Primary polydipsia, excessive drinking without known medical cause, is especially associated with a diagnosis of schizophrenia. We used animal models of schizophrenia-like symptoms to examine the effects on schedule-induced polydipsia: post-weaning social isolation rearing, subchronic MK-801 treatment (an NMDA-receptor antagonist) or the two combined. Male, Sprague-Dawley rats reared in groups ...

Glutamate receptors are concentrated in the postsynaptic complex of central synapses. This implies a highly organized and stable postsynaptic membrane with tightly anchored receptors. Recent reports of rapid AMPA receptor insertion and removal at synapses have challenged this view. We examined the stability of synaptic NMDA receptors on cultured hippocampal neurons using the open-channel blocke...

Ketamine (KET) induced blockade of cortical spreading depression (CSD) declines with repeated KET applications in a way suggesting the development of tolerance. Possible mechanism of this process was studied in 31 rats anestheized with pentobarbital. CSD was elicited by injection of 1µl of 5% KCl into cortex at 15 min intervals and monitored by recording the accompanying slow potential waves....

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists have been found to have potent anti-inflammatory actions and suggested as potential therapies for brain ischaemia. Glutamate is the most common excitatory neurotransmitter in the central nervous system and is released excessively during ischaemia. Stroke therapy will require combinations of drug classes, because no single dr...

The ability of the noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 to prevent neuronal degeneration in the rat striatum and hippocampus caused by intracerebral injection of excitotoxins has been examined. Excitotoxic damage was assessed after 7 d, using histological and biochemical [choline acetyltransferase (ChAT) glutamate decarboxylase (GAD)] measurements. Systemically ...

The purported competitive excitatory amino acid antagonist CGS 19755 was compared to the non-competitive antagonists ketamine and MK-801 in three rhesus monkeys discriminating between 1.78 mg/kg of ketamine and saline while responding under a fixed-ratio 100 schedule of food presentation. MK-801 substituted completely for the ketamine discriminative stimulus and was 32 times more potent than ke...

In the present study, involvement of the N-methyl-d-aspartate (NMDA) receptors of the CA1 region of dorsal hippocampus (intra-CA1) in the acquisition or expression of morphine-induced conditioned place preference in rats was studied. Male Wistar rats were used in these experiments. NMDA-receptor agonist (NMDA) and antagonist (MK-801) were injected into the CA1 region of the dorsal hippocampus (...

INTRODUCTION In vitro experiments have demonstrated that preconditioning primary neuronal cultures by temporary application of NMDA receptor antagonists induces long-term tolerance against lethal insults. In the present study we tested whether similar effects also occur in brain submitted to ischemia in vivo and whether the potential benefit outweighs the danger of enhancing the constitutive ap...