Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2005-7-4
pubmed:abstractText
The N-methyl-D-aspartate receptor (NMDAR) antagonists: MK-801, phencyclidine and ketamine are open-channel blockers with limited clinical value due to psychotomimetic effects. Similarly, the psychotomimetic effects of the dextrorotatory opioids, dextromethorphan and its metabolite dextrorphan, derive from their NMDAR antagonist actions. Differences in the use dependency of blockade, however, suggest that the binding sites for MK-801 and dextrorphan are distinct. In the absence of exogenous glutamate and glycine, the rate of association of [3H]MK-801 with wild-type NR1-1a/NR2A receptors was considerably slower than that for [3H]dextrorphan. Glutamate individually, and in the presence of the co-agonist glycine, had substantial effects on the specific binding of [3H]MK-801, while the binding of [3H]dextrorphan was not affected. Mutation of residues N616 and A627 in the NR1 subunit had a profound effect on [3H]MK-801 binding affinity, while that of [3H]dextrorphan was unaltered. In contrast, NR1 residues, W611 and N812, were critical for specific binding of [3H]dextrorphan to NR1-1a/NR2A complexes with no corresponding influence on that of [3H]MK-801. Thus, [3H]dextrorphan and [3H]MK-801 have distinct molecular determinants for high-affinity binding. The ability of [3H]dextrorphan to bind to a closed channel, moreover, indicates that its recognition site is shallower in the ion channel domain than that of MK-801 and may be associated with the extracellular vestibule of the NMDAR.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0028-3908
pubmed:author
pubmed:issnType
Print
pubmed:volume
49
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1-16
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:15992576-Animals, pubmed-meshheading:15992576-Binding Sites, pubmed-meshheading:15992576-COS Cells, pubmed-meshheading:15992576-Cell Membrane, pubmed-meshheading:15992576-Cercopithecus aethiops, pubmed-meshheading:15992576-Competitive Bidding, pubmed-meshheading:15992576-Dextrorphan, pubmed-meshheading:15992576-Dizocilpine Maleate, pubmed-meshheading:15992576-Dose-Response Relationship, Drug, pubmed-meshheading:15992576-Drug Interactions, pubmed-meshheading:15992576-Excitatory Amino Acid Antagonists, pubmed-meshheading:15992576-Glutamic Acid, pubmed-meshheading:15992576-Glycine, pubmed-meshheading:15992576-Models, Biological, pubmed-meshheading:15992576-Mutagenesis, pubmed-meshheading:15992576-Radioligand Assay, pubmed-meshheading:15992576-Receptors, N-Methyl-D-Aspartate, pubmed-meshheading:15992576-Sequence Alignment, pubmed-meshheading:15992576-Sequence Analysis, pubmed-meshheading:15992576-Transfection, pubmed-meshheading:15992576-Tritium
pubmed:year
2005
pubmed:articleTitle
Differential binding properties of [3H]dextrorphan and [3H]MK-801 in heterologously expressed NMDA receptors.
pubmed:affiliation
Department of Physiology and Pharmacology, The University of Georgia, College of Veterinary Medicine, Athens, GA 30602, USA. klepage@uga.edu
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, N.I.H., Extramural