title: Effects of stress and hippocampal NMDA receptor antagonism on recognition memory in rats.
abstract: Exposures to uncontrollable stress have been shown to alter ensuing synaptic plasticity in the hippocampus and interfere with hippocampal-dependent spatial memory in rats. The present study examined whether stress, which impairs hippocampal long-term potentiation (LTP), also affects (nonspatial) hippocampal-dependent object-recognition memory, as tested on the visual paired comparison task (VPC) in rats. After undergoing an inescapable restraint-tailshock stress experience, rats exhibited markedly impaired recognition memory at the 3-h (long) familiarization-to-test phase delay but not at the 5-min (short) delay. In contrast, unstressed control animals showed robust recognition memory (i.e., they exhibited reliable preferences for novel over familiar objects) at both short- and long-delay periods. The impairing effect of stress on long-delay recognition memory was transient because 48 h after undergoing stress experience, animals performed normally at the long delay. Similar to stress, microinfusions of DL-2-amino-5-phosphonovaleric acid (APV), a competitive N-methyl-D-aspartate receptor (NMDAR) antagonist that blocks LTP, into the dorsal hippocampus selectively impaired object-recognition memory at the long-delay period. Together, these results suggest that stress and intrahippocampal administration of APV affect recognition memory by influencing synaptic plasticity in the hippocampus.
authors: Department of Psychology, Yale University, New Haven, Connecticut 06520-8205, USA.
authors: Kevin B
authors: KB
authors: Baker
authors: Jeansok J
authors: JJ
authors: Kim
mesh_terms: D000818:Animals; D004597:Electroshock; D005528:Foot; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology; D008297:Male; D008845:Microinjections; D010364:Pattern Recognition, Visual / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D013312:Stress, Physiological / Q000209:etiology / Q000523:psychology*; D013623:Tail; D014633:Valine / Q000031:analogs & derivatives* / Q000494:pharmacology*
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; C056639:2-amino-5-phosphopentanoic acid; D014633:Valine