title: Probing the pharmacophore of ginkgolides as glycine receptor antagonists.
abstract: Ginkgolides are antagonists of the inhibitory ligand-gated ion channels for the neurotransmitters glycine and gamma-aminobutyric acid (GABA). In this study the ginkgolide structure was modified in order to investigate the minimum structural requirements for glycine receptor antagonism. The five native ginkgolides and a series of 29 ginkgolide derivatives were characterized at the three glycine receptor subtypes alpha1, alpha1beta, and alpha2, which revealed that only minor changes in the ginkgolide skeleton were allowed for maintaining glycine receptor antagonism. A pharmacophore model was generated and applied in a virtual screening of a compound database (300000 compounds), resulting in the identification of 31 hits. Twenty-seven of these hits were screened for biological activity, but none displayed antagonist activity at the glycine receptors. This strongly suggests the importance of other pharmacophore components in the binding of ginkgolides to glycine receptors, and we propose that the structural rigidity of the ginkgolide molecule may be crucial for its glycine receptor activity.
authors.affiliation: Department of Medicinal Chemistry, The Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark. aaj@farma.ku.dk
authors.forename: Anders A
authors.initials: AA
authors.lastname: Jensen
authors.forename: Nasreen
authors.initials: N
authors.lastname: Begum
authors.forename: Stine B
authors.initials: SB
authors.lastname: Vogensen
authors.forename: Kolja M
authors.initials: KM
authors.lastname: Knapp
authors.forename: Klaus
authors.initials: K
authors.lastname: Gundertofte
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Dzyuba
authors.forename: Hideki
authors.initials: H
authors.lastname: Ishii
authors.forename: Koji
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Uffe
authors.initials: U
authors.lastname: Kristiansen
authors.forename: Kristian
authors.initials: K
authors.lastname: Strømgaard
mesh_terms: D002460:Cell Line; D018360:Crystallography, X-Ray; D016208:Databases, Factual; D046934:Ginkgolides / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D008958:Models, Molecular; D018408:Patch-Clamp Techniques; D018009:Receptors, Glycine / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000502:physiology; D013329:Structure-Activity Relationship
chemical_list: D046934:Ginkgolides; D018009:Receptors, Glycine