title: Stereoselectivity for the (R)-enantiomer of HA-966 (1-hydroxy-3-aminopyrrolidone-2) at the glycine site of the N-methyl-D-aspartate receptor complex.
abstract: HA-966 (1-hydroxy-3-aminopyrrolidone-2) is an antagonist at the glycine allosteric site of the N-methyl-D-aspartate receptor ionophore complex. Unlike presently known glycine antagonists, HA-966 is chiral. We report stereoselectivity for the (R)-enantiomer at the glycine antagonist site. In [3H]glycine binding, the (R)-enantiomer has an IC50 of 4.1 +/- 0.6 microM. The racemic mixture has an IC50 of 11.2 +/- 0.5 microM, whereas (S)-HA-966 has an IC50 greater than 900 microM. In glycine-stimulated [3H]1-[1-(2- thienyl)cyclohexyl]piperidine binding, the (R)-enantiomer inhibits with an IC50 of 121 +/- 61 microM, whereas the racemic mixture has an IC50 of 216 +/- 113 microM and (S)-HA-966 is inactive. The inhibition by (R)-HA-966 can be prevented by the addition of glycine. (R)-HA-966 and racemic HA-966, but not (S)-HA-966, also prevent N-methyl-D-aspartate cytotoxicity in cortical cultures. The (R)-enantiomer and, less potently, the (S)-enantiomer inhibit N-methyl-D-aspartate-evoked [3H]norepinephrine release from rat hippocampal slices (IC50 values of about 0.3 mM and 1.6 mM, respectively), but only the inhibition by (R)-HA-966 is reversed by added glycine. In glutamate-evoked contractions of the guinea pig ileum, (R)-HA-966 causes a glycine-reversible inhibition (IC50 of about 150 microM), whereas (S)-HA-966 is much less potent (IC50 of greater than 1 mM). These results demonstrate stereoselectivity of the glycine antagonist site of the N-methyl-D-aspartate receptor complex in a variety of tissues and assays. The stereoselectivity also confirms the specificity of N-methyl-D-aspartate receptors in glutamate-evoked contractions of the guinea pig ileum, and supports their similarity to central N-methyl-D-aspartate receptors.
authors.affiliation: ICI Pharmaceuticals Group, ICI Americas Inc., Wilmington, Delaware 19897.
authors.forename: L M
authors.initials: LM
authors.lastname: Pullan
authors.forename: M
authors.initials: M
authors.lastname: Britt
authors.forename: M J
authors.initials: MJ
authors.lastname: Chapdelaine
authors.forename: R A
authors.initials: RA
authors.lastname: Keith
authors.forename: D
authors.initials: D
authors.lastname: LaMonte
authors.forename: T J
authors.initials: TJ
authors.lastname: Mangano
authors.forename: J
authors.initials: J
authors.lastname: Patel
authors.forename: R J
authors.initials: RJ
authors.lastname: Powel
authors.forename: R J
authors.initials: RJ
authors.lastname: Stumpo
authors.forename: P J
authors.initials: PJ
authors.lastname: Warwick
mesh_terms: D000495:Allosteric Site; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D005998:Glycine / Q000378:metabolism*; D006168:Guinea Pigs; D006624:Hippocampus / Q000378:metabolism*; D007082:Ileum / Q000187:drug effects / Q000502:physiology; D007537:Isometric Contraction / Q000187:drug effects; D007700:Kinetics; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D016202:N-Methylaspartate; D009474:Neurons / Q000166:cytology / Q000187:drug effects; D009638:Norepinephrine / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology*; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000378:metabolism*; D013237:Stereoisomerism; D013574:Synaptosomes / Q000378:metabolism*
chemical_list: D005971:Glutamates; D011760:Pyrrolidinones; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D001224:Aspartic Acid; D018698:Glutamic Acid; D016202:N-Methylaspartate; C001369:1-hydroxy-3-amino-2-pyrrolidone; D005998:Glycine; D009638:Norepinephrine