We investigated the effects of the second generation antipsychotics olanzapine, sertindole and clozapine on visual recognition memory using the novel object recognition (NOR) test in naive and MK-801-treated animals. The effects of drug treatment on locomotion and anxiety were also determined using the open field test. Male Balb-c mice were treated with olanzapine (0.2, 0.4 and 0.6 mg/kg; i.p.)...

Zebrafish are a genetically tractable vertebrate that hold considerable promise for elucidating the molecular basis of behavior. Although numerous recent advances have been made in the ability to precisely manipulate the zebrafish genome, much less is known about many aspects of learning and memory in adult fish. Here, we describe the development of a contextual fear conditioning paradigm using...

Realistic estimates of channel-gating parameters of synaptic receptors are essential to an understanding of synaptic transmission and modulation. However, the gating of N-methyl-D-aspartate (NMDA) channels appears to differ, depending on recording conditions; thus, it remains unclear what measurements are most relevant to synaptic receptors. To further explore this discrepancy, we examined the ...

Recent findings reveal qualitative developmental differences in extinction of learned fear. The present study explored potential developmental differences in the role of NMDA in acquisition and extinction. Rats were injected with MK-801 prior to fear conditioning or extinction training. Acquisition was found to be NMDA dependent in both age groups, whereas extinction was found to be NMDA depend...

The relationship between the effects of the N-methyl-D-aspartate (NMDA) antagonist MK-801 on acute responses to ethanol and its ability to block ethanol sensitization and tolerance was examined in DBA/2J mice. Cross-sensitization between these drugs was also studied. Repeated administration of 0.1 mg/kg MK-801 with ethanol potentiated, whereas 0.25 mg/kg attenuated, sensitization to ethanol's l...

The present study investigates the impact of dexamethasone (DEX) given in tapering doses in the postnatal period on MK-801-induced locomotor activity and MK-801-evoked deficits of sensorimotor gating of adult rats (60 days old). It has been found that DEX given on postnatal day 1 (0.5 microg/g), day 2 (0.3 microg/g) and day 3 (0.1 microg/g) has no effects on spontaneous locomotor activity and d...

MK-801 induces psychotomimetic behavioural changes in animals. ERKs play an important role in the pathogenesis of schizophrenia and in the action of antipsychotics and psychotomimetics. We observed phosphorylation of ERK-signalling-pathway-associated molecules in the rat frontal cortex and their association with rat behaviour after MK-801 administration. After injecting 0.25-1 mg/kg MK-801, ERK...

Schizophrenia is a devastating disorder affecting 1 % of the world's population. An important role in the study of this disease is played by animal models. Since there is evidence that acute psychotic episodes can have consequences on later cognitive functioning, the present study has investigated the effects of a single systemic application of higher doses of (+)MK-801 (3 mg/kg and 5 mg/kg) to...

Contextual fear conditioning emerges around post-natal day (PD) 23 in the rat. This is thought to reflect hippocampus-dependent conjunctive learning, which binds the individual features of the context into a unified representation (Rudy, 1993). However, context conditioning can also be supported by hippocampus-independent, feature-based simple associations (Rudy, 2009) and these may operate at ...

We resolved 1,2-diphenylethylamine (DPEA) into its (S)- and (R)-enantiomer and used them as precursors for synthesis of (S)- and (R)-1-(1,2-diphenylethyl)piperidine, flexible homeomorphs of the NMDA channel blocker MK-801. We also describe the synthesis of the dicyclohexyl analogues of DPEA. These and related compounds were tested as inhibitors of [(3)H]MK-801 binding to rat brain membranes. St...