title: A dose of MK801 previously shown to impair spatial learning in the radial maze attenuates primed burst potentiation in the dentate gyrus of freely moving rats.
abstract: Spatial learning but not memory performance in the radial maze is disrupted by low doses of MK801 (0.0625 mg/kg ip), a noncompetitive N-methyl-D-aspartate receptor channel blocker (M. L. Shapiro & C. O'Connor, 1992). The effect of this low dose of MK801 on hippocampal physiology and synaptic plasticity was assessed in 16 behaving female Sprague-Dawley rats. The drug increased the frequency (0.5 Hz), marginally reduced the amplitude of hippocampal rhythmical slow wave activity (RSA), did not alter non-RSA slow wave activity, and reduced normal synaptic transmission from the entorhinal cortex to the dentate gyrus by approximately 8%. Independent of these effects on normal physiology. MK-801 also reduced primed burst potentiation, a form of synaptic plasticity produced by physiologically patterned stimulation, by approximately 20% in the same pathway. Thus, low doses of MK801 may impair spatial learning by reducing, directly or indirectly, the likelihood of synaptic plasticity in the hippocampus.
authors.affiliation: Department of Psychology, McGill University, Montreal, Quebec, Canada. erk@blaise.psych.mcgill.ca
authors.forename: E L
authors.initials: EL
authors.lastname: Hargreaves
authors.forename: D
authors.initials: D
authors.lastname: Côte
authors.forename: M L
authors.initials: ML
authors.lastname: Shapiro
mesh_terms: D000818:Animals; D018891:Dentate Gyrus / Q000187:drug effects*; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005260:Female; D007274:Injections, Intraperitoneal; D017774:Long-Term Potentiation / Q000187:drug effects; D018782:Maze Learning / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects*; D009473:Neuronal Plasticity / Q000187:drug effects; D009949:Orientation / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D009435:Synaptic Transmission / Q000187:drug effects*
chemical_list: D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate