Effects of the NMDA receptor antagonist MK-801 on short-interval timing in rats.
Effects of MK-801, an N-methyl-D-aspartate antagonist, on short-interval timing were examined using the peak-interval (PI) and PI-gap procedures. Fisher 344 rats were given daily injections of 0.025 mg/kg, 0.05 mg/kg, and 0.2 mg/kg MK-801. The main results were (a) 0.2 mg/kg MK-801 produced an immediate overestimation of the criterion time; (b) MK-801 increased peak rate of responding; (c) 0.2 mg/kg MK-801 produced an increase in variability; (d) during the PI-gap procedure, a reset pattern was observed for all rats (MK-801 and saline). Results suggest that MK-801 has at least 2 effects. First, MK-801 interferes with short-interval timing by producing an overestimation of time and a nonscalar increase in variability. Second, MK-801 increases response rate, suggesting a decrease in response inhibition.
Department of PsychologyBowling Green State University, Bowling Green, OH, US.
Jonathan P
JP
Miller
J Devin
JD
McAuley
Kevin C H
KC
Pang
D000818:Animals; D016291:Dizocilpine Maleate / Q000008:administration & dosage / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D011930:Reaction Time / Q000187:drug effects*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*
D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate