Immediate and long-lasting effects of MK-801 on motor activity, spatial navigation in a swimming pool and EEG in the rat.
In a series of experiments, rats received the noncompetitive N-methyl-D-aspartate (NMDA) antagonist MK-801 and measures were made of motor behavior, spatial navigation in a swimming pool, and electroencephalographic (EEG) activity. High doses (0.25-10 mg/kg IV) produced somnolence and akinesia, impaired food consumption, locomotion and swimming, and also impaired navigation to a hidden platform but complete recovery on all measures was obtained between 3 and 5 days postinjection. Lower doses (0.05-0.10 mg/kg, IV) impaired acquisition of a new place response in a swimming pool and produced hyperactivity but did not impair performance on a new cue response or on a well-learned place response. Two forms of hippocampal EEG activity, atropine-sensitive and atropine-resistant EEG were present with the low doses. The results demonstrate that a single dose of MK-801 causes changes in motor behavior and learning lasting a few days, but complete recovery occurs within 5 days of administration of even very high doses of MK-801. They further demonstrate that low doses of the drug selectively impair acquisition of new place responses. Although the general changes in behavior produced by MK-801 suggest that NMDA receptors are involved in many aspects of the control of behavior, the results additionally suggest that NMDA receptors are important for place learning.
Whishaw
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Department of Psychology, University of Lethbridge, Alberta, Canada.
Auer
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D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D001285:Atropine / Q000494:pharmacology; D001835:Body Weight / Q000187:drug effects; D003986:Dibenzocycloheptenes / Q000494:pharmacology*; D016291:Dizocilpine Maleate; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D005260:Female; D009043:Motor Activity / Q000187:drug effects*; D009949:Orientation / Q000187:drug effects*; D010830:Physostigmine / Q000494:pharmacology; D051381:Rats; D011930:Reaction Time / Q000187:drug effects; D013028:Space Perception / Q000187:drug effects*; D013550:Swimming; D013997:Time Factors
D000927:Anticonvulsants; D003986:Dibenzocycloheptenes; D016291:Dizocilpine Maleate; D001285:Atropine; D010830:Physostigmine