MK-801 induced retrieval, but not acquisition, deficits for passive avoidance conditioning.
Two experiments using a state-dependent retention (SDR) design determined whether MK-801 blocked the acquisition and retention of an avoidance response. In Experiments 1 and 2, rats were trained and tested 30 min after injections of either saline or MK-801 (0.05 and 0.10 mg/kg, respectively). Two minutes after training, subjects were immediately tested, and in both experiments, the avoidance response was acquired. The 24-h retention tests for Experiment 1 revealed that the data marginally supported a SDR interpretation. In Experiment 2, the dose of MK-801 was increased to 0.10 mg/kg, and the results showed that MK-801 rendered passive avoidance (PA) state-dependent. These experiments indicate that neither the 0.05 nor 0.10 mg/kg doses of MK-801 prevented acquisition of the avoidance response and that the latter dose rendered memory for PA training state-dependent. It is suggested that doses of MK-801 that did not impair PA learning can function as a cue state and influence expression of memory for PA.
Harrod
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SB
Department of Psychology, University of Kentucky, Lexington, KY 40506, USA. sharr2@pop.uky.edu
Flint
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RW
Riccio
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DC
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D003624:Darkness; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D008027:Light; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012153:Retention, Psychology / Q000187:drug effects / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists; D016291:Dizocilpine Maleate