Pregnenolone sulfate (PS), an endogenously occurring neurosteroid, has been shown to modulate the activity of several neurotransmitter-gated channels, including the NMDA receptor (NMDAR). NMDARs are glutamate-gated ion channels involved in excitatory synaptic transmission, synaptic plasticity, and excitotoxicity. In this study, we analyzed the effects of PS on calcium signaling in cultured hipp...

N-methyl-D-aspartate (NMDA) receptors play critical roles in synaptic transmission and plasticity. Activation of NMDA receptors by synaptically released L-glutamate also requires occupancy of co-agonist binding sites in the tetrameric receptor by either glycine or D-serine. Although D-serine appears to be the predominant co-agonist at synaptic NMDA receptors, the transport mechanisms involved i...

The interaction between uncompetitive NMDA receptor antagonists (memantine and ketamine), and morphine (mu-opioid receptor agonist) and pentazocine (kappa-opioid receptor agonist) was studied in the writhing test in mice. Memantine and ketamine, administered at subthreshold doses, potentiated antinociceptive effect of the threshold (1 mg/kg) dose of morphine. The effects of the threshold (6 mg/...

The NMDA receptor is a key player in excitatory transmission and synaptic plasticity in the central nervous system. Its activation requires the binding of both glutamate and a co-agonist like D-serine to its glycine site. As D-serine is released exclusively by astrocytes, we studied the physiological impact of the glial environment on NMDA receptor-dependent activity and plasticity. To this end...

The present study aimed to investigate the effects of N-methyl-d-aspartate (NMDA)-type glutamate receptor agonist, NMDA, on anxiety-like behavior induced by δ-opioid receptor agents in rats, using the elevated plus maze instrument. The dorsal hippocampus (CA1) is known to play an important role in anxiety formation and modulation. Bilateral administration of different doses of δ-opioid receptor...

We have used site-directed mutagenesis of amino acids located within the S1 and S2 ligand binding domains of the NR2A N-methyl-D-aspartate (NMDA) receptor subunit to explore the nature of ligand binding. Wild-type or mutated NR1/NR2A NMDA receptors were expressed in Xenopus laevis oocytes and studied using two electrode voltage clamp. We investigated the effects of mutations in the S1 and S2 re...

The N-methyl-D-aspartate (NMDA) receptor (NMDA-R) has pivotal roles in neural development, learning, memory, and synaptic plasticity. Functional impairment of NMDA-R has been implicated in schizophrenia. NMDA-R activation requires glycine to act on the glycine-B (GlyB) site of the NMDA-R as an obligatory co-agonist with glutamate. Extracellular glycine near NMDA-R is regulated effectively by a ...

Recent work has shown substantial alterations in NMDA receptor subunit expression, assembly, and phosphorylation in the dopamine-depleted striatum of a rodent 6-hydroxydopamine model of Parkinson's disease. These modifications are hypothesized to result from the trafficking of NMDA receptors between subcellular compartments. Here we show that in rat striatal tissues the NR2A and NR2B subunits i...

Objective(s) The central nucleus of the amygdala (CeA) is a forebrain structure which is important in regulation of ingestive behavior and there is direct and circumstantial evidence to indicate that some circuits involved with feeding behavior include glutamatergic elements. The present study examined whether administration of NMA (N-Methyl-DL-aspartic acid) or MK801 into the CeA altered water...

Spironolactone has produced beneficial effects in animal models of neurodegenerative disorders. However, the underlying mechanisms of this agent on neurons and glia are mostly unknown. Therefore, we aimed to show the effects of spironolactone and fludrocortisone, a mineralocorticosteroid receptor agonist, on neuronal and glial toxicity induced by N-methyl-D-aspartate (NMDA) activation and chlor...