MK-801, an N-methyl-D-aspartate antagonist in mammalian brain tissue, is a potent nematocidal agent. Specific MK-801 binding sites have been identified and characterized in a membrane fraction prepared from the free-living nematode Caenorhabditis elegans. The high-affinity MK-801 binding site has an apparent dissociation constant, Kd, of 225 nM. Unlike the MK-801 binding site in mammalian tissu...

We examined the effect of 1-amino-3,5-dimethyladamantane (memantine) and (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) on the inhibition of [(3)H]MK-801 binding to crude synaptic membranes of rat forebrains in the absence or presence of Ca(2+). Ca(2+) decreased the potency of memantine to inhibit [(3)H]MK-801 binding. The effect of Ca(2+) was apparently competitive w...

Dizocilpine (MK-801) is a non-competitive NMDA antagonist that induces schizophreniclike effects. It is therefore widely used in experimental models of schizophrenia including prepulse inhibition (PPI) impairments in rodents. Nevertheless, MK-801 has never been tested in monkeys on a PPI paradigm. In order to evaluate MK-801 effects on monkeys' PPI, we tested eight capuchin monkeys (Sapajus spp...

Six experiments studied the role of conditioned stimulus (CS) familiarity in determining the effects of the N-methyl-d-aspartate (NMDA) receptor antagonist MK-801 on fear extinction. Systemic administration of MK-801 (0.1 mg/kg) impaired initial extinction but not reextinction learning. MK-801 impaired reextinction learning when the CS was relatively novel during reextinction training but not i...

Kevin C. H. Pang, Advisor J. Devin McAuley, Co-Chair The present series of studies examined effects of MK-801, an NMDA antagonist, on short-interval timing in rats. The first study used two experiments to examine timing performance using the peak-interval (PI) and PI-gap procedures during chronic exposure of MK801. The first of these experiments investigated the effects of three MK-801 doses (0...

Systemic injection of MK-801, a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptor ion channels, increases meal size and delays satiation. We examined whether MK-801 increases food intake by directly interfering with actions of cholecystokinin (CCK). Prior administration of MK-801 (100 microg/kg ip) reversed the inhibitory effects of CCK-8 (2 and 4 microg/kg ip) on real feeding o...

Alterations of cocaine effects, which were induced by prior repeated 5-time administration of MK-801 ((+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine) (i.p.) alone or in combination with cocaine (s.c.) at 3- to 4-day intervals, were investigated by means of ambulatory activity in mice. The repeated administration of either cocaine (10 and 20 mg/kg) alone or MK-801 (0.3 mg/kg) a...

Stress is known to modulate sensitisation to repeated psychostimulant exposure. However, there is no direct evidence linking glucocorticoids and sensitisation achieved by repeated administration of the NMDA receptor antagonist MK-801. We tested the hypothesis that co-administration of RU486, a glucocorticoid receptor (GR) antagonist, prior to repeated daily MK-801 injections would block the exp...

The current research aimed to investigate the effects of early postnatal exposure to low-level lead on the spatial learning of Long-Evans Hooded rats tested in the Morris water maze. To explore possible neurotoxic actions of lead on the N-methyl-D-aspartate (NMDA) receptors, the noncompetitive NMDA receptor antagonist (+)-5-methyl-10,11-dihydroxy-5hdibenzo(a,d)cyclohepten-5,10-imine (MK-801) wa...