N-methyl-D-aspartate receptor antagonist APV blocks acquisition but not expression of fear conditioning.

摘要: The role of N-methyl-o-aspartate (NMDA) receptors in Pavlovian fear conditioning was examined using the NMDA antagonist DL-2-amino-5-phosphonovaleric acid (APV). Either APV (5 #g/rat) or saline administered before training phase, testing both. completely blocked acquisition but not expression conditioning. L enantiomer did affect conditional fear. To separate encoding from consolidation processes, either immediately after footshock unconditional stimulus (US) during phase. results indicate that must be present US to produce its effects on behavioral effect drug is due analgesic action because alter pain sensitivity. data suggest are critical for These parallel vitro long-term potentiation (LTP) and endogenously generated NMDAdependent LTP participates neural plasticity underlying Fear a rapidly acquired persistent form simple associative learning. When rat placed novel chamber presented with mild footshock, shortly afterward animal freezes. For rats, this freezing response dominant species-specific defense reaction