MK801-induced hyperactivity: duration of effects in rats.
MK801, a noncompetitive NMDA antagonist, induces hyperactivity, the duration of which is unknown. Thus, the hyperactivity induced by three different doses of MK801 was measured for 4 h using an automated open-field system. Adult male rats were habituated to the monitors for 1 h immediately prior to data collection. Rats were then administered one of three doses (0.05 mg/kg, n = 15; 0.1 mg/kg, n = 14; 0.5 mg/kg, n = 11) of MK801 or equivalent volumes of saline (n = 14). Upon injection, individual monitors were activated, and 48 consecutive 5-min samples were collected. Results indicated that MK801 induced hyperactivity in a dose-dependent fashion, with the two lower doses being significantly different from saline controls, but not from each other. The 0.5 mg/kg dose indicated that the peak behavioral activation occurred approximately 30 min after administration. This was followed by either a slow decline or a plateau phase, dependent upon the measure examined. By approximately 3 h after administration all measures had returned to the level of saline controls.
Hargreaves
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Department of Psychology, University of Western Ontario, London, Canada.
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D000818:Animals; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D013268:Stimulation, Chemical; D013997:Time Factors
D016291:Dizocilpine Maleate