-week period when administered daily following the induction of LTP, and blocked decay of the late, protein-synthesis-dependent phase of LTP when administered two days after LTP induction. CPP administered for a five-day period following spatial memory training enhanced subsequent memory retention. These data suggest that LTP is normally a persistent process that is actively reversed by NMDA receptor activation, and that both the early and late phases of LTP are dynamic processes regulated by NMDA receptors. These data also support the view that LTP is involved in maintaining spatial memory.
authors.affiliation: The Department of Biology and The Cajal Neuroscience Research Center, Division of Life Sciences, The University of Texas at San Antonio, 6900 N. Loop 1604 W., San Antonio, Texas 78249-0662, USA.
authors.forename: Desiree M
authors.initials: DM
authors.lastname: Villarreal
authors.forename: Viet
authors.initials: V
authors.lastname: Do
authors.forename: Evelyn
authors.initials: E
authors.lastname: Haddad
authors.forename: Brian E
authors.initials: BE
authors.lastname: Derrick
mesh_terms: D000818:Animals; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005508:Food Deprivation; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D018782:Maze Learning; D008568:Memory / Q000187:drug effects* / Q000502:physiology; D010879:Piperazines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology; D013997:Time Factors
chemical_list: D018691:Excitatory Amino Acid Antagonists; D010879:Piperazines; D016194:Receptors, N-Methyl-D-Aspartate; C050592:3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid